JP4876785B2 - Copper alloy backing plate and method for producing the copper alloy - Google Patents

Description

  The present invention relates to a copper alloy backing plate and a method for producing the copper alloy, and more particularly to a copper alloy backing plate and a method for producing the copper alloy used for cooling a target material in a sputtering apparatus.

  In sputtering, a high voltage is applied between two electrodes in a low-pressure inert gas to cause glow discharge, and the constituent atoms are struck out from a target placed on the cathode by gas ion bombardment. It is one of the thin film formation techniques deposited on

  In sputtering, most of the energy input to the target is converted to heat in the surface area of the target. When the temperature of the target rises excessively due to this heat, the structure of the target material may change, and the desired film quality may not be obtained. For this reason, a cooling plate called a backing plate is disposed on the back surface of the target so that the temperature of the target does not rise excessively. As an example of the structure of the backing plate, a structure in which a groove is formed on a smooth plate and this is covered with a lid and joined to form an internal water channel is an example.

  The backing plate plays a role of dissipating heat from the target (cooling the target), a role of fixing (holding) the target, and a role of a sputtering electrode. In many cases, the target and the backing plate are bonded (bonded) with an In or Sn alloy-based low melting point brazing material or the like.

  In order to cool the target efficiently, it is desirable that the thermal conductivity of the backing plate itself is good. If the thermal conductivity of the backing plate itself is low, the cooling effect is small, and it is difficult to avoid an increase in the temperature of the target material. For this reason, generally, a metal material having good thermal conductivity is used as the backing plate material.

Conventionally, oxygen-free copper, copper alloy, aluminum alloy, stainless steel, or other metals and alloys are used for the backing plate (see, for example, Patent Documents 1 to 4).
JP-A-10-110226 Japanese Patent Laid-Open No. 10-168532 JP-A-4-165039 JP 2001-329362 A

  As described above, the backing plate is required to have good thermal conductivity. On the other hand, the backing plate has a high mechanical strength (for example, high 0) that can withstand stress caused by a temperature difference or a pressure difference between the front and back sides. .2% yield strength and high Young's modulus).

  The backing plate generally has a structure in which the target material is bonded to one side and the other side is water-cooled. During sputtering, a temperature gradient is generated inside the backing plate due to the temperature difference between the target material side and the water-cooled side. . For this reason, the thermal stress resulting from a temperature difference generate | occur | produces inside a backing plate. Further, since the target material side (inside the chamber) is at a low pressure (vacuum state) and the water cooling side is at atmospheric pressure or higher, the backing plate also generates stress due to the pressure difference between the front and back sides.

  At this time, if the backing plate has low mechanical strength (for example, 0.2% proof stress or Young's modulus), these stresses may cause large elastic deformation or plastic deformation. If the backing plate is plastically deformed, it cannot be used repeatedly and needs to be replaced, that is, the cost increases. In addition, when large elastic deformation occurs, cracks may occur in the joint portion with the target material or the target material itself.

  In addition, it is desirable that the backing plate has good heat resistance in order to minimize the reduction of the mechanical strength with time due to the softening of the backing plate due to heating in the bonding process or the like.

  On the other hand, a process technology utilizing sputtering (that is, a backing plate application) has been developed as a basic technology in a wide range of fields such as semiconductor device manufacturing and flat display manufacturing. In recent years, in order to improve the productivity of the sputtering process and reduce the cost, the processing substrate has been steadily increasing in area.

  In particular, in the field of manufacturing flat panel displays (FPD) such as liquid crystal displays (LCD) and plasma display panels (PDP), in addition to increasing the screen size of the display panel itself to meet market needs, a single glass substrate Cost reduction is achieved by increasing the number of display panels (number of chamfers) that are simultaneously processed with (mother glass substrate).

The size of the mother glass substrate rapidly expanded from the fourth generation (730 × 920 mm ² ) around 2000, and the fifth generation (1100 × 1300 mm ² ), the sixth generation (1500 × 1800 mm ² ), and the seventh generation (1800). × 2100 mm ^2), finally is expected to eighth generation (2200 × 2600mm ^2), and the further the 9th generation (2600 × 3100mm ²⁾ to a larger area is gradually progress.

