WO2008153268A1

WO2008153268A1 - Semiconductor package inspection system and inspection method using semiconductor package inspection system

Info

Publication number: WO2008153268A1
Application number: PCT/KR2008/002110
Authority: WO
Inventors: Sun-Yeol Lee
Original assignee: Hits Co., Ltd.
Priority date: 2007-06-14
Filing date: 2008-04-15
Publication date: 2008-12-18
Also published as: KR100884582B1; KR20080110045A

Abstract

Disclosed are a semiconductor package inspection system, and a semiconductor package inspection method using the same. The semiconductor package inspection system includes ball photographing equipment, wire photographing equipment and stitch photographing equipment, and precisely and rapidly screens a defective product through images photographing pads, balls, wires to thereby lead to remarkable reduction in a defective rate.

Description

SEMICONDUCTOR PACKAGE INSPECTION SYSTEM AND INSPECTION METHOD USING SEMICONDUCTOR PACKAGE

INSPECTION SYSTEM

Technical Field

[1] The present invention relates to a semiconductor package inspection system and method and, more particularly, to a semiconductor package inspection system, which includes ball photographing equipment, wire photographing equipment and stitch photographing equipment, and precisely and rapidly screens a defective product through images photographing pads, balls, wires to thereby lead to remarkable reduction in a defective rate, and a semiconductor package inspection method using the same. Background Art

[2] In general, a semiconductor package is mounted therein with an integrated circuit, a semiconductor chip, and includes leads for electrical connection between elements, pads connected with the semiconductor chip, wires interconnecting the leads and the pads, and so on.

[3] This semiconductor package is produced by several processes such as sawing, die bonding, wire bonding, molding, marking, and so on. Thus, the semiconductor package produced in this way is applied to a variety of electronic parts, performing precise work.

[4] Particularly, the semiconductor package employs micro-scaled elements, and thus has difficulty in production and inspection.

[5] As such, a wire bonding monitoring system (WBMS), in which in the event of the wire bonding, a slight quantity of current flows to inspect whether or not wires are bonded, is partly applied to the production of the semiconductor package. However, this conventional inspection is performed on an unfinished product, so that the defects occurring in the following processes cannot be inspected.

[6] Further, although the weak current flows, it cannot be checked whether or not the semiconductor package is produced in compliance with its original circuit layout. Accordingly, technology capable of more precisely and rapidly inspecting the semiconductor package is required. Disclosure of Invention

Technical Problem

[7] The present invention has been made to solve the foregoing problems with the prior art, and therefore the present invention is directed to photograph and inspect a semi- conductor package that has been produced, thereby enabling precise rapid inspection without using naked eyes and remarkable reduction in a defective rate.

[8] Further, the present invention is directed to inspect a semiconductor package in a manner such that pads, balls, leads and wires are divided and inspected individually, thereby producing the semiconductor package having good quality due to precise inspection.

[9] Furthermore, the present invention is directed to precisely inspect a semiconductor package using an analog image as a pixel-based digital image, thereby producing the semiconductor package having good quality, and to automate inspection work, thereby producing the semiconductor package in a rapid inexpensive manner. Technical Solution

[10] According to an aspect of the present invention, there is provided a semiconductor package inspection system (A) for a semiconductor package (12), which includes: ball photographing equipment (20), wire photographing equipment (30) and stitch photographing equipment (40); wherein the ball photographing equipment (20) includes a ball camera (21) photographing pads (121) and balls (122) of the semiconductor package (12) to generate ball image signals including images of the pads (121) and the balls (122); wherein the wire photographing equipment (30) includes a wire camera (31) photographing leads (123), the pads (121) and wires (124) of the semiconductor package (12) to generate wire image signals including images of the leads (123), the pads (121) and the wires (124); wherein the stitch photographing equipment (40) includes a stitch camera (41) photographing the leads (123) and the wires (124) of the semiconductor package (12) to generate stitch image signals including images of the leads (123) and the wires (124); a worktable (13) transferring the semiconductor package (12) to the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40); and a main controller (11) controlling the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40), the main controller (11) including an image signal input (14) receiving the image signals of the semiconductor package (12) from the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40), and a memory (15).

[11] According to another aspect of the present invention, there is provided a semiconductor package inspection method using a semiconductor package inspection system, which includes:

[12] preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl);

[13] photographing, at a ball photographing equipment (20) controlled by a main controller (11) of the semiconductor package inspection system (A), the pads (121) and balls (122) of the semiconductor package (12) mounted on the worktable (13) to generate a ball image signal (S021);

[14] transmitting, through an image signal input (14) of the main controller (11), the ball image signals generated by the ball photographing equipment (20) (S022);

[15] calculating ball image data by calculating data values of shapes of the pads (121) and the balls (122) from the transmitted ball image signals (S023); and

[16] analyzing ball data, at the main controller (11), through comparison with the data values of the pads (121) and the balls (122), to inspect ball states and bonded states of the pads (121) and the balls (122) (S024).

