JP4475239B2 - Manufacturing method of heat sink plate - Google Patents

Description

  The present invention relates to a method of manufacturing a heat sink plate (packing plate), and is suitable for obtaining a smooth and highly accurate heat sink plate by reducing thermal distortion due to bonding in bonding of a cooling hole and a lid provided in the heat sink plate. Related to the production method.

  A semiconductor heat sink plate (packing plate) is required to hold the wafer and the glass substrate and to have an efficient cooling function in an etching or sputtering process of the silicon wafer or the glass substrate. For this reason, it is a structure which has a cooling hole inside the smooth board which consists of copper, a copper alloy, or an aluminum alloy, and seals this metallically with the lid | cover which consists of the same material. Conventionally, the cooling hole and the lid of the heat sink plate are sealed by metal bonding by electron beam welding, diffusion bonding, brazing, or the like.

  The heat sink plate needs to increase the cooling efficiency, and the surface of the heat sink plate in contact with the silicon wafer or the like needs to have high smoothing accuracy. However, conventionally, electron beam welding, laser welding, diffusion bonding, brazing, or the like has been employed for joining the cooling hole provided in the heat sink plate and its lid. However, even in electron beam welding with a relatively small input heat amount, a large thermal strain occurs after joining. For this reason, it is necessary to make it smooth by correction work after joining or by machine cutting. Therefore, there are problems in terms of quality, accuracy, and cost after joining.

  In order to solve the above problem, the cooling hole provided in the heat sink plate and the lid are joined by a friction stir welding method. The bonding method can be performed at a low temperature below the melting point of copper or aluminum. Further, the joining is performed in a coolant such as water, oil, or a cooling gas, or while applying the coolant to the vicinity of the joint and the entire heat sink plate.

  In the friction stir welding method, a metal rod (tool) substantially harder than the aluminum or copper material is inserted into the joint and moved while rotating the tool or the heat sink plate itself is moved. This is a method of joining using the frictional heat and plastic flow generated between the tool and the heat sink plate. This is known in Japanese Patent Publication No. 7-505090 (EPO615480B1). That is, it uses a plastic flow phenomenon caused by frictional heat between the tool and the bonding material, and does not melt and weld the bonding material as in arc welding. Furthermore, unlike the conventional friction welding method, the friction stir welding method is different from the welding method in which the workpieces are rotated and the frictional heat is used, and the workpieces are continuously joined in the longitudinal direction of the joining line, that is, in the longitudinal direction. Is characterized in that it can be joined at a temperature below the melting point of the joining material.

  By joining by the friction stir welding method, joining can be performed at a low temperature below the melting point of copper or aluminum. For this reason, the distortion by joining is small compared with the conventional electron beam welding etc., and a heat sink board with high precision can be manufactured. Therefore, the correction work time after joining can be shortened.

  Further, the bonding method can be performed in a coolant such as water, oil, or a cooling gas, or while applying the coolant to the vicinity of the joint and the entire heat sink plate. Thereby, the temperature rise in the position several millimeters away from the junction part is 100 degrees C or less. For this reason, the distortion after joining can be reduced to the limit. Therefore, a heat sink plate having a smooth surface in contact with the silicon wafer and high accuracy and reliability can be manufactured at low cost.

  According to the present invention, since the heat sink plate joined by friction stir welding has a small thermal strain, a high-quality semiconductor heat sink plate can be manufactured at low cost. In particular, in the present invention, since the joining is performed while cooling with water, the thermal strain can be minimized. Therefore, the correction work after joining is not necessary and can be manufactured at low cost.

Example 1
FIG. 1 shows the structure and bonding method of a heat sink plate observed from above when the present invention is applied to bonding of a heat sink plate (packing plate) for a semiconductor. FIG. 2 shows a cross section in the direction AB of FIG. The material of the heat sink plate 1 in FIGS. 1 and 2 is JIS standard C1020 oxygen-free copper. The heat sink plate 1 is provided with a plurality of independent water cooling holes 2 and cooling water supply / drain ports 3. The water-cooled holes 2 are joined by a friction stir welding method of the present invention with a lid made of a copper plate made of the same material.

  In this embodiment, the copper plate has a thickness of 15 mm, a width of 1000 mm, a length of 1200 mm, a cooling hole width of 40 mm, and a height of 10 mm. Four said cooling holes are provided in the said copper plate.