  Here, in order to improve the productivity (yield) of FPD and reduce the cost by using such a large area glass substrate, uniform and high-quality film formation over the entire surface of the large area glass substrate. Technology to realize the process is indispensable. Along with this, the size of the sputtering target and the backing plate is inevitably increased.

Examples of the size of the sputtering target include 1130 × 1200 mm ² for the fourth generation and 1430 × 1700 mm ² for the fifth generation. Examples of backing plate sizes include 1170 x 1300 mm ² for the 4th generation and 1450 x 2050 mm ² for the 5th generation, requiring a larger area than the mother glass substrate and sputtering target described above. It can be seen that

  However, the conventional backing plate made of oxygen-free copper (pure copper), for example, has good thermal conductivity, but has low mechanical strength (for example, 0.2% proof stress and Young's modulus), so it is deformed by stress. Prone to occur. In addition, the stainless steel backing plate has an advantage of high 0.2% yield strength (yield strength), but has a drawback that the cooling effect is small and the target temperature is likely to rise because the thermal conductivity is extremely small. .

  As described above, in particular, a sputtering apparatus for FPD manufacturing apparatus uses a large-area target material and a backing plate, which increases the absolute amount of generated heat and at the same time causes deformation (displacement) of the backing plate due to various stresses. ) Tends to be large (for example, when the curvature of warpage is the same, the large-area backing plate has a larger absolute value of warp deformation than the conventional small-area backing plate).

  For this reason, a measure of using pure copper on the target material side and using a material having high 0.2% proof stress (yield strength) such as stainless steel on the opposite surface side may be taken. However, in this case, there arises a problem that a thermal strain generated between copper and stainless steel and a manufacturing cost for combining different materials increase.

  Furthermore, the use of a large area target material and backing plate has led to the emergence of phenomena that were not noticeable in the past.

  For example, during storage of the backing plate or bonding of the target, gas components such as water vapor or oxygen in the atmosphere are adsorbed on the surface of the backing plate, penetrate into the surface layer portion, or the surface layer portion is oxidized (hereinafter collectively referred to as The problem is that the gas components are dissociated from the backing plate during sputtering, which is a vacuum process, and adversely affects the film-forming quality (for example, homogeneity in a large-area film).

  In particular, in a large area (large) backing plate with one side extending over 1 to 2 m or more, the problem is even more remarkable because the absolute surface area is large. For this reason, with the increase in size of the backing plate, a demand for characteristics that are difficult to oxidize and dissociate (hereinafter referred to as “oxidation resistance”) has emerged as a new issue.

  However, conventional backing plates, such as oxygen-free copper backing plates, have low oxidation resistance, so that gas components such as water vapor and oxygen are likely to be dissociated during sputtering, which requires a lot of labor for baking before sputtering. There is a disadvantage that it takes. Generally, there is a restriction that the baking temperature must be set below the melting point of the bonding material (low melting point brazing material or the like) used for bonding. In addition to this, particularly when the backing plate is enlarged, an effective baking process becomes even more difficult.

  Considering the above, a backing plate having excellent thermal conductivity, mechanical strength, and particularly oxidation resistance is desired.

  Therefore, the object of the present invention is to meet the demand for larger backing plates, less susceptible to thermal effects during sputtering, thermal effects due to repeated use, and pressure differences between the front and back surfaces, and thermal conductivity and mechanical strength (for example, An object of the present invention is to provide a copper alloy backing plate having excellent 0.2% proof stress and Young's modulus and also having excellent oxidation resistance and a method for producing the copper alloy.

In order to achieve the above object, the present invention is a large-area backing plate that is bonded to a sputtering target and used. Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass% Inclusion in which the mass ratio Ni / Si is in the range of 3.5 to 5.5, the balance is made of Cu and inevitable impurities, the maximum crystal grain size is 0.06 mm or less, and the diameter exceeds 0.005 mm not including, the thermal conductivity of Ri 170 W / m · K or more 203W / m · K der less and atmospheric, characterized in that 0.2% proof stress is produced using a copper alloy is not less than 600MPa An area backing plate is provided.
In the present specification, the large area means that the main surface is 1521000 mm ² or more.