[17] According to another aspect of the present invention, there is provided a semiconductor package inspection method using a semiconductor package inspection system, which includes:

[18] preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl);

[19] photographing, at a wire photographing equipment (30) controlled by a main controller (11) of the semiconductor package inspection system (A), the pads (121) and balls (122), leads (123) and wires (124) of the semiconductor package (12) mounted on the worktable (13) to generate wire image signals (S031);

[20] transmitting, through an image signal input (14) of the main controller (11), the wire image signals generated by the wire photographing equipment (30) (S032);

[21] calculating wire image data by calculating data values of the pads (121), the balls

(122), the leads (123) and the wires (124) from the transmitted wire image signals (S033); and

[22] analyzing wire data, at the main controller (11), through comparison with the data values of the pads (121), the balls (122), the leads (123) and the wires (124), to inspect wire states (S034).

[23] According to an embodiment of the present invention, the wire image data calculating process (S033) calculates data values about sizes, shapes and numbers of the pads (121), the balls (122), the leads (123) and the wires (124); and the wire data analyzing process (S034) includes:

[24] - inspecting foreign materials, shapes of which are different from those of the pads

(121), the balls (122), the leads (123) and the wires (124), through comparison of the data values of the pads (121), the balls (122), the leads (123) and the wires (124), calculated in the wire image data calculating process (S033), with data values stored in a memory (15) of the main controller (11) (S0341);

[25] - determining connection states of the wire (124) through comparison of the data values of the pads (121), the balls (122), the leads (123) and the wires (124), calculated in the wire image data calculating process (S033), with data values stored in the memory (15) of the main controller (11) (S0342); and

[26] - determining wire states of the wire (124) calculated in the wire image data calculating process (S033), the wire states including widths and shapes of the wires.

[27] According to another aspect of the present invention, there is provided a semiconductor package inspection method using a semiconductor package inspection system, which includes:

[28] preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl);

[29]

[30] *photographing, at a stitch photographing equipment (40) controlled by a main controller (11) of the semiconductor package inspection system (A), leads (123) and wires (124) of the semiconductor package (12) mounted on the worktable (13) to generate stitch image signals (S041);

[31] transmitting, through an image signal input (14) of the main controller (11), the stitch image signals generated by the stitch photographing equipment (40) (S042);

[32] calculating stitch image data by calculating data values of the leads (123), wires

(124) and stitches (125) from the transmitted stitch image signals (S043); and

[33] analyzing stitch data, at the main controller (11), through comparison with the data values of the leads (123), the wires (124) and the stitches (125) to inspect stitch states (S044). Brief Description of the Drawings

[34] FIG. 1 is a schematic diagram illustrating a semiconductor package inspection system according to an embodiment of the present invention.

[35] FIGS. 2 and 3 illustrate the configuration of a semiconductor package, which is applied to a semiconductor package inspection system according to an embodiment of the present invention.

[36] FIG. 4 is a schematic block diagram illustrating a semiconductor package inspection system according to an embodiment of the present invention.

[37] FIGS. 5 through 8 illustrate a teaching method of a semiconductor package inspection system according to an embodiment of the present invention. [38] FIGS. 9 and 10 illustrate ball state inspection of a semiconductor package inspection system according to an embodiment of the present invention.

[39] FIGS. 11 through 16 illustrates illustrate wire state inspection of a semiconductor package inspection system according to an embodiment of the present invention.

[40] FIG. 17 illustrates wire stitch state inspection of a semiconductor package inspection system according to an embodiment of the present invention.

[41] FIGS. 18 through 21 are flow charts illustrating a semiconductor package inspection method using a semiconductor package inspection system according to an embodiment of the present invention.

[42] <Major Reference Numerals and Symbols of the Drawings>

[43] A: semiconductor package inspection system

[44] 11 : main controller

[45] 12: semiconductor package

[46] 13: worktable

[47] 15: memory

[48] 20: ball photographing equipment

[49] 30: wire photographing equipment

[50] 40: stitch photographing equipment

[51] 121: pad

[52] 122: ball

[53] 123: lead

[54] 124: wire

Best Mode for Carrying Out the Invention

[55] Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[56] FIG. 1 is a schematic diagram illustrating a semiconductor package inspection system according to an embodiment of the present invention. FIGS. 2 and 3 illustrate the configuration of a semiconductor package, which is applied to a semiconductor package inspection system according to an embodiment of the present invention. FIG. 4 is a schematic block diagram illustrating a semiconductor package inspection system according to an embodiment of the present invention.

[57] FIGS. 5 through 8 illustrate a teaching method of a semiconductor package inspection system according to an embodiment of the present invention, in which a main controller 11 receives and analyzes each image data.

[58] Further, FIGS. 9 and 10 illustrate ball state inspection of a semiconductor package inspection system according to an embodiment of the present invention. FIGS. 11 through 16 illustrates illustrate wire state inspection of a semiconductor package in- spection system according to an embodiment of the present invention. FIG. 17 illustrates wire stitch state inspection of a semiconductor package inspection system according to an embodiment of the present invention.

[59] In addition, FIGS. 18 through 21 are flow charts illustrating a semiconductor package inspection method using a semiconductor package inspection system according to an embodiment of the present invention.