  The lid 4 that seals the water cooling hole 2 is metallicly bonded by friction stir welding as described below. The rotary tool 5 used for the friction stir welding is made of metal such as tool steel which is harder than the heat sink plate 1. The rotary tool 5 includes a pin portion 6 at the tip and a shoulder portion 7 that is thicker than the pin portion 6. The entire length of the pin portion 6 is inserted into the joint portion in a rotated state. Here, the shoulder portion 7 is also inserted slightly. Next, the rotating tool 5 moves in the joining line direction in a rotated state. At this time, the lid 4 of the water cooling hole 2 is joined by frictional heat generated between the rotating tool 5 and the heat sink plate 1 and a plastic flow phenomenon. The joining portion 8 obtained by the joining method is smooth and free from joining defects.

  In this embodiment, the diameter of the pin portion 6 of the rotary tool 5 is 6 mm, the length is 5 mm, the diameter of the shoulder portion 7 is 15 mm, the joining speed is 400 mm / min, and the rotational speed is 800 rpm. The rotating tool is preferably inclined at an angle of 1 to 5 degrees in the direction opposite to the joining progress direction.

  In the joining method, defects are likely to occur at the start and end of the joining. For this reason, in the present invention, the dummy plate 9 is provided at the starting point and the terminal end of the bonding, the bonding is started from the dummy plate 9, and the bonding is terminated at the dummy plate 9. The dummy plate is mechanically removed after joining.

The heat sink plate joined by the joining method has a strain reduced by about half compared to the case of joining by conventional electron beam welding, and the machining time of the strain correction work after joining can be halved. Improvement can be realized. The heat sink plate is applied as a packing plate for holding and cooling a silicon substrate of a semiconductor sputtering apparatus.
(Example 2)
FIG. 3 shows the structure and joining method of the heat sink plate observed from above when the present invention is applied to joining of heat sink plates for semiconductors. 4 shows a cross section in the direction AB of FIG. The material of the heat sink plate is JIS standard 1201. However, the material, shape and joining conditions of the rotary tool are the same.

  In this embodiment, the lid 4 for keeping the water-cooled hole 2 secret is joined simultaneously using two rotating tools. First, the joining part of A and B is joined with two rotating tools. Next, C and D are bonded simultaneously, and then E and F are bonded simultaneously. Next, H and G are bonded simultaneously. The intervals between A-B, C-D, and EF are as narrow as 40 mm. For this reason, when the two tools with respect to the joining direction are arranged at the same time and in parallel, the tools collide with each other or the temperature of the joint rises. Accordingly, the two tools are arranged with a certain distance (L) with respect to the joining progress direction.

  On the other hand, the junction A or B and the junction H or G are junctions in which part of the junction intersects each other. Thereby, since the said joining is joining only to a linear direction, the structure of the said joining apparatus becomes simple and it becomes cheap. Furthermore, in the joining method, defects are likely to occur at the starting point and the terminal end of the joining. For this reason, in the present invention, the dummy plate 9 is provided at the starting point and the terminal end of the bonding, the bonding is started from the dummy plate 9, and the bonding is terminated at the dummy plate 9. The dummy plate is mechanically removed after joining.

  By the way, in this embodiment, since two tools are used for simultaneous bonding, there is much frictional heat. For this reason, it joins, flowing cooling water to the vicinity of a junction part, the whole heat sink board, and a water cooling hole. As in this embodiment, the temperature of the heat sink plate, which is 3 mm away from the tool, is 100 ° C. or lower because the bonding is performed while cooling. For this reason, the distortion after joining becomes about half or less compared with the case where water cooling is not carried out. Therefore, machining for correcting the strain after joining becomes unnecessary. Even if water is applied to the vicinity of the joint portion, the inside of the joint portion is higher than the atmospheric pressure due to the rotation and frictional heat of the tool, so that water does not enter the joint portion. Therefore, no defects occur in the joint 8 and the mechanical characteristics do not deteriorate.

The distortion of the heat sink plate joined by the joining method is reduced to about 1/10 or less compared to the case of joining by conventional electron beam welding. Therefore, the machining time for strain correction work after joining is not required, and cost reduction and quality improvement can be realized. The heat sink plate is applied as a packing plate for holding and cooling a glass substrate of a semiconductor sputtering apparatus.
(Example 3)
In this embodiment, the JIS standard 5052 for aluminum alloy was used. The shape and joining conditions of the heat sink plate were the same as in Example 1, and the same effects as in Example 1 were confirmed in this example.
Example 4
FIG. 5 shows an enlarged cross-sectional view of the cooling hole, tool, and joint of Example 1. The heat sink plate 1 and the lid 4 are characterized by being locally thicker than other portions. The width (W) of the locally thick portion is preferably about the same as the outer diameter of the shoulder portion 7 of the rotary tool 5.