In order to achieve the above object, the present invention is a large-area backing plate that is bonded to a sputtering target and used. Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 The mass ratio Ni / Si is in the range of 3.5 to 5.5, Zn: 0.1 to 2.0 mass%, P: 0.003 to 0.2 mass%, and the balance It consists of Cu and unavoidable impurities, has a maximum crystal grain size of 0.06 mm or less, does not contain inclusions with a diameter exceeding 0.005 mm, and has a thermal conductivity of 170 W / m · K or more and 203 W / m · K or less . There is provided a large-area backing plate produced using a copper alloy having a 0.2% proof stress of 600 MPa or more .

In order to achieve the above object, the present invention provides a method for producing a copper alloy for a large area backing plate, wherein after the casting step, the steel is heated and held at a temperature of 800 ° C. or higher for 30 minutes or more and 50% or more. A hot rolling process in which hot rolling is performed at a processing rate of, and a solution treatment for cooling a copper alloy sheet obtained by performing hot rolling from a temperature of 600 ° C. to 250 ° C. at a cooling rate of 20 ° C./min or more. A copper alloy for a large area backing plate, comprising: a treatment step; and an aging treatment step of holding the solution-treated copper alloy plate at a temperature range of 300 to 600 ° C. for 0.5 to 12 hours (h). A manufacturing method is provided.

  According to the present invention, there is provided a backing plate having characteristics excellent in thermal conductivity, mechanical strength (for example, 0.2% proof stress and Young's modulus), and oxidation resistance corresponding to the demand for larger backing plate. it can.

[First Embodiment]
(Composition of copper alloy for backing plate)
The copper alloy for a backing plate in the present embodiment has Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass%, and a mass ratio Ni / Si of 3.5 to 5.5. In the range, the balance is made of Cu and inevitable impurities, the maximum crystal grain size is 0.06 mm or less, does not contain inclusions with a diameter exceeding 0.005 mm, and the thermal conductivity is 170 W / m · K or more. It is characterized by being.

  In the present embodiment, the reason for addition and limitation of the alloy components constituting the copper alloy for the backing plate will be described below.

The reason why Ni and Si are added is to improve mechanical strength by precipitating a Ni ₂ Si phase as a compound as an inclusion in the Cu matrix and making it an obstacle to dislocation movement. However, since inclusions having a diameter exceeding 0.005 mm do not contribute to the improvement of mechanical strength, the diameter of the inclusions is preferably 0.005 mm or less. More desirably, the diameter of the inclusion is set to 0.0001 mm or more and 0.003 mm or less.

When Ni is less than 1.0% by mass, the precipitation amount of the Ni ₂ Si phase as a compound is small and the effect of improving the strength is small, and when it exceeds 5.0% by mass, the effect of improving the mechanical strength is saturated, and heat conduction Reduce sex.

Similarly, when the content of Si is less than 0.2% by mass, the precipitation amount of the Ni ₂ Si phase is small and the effect of improving the strength is small, and when it exceeds 1.0% by mass, the effect of improving the mechanical strength is obtained. Saturates and reduces thermal conductivity.

  In addition, the mechanism of improving the oxidation resistance of the copper alloy by containing Ni and / or Si has not been completely elucidated at present, but it is adsorbed on the surface of the backing plate and penetrates into the surface layer portion or is oxidized at the surface layer portion. It is considered that the gas components such as water vapor and oxygen are selectively bonded to the Ni and / or Si components in Cu selectively and firmly as compared with Cu, thereby dissociating the gas components from the backing plate during sputtering. It is considered that the effect of suppressing this (improves oxidation resistance) appears.

  Therefore, it is necessary to contain Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass%, preferably Ni: 1.5 to 3.0 mass%, Si : 0.3 to 0.6% by mass.

  In addition, the Ni / Si mass ratio is set to 3.5 to 5.5 by improving the mechanical strength and reducing the amount of Ni and Si dissolved in the Cu matrix as much as possible to 170 W / m · K. This is to ensure the above thermal conductivity. In other words, the thermal conductivity of 170 W / m · K or more means that the amount of Ni and Si dissolved in the Cu matrix is small.

