WO2008035617A1

WO2008035617A1 - Ag ALLOY THIN FILM, AND Ag ALLOY SPUTTERING TARGET FOR FORMATION OF THE Ag ALLOY THIN FILM

Info

Publication number: WO2008035617A1
Application number: PCT/JP2007/067847
Authority: WO
Inventors: Toshiki Sato; Takao Kawanaka; Jun Suzuki; Katsutoshi Takagi
Original assignee: Kabushiki Kaisha Kobe Seiko Sho
Priority date: 2006-09-21
Filing date: 2007-09-13
Publication date: 2008-03-27

Abstract

Disclosed are: an Ag alloy thin film having an initial reflectivity of 88% or more which is comparable to that of Al and having excellent aggregation resistance and sulfur resistance; and an Ag alloy sputtering target for forming the Ag alloy thin film. Specifically disclosed are: [1] an Ag alloy thin film which contains Au or at least two members selected from Au, Bi and Sn, which satisfies the requirements represented by the following formulae (1) to (3): (1) 5.28[Bi]+0.15[Au]+1.14[Sn]≤8.7; (2) 1.0≤10[Bi]+[Au]; and (3) 2.0≤[Sn]+2[Au]4, and which is treated with heat in an inert gas atmosphere at 130 to 200˚C; and [2] an Ag alloy sputtering target for forming the Ag alloy thin film, which contains Au or at least two members selected from Au, Bi and Sn, and which satisfies the requirements represented by the following formulae (4) to (6): (4) 2.64[Bi]+0.15[Au]+1.14[Sn]≤8.7; (5) 1.0≤5[Bi]+[Au]; and (6) 2.0≤[Sn]+2[Au]4 (provided that the variables [Bi], [Au] and [Sn] in the formulae represent the contents (at%) of Bi, Au and Sn, respectively).

Description

Specification

Ag alloy thin film and Ag alloy sputtering ticket for forming this Ag alloy thin film

Technical field

[0001] The present invention belongs to a technical field related to an Ag alloy thin film and an Ag alloy sputtering target for forming the Ag alloy thin film, and in particular, an Ag alloy for a reflective film such as a lighting fixture, an automobile headlamp, and a rear lamp. The present invention belongs to a technical field relating to a thin film (Ag alloy reflective film) and an Ag alloy sputtering target for forming the Ag alloy reflective film.

Background art

[0002] As a reflection film for lighting fixtures, a headlight for automobiles, and a reflection lamp for rear lamps, a film in which A1 having a film thickness of about lOOnm is formed on a resin substrate by sputtering is mainly used. However, A1 is easily corroded by acids and alkalis with poor corrosion resistance and its reflectivity is lowered. To prevent this, a protective coating such as resin is applied on the reflective film of A1. Coats are a factor in increasing costs.

[0003] On the other hand, Ag has an initial reflectivity of around 97%, which is about 10% higher than the initial reflectivity of A1 of 88%. Although it was expected to be used without a protective coating as a spray film, there was a problem that the Ag thin film was agglomerated when halogen ions and moisture were present in the environment, and the reflectivity decreased due to agglomeration. Moreover, when aggregation occurs, innumerable white spots and discoloration occur on the surface of the Ag thin film, which causes a problem of deteriorating design and commercial properties.

[0004] Further, Ag reacts with the environmental blue component and easily sulfidizes and discolors black, so that there is a problem that the reflectance is lowered.

[0005] As described above, although Ag has excellent corrosion resistance, it has a problem of aggregation and sulfidation. Therefore, like A1, it requires a protective coat that blocks the environment on the surface. There was a problem of high costs. For this reason, an Ag alloy thin film that is excellent in cohesion resistance, excellent in sulfation resistance, and does not require a protective coating has been desired.

[0006] Various techniques have been proposed to improve the aggregation resistance of such an Ag film! Example For example, in Japanese Patent Laid-Open No. 2001-226765, 0.1 to 3.0 wt% of Au and Ru are added to Ag, and at least one element of Cu, Ti, Cr, Ta, Ni, Mo, and Al is added. Ag alloy materials with 0.1-3.0 \ ^% added have been proposed. JP 2005-15893 discloses that a Bi layer and / or a Bi oxide layer is formed on the surface of an Ag alloy containing Bi and / or an interface with another layer on the Ag alloy thin film. An Ag alloy reflective film having a structure has been proposed.

[0007] According to these techniques, although aggregation of Ag can be suppressed, a sufficient effect cannot be obtained with respect to suppression of sulfidation, and it is insufficient for use as a reflection film without a protective coating.