On the other hand, the local thickness is preferably 0.3 to 3 mm higher than other parts. Furthermore, it is desirable that the joint portion of the heat sink plate 1 is stepped at the tip of the rotary tool 5. The width (D) of the stepped portion is preferably equal to or greater than the diameter of the pin portion of the tool. The height (H) is preferably equal to or approximately 1 mm larger than the length of the pin portion 6 of the rotary tool 5. The lid 4 is stably fixed by the joint structure, and buckling does not occur at the tip of the joint. Further, the surface of the joint does not dent.
(Example 5)
FIG. 6 shows the structure and bonding method of the heat sink plate observed from above when the present invention is applied to the bonding of the heat sink plate for semiconductor. FIG. 7 shows a cross section in the direction AB of FIG. The material of the heat sink plate 1 in FIGS. 6 and 7 is oxygen-free copper of JIS standard C1020. The heat sink plate 1 is provided with a continuous water cooling hole 2 and a cooling water supply / drain port 3. The water cooling holes are joined by the friction stir welding method of the present invention with the lid 4 made of a copper plate made of the same material.

  In this embodiment, the heat sink plate has a thickness of 15 mm, a width of 800 mm, a length of 1000 mm, a water cooling hole 2 having a width of 50 mm and a height of 10 mm.

  The lid 4 that keeps the water-cooled hole 2 secret is metallicly joined by friction stir welding as described below. The shape and size of the rotary tool used for the friction stir welding and the welding conditions are the same as those in the first embodiment. Since the water cooling holes provided in the heat sink plate are continuous from the water supply port to the drain port, the joining is also performed continuously. Here, since the joining is continuous, in the joining process, the temperature of the tool becomes as high as 400 ° C. or more due to frictional heat. Furthermore, the distortion of the heat sink plate also increases due to frictional heat. Therefore, in this embodiment, a method was adopted in which a part of the tool, the joint portion, and the entire heat sink plate were immersed in water and joined while cooling. The cooling water is circulated and cooled so as to be always 20 ° C. or lower. As in this embodiment, the temperature of the heat sink plate, which is 2 mm away from the tool, is 100 ° C. or lower because the bonding is performed while cooling. For this reason, the distortion after joining becomes about half or less compared with the case where water cooling is not carried out. Therefore, machining for correcting the strain after joining becomes unnecessary.

  In the bonding method, defects are likely to occur at the start and end of the bonding. For this reason, in the present invention, the dummy plate 9 is provided at the starting point and the terminal end of the bonding, the bonding is started from the dummy plate 9, and the bonding is terminated at the dummy plate 9. The dummy plate is mechanically removed after joining.

The heat sink plate joined by the joining method has a strain reduced by about half compared to the case of joining by conventional electron beam welding, and the machining time of the strain correction work after joining can be halved. Improvement can be realized. The heat sink plate is applied as a packing plate for holding and cooling a silicon substrate of a semiconductor sputtering apparatus.
(Example 6)
In this embodiment, the heat sink plate is a disc having an outer diameter of 500 mm. The structure of the cooling holes is the same shape as in Example 5 and is continuous. The material and thickness of the heat sink plate are the same as in the fifth embodiment. Furthermore, the joining conditions are the same as in Example 5. In this example, the same effect as in Example 5 was confirmed.

It is an observation view from the top showing an example of the present invention. It is sectional drawing of FIG. 1 which shows the Example of this invention. It is an observation view from the top showing an example of the present invention. It is sectional drawing which shows the Example of this invention. It is sectional drawing which shows the Example of this invention. It is an observation view from the top showing an example of the present invention. It is sectional drawing which shows the Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat sink plate (packing plate), 2 ... Water cooling hole, 3 ... Water supply / drain port, 4 ... Cover, 5 ... Rotating tool, 6 ... Pin part, 7 ... Shoulder part, 8 ... Joint part, 9 ... Dummy board.

Claims (4)

In the method of manufacturing a heat sink plate made of copper, copper alloy, aluminum or aluminum alloy, having a cooling hole inside, and the cooling hole is sealed with a lid, the sealing between the cooling hole of the heat sink plate and the lid is a friction It is manufactured by metal joining by a stir welding method, and by joining a plurality of tools at a certain distance at the same time or in a joining progress direction by a plurality of rotating tools. Manufacturing method of heat sink plate.   2. The method of manufacturing a heat sink plate according to claim 1, wherein the plurality of rotary tools are joined in a direction crossing each other.   3. The heat sink plate according to claim 1 or 2, wherein the heat sink plate is joined in the cooling plate of water, oil, or inert gas, or while applying the coolant in the vicinity of or in the whole of the joint portion. How to make. 3. The method of manufacturing a heat sink plate according to claim 1, wherein the joining start point or end point is a heat sink plate or a dummy part separated from the cooling hole.

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