[60] As illustrated in FIGS. 1 through 21, a semiconductor package inspection system A according to an embodiment of the present invention includes ball photographing equipment 20, wire photographing equipment 30 and stitch photographing equipment 40 for a semiconductor package 12.

[61] This semiconductor package inspection system A is adapted to inspect defects of the semiconductor package 12 that has been produced. The semiconductor package inspection system A is used for inspecting the defects of the semiconductor package 12 that has been produced, particularly for synthetically inspecting whether or not pads 121 and leads 123 of a semiconductor chip 120 are properly bonded by wires 124. Particularly, the semiconductor package inspection system A performs inspection by analyzing image data photographed by photographing equipment for each component and by using the analyzed white and black pixel data. Here, the wire photographing equipment 30 checks the states of the wires 124 on the semiconductor package 12. The ball photographing equipment 20 checks the states of the pads 121 and wires 124 that are connected with the semiconductor chip 120. The stitch photographing equipment 40 checks the states of the wires 124 and the leads 123.

[62] Thus, the ball photographing equipment 20 photographs the pads 121 and balls 122 of the semiconductor package 12 to generate ball image signals based on images of the pads 121 and balls 122. The wire photographing equipment 30 photographs the leads 123, pads 121 and wires 124 of the semiconductor package 12 to generate wire image signals based on images of the leads 123, pads 121 and wires 124. The stitch photographing equipment 40 photographs the leads 123 and wires 124 of the semiconductor package 12 to generate stitch image signals based on images of the leads 123 and wires 124.

[63] This semiconductor package inspection system A is designed so that the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40 are spaced apart from each other by a predetermined distance. As illustrated, the semiconductor package inspection system A is designed so that these pieces of equipment are sequentially installed so as to be able to inspect the semiconductor package 12 in a series of orders.

[64] More specifically, as in FIG. 1, the semiconductor package inspection system A includes a worktable 13, which transfers the semiconductor package 12 to the ball pho- tographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40, and the main controller 11, which controls the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40. The main controller 11 includes an image signal input 14 receiving image signals from the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40, and a memory 15. Further, the main controller 11 is adapted to control the operation of the worktable 13.

[65] This semiconductor package inspection system A inspects circuit connection of the semiconductor package 12, which transferred together on the worktable 13. In other words, the semiconductor package inspection system A drives a worktable actuator (not shown, e.g. hydraulic actuator) under the control of the main controller 11 to transfer the worktable 13, thereby transferring the semiconductor package 12 to the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40.

[66] Thereby, the ball photographing equipment 20, the wire photographing equipment

30, and the stitch photographing equipment 40 photograph the semiconductor package 12 to transmit the image data to the main controller 11 through the image signal input 14. Thereby, it is determined whether or not the semiconductor package 12 is abnormal.

[67] The ball photographing equipment 20 includes a ball camera 21 installed above the worktable 13 on which the semiconductor package 12 is placed, and a coaxial lighting mechanism 22 installed between the worktable 13 and the ball camera 21. This coaxial lighting mechanism 22 includes a reflector 23 mounted therein at an angle of inclination of 45 and a lamp 24 on one side of the reflector 23. The light emitted from the lamp 24 in a horizontal direction is incident onto the semiconductor package 12 on the worktable 13 below the reflector 23. The lamp 24 makes use of a blue light- emitting diode (LED) having a short wavelength within a wavelength range of visible light (between about 400 nm and about 700 nm).

[68] In particular, the light reflected from the reflector 23 has the same direction as an optic axis of lens of the ball camera 21, so that part of the light, which is incident onto and reflected from the semiconductor package 12 in a direction perpendicular to the surface of the semiconductor package 12 enters the ball camera 21. This is for receiving only the light reflected by the pads 121, the flat regions, of the semiconductor package 12. Thus, the balls 122 and the wires 124, which are curved regions, are not photographed because the light from the coaxial lighting mechanism 22 is reflected from the curved regions in directions other than the incident direction, i.e. is not reflected toward the ball camera 21, so that the curved regions are not photographed. In other words, the ball photographing equipment 20 preferably makes use of the coaxial lighting mechanism 22, the lighting direction of which is identical to the optic axis of the ball camera 21. Thus, the balls 122, which are not photographed within the total-reflected pads 121, have clearer boundaries. In this manner, in the state in which the coaxial lighting mechanism 22 having the blue LED emits the light, the images photographed by the ball photographing equipment 20 are converted into white pixels, as illustrated in FIGS. 9 and 10.

[69] The wire photographing equipment 30 includes a wire camera 31 above the worktable 13 on which the semiconductor package 12 is placed, and a dome lighting mechanism 32 between the worktable 13 and the wire camera 32. The dome lighting mechanism 32 includes a plurality of lamps therein, which are arranged in a circular shape. The dome lighting mechanism 32 uniformly illuminates an entire surface of the wires 124 having a circular cross section, thereby allowing the wires 124 to be photographed by the wire camera 31. Light emitted from the dome lighting mechanism 32 is produced from a red light-emitting diode (LED) having a long wavelength within a wavelength range of visible light (between about 400 nm and about 700 nm). In the state in which the dome lighting mechanism 32 having the red LED emits the light, the images photographed by the wire photographing equipment 30 are converted into white pixels, as illustrated in FIGS. 11 through 16.