[0008] On the other hand, since Ag is used as an electrical contact material or a decorative film, various improvements have been made in this field by alloying or multilayering. For example, Japanese Patent Laid-Open No. 55-85646 discloses an alloy characterized in that Ag contains a total of 10 to 60 wt% of Pd, Pt, and Au among Pd, Pt, and Au. Japanese Patent No. 47251 discloses an alloy film structure excellent in sulfidation resistance in which Au or an Au alloy is formed in a thickness of 10 to 200 nm on the surface of an Ag-Sn alloy layer. These alloys or alloy films have excellent resistance to sulfidation S, and for the former, if the amount added is too small, the decrease in reflectance due to sulfidation cannot be sufficiently suppressed. When there is a large amount, the reflectivity drop due to sulfidation is suppressed. There are problems that the color of the reflective film turns yellow or the reflectivity is lower than A1 and the initial reflection characteristics deteriorate. Japanese Patent Application Laid-Open No. 2005-48231 describes an Ag—B to Sn alloy, an Ag—Bi—Au alloy film, and the like. Although these alloys have improved cohesion resistance and sulfidation resistance, as shown in the examples, the reflectance decreased by 10% or more in the sulfidation resistance test, and as a reflective film for lighting fixtures and automobiles. The properties are insufficient for use. Patent Document 1: Japanese Patent Laid-Open No. 2001-226765

Patent Document 2: Japanese Patent Laid-Open No. 2005-15893

Patent Document 3: Japanese Patent Laid-Open No. 55-85646

Patent Document 4: JP-A-5-47251

Patent Document 5: JP-A-2005-48231

Disclosure of the invention

Problems to be solved by the invention

[0009] The present invention has been made paying attention to such a situation, and the purpose thereof is the initial reflectance. The aim is to provide an Ag alloy thin film with an Al content of 88% or more, comparable to that of Al, and excellent in aggregation resistance and sulfidation resistance, and an Ag alloy sputtering target for forming this Ag alloy thin film.

Means for solving the problem

[0010] As a result of intensive studies to achieve the above object, the present inventors have completed the present invention. According to the present invention, the above object can be achieved.

The present invention thus completed and capable of achieving the above object relates to an Ag alloy thin film and an Ag alloy sputtering target for forming this Ag alloy reflective film, and claims in the scope of patent claims. The Ag alloy reflective film according to Item 1 (Ag alloy reflective film according to the present invention) and the Ag alloy sputtering target according to Claim 2, which are configured as follows.

Yes

That is, the Ag alloy thin film according to claim 1 is an Ag alloy thin film containing two or more of Au, Au, Bi, and Sn, and satisfies the following formulas (1) to (3): An Ag alloy thin film characterized by being heat-treated in an inert gas atmosphere at 130 to 200 ° C. [first invention]. However, in the following formulas (1) to (3), [Bi] is the Bi content (atomic%), [Au] is the Au content (atomic%), and [Sn] is the Sn content (atomic%). It is shown.

[0013] 5.28 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7 Equation (1)

1.0≤10 [Bi] + [Au] Equation (2)

2.0≤ [Sn] + 2 [Au] ⁴ formulas (3)

[0014] An Ag alloy sputtering target according to claim 2 is an Ag alloy sputtering target for forming an Ag alloy thin film according to claim 1, and contains two or more of Au, Au, Bi, and Sn, An Ag alloy sputtering target satisfying the following formulas (4) to (6) [second invention]. However, in the following formulas (4) to (6), [Bi] represents Bi content (atomic%), [Au] represents Au content (atomic%), and [Sn] represents Sn content (atomic%). Is.

[0015] 2.64 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7 Equation (4)

1.0≤5 [Bi] + [Au] Equation (5)

2.0≤ [Sn] + 2 [Au] ⁴ formulas (6)

The invention's effect [0016] The Ag alloy thin film according to the present invention has an initial reflectance of 88% or more, and is excellent in aggregation resistance and sulfidation resistance. For this reason, even if there is no protective coating, it can be used with a force S that can be suitably used as a reflective film.

[0017] According to the Ag alloy sputtering target of the present invention, the force S for forming such an Ag alloy reflective film can be achieved. That is, an Ag alloy reflective film is formed using the Ag alloy sputtering target according to the present invention, and this is heat-treated in an inert gas atmosphere at 130 to 200 ° C. to obtain an Ag alloy thin film according to the present invention. be able to.

Brief Description of Drawings

[0018] FIG. 1 is a graph showing the relationship between the Au composition and the reflectance before and after the sulfidation test for an Ag—Au alloy thin film.

BEST MODE FOR CARRYING OUT THE INVENTION

[0019] Regarding the suppression of Ag aggregation, sufficient effects have been obtained by the addition of Au and Bi disclosed so far, but the problem is the improvement of sulfidation resistance. For example, JP-A-55-85646 proposes the addition of Pd, Pt, and Au to improve sulfidation resistance. For example, Pd is reflected when added at 4at% (approximately 4wt%) or more in Ag. Since the rate becomes 88% or less, it is impossible to add even a composition that can prevent the aggregation of Ag! /. In addition, in the case of an Ag alloy thin film formed by sputtering with Au added, as shown in Fig. 1, in the sulfidation test immersed in 0.01M Na S aqueous solution for 30 minutes, Au is added compared to pure Ag. This will certainly reduce sulfidation and improve the decrease in reflectivity, but in order to maintain a reflectivity of 88% or higher, it is necessary to add approximately 30 at% (approximately 44 wt%), and a large amount of Au is added. It becomes expensive because it is necessary. In addition, Ag-B to Sn alloy and Ag-Bi-Au alloy disclosed in Japanese Patent Application Laid-Open No. 2005-48231 are excellent in aggregation resistance due to the effect of Bi. This is effective because it is small, but it cannot maintain a reflectance of 88% or more.