The deposited Ni ₂ S has a Ni / Si atomic ratio of 2 (Ni / Si mass ratio of about 4.2). When the Ni / Si mass ratio is 3.5 or less, Si becomes excessive. Excess Si remains in the Cu matrix and causes a decrease in thermal conductivity. On the other hand, when the mass ratio of Ni / Si is 5.5 or more, Ni is excessively excessive, and excessive Ni remains in the matrix phase, resulting in a decrease in thermal conductivity. Therefore, the Ni / Si mass ratio needs to be 3.5 to 5.5, and preferably the Ni / Si mass ratio is 3.7 to 5.0.

  The maximum crystal grain size in the copper alloy is preferably 0.06 mm or less. More preferably, it is 0.05 mm or less, More preferably, it is 0.04 mm or less. When the maximum crystal grain size is greater than 0.06 mm, the metal structure tends to be non-uniform, leading to non-uniform mechanical strength (the mechanical strength of the portion having a large crystal grain size is reduced). Therefore, the maximum crystal grain size is 0.06 mm or less. The average crystal grain size (crystal grain size) is preferably 0.03 mm or less, and more preferably 0.02 mm or less.

[Second Embodiment]
(Composition of copper alloy for backing plate)
The copper alloy for a backing plate in the present embodiment has Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass%, and a mass ratio Ni / Si of 3.5 to 5.5. In addition, Zn: 0.1 to 2.0 mass%, P: 0.003 to 0.2 mass%, the balance is made of Cu and inevitable impurities, the maximum crystal grain size is 0.06 mm or less It is characterized by not including inclusions having a diameter exceeding 0.005 mm and having a thermal conductivity of 170 W / m · K or more.

  In the present embodiment, the reason for addition and limitation of the alloy components constituting the copper alloy for the backing plate will be described below.

  Reasons for adding Ni and Si, reasons for making the Ni / Si mass ratio 3.5 to 5.5, reasons for making the maximum crystal grain size 0.06 mm or less, and making inclusion diameters 0.005 mm or less The reason and the reason for setting the thermal conductivity to 170 W / m · K or more are the same as in the first embodiment. In the second embodiment, a more preferable range of the Ni / Si mass ratio is 3.9 to 5.3.

  Furthermore, the addition of Zn: 0.1 to 2.0 mass% and P: 0.003 to 0.2 mass% has the effect that Zn and P improve the bonding strength and life of solder, brazing material, etc. This is because P has a deoxidizing effect and a heat resistance improving effect.

  In addition, the mechanism of improving the oxidation resistance of the copper alloy by containing Ni, Si, Zn, and / or P is not completely elucidated at present, but it is adsorbed on the surface of the backing plate or on the surface layer portion. Gas components such as water vapor and oxygen that have been invaded or oxidized at the surface layer portion are considered to be selectively and firmly combined with the above-mentioned additive components in Cu as compared with Cu, and this causes the components to be released from the backing plate during sputtering. It is considered that an effect of suppressing dissociation (improves oxidation resistance) appears.

  If the Zn content is 0.1% by mass or less, these effects are small, and if it exceeds 2.0% by mass, the thermal conductivity is lowered.

  Further, when the P content is 0.003% by mass or less, those effects are insufficient, and when the P content is 0.2% by mass or more, not only the thermal conductivity is lowered, but also cracking at the time of casting is caused.

  Therefore, it is necessary that Zn: 0.1 to 2.0% by mass, P: 0.003 to 0.2% by mass, and preferably Zn: 0.1 to 1.7% by mass, P: 0.0. 01-0.05 mass%. Desirably, the total amount of Zn and P is 2.0 mass% or less.

[Method of manufacturing copper alloy for backing plate]
FIG. 1 is a diagram showing a flow of a manufacturing process of a copper alloy for a backing plate according to an embodiment of the present invention. The copper alloy for backing plates of the first and second embodiments is melted, mixed with ingredients and cast into a copper alloy ingot containing the above ingredients (step a) and then heated at a temperature of 800 ° C. or higher for 30 minutes or more. A hot rolling step (step b) for holding and hot rolling at a processing rate of 50% or higher, and a copper alloy plate obtained by hot rolling from a temperature of 600 ° C. to 250 ° C. at 20 ° C. / A solution treatment step (step c) for cooling at a cooling rate of at least minutes, and an aging treatment step (step d) for holding the solution-treated copper alloy plate in a temperature range of 300 to 600 ° C. for 0.5 to 12 hours. It is manufactured by doing. In the casting step (step a), oxygen-free copper having an oxygen concentration of 10 ppm or less is preferably used as the copper raw material. The processing rate is defined as “processing rate (%) = {1− (thickness after rolling / thickness before rolling)} × 100”.