[70] Further, the stitch photographing equipment 40 includes a stitch camera 41 above the worktable 13 on which the semiconductor package 12 is placed, and a lateral lighting mechanism 42 between the worktable 13 and the stitch camera 41. The lateral lighting mechanism 42 is for photographing the leads 123 and the stitches 125 that are ends of the wires 124 bonded on the leads 123. Particularly, the lateral lighting mechanism 42 is preferably adapted to emit light above opposite sides of the stitches, thereby allowing boundaries between the leads 123 and the stitches 125 to be clearly observed. The light emitted from the lateral lighting mechanism 42 is produced from a green light-emitting diode (LED) having a long wavelength within a wavelength range of visible light (between about 400 nm and about 700 nm). In the state in which the lateral lighting mechanism 42 having the green LED emits the light, the images photographed by the stitch photographing equipment 40 are converted into white pixels, as illustrated in FIG. 18.

[71] In this manner, the image data from the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40, which photograph the semiconductor package 12 transferred together with the worktable 13 according to their characteristics, are converted into the white pixels, so that an defect in connection is inspected. The defect inspection based on the image data is carried out by defect determiners, which are equipped with the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40, and then the resulting data or defect data signals are transmitted to the main controller 11.

[72] Further, as in the following example, the defect inspection can be carried out by transmitting the image data signals from the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40 to the main controller 11. Hereinafter, the exemplary embodiment is configured to generate the image data from each photographing equipment, transmit the generated image data to the main controller 11, convert the received image data into the white pixels using the main controller 11, inspect the defects, and screen the defective products based on the results of the defect inspection, and particularly to convert the image data into the white pixels, and inspect the defect on the basis of each image data.

[73] In this inspection method as illustrated in FIGS. 18 through 21, the semiconductor package 12, in which the pads 121 and the leads 123 of the semiconductor chip 120 are connected with the wires 124, is prepared for inspection in the state in which it is loaded on the worktable 13 of the semiconductor package inspection system A (SOl). Then, while the worktable 13 is transferred, a process of inspecting ball states (S02), a process of inspecting wire states (S03), and a process of inspecting stitch states (S04) are performed. Thereby, the inspection of the semiconductor package 12 is completed.

[74] First, the ball state inspecting process (S02) will be described below in detail. As illustrated in FIGS. 9, 10 and 19, the ball photographing equipment 20, which is controlled by the main controller 11 of the semiconductor package inspection system A, photographs the pads 121 and the balls 122 of the semiconductor package 12 loaded on the worktable 13 to generate ball image signals (ball image photographing process S021).

[75] The ball image signals generated from the ball photographing equipment 20 are transmitted through the image signal input 14 of the main controller 11 (ball image signal transmitting process S022).

[76] In this manner, data values of the images of the pads 121 and the balls 122 are calculated from the ball image signals transmitted from the ball photographing equipment 20 (ball image data calculating process S023). Then, the main controller 11 compares the data values of the images of the pads 121 and the balls 122 with preset data values, thereby inspecting bonded states of the pads 121 and the balls 122 (ball data analyzing process S024). Thereby, the states of the pads 121 and the balls 122 are inspected.

[77] In the wire state inspecting process S03 as illustrated in FIGS. 11 through 16 and

FIG. 20, the wire photographing equipment 30, which is controlled by the main controller 11 of the semiconductor package inspection system A, photographs the pads 121, the balls 122, the leads 123, and the wires 124 of the semiconductor package 12 loaded on the worktable 13 to generate wire image signals (wire image photographing process S031).

[78] The wire image signals generated from the wire photographing equipment 30 are transmitted through the image signal input 14 of the main controller 11 (wire image signal transmitting process S032).

[79] Subsequently, data values of the pads 121, the balls 122, the leads 123, and the wires

124 are calculated from the wire image signals transmitted from the wire photographing equipment 30 (wire image data calculating process S033). Then, the main controller 11 compares the data values of the pads 121, the balls 122, the leads 123, and the wires 124 with preset data values, thereby inspecting the wire states (wire data analyzing process S034). Thereby, the states of the pads 121, the balls 122, the leads 123, and the wires 124 are inspected.

[80] Similarly, in the stitch state inspecting process S04 as illustrated in FIGS. 17 and 21, the stitch photographing equipment 40, which is controlled by the main controller 11 of the semiconductor package inspection system A, photographs the leads 123 and the wires 124 of the semiconductor package 12 loaded on the worktable 13 to generate stitch image signals (stitch image photographing process S041).

[81] The stitch image signals generated from the stitch photographing equipment 40 are transmitted through the image signal input 14 of the main controller 11 (stitch image signal transmitting process S042).