[0020] Therefore, as a result of intensive studies, the inventors of the present invention have found that an Ag alloy thin film containing one or more of Au and Sn is heat-treated at 130 to 200 ° C in an inert gas atmosphere, thereby being resistant to sulfidation. We found that the performance is greatly improved.

[0021] The reason for this improvement in sulfidation resistance is not clear, but when Sn is contained, As a result of the heat treatment, the Sn concentration on the surface of the Ag alloy thin film is higher than the average concentration of Sn in the film. On the other hand, when Au is contained, there is no change in the Au composition such as Au concentration on the surface of the Ag alloy thin film due to the above heat treatment. Is thought to be suppressed! /.

[0022] Bi and Au have an effect of suppressing aggregation due to halogen ions, as in the prior art.

[0023] Therefore, when an Ag alloy thin film containing two or more of Au, Au, Bi, and Sn is heat-treated in an inert gas atmosphere at 130 to 200 ° C, it has excellent agglomeration resistance and sulfidation resistance. Become

Yes

That is, this Ag alloy thin film may contain (A) Bi and Sn but not Au, and (B) may contain two or more of Au, Bi and Sn. In the case of (A), the effect of improving the aggregation resistance due to the inclusion of Au (hereinafter referred to as the effect of improving the resistance to aggregation of Au) and the resistance to sulfidation by heat treatment at 130 to 200 ° C in an inert gas atmosphere of the Au-containing material Effect (hereinafter referred to as the effect of improving the sulfidation resistance of Au + heat treatment), and has excellent agglomeration resistance and sulfidation resistance.

[0025] In the case of the latter (B), (1) the case of not containing Sn, and containing Au and Bi, and (2) the case of not containing Bi, and containing Au and Sn, and (3) There are cases in which Au is not contained and Bi and Sn are contained, and (4) Au, Bi and Sn are contained. Among these, in the case of (1), the effect of improving the aggregation resistance of Au, the effect of improving the aggregation resistance due to the inclusion of Bi (hereinafter referred to as the effect of improving the aggregation resistance of Bi), and the effect of improving the sulfidation resistance of Au + heat treatment And has excellent resistance to aggregation and sulfidation. In the case of (2), the effect of improving the aggregation resistance of Au, the effect of improving the sulfidation resistance of Au + heat treatment, and the improvement of sulfidation resistance by heat treatment at 130 to 200 ° C in an inert gas atmosphere of Sn-containing material The effect (hereinafter referred to as the effect of improving the sulfidation resistance of the Sn + heat treatment and the repellency) is obtained, and the flocculation resistance and the sulfidation resistance are excellent. In the case of (3), the effect of improving the aggregation resistance of Bi and the effect of improving the sulfidation resistance of Sn + heat treatment are exhibited, and the aggregation resistance and sulfidation resistance are excellent. In the case of (4), the effect of improving the aggregation resistance of Au, the effect of improving the aggregation resistance of Bi, the effect of improving the sulfidation resistance of Au + heat treatment, and the effect of improving the sulfidation resistance of Sn + heat treatment are exhibited. Excellent cohesion and sulfidation resistance

[0026] At this time, the amount of the additive element (two or more of Au, Au, Bi, Sn) satisfies the above formulas (1) to (3). It is necessary to add.

That is, in order to exhibit the effect of improving the anti-aggregation property of Au and / or the effect of improving the anti-aggregation property of Bi, it is necessary to satisfy the above formula (2). If this formula (2) is satisfied, the anti-agglomeration effect is improved and the anti-agglomeration property is excellent. The variables in this equation (2) are [Au] and [Bi]. When adding only Au among Au and Bi, addition of 1.0 atomic% (hereinafter also referred to as at%) or more is required. When adding only Bi, addition of 0.1 at% or more is required. However, when Au and Bi are added, for example, even if Au is 0.5 at%, if 0.05 at% or more of Bi is added, the anti-aggregation effect is improved and the anti-agglomeration resistance is excellent.

[0028] In order to achieve the effect of improving the sulfidation resistance of the Au + heat treatment and / or the effect of improving the sulfidation resistance of the Sn + heat treatment, it is necessary to satisfy the above formula (3). If this formula (3) is satisfied, the above-mentioned effect of improving the sulfidation resistance is achieved and the sulfidation resistance is excellent. The variables in this equation (3) are [Au] and [Sn]. When adding only Sn among Au and Sn, it is necessary to add 2.0at% or more, and when adding only Au, it is necessary to add 1.0at% or more S, Sn and When adding Au, for example, when adding 1.9 at% of Sn, adding 0.5 at% or more of Au provides an effect of improving sulfidation resistance and excellent sulfidation resistance.