  In the hot rolling step (step b), the reason for performing the hot rolling by heating and holding at a temperature of 800 ° C. or higher for 30 minutes or more is that during the casting by heating and holding at a temperature of 800 ° C. or higher for 30 minutes or more. This is because the non-uniform precipitate generated by the segregation of the additive element disappears and is uniformly dissolved in the Cu base material. When the heating temperature is 800 ° C. or less or the heating time is 30 minutes or less, the effect is insufficient, and preferably 850 to 950 ° C. × 2 to 5 hours.

  Moreover, the reason why hot rolling is performed at a processing rate of 50% or more after heating is to break the cast structure and obtain a uniform recrystallized structure. When the processing rate is less than 50%, a cast structure remains partially and a uniform recrystallized structure cannot be obtained. Therefore, it is necessary to perform hot rolling at a processing rate of 50% or more after heating, and the processing rate is preferably 60 to 90%.

In the solution treatment step (step c), the copper alloy sheet obtained by hot rolling is cooled from a temperature of 600 ° C. to 250 ° C. at a cooling rate of 20 ° C./min or more. This is because a solution treatment is performed in which Cu is solid-solved (not precipitated). In the copper alloy of the present embodiment, Ni and Si are most likely to precipitate as Ni ₂ Si in the temperature range of 300 to 600 ° C. Therefore, in order to obtain a solutionizing effect (which does not cause Ni ₂ Si to precipitate), it is necessary to rapidly cool from a temperature higher than the temperature at which Ni ₂ Si is most likely to precipitate. Preferably it is 650 degreeC or more. On the other hand, when the cooling rate is less than 20 ° C./min, Ni ₂ Si precipitates non-uniformly during cooling, resulting in insufficient solution effect. The cooling rate is preferably 30 ° C./min or more. In addition, since precipitation of Ni ₂ Si hardly occurs at 250 ° C. or lower, there is no problem even at a cooling rate of 20 ° C./min or lower at 250 ° C. or lower.

In the aging treatment step (step d), the solution-treated copper alloy plate is held at a temperature range of 300 to 600 ° C. for 0.5 to 12 hours because Ni and Si dissolved in Cu by solution treatment are dissolved. it is to uniformly precipitated as Ni ₂ Si. As described above, Ni ₂ Si is most likely to precipitate in the temperature range of 300 to 600 ° C. At a low temperature of 300 ° C. or lower, the diffusion of Ni and Si is slow, the precipitation of Ni ₂ Si is small and non-uniform. On the other hand, at 600 ° C. or higher, Ni ₂ Si hardly precipitates (it is easy to be dissolved in Cu), and the amount of Ni ₂ Si deposited decreases. Further, if the holding time is less than 0.5 hours, Ni ₂ Si is not sufficiently precipitated, and if it is 12 hours or longer, the Ni ₂ Si precipitates become coarse and the so-called overaging is reduced. . Therefore, it is necessary to hold for 0.5 to 12 hours in a temperature range of 300 to 600 ° C, and preferably 1 to 6 hours in a temperature range of 400 to 550 ° C.

[Other Embodiments]
In the casting step a, there is no restriction on the melting and casting method, and there is no restriction on the dimensions of the material. Further, in the aging treatment step d, the aging treatment may be performed only once, or a plurality of aging treatments may be performed. Moreover, you may perform cold rolling after an aging treatment.

[Manufacture of backing plate]
The backing plate used for a sputtering apparatus can be obtained by the manufacturing method normally performed using the copper alloy for backing plates of the said embodiment. There is no restriction | limiting in joining with the lid | cover which covers a water channel (groove), Any of electron beam welding, brazing, and friction stir welding may be sufficient. There is no limitation on the cooling medium for the backing plate.