[82] Subsequently, data values of the leads 123, the wires 124, and the stitches 125 are calculated from the stitch image signals transmitted from the stitch photographing equipment 40 (stitch image data calculating process S043). Then, the main controller 11 compares the data values of the leads 123, the wires 124, and the stitches 125 with preset data values, thereby inspecting the stitch states (stitch data analyzing process S044). Thereby, the states of the leads 123, the wires 124, and the stitches 125 are inspected.

[83] As described above, the ball state inspecting process S02, the wire state inspecting process S03, and the stitch state inspecting process S04, which constitutes the semiconductor package inspection method, are adapted to convert the image photographing the pads 121, the balls 122, the leads 123, and the wires 124 into the white pixels and the black pixels, thereby determining whether or not the semiconductor package is abnormal.

[84] When the semiconductor package is prepared for inspection (SOl), the photograph is taken in each inspection process, and then each image signal is transmitted to the main controller 11 through the image signal input 14. These image data signals including the ball image signals, the wire image signals, and the stitch image signals are converted into gray images based on brightness by the main controller 11 in the ball image data calculating process S023, the wire image data calculating process S033, and the stitch image data calculating process S023, so that the boundaries of the images are set using the white pixels. Then, the images are compared with basic images stored in the memory 15 of the main controller 11, thereby inspecting the defects.

[85] Now, each data calculating process will be described in detail. When placed on the worktable 13 as illustrated in FIG. 2, the semiconductor package 12 is photographed by the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40 of FIG. 1. The image signals based on the images of the semiconductor package 12 photographed by the respective photographing equipment are transmitted to the main controller 11 through the image signal input 14. Then, the main controller 11 converts each image signal into a gray image, thereby classifying the images into the white and black pixels on the basis of the brightness.

[86] The classification using these white pixels will be described below with reference to

FIG. 5. As illustrated, the contrast is set to 256 levels that are general gray scale values. In other words, as in FIG. 5, the darkest level is set to 0(zero), and the brightest level is set to 255. In this manner, the gray scale values are set according to the brightness of each pixel, and then a region of interest (ROI) is defined as in FIG. 5. In FIG. 5, six pixels (2x3) are shown, and a threshold value that is an average value of the gray scale values is obtained.

[87] Threshold = (80+0+255+0+0+255)/6 = 98.33333

[88] This, the threshold value of the ROI in FIG. 5 is 98.33333. In conjunction with the

ROI, when the gray scale value of each pixel is greater than the threshold value, the pixel is defined as the white pixel. In contrast, when the gray scale value of each pixel is less than the threshold value, the pixel is defined as the black pixel.

[89] The ball camera 21, the wire camera 31, and the stitch camera 41 used for the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40 are five mega pixel cameras, the resolution of which has 2448*2050 pixels. It is assumed that one strip has a unit length of 12 mm, the vision resolution becomes 12 mm/2449 px @ 0.0049 mm (=4.9 mm). Thus, the image defect can be determined by setting the size of one pixel in the general semiconductor package to several microns, so that the bonding of the wires can be precisely determined.

[90] In this method, the data images based on the ball image signals, the wire image signals, and the stitch image signals of the semiconductor package 12 are divided into the white pixels and the black pixels. Thereby, basic values of position, size and shape of each component are obtained.

[91] The pixels of the photographed images are divided using the gray scale values, and then teaching data are calculated on the basis of the white pixel and the black pixel. The teaching data are for calculating the basic values of the images, which are used to determine the image defect in the ball state inspection process, the wire state inspection process, and the stitch state inspection process.

[92] As one example of the present invention, as in FIG. 5, the images of the entire semiconductor package 12 photographed by the ball photographing equipment 20, the wire photographing equipment 30, and the stitch photographing equipment 40 will be described below. As illustrated in FIGS. 5 through 8, data values are calculated for basic coordinate values. The calculation of the data values for the basic coordinate values is based on the images shown in common in the case of the images photographed by the respective photographing equipment. Thus, in the case in which the configuration of the semiconductor package, particularly the configuration of the wires, the leads, the balls, and the stitches, is somewhat deformed, it is apparent that the basic data can be calculated adopting on the basis of the reference point set according to the deformation. Further, after the basic data values corresponding to a basic coordinate, described below, are calculated, the image data based on the ball image signals, the wire image signals, and the stitch image signals are individually determined by the classification into the white pixels and the black pixels.

[93] As for one example of calculating the basic data values, an upper right-hand Align 1 and a lower right-hand Align2 are set as white pixel regions, and then each central point is calculated. In other words, with respect to the Align 1 and the Align2, white pixel boundaries, i.e. upper, lower, left-hand, and right-hand boundaries, are set using the Cartesian coordinate system, and then the central point is calculated. Alternatively, the central point may be calculated using a circular or elliptical coordinate system.

[94] It is assumed that the central points of the Align 1 and the Align2 are connected by a line segment, the midpoint of the line segment is set as a central point a. This central point becomes a reference point for calculating the teaching data used to calculate the basic data of the semiconductor package 12.

[95] Similarly, the white pixels are calculated with respect to the other images of the semiconductor packages.

[96] Then, a distance and an angle with respect to the central point a are set for the white pixel of each image. At this time, a reference angle is 0 when the central point a is oriented toward the Align 1 adopting the central point a as the reference point.