[0029] These additive elements (two or more of Au, Au, Bi, and Sn) improve the aggregation resistance and sulfidation resistance of the Ag alloy thin film as the addition amount (content) increases. On the other hand, the reflectivity decreases. For this reason, the amount of addition is limited, and in order to obtain a reflectance of 88% or more, it is necessary to satisfy the above formula (1).

Based on the above, the Ag alloy thin film according to the present invention is an Ag alloy thin film containing two or more of Au, Au, Bi, and Sn, and satisfies the above formulas (1) to (3) In addition, the Ag alloy thin film is characterized by being heat-treated in an inert gas atmosphere at 130 to 200 ° C. Therefore, this Ag alloy thin film has an initial reflectance of 88% or more, and is excellent in aggregation resistance and sulfation resistance. For this reason, even if there is no protective coat, it can be suitably used as a reflective film. The Ag alloy thin film containing two or more of Au, Au, Bi, and Sn is an Ag alloy thin film containing Au or an Ag alloy thin film containing two or more of Au, Bi, and Sn. Ag alloy thin film containing Au, Bi, Sn, Ag alloy thin film containing Au, Bi, Ag alloy thin film containing Au, Sn, Ag alloy thin film containing Bi, Sn, Au A containing Bi, Sn There is a g alloy thin film. These always contain Au or Sn. Of these, when Au is not contained, and Sn is contained, Bi must be contained! /.

[0031] Here, the temperature of the inert gas atmosphere: 130 200 ° C (that is, the temperature of the heat treatment in the inert gas atmosphere: 130 200 ° C) is that this temperature is higher than 130 ° C. If it is low, the effect of improving the sulfidation resistance of the Au + heat treatment and the effect of improving the sulfidation resistance of the Sn + heat treatment cannot be achieved, and if it is higher than 200 ° C, heat aggregation occurs during the heat treatment. This is because the reflectance is less than 88%. When the heat treatment temperature is 130 ° C. and the heat treatment temperature is low, it is preferable to lengthen the heat treatment time. For example, it may be 12 hours or longer at 130 ° C and 1 hour or longer at 150 ° C. If it is 200 ° C, it should be heat-treated for 10 minutes or longer.

[0032] The atmosphere of the heat treatment is an inert gas atmosphere. When other atmospheres (for example, air, oxygen atmosphere, vacuum atmosphere) are used, there is almost no difference from those without heat treatment. This is because it is not possible to achieve the effect of improving the resistance and the effect of improving the sulfidation resistance of the Sn + heat treatment. In other words, only when an inert gas atmosphere is used as the heat treatment atmosphere, the effect of improving the sulfidation resistance of Au + heat treatment and the improvement of sulfidation resistance of Sn + heat treatment can be achieved. This is because The inert gas is a rare gas such as nitrogen gas or argon gas. The inert gas atmosphere is, for example, a nitrogen gas atmosphere, an argon gas atmosphere, or a mixed gas atmosphere of nitrogen gas and argon gas. The vacuum atmosphere is not an inert gas atmosphere.

[0033] The thickness of the Ag alloy thin film according to the present invention is desirably 100 or more. This is because when the film thickness is less than 100 nm, visible light is not completely reflected and a transmission component is generated. More preferably, it is 120 nm or more, and further preferably 150 nm or more.

[0034] The composition of the sputtering target for producing the Ag alloy thin film according to the present invention may be the same as the film composition except for Bi. This is because a film having the same composition (content) as Sn is formed for Sn and Au. On the other hand, Bi has a lower composition in the film than the composition (content) in the target. This is thought to be because Bi re-evaporates from the film during film formation. For this reason, it is necessary to make the Bi composition in the target higher than the Bi composition in the film. The yield of Bi in the film varies depending on the deposition conditions and deposition equipment S, and the Bi composition in the target is It is desirable that it is at least twice the composition in the film. Therefore, the composition of the sputtering target for producing the Ag alloy thin film according to the present invention should satisfy the above formulas (4) to (6).

[0035] Based on the force and the point, the sputtering target for forming an Ag alloy thin film according to the present invention contains two or more of Au, Au, Bi, Sn and the above formulas (4) to (6) A sputtering target made of an Ag alloy (Ag alloy sputtering target) characterized by satisfying According to this Ag alloy sputtering target, it is possible to form an Ag alloy thin film according to the present invention. That is, an Ag alloy thin film according to the present invention is obtained by forming an Ag alloy reflective film using this Ag alloy sputtering target and heat-treating it in an inert gas atmosphere at 130 to 200 ° C. Can do.

Example

[0036] Examples and comparative examples of the present invention will be described below. It should be noted that the present invention is not limited to these examples, and can be implemented with appropriate modifications within a range that can be adapted to the gist of the present invention, all of which fall within the technical scope of the present invention. included.

[0037] [Example 1]

Ag-Au-Sn alloy, Ag-Au-Sn alloy with various compositions of lOOnm on a glass substrate (Cowung # 1737) with a diameter of 2 inches (5.08 cm) and a thickness of 0.7 mm using a DC magnetron sputtering system A thin film and an Ag thin film were formed. At this time, Ag alloy sputtering targets having various compositions were used as the sputtering target. Deposition conditions are: substrate temperature: room temperature, Ar gas pressure:;! ~

133-0.399? &), The distance between electrodes: 550101, and the deposition rate: 7-8 nm / s. Ultimate vacuum before film formation was less than ^{1 X 10- 5 torr (1.33 X} 10- 3 Pa).