[Effect of the embodiment]
According to the above embodiment of the present invention, the following effects can be obtained.
(1) Thermal conductivity is 170 W / m · K or more, 0.2% proof stress is 600 MPa or more, Young's modulus (longitudinal elastic modulus) is 125 GPa or more, 0.2% proof stress, Young's modulus, and thermal conductivity A sputtering backing plate having excellent characteristics can be obtained.
(2) A backing plate for sputtering having high oxidation resistance can be obtained.
(3) A backing plate for sputtering having a long life (including repeated use such as rebonding) and high reliability (including film forming quality) can be obtained.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to these.

(Examples 1-8, Comparative Examples 1-12)
In accordance with the flow shown in FIG. 1, an alloy having the composition shown in Table 1 is melted and compounded in a medium frequency melting furnace, an ingot having a thickness of 50 mm × width of 180 mm × length of 500 mm is cast, and then the conditions shown in Table 2 are used. The sample for evaluation of Examples 1-8 and Comparative Examples 1-11 was produced by performing hot rolling, solution treatment, and aging treatment. In addition, as Comparative Examples 12 to 13, samples for evaluation made of oxygen-free copper (JIS H3300 C1020) were also prepared.

  In addition, it tempered so that the comparative example 12 might be a hardening material (H material), and the comparative example 13 might be a semi-softening material (1 / 2H material). Comparative Example 12 is intended for an ideal new oxygen-free copper backing plate, and Comparative Example 13 is intended for an oxygen-free copper backing plate during repeated use.

  From these samples, thermal conductivity measurement test pieces, tensile test pieces, Young's modulus measurement test pieces, metal structure observation test pieces, and oxidation resistance evaluation test pieces were cut out and subjected to various measurements. Table 3 shows the evaluation results of thermal conductivity measurement, tensile test, Young's modulus measurement, and metal structure observation.

  In addition, the thermal conductivity measurement used the laser flash method (the ULVAC-RIKO Co., Ltd. make, model: TC-7000). The tensile test was performed based on JIS Z2241, using a universal testing machine (manufactured by Shimadzu Corporation, model: AG-I). Young's modulus was measured using a Ewing apparatus (Shimadzu Rika Kikai Co., Ltd., model: TY-400). Metal structure observation was performed based on the cutting method in JIS H 0501 using an optical microscope (Olympus Co., Ltd., model: PMG3), and at the same time, the presence or absence of inclusions having a diameter exceeding 0.005 mm was confirmed.

  Moreover, the test piece for evaluating oxidation resistance was obtained by cutting a plurality of plate materials (vertical × horizontal = 4 cm × 4 cm) of Examples 1 to 8 and Comparative Examples 12 to 13, overlapping the same material, and sandwiching them between glass plates. A clip was prepared from the outside of the plate. The evaluation of oxidation resistance was carried out by holding the test piece prepared as an accelerated test in a constant temperature and humidity chamber (temperature = 60 ° C., relative humidity = 90%) for 40 hours, and then measuring the thickness of the oxide film formed on the superimposed surface. Measured and calculated by the cathode reduction method.

The measurement conditions for the cathode reduction method were set as follows.
Electrolysis conditions: KCl aqueous solution [0.1 mol / L], nitrogen gas saturated electrolysis area: 1 cm ²
Current density: 50 μA / cm ²
Reference electrode: Ag / AgCl
Counter electrode: Pt

The oxide film thickness was calculated according to the following non-patent document based on Faraday's law from the amount of electricity required to reduce the oxide film and the theoretical density of the oxide film. The calculation results are also shown in Table 3.
M. Seo et al .: Cathodic reduction of the duplex oxide films formed on copper in air with high relative humidity at 60 ℃, Corrosion Science, Volume 47 (2005) 2079-2090.

  As shown in Table 3, all of the test pieces (Examples 1 to 8) according to the present invention have a thermal conductivity of 170 W / m · K or more, a 0.2% proof stress of 600 MPa or more, a Young's modulus of 125 GPa or more, a crystal Inclusions having a uniform structure with a maximum particle size of 0.06 mm or less and a diameter exceeding 0.005 mm were not confirmed. Moreover, from the oxidation resistance evaluation results, the test pieces (Examples 1 to 8) according to the present invention are very small and excellent in comparison with the case where the formed oxide film thickness is oxygen-free copper (Comparative Examples 12 to 13). It can be seen that it has high oxidation resistance. Therefore, it can be said that the copper alloys of Examples 1 to 8 are suitable as a backing plate for sputtering.