[97] In other words, the white pixels are sequentially checked with respect to the image from one side, and then their coordinates represented by the distance and the angle are stored as the data values. When one white pixel is detected, the central point thereof is calculated by setting the upper, lower, left-hand and right-hand boundaries of the white pixel on the basis of the measured point. The shape and size of the white pixel are detected on the basis of the central point of the white pixel. [98] When the shape and size of the white pixel correspond to set values of each lead, the image is set as the lead. When the shape and size of the white pixel correspond to set values of the ball, the image is set as the ball. The basic data of these reference shape and size are based on the values pre-stored in the memory 15.

[99] As for one example of FIG. 6, with respect to the upper leads detected as rectangular white pixels, the left-hand lead is assigned an index number of 0, and then the other leads are sequentially assigned the index numbers. Thereby, the teaching data are generated.

[100] Similarly, in the case in which the white pixels are determined to correspond to the size and shape of the ball set in a circular shape, the white pixels are set as the balls. The balls are sequentially endowed with the index numbers. Thereby, the teaching data are generated. Further, in the case of the wires, the index numbers are endowed in the same method.

[101] In FIG. 7, the teaching data of the leads, wires, balls and pads are shown on a teaching map.

[102] However, the teaching data of FIG. 7 are set only for the semiconductor package 12 of FIG. 6. In the case in which the semiconductor package 12 has another configuration, the endowment of the index numbers and the calculation of the teaching data can be somewhat modified according to the configuration of the semiconductor package 12. Further, it is apparent that the setting of the central point and the coordinate system based on the Align 1 and Align 2 can use a proper method according to the configuration of the semiconductor package. In FIG. 6, the reference central point is set based on the Align 1 and Align 2 that are the upper and lower right-hand white pixels. The Align 1 and Align 2 can be set on the basis of first and second left-hand white pixels of FIG. 6. Further, in the case in which the semiconductor package has yet another configuration, it is apparent that the Align 1 and Align2 for the central point are set and determined on the basis of preset basic white pixels.

[103] Of course, it is apparent that a method of setting the camera resolution, the threshold value or the white pixel, which has been described above, can be substituted by a proper method according to production process and inspection environment of the semiconductor package and semiconductor.

[104] As one example, in FIGS. 6 and 8, the images are configured of top leads, top balls, bottom balls, bottom leads, and top wires between the top leads and the top balls, and bottom wires between the bottom balls and the bottom leads. The top side and the bottom side on which the leads, wires and balls are shown are symmetrical with respect to each other. Here, the data values are calculated from the total number of 13 top leads (lead index numbers ranging from 0 to 12), the total number of 14 top wires (wire index numbers ranging from 0 to 13), and the total number of 14 top balls (ball index numbers ranging from 0 to 13).

[105] Further, in the image data calculating process, the data values of the sizes and shapes of each lead, ball and wire are calculated together. The data values for the pads bonded with the balls are calculated in the same method.

[106] In this manner, the corresponding teaching data are calculated in the ball state inspecting process S02, the wire state inspecting process S03, and the stitch state inspecting process S04 for the semiconductor package 12, and thus the basic data for determining the states are calculated.

[107] Particularly, a blob object method is applied to the white pixel and the black pixel analyzed from the image. Thus, the size, position, shape, etc. of each pad 121, ball 122, lead 123 and wire 124 are analyzed in the case of the white pixel, and the size, position, shape, etc. of each lead 123, wire 124 and stitch 125 are analyzed in the case of the black pixel. This blob object method is track a blob of white pixels, which is formed by continuation of the respective white (black) pixels. The boundaries of the white pixels and the black pixels are tracked along a clockwise or counterclockwise mask contour, and each boundary is analyzed using the distance Dist and the angle q with respect to the central point a between the Align 1 and the Align2. The analysis is made in a manner such that the white pixel blob is set, and then the position and shape of the set white pixel blob are defined as corresponding to the pads 121, balls 122, leads 123 or wires 124.

[108] Since the images photographed by the ball photographing equipment 20 are images of the pads 121 and the ball 122 for the analysis based on the blob object method, the blob object method is applied to the pads 121 on the basis of the white pixel and the balls 122 on the basis of the black pixel. The images photographed by the wire photographing equipment 30 are associated with the images of the entire semiconductor package 12 as in FIG. 6, and thus the size, position, shape, etc. of each white pixel are analyzed with respect to the pads, balls, leads, wires, Alignl and Align2.

[109] Similarly, in the case of the images of the leads 123, wires 124 and stitches 125 photographed by the stitch photographing equipment 40, the blob object method is applied to the leads 123 on the basis of the white pixel, and the stitches 125 on the basis of the black pixel. Thereby, the size, position, shape, etc. of the white (black) pixel are analyzed. Afterwards, when these data are analyzed, compared and determined, the blob object method is used.

[110] First, the ball data analyzing process S024 of the ball state inspecting process S02 will be described. As in FIG. 9, the shape of each ball represented by the black pixel is calculated along a contour, and then the central point of the ball is obtained. Similarly, the shape of each pad represented by the white pixel is calculated along a contour, and then the central point of the pad is obtained. A degree of alignment of the central points of the ball and the pad is calculated, so that it can be inspected how much the ball bonded to the pad deviates from the pad (ball placement determining process).