[0038] Except for some of the Ag alloy thin films (Ag-Au alloy thin films, Ag-Au-Sn alloy thin films) and Ag thin films formed in this way, nitrogen gas, argon gas, oxygen gas, heat-treated for one hour at 160 ° C in various atmospheres vacuum ^{(3 X 10- 6 torr (3.99} X 10- 4 Pa)) was performed. More specifically, this heat treatment was performed as follows. If the heat treatment in a nitrogen gas atmosphere, first, putting the Ag alloy thin film and Ag thin films in a quartz tube, pulling the quartz tube to 3 X 10- ⁶ torr with a vacuum pump (3.99 X 10- ⁴ Pa) After that, nitrogen is introduced into the quartz tube to return to atmospheric pressure, and then the atmospheric pressure in the quartz tube is kept, and nitrogen is flown at a flow rate of 4 L (liter) / min. And maintain this state for 1 hour It was done by doing. In the case of heat treatment in an argon gas atmosphere and in the case of heat treatment in an oxygen gas atmosphere, the same method as in the case of the heat treatment in the above nitrogen gas atmosphere (same as above except that the above nitrogen is replaced with argon and oxygen) A heat treatment was performed. For heat treatment in a vacuum atmosphere, putting Ag alloy thin film and Ag thin films in a quartz tube, after subtraction of the quartz tube to 3 X 10- ⁶ torr with a vacuum pump (3.99 X 10- ⁴ Pa), a quartz tube This was carried out by heating to around 160 ° C with infrared rays and maintaining this state for 1 hour.

[0039] Measurement of visible light reflectance (initial reflectance) of Ag alloy thin films and Ag thin films that have been heat-treated in this way, and Ag alloy thin films and Ag thin films (after film formation) that have not been heat-treated A sulfidation test for evaluating sulfidation resistance and an agglomeration test for evaluating flocculation resistance were performed.

[0040] At this time, the visible light reflectance was measured by the method of JIS 3106. The sulfide test was performed by immersing the thin film (Ag alloy thin film, Ag thin film) in 0.01 M Na S aqueous solution for 30 minutes and then measuring the visible light reflectance of the thin film. In the agglomeration test, the above thin film is placed in a constant temperature and humidity test bath at 60 ° C and 90RH%, and after 500 hours, the surface of the thin film is visually observed and the number of white spots (aggregation points) on the thin film surface is measured. It was done by doing.

[0041] Alloy composition of the above Ag alloy thin film, the value of the left side of equation (1) (5.28 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7), the right side of equation (2) (10 [Bi] + The value of [Au]), the right side of equation (3) ([Sn] + 2 [Au] ⁴ ), and the post-deposition (heat-treated les! /,)! /, Table 1 shows the measurement results of the reflectance (initial reflectance). After film formation (heat-treated, re-!,)! /, Reflectivity (initial reflectivity), sulfurization test result (reflectance after sulfurization test), and agglomeration test result [ Table 2 shows the number of white spots generated after the agglomeration test (constant temperature and humidity test). Measurement results of reflectance before sulfidation test, heat treatment in each atmosphere, sulfidation test result (reflectance after sulfidation test), and agglomeration test result [white after agglomeration test (constant temperature and humidity test) The number of points generated] is shown in Tables 3-6. In Tables! To 6, the number 1 indicates the results for the Ag thin film that is not the Ag alloy thin film.

[0042] As can be seen from Table 1, among the Ag alloy thin films after film formation (not heat-treated), those with the number 13 exceeded the value power .7 on the left side of the equation (1), and the equation (1) The initial reflectance is below 88% because the above is not satisfied. Therefore, for the Ag alloy thin film of No. 13, the heat treatment and The evaluation test was not conducted.

[0043] As can be seen from Table 2, the Ag alloy thin film (not heat-treated) after film formation has improved sulfidation resistance due to the addition of Au and Sn compared to the Ag thin film, but it is not sulfurized. After the test, the reflectivity has decreased to less than 88% (sulfuration resistance is not sufficient). In addition, those with numbers 2, 10, and 14 with an Au content of less than 1. Oat% have not sufficiently suppressed the occurrence of white spots (coagulation resistance is not sufficient).

[0044] As can be seen from Tables 3 to 4, for Ag alloy thin films heat-treated in a nitrogen atmosphere and Ag alloy thin films heat-treated in an argon atmosphere, those with numbers 2 and 14 do not satisfy equation (3) Therefore, the reflectivity was below 88% after the sulfidation test. In addition, those with numbers 2, 10, and 14 do not satisfy the formula (2), and therefore white spots are generated and the aggregation resistance is not sufficient. On the other hand, those with numbers 3 to 9, 11 to 12 (examples of the present invention) had a reflectance of 88% or more after the sulfidation test, had no white spots, and had excellent sulfidation resistance and aggregation resistance. Talk!