  On the other hand, Comparative Examples 1 to 3 whose compositions deviate from the present invention have a thermal conductivity lower than the desired value (170 W / m · K). This is presumably because excess or excessive additive components were dissolved in Cu. Further, in Comparative Examples 4 to 11 in which the production method is out of the present invention, the thermal conductivity is lower than the desired value (170 W / m · K), or the maximum crystal grain size is larger than 0.06 mm. Or it turns out that the inclusion (coarse inclusion) whose diameter exceeds 0.005 mm exists. In addition, one or more of 0.2% proof stress and Young's modulus is lower than the desired value.

  Among these, since Comparative Examples 4 to 6 deviated from the heating condition or hot rolling condition of the present invention, segregation of Ni and Si and / or remaining cast structure was observed in the metal structure. In Comparative Examples 7 to 8, since the cooling condition was deviated, coarse inclusions having a diameter exceeding 0.005 mm were confirmed. In Comparative Examples 9 to 11, since the aging conditions deviated, a decrease in thermal conductivity was confirmed. In Comparative Example 9, crystal grain coarsening (the maximum crystal grain size was larger than 0.06 mm) was also observed. It was. Metal structure non-uniformity such as segregation, residual cast structure, and coarse inclusions is not preferable because it leads to non-uniform characteristics in a large backing plate. Therefore, it can be said that Comparative Examples 1 to 11 are not suitable as a backing plate for sputtering.

  In Comparative Examples 12 to 13, as described above, the thermal conductivity is good, but the 0.2% proof stress and Young's modulus are small. Furthermore, in the oxidation resistance evaluation test, it can be seen that the formed oxide film thickness is very large, and in particular, the oxide film thickness of Comparative Example 13 intended for repeated use is large.

It is a figure which shows the flow of the manufacturing process of the copper alloy for backing plates of embodiment of this invention.

Claims (4)

A large-area backing plate that is bonded and used with a sputtering target, Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass%, and a mass ratio Ni / Si of 3.5 to It is included in the range of 5.5, the balance is made of Cu and inevitable impurities, the maximum crystal grain size is 0.06 mm or less, does not contain inclusions with a diameter exceeding 0.005 mm, and the thermal conductivity is 170 W / m. · K or more 203W / m · K Ri der less, large-area backing plate, wherein a 0.2% proof stress is produced using a copper alloy is not less than 600 MPa. A large-area backing plate that is bonded and used with a sputtering target, Ni: 1.0 to 5.0 mass%, Si: 0.2 to 1.0 mass%, and a mass ratio Ni / Si of 3.5 to In addition to being included in the range of 5.5, Zn: 0.1 to 2.0% by mass, P: 0.003 to 0.2% by mass, the balance is made of Cu and inevitable impurities, the maximum crystal grain size is It is 0.06 mm or less, does not include inclusions with a diameter exceeding 0.005 mm, has a thermal conductivity of 170 W / m · K or more and 203 W / m · K or less , and has a 0.2% proof stress of 600 MPa or more. A large-area backing plate manufactured using a copper alloy. Large area backing plate according to claim 1 or claim 2 Young's modulus (longitudinal elastic modulus) is equal to or not less than 125 GPa. A method for producing a copper alloy for a large area backing plate according to any one of claims 1 to 3,
After the casting process, a hot rolling process of heating and holding at a temperature of 800 ° C. or higher for 30 minutes or more and performing hot rolling at a processing rate of 50% or more,
A solution treatment step of cooling a copper alloy plate obtained by hot rolling from a temperature of 600 ° C. or higher to 250 ° C. at a cooling rate of 20 ° C./min or more;
An aging treatment step of holding a solution-treated copper alloy plate at a temperature range of 300 to 600 ° C. for 0.5 to 12 hours, and a method for producing a copper alloy for a large area backing plate.

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