[I l l] As in FIG. 10, the size of each ball (right-hand part of FIG. 10) stored in the main controller 11 is compared with the ball data values (left-hand part of FIG. 10) calculated from the image, so that it can be inspected whether or not the size of the ball bonded to the pad is proper (ball size determining process).

[112] In the wire state inspecting process S03), the inspection as illustrated in FIGS. 11 through 16 can be performed.

[113] Specifically, in the wire image data calculating process S033, the data values, i.e. the teaching data values, of the size, shape, and number of each pad 121, ball 122, lead 123 and wire 124 are calculated.

[114] The inspection associated with the wires is performed using the teaching data of the images in the wire data analyzing process S034.

[115] In detail, the data values of the pads 121, balls 122, leads 123 and wires 124 calculated in the wire image data calculating process S033 are compared with those stored in the memory 15 of the main controller 11, and thereby foreign materials, shapes of which are different from those of the pads 121, balls 122, leads 123 and wires 124, are inspected (foreign material inspecting process S0341). The data values of the pads 121, balls 122, leads 123 and wires 124 calculated in the wire image data calculating process S033 are compared with those stored in the memory 15 of the main controller 11, and thereby connection states of the wires 124 are determined (wire connection determining process S0342). Further, the width and shape of each wire 124 calculated in the wire image data calculating process S033 are determined (wire state determining process S0343).

[116] First, in the wire related inspection, the foreign material inspecting process will be described. The data values of the pads 121, balls 122, leads 123 and wires 124, which are calculated in the wire image data calculating process S033 of calculating the teaching data from the images as in FIG. 11, are compared with those stored in the memory 15 of the main controller 11, and thereby foreign materials (upper middle part of FIG. 11) having different shapes compared to the pads 121, balls 122, leads 123 and wires 124 are inspected (wire foreign material determining process).

[117] In the wire connection determining process, the state of each wire 124 running from the ball 122 of each pad 121 to each lead 123 is inspected. First, as in FIGS. 6 and 7, the inspection of "defective connection" of the wires, i.e. the inspection of whether or not the teaching data values of the pads 121, balls 122, leads 123 and wires 124, which are calculated in the wire image data calculating process S033 are matched with those, particularly the numbers of pads 121, balls 122, leads 123 and wires 124, stored in the memory 15 of the main controller 11 is made. Thereby, in the case in which the semi- conductor package 12 is fabricated in the state in which the number of pads 121, balls 122, leads 123 or wires 124 is different from that of the teaching data, the semiconductor package 12 is determined to be defective (incorrect wire determining process).

[118] Further, as in FIG. 12, the white pixels are inspected along the contours of the leads 123 and the balls 122 using the teaching data (blob object method). Thereby, it is inspected whether or not each wire 124 connected between the corresponding lead 123 and ball 122 is represented by the white pixel. For example, when any wire is disconnected as in FIG. 12, the semiconductor package 12 is determined to be defective (unconnected wire determining process).

[119] As in FIG. 13, when the wires 124 connected between the leads 123 and the balls 122 are inspected along the contours of the white pixels (blob object method). When any white pixel different from that of each wire 124 is detected, the wire is in a short state. Thus, the semiconductor package 12 is determined to be defective (wire short determining process).

[120] Furthermore, as in FIG. 14, the white pixels between the leads 123 and the balls 122 are tracked (blob object method). When two or more wires 124 are bonded to one ball 122, and when this bonding is not supported by the wire data stored in the memory 15 of the main controller 11, the semiconductor package 12 is determined to be defective (wire double bonding determining process).

[121] Next, in the wire state determining process, each wire state is determined using the width and shape of each wire 124 calculated in the wire image data calculating process S033, as in FIGS. 15 and 16. As in FIG. 15, the white pixels of the wires 124 are tracked, and the width of each wire is not uniform, for instance narrow. In this case, the semiconductor package 12 is determined to be defective (wire damage determining process). Further, as in FIG. 16, the white pixels of the connected wires 124 are tracked, and the linearity of each wire 124 is inspected by calculating the distance and orientation with respect to the central point. When any wire is curved, the semiconductor package 12 is determined to be defective (bending wire determining process).

[122] The states of the leads 123 and the stitches 125 that are the ends of the wires 124 on the leads 123 are inspected. Specifically, as in FIG. 17, it is inspected whether or not each stitch 125 represented by the black pixel exists on the corresponding lead 123 represented by the white pixel. Further, it is determined whether or not the end of each stitch 125 has a Y shape (lifted stitch determining process)

[123] In this manner, the semiconductor package 12 transferred together with the worktable 13 can be photographed and undergo defect inspection within a short time by the semiconductor package inspection system A and the semiconductor package inspection method using the same, so that system A, so that the efficiency of inspection is improved.

[124] Further, since the teaching data including the white and black pixels are used, the bonded state of the semiconductor package can be precisely inspected.