[0045] As can be seen from Table 5, regarding the Ag alloy thin films heat-treated in an oxygen atmosphere, the numbers 10 and 14 have a reflectance of less than 88% after the heat treatment and before the sulfidation test. Other than this, the reflectivity decreased to less than 88% by the sulfidation test, and the sulfidation resistance was poor.

[0046] As can be seen from Table 6, the reflectance of the Ag alloy thin film heat-treated in a vacuum atmosphere was lowered to less than 88% by the sulfidation test, and the sulfidation resistance was poor.

[Example 2]

Using an RF magnetron sputtering system, Ag_Sn alloy thin films, Ag-Bi-Sn alloy thin films with various compositions of lOOnm on a glass substrate (Counging # 1737) with a diameter of 2 inches (5.08 cm) and a thickness of 0.7 mm, An Ag-Bi-Sn-Au alloy thin film was formed. At this time, the film formation conditions are: substrate temperature: room temperature, Ar gas pressure:;

133-0.399? &), The distance between the electrodes: 1000101, and the deposition rate: 0.4-0.5 nm / s. Ultimate vacuum before film formation was filed with ^{1 X 10- 5 torr (1.33 X} 10- 3 Pa) or less. As the sputtering target, an Ag alloy sputtering target having the composition shown in Table 7 was used. Of these targets, those with numbers 15, 16, and 19 do not satisfy equation (5) (1.0≤ 5 [Bi] + [Au]), and those with number 17 have equations (6). (2.0≤ [Sn] + 2 [Au] ⁴ ) is not satisfied, and the one with number 22 satisfies equation (4) (2.64 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7) No! Other targets (numbers 18, 20, 21, 23, 24) satisfy the formulas (4) to (6). ing.

[0048] Table 8 shows the composition of the Ag alloy thin film thus formed. The numbers in Table 8 indicate that deposition was performed using targets with the same target number. That is, the Ag alloy thin films of numbers 15 to 24 in Table 8 were formed using the targets of numbers 15 to 24 in Table 7. From Table 7 and Table 8, it can be seen that the content of Au and Sn in the film is equal to the content of Au and Sn in the target, and the Bi content in the film is almost 50% of the Bi content in the target. . The Bi content was quantitatively analyzed using ICP-mass spectrometry (SPQ-8000 manufactured by Seiko Instruments Inc.). Specifically, a sample of lOOmg or more was dissolved in an aqueous solution of nitric acid: pure water = 1: 1 as a pretreatment, and this was heated on a 200 ° C hot plate to confirm that the sample was completely dissolved. Cooled and analyzed.

[0049] Except for some of the above Ag alloy thin films (Ag-Sn alloy thin film, Ag_Bi_Sn alloy thin film, Ag-Bi_Sn-Au alloy thin film), nitrogen gas, argon gas, oxygen gas, vacuum (3 X 10ΛΟΓΓ ( 3.99 was carried out for 1 hour heat treatment at 160 ° C with X 10- ⁴ Pa)) various atmospheres. This heat treatment was performed in the same manner as in Example 1 described above.

[0050] For the heat-treated Ag alloy thin film and the heat-treated! /, NA! /, Ag alloy thin film, for the measurement of the visible light reflectance (initial reflectance) and the evaluation of the sulfidation resistance A sulfidation test and an agglomeration test were conducted to evaluate the anti-agglomeration resistance. These measurements and tests were performed in the same manner as in Example 1 above.

[0051] The alloy composition of the Ag alloy thin film, the value on the left side of Equation (1), the value on the right side of Equation (2), the value on the right side of Equation (3), and the value after film formation (heat treated) Table 8 shows the measurement results of the reflectance (initial reflectance). Table 9 shows the reflectivity (initial reflectivity), the reflectivity after the sulfidation test, and the number of white spots after the agglomeration test (constant temperature and humidity test) for the film after film formation (not heat-treated). . Tables 10 to 13 show the reflectivity before the sulfidation test, the reflectivity after the sulfidation test, and the number of white spots after the agglomeration test (constant temperature and humidity test) for those after heat treatment in each atmosphere.

[0052] As can be seen from Table 8, among the Ag alloy thin films after film formation (not heat-treated), those with the number 22 exceeded the value power .7 on the left side of the equation (1), and the equation (1) The initial reflectance is below 88% because the above is not satisfied. Therefore, for the Ag alloy thin film with the number 22, The evaluation test was not conducted.

[0053] As can be seen from the results of the Ag thin film in Table 2 and Table 9, the Ag alloy thin film (not heat-treated) after film formation has improved sulfidation resistance due to the addition of Sn and Au compared to the Ag thin film However, the reflectivity has all dropped to less than 88% after the sulfidation test.

[0054] As can be seen from Tables 10 to 11, the Ag alloy thin films heat-treated in a nitrogen atmosphere and the Ag alloy thin films heat-treated in an argon atmosphere have improved resistance to sulfidation with numbers 15, 16, and 19. However, white dots are generated because Equation (2) is not satisfied. In addition, No. 17 does not satisfy the formula (3), and therefore has insufficient sulfidation resistance. On the other hand, those with numbers 18, 20, 21, 23, and 24 (examples of the present invention) maintained a reflectance of 88% or more after the sulfidation test, did not generate white spots, and were resistant to sulfidation and aggregation. It has excellent characteristics.

[0055] As shown in Table 12, the Ag alloy thin films heat-treated in an oxygen gas atmosphere have a reflectance of 88% after heat treatment and before the sulfidation test. Is below. Numbers 16, 19, 23, and 24 have a force S that the reflectivity after heat treatment and before the sulfidation test is 88% or more, and the reflectivity has decreased to less than 88% after the sulfidation test, and are inferior in sulfidation resistance. Have

Yes

[0056] As can be seen from Table 13, the Ag alloy thin film heat-treated in a vacuum atmosphere had a reflectivity decreased to less than 88% by the sulfidation test, and was inferior in sulfidation resistance. Even when the composition of the Ag alloy thin film satisfies the formulas (1) to (3)! /, It may not be possible to obtain excellent performance by heat treatment in an oxygen gas atmosphere or under vacuum. Recognize.

[0057] [Example 3]

Using a DC magnetron sputtering system, an Ag-2.0at% Sn-1.5at% Au alloy thin film with a thickness of lOOnm is formed on a glass substrate (Counging # 1737) with a diameter of 2 inches (5.08cm) and a thickness of 0.7mm. did. At this time, the film forming conditions were as follows: substrate temperature: room temperature, Ar gas pressure:;! To 3 mtorr (0.133 to 0.3 99 Pa), distance between electrodes: 55 mm, film forming speed: 7 to 8 nm / s. Ultimate vacuum before film formation was less than ^{1 X 10- 5 torr (1.33 X} 10- 3 Pa). Eight _8-2. (^% 5.-1.5 & 1% eight 11 Go gold reflectance of the thin film immediately after the film formation was 94.3%.

[0058] The Ag alloy thin film (Ag-2.0at% Sn-1.5at% Au alloy thin film) thus formed is 100 in an argon gas atmosphere. CX 20 hours, 130. CX 12 hours, 180. CX 20 minutes, 210 After heat treatment at ° CX for 10 minutes, a sulfidation test for evaluating sulfidation resistance and an agglomeration test for evaluating flocculation resistance were performed. The results are shown in Table 14.

[0059] As can be seen from Table 14, when the heat treatment temperature was 100 ° C, the reflectivity decreased to less than 88% after the sulfidation test, the sulfidation resistance was insufficient, and the sulfidation resistance was improved. has no effect. When the heat treatment temperature was 210 ° C, the Ag alloy agglomerated by the heat treatment, and the reflectivity after the heat treatment before the sulfidation test was lower than 88% (therefore, the sulfidation test and the agglomeration test after the heat treatment were not performed). ). Those heat-treated at 130 ° C and those heat-treated at 180 ° C have a reflectance of 88% or more after the sulfation test, and are excellent in sulfidation resistance.

[0060] [Table 1]

[0061] [Table 2]

Reflection rate (%) Reflection rate (%) Reflection rate (%) Number of white spots (number)

96. 7 47. 2 86

96. 5 53. 0 1 0

96. 5 58. 3 0

96. 4 63. 1 0

96. 5 67. 8 0

96. 1 76. 3 0

95. 5 79. 5 0

95. 2 80. 7 0

94. 5 83. 0 0

95. 3 7 1. 5 1 2

9 1. 3 83. 1 0

88. 6 85. 9 0 Not tested Not tested »Not tested

95. 2 7 1. 3 9

Before sulfidation test (constant constant after nitrogen sulfidation test; after atmospheric heat treatment after fi test) Reflectivity (%) Reflectance of number of white spots (pieces) (%)

97. 0 46. 1 76

96. 6 72. 0 8

96. 8 88. 3 0

97. 3 90. 0 0

97. 4 9 1. 0 0

97. 0 90. 2 0

96. 6 90. 0 0

95. 8 89. 5 0

95. 2 89. 0 0

95. 7 92. 5 10

9 1. 9 89. 7 0

88. 7 88. 4 0 Trial 《No Trial «No Trial Without Trial

95. 7 86. 7 1 1

Before sulfidation test (after tantalum sulfidation test »after atmospheric heat treatment after constant humidity test) Reflectivity (%) Reflectance of number of white spots (pieces) (%)

96. 8 45. 3 87

96. 7 70. 5 9

97. 0 89. 0 0

97. 2 90. 5 0

97. 2 9 1. 6 0

96. 8 90. 9 0

96. 4 90. 3 0

95. 7 89. 9 0

95. 2 89. 4 0

95. 9 92. 3 1 2

9 1. 7 89. 9 0

89. 5 88. 6 0 Not tested Not tested Not converted

95. 1 86 .9 1 4

Before sulfidation test »Element After sulfidation test After atmospheric heat treatment after humidity and humidity test) Reflectivity (%) Reflectance of number of white spots (pieces) (%)