[125] Although exemplary embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Industrial Applicability

[126] According to the present invention, the semiconductor package that has been produced is inspected by photographing, so that it can be precisely and rapidly inspected without using naked eyes, and thus the defective rate is remarkably reduced.

[127] Further, the semiconductor package is inspected in a manner such that pads, balls, leads and wires are divided and inspected individually, so that the semiconductor package having good quality can be produced due to the precise inspection.

[128] Furthermore, the semiconductor package undergoes precise inspection using an analog image as a pixel-based digital image, so that the semiconductor package having good quality can be produced. The inspection work is automated, so that the semiconductor package can be produced in a rapid inexpensive manner.

Claims

[1] A semiconductor package inspection system (A) for a semiconductor package

(12), the system comprising: ball photographing equipment (20), wire photographing equipment (30) and stitch photographing equipment (40); wherein the ball photographing equipment (20) comprises a ball camera (21) photographing pads (121) and balls (122) of the semiconductor package (12) to generate ball image signals including images of the pads (121) and the balls (122); wherein the wire photographing equipment (30) comprises a wire camera (31) photographing leads (123), the pads (121) and wires (124) of the semiconductor package (12) to generate wire image signals including images of the leads (123), the pads (121) and the wires (124); wherein the stitch photographing equipment (40) comprises a stitch camera (41) photographing the leads (123) and the wires (124) of the semiconductor package (12) to generate stitch image signals including images of the leads (123) and the wires (124); a worktable (13) transferring the semiconductor package (12) to the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40); and a main controller (11) controlling the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40), the main controller (11) comprising an image signal input (14) receiving the image signals of the semiconductor package (12) from the ball photographing equipment (20), the wire photographing equipment (30) and the stitch photographing equipment (40), and a memory (15).

[2] A semiconductor package inspection method using a semiconductor package inspection system, comprising: preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl); photographing, at a ball photographing equipment (20) controlled by a main controller (11) of the semiconductor package inspection system (A), the pads (121) and balls (122) of the semiconductor package (12) mounted on the worktable (13) to generate a ball image signal (S021); transmitting, through an image signal input (14) of the main controller (11), the ball image signals generated by the ball photographing equipment (20) (S022); calculating ball image data by calculating data values of shapes of the pads (121) and the balls (122) from the transmitted ball image signals (S023); and analyzing ball data, at the main controller (11), through comparison with the data values of the pads (121) and the balls (122), to inspect ball states and bonded states of the pads (121) and the balls (122) (S024).

[3] A semiconductor package inspection method using a semiconductor package inspection system, comprising: preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl); photographing, at a wire photographing equipment (30) controlled by a main controller (11) of the semiconductor package inspection system (A), the pads (121) and balls (122), leads (123) and wires (124) of the semiconductor package (12) mounted on the worktable (13) to generate wire image signals (S031); transmitting, through an image signal input (14) of the main controller (11), the wire image signals generated by the wire photographing equipment (30) (S032); calculating wire image data by calculating data values of the pads (121), the balls (122), the leads (123) and the wires (124) from the transmitted wire image signals (S033); and analyzing wire data, at the main controller (11), through comparison with the data values of the pads (121), the balls (122), the leads (123) and the wires (124), to inspect wire states (S034).

[4] The method according to claim 3, wherein: the wire image data calculating process (S033) calculates data values about sizes, shapes and numbers of the pads (121), the balls (122), the leads (123) and the wires (124); and the wire data analyzing process (S034) comprises:

- inspecting foreign materials, shapes of which are different from those of the pads (121), the balls (122), the leads (123) and the wires (124), through comparison of the data values of the pads (121), the balls (122), the leads (123) and the wires (124), calculated in the wire image data calculating process (S033), with data values stored in a memory (15) of the main controller (11) (S0341);

- determining connection states of the wire (124) through comparison of the data values of the pads (121), the balls (122), the leads (123) and the wires (124), calculated in the wire image data calculating process (S033), with data values stored in the memory (15) of the main controller (11) (S0342); and - determining wire states of the wire (124) calculated in the wire image data calculating process (S033), the wire states including widths and shapes of the wires. [5] A semiconductor package inspection method using a semiconductor package inspection system, comprising: preparing for an inspection of a semiconductor package (12) by mounting the semiconductor package (12) on a worktable (13) of the semiconductor package inspection system (A), the semiconductor package (12) having pads (121) and leads (123) of a semiconductor chip (12), which are connected with wires (124) (SOl); photographing, at a stitch photographing equipment (40) controlled by a main controller (11) of the semiconductor package inspection system (A), leads (123) and wires (124) of the semiconductor package (12) mounted on the worktable (13) to generate stitch image signals (S041); transmitting, through an image signal input (14) of the main controller (11), the stitch image signals generated by the stitch photographing equipment (40) (S042); calculating stitch image data by calculating data values of the leads (123), wires (124) and stitches (125) from the transmitted stitch image signals (S043); and analyzing stitch data, at the main controller (11), through comparison with the data values of the leads (123), the wires (124) and the stitches (125) to inspect stitch states (S044).