97. 0 41. 3 90

96. 8 62. 5 10

96. 7 68. 0 0

96. 9 71. 0 0

97. 0 75. 0 0

96. 5 86. 8 0

95. 6 87. 0 0

95. 4 86. 8 0

94. 6 87. 0 0

85. 6 Not tested

89. 4 82. 1 0

89. 0 8 1. 4 0 Not tested Wipe »Not tested

85.2 Not tested Not tested

Reflectivity (%) Number of white spots (pieces) Reflectivity (° /.) Before sulfidation test (after air-heat treatment after constant humidity test after huge sulfidation test)

1 96. 0 44. 5 90

2 96. 1 68. 3 1 0

3 96. 0 7 1. 3 0

4 95. 7 74. 5 0

5 95. 6 79. 9 0

6 96. 3 84. 6 0

7 95. 3 85. 4 0

8 95. 3 86. 0 0

9 94. 5 86. 2 0

10 95. 3 82. 3 9

11 89. 0 84. 1 0

12 88. 5 8 1. 4 0

13 Not tried Not tested Not tested

14 95. 3 8 1. 0 1 2

[0066] [Table 7]

[0067] [Table 8]

[0068] [Table 9]

[0069] [Table 10] No. Before sulfidation test (after nitrogen sulfidation test ft after atmospheric heat treatment after constant temperature and humidity test) Reflectivity (%) Reflectance of number of white spots (pieces) (%)

15 94. 4 90. 6 68

16 9 1. 2 89. 3 62

17 93. 3 86. 8 0

18 93. 8 90. 1 0

19 90. 6 89. 0 1 5

20 95. 4 90. 9 0

21 93 .9 9 1 .0 0

22 No test >> No test No test

23 95. 5 88. 2 0

24 96. 1 9 1. 0 0

[0070] [Table 11]

[0071] [Table 12] Number Before sulfidation test (after oxygen heat treatment after atmospheric heat treatment after constant temperature and humidity test) Reflectivity (%) Reflectance (%) of number of white spots (number)

15 87.3 Not tested Not tested

16 90. 6 85. 3 56

17 85. 4 Not tested »Not tested

18 84. 6 Not tested Not tested

19 90. 5 84. 2 1 6

20 86. 0 Trial »Not tested Not tested

21 87. 6 Not tested Not tested

22 Not tested Not tested Not tested

23 96. 0 7 1. 0 0

24 95. 7 74. 9 0

[0072] [Table 13] No. Reflectivity (%) Number of white spots generated (%) Reflectivity (° /.) Before sulfidation test (after air heat treatment after constant temperature and humidity test after true sulfidation test)

15 95. 0 82. 1 63

16 92. 8 87. 6 53

17 96. 0 8 1. 1 44

18 95. 6 80. 8 0

19 92. 4 86. 6 0

20 95. 2 83. 9 0

21 94. 8 84. 6 0

22 Do not try Do not test

23 95. 5 80. 7 0

24 94. 9 79. 9 0

[0073] [Table 14] Heat treatment conditions After constant temperature and temperature test after sulfidation test after heat treatment

Reflectance (%) Reflectance (%) Number of white spots generated (pieces)

100 ° O 20 hours 94. 2 83. 6 0

130 ° Ο 1 2 o'clock 94.0 90.5 0

180 ° Ο20min 94. 6 91 .4 0

210 ° Ο10min 85.0 Not tested Not tested

[0074] Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. is there. This application is based on a Japanese patent application filed on September 21, 2006 (Japanese Patent Application No. 2006-256136), the contents of which are incorporated herein by reference.

Industrial applicability

[0075] The Ag alloy thin film according to the present invention has an initial reflectivity of 88% or more, and is excellent in aggregation resistance and sulfidation resistance. It can be suitably used as a reflective film for automobile headlamps and rear lamps, and is useful.

Claims

The scope of the claims

An Ag alloy thin film containing two or more of Au, Au, Bi, and Sn, satisfying the following formulas (1) to (3), and heat-treated in an inert gas atmosphere of 130 to 200 ° C Ag alloy thin film characterized by

5.28 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7 Equation (1)

1.0≤10 [Bi] + [Au] Equation (2)

2.0≤ [Sn] + 2 [Au] ⁴ formulas (3)

However, in the above formulas (1) to (3), [Bi] is the Bi content (atomic%), [Au] is the Au content (atomic%), and [Sn] is the Sn content (atomic%). It is shown.

[2] An Ag alloy sputtering target for forming an Ag alloy thin film according to claim 1, comprising two or more of Au, Au, Bi, Sn and satisfying the following formulas (4) to (6): Ag alloy sputtering target.

2.64 [Bi] + 0.15 [Au] + 1.14 [Sn] ≤8.7 Equation (4)

1.0≤5 [Bi] + [Au] Equation (5)

2.0≤ [Sn] + 2 [Au] ⁴ formulas (6)

However, in the above formulas (4) to (6), [Bi] is the Bi content (atomic%), [Au] is the Au content (atomic%), and [Sn] is the Sn content (atomic%). It is shown.