JP2007149831A - Jointing method and jointing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a high sealing characteristics at a jointing part using a simple equipment when jointing a device to a metal plate. <P>SOLUTION: A device B is plated with a gold frame 71 of thickness 1-5 μm. A metal plate A is plated with a gold frame 60 whose dimension is identical with the gold frame 71 of the device B, having thickness of 5-10 μm. The device B and the metal plate A are heated to 250-300°C. The gold frame 71 of the device B and the gold frame 60 of the metal plate A are pressed for bonding against each other under the pressure of 5.0-7.0 kg/mm<SP>2</SP>for 15-70 minutes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for joining a device and a member to be joined, and a joining unit including the device and the member to be joined.

  In recent years, extremely minute devices such as MEMS (Micro Electro Mechanical System) having functions such as a flow sensor and a pressure sensor have been developed. When such a device is mounted on a pipe or the like through which a fluid flows, for example, the device is bonded to a metal plate to be attached to the pipe, for example, and the metal plate is attached to the pipe.

  The above-mentioned device and metal plate must be joined with high sealing performance at the joint so that the fluid in the pipe does not leak. Generally, the device is screwed or welded via an O-ring. Alternatively, brazing can be considered. However, when joining micro devices on the order of millimeters, there is no O-ring that matches the size of the device when screwing, and high precision joining is not possible when welding or brazing. Therefore, when using screwing or welding, it is limited to large devices. In this case, the space for the device mounting area is increased and the cost becomes high. Thus, for example, it has been proposed to deposit metal in a contoured manner on a device or an object to be bonded by plating, activate the bonding surface with an electron beam or the like in a vacuum chamber, and bond at a low temperature of 180 ° C. or less (Patent Document 1). reference).

JP 2005-191556 A

  However, even in the above-described bonding method, it is necessary to depressurize the inside of the decompression chamber or to activate the bonding surface with an electron beam or the like, and the size and cost of the apparatus cannot be avoided. Also, the sealing performance at the device junction is not sufficient.

  The present invention has been made in view of the above points, and when joining a minute device such as MEMS and a member to be joined such as a metal plate, a simpler apparatus is used and a high sealing property of the joining portion is achieved. The purpose is to realize.

In order to achieve the above object, the present invention is a method for joining a device and a member to be joined, the step of plating the device with gold in a frame shape, and the method of plating the member to be joined with gold in a frame shape And heating the device plated with gold and the member to be joined, and pressurizing and joining the parts of the metal frame of the device and the member to be joined together. (1) the thickness of the metal frame of the member to be bonded, (2) the thickness of the metal frame of the device, so that the He leak rate at the junction with the metal is 1 × 10 ⁻¹¹ Pa · m ³ / sec or less, (3 The heating temperature of the device and the member to be joined, (4) the pressure of the device and the member to be joined, and (5) the pressure time of the device and the member to be joined are adjusted.

According to the inventor, it has been confirmed that there is a correlation between the above conditions (1) to (5) and the leak rate of the joint. According to the present invention, by adjusting the conditions (1) to (5), the leak rate of the joint portion between the device and the member to be joined can be reduced to 1 × 10 ⁻¹¹ Pa · m ³ / sec or less. it can. Therefore, bonding can be performed by gold plating, heating and pressurization of the device and the member to be bonded, and a high sealing performance can be ensured by using a simpler apparatus than in the past.

The thickness of the metal frame of the joined member (1) may be adjusted to 5 to 10 μm, and the thickness of the metal frame of the device (2) may be adjusted to 1 to 5 μm. The heating temperature of the device of (3) and the member to be joined may be adjusted to 250 to 350 ° C., and the pressure of the device of (4) and the member to be joined is set to 5.0 to 7. You may adjust to 0 kg / mm < ² >. Furthermore, you may adjust the pressurization time of the device of said (5), and a to-be-joined member to 15 to 70 minutes.

Another aspect of the present invention is a method of joining a device and a member to be joined, the step of plating gold on the device in a frame shape having a thickness of 1 to 5 μm, and the member to be joined having a thickness of 5 to 5. The step of plating gold in a frame shape of 10 μm μm, the gold-plated device and the member to be bonded are heated at 250 to 350 ° C., and the metal frame portions of the device and the member to be bonded are 5.0 to each other. And pressurizing for 15 to 70 minutes at a pressure of ˜7.0 kg / mm ² .

  The device may have a non-metallic surface, and the device may be plated with gold via an intermediate material on the non-metallic surface, and the intermediate material may be chromium or titanium.

  The material of the surface of the device may be any of silicon, sapphire, quartz or ceramics.

  The member to be joined may be made of metal. Further, the member to be joined may be stainless steel.

  The device may be a MEMS. The device may be any one of a flow sensor, a pressure sensor, a temperature sensor, and a strain sensor.

  According to another aspect of the present invention, there is provided a joining unit including a device joined by the joining method according to any one of claims 1 to 13 and a member to be joined.

  According to the present invention, it is possible to join a device and a member to be joined with a simple apparatus, and further, it is possible to ensure high sealing performance.

  Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 is an explanatory view of a longitudinal section showing an outline of the configuration of a joining apparatus 1 used in the joining method according to the present embodiment.

  The joining apparatus 1 has a processing container 10 that can be closed in an airtight manner, for example. In the center of the processing container 10, for example, a lower chuck 11 is provided as a first holding member for placing and holding a metal plate A as a member to be joined. Further, an upper chuck 12 as a second holding member for holding the device B, for example, is provided at a position facing the lower chuck 11 above the lower chuck 11.

  The lower chuck 11 has, for example, a thick and substantially disk shape. A projecting portion 11a that protrudes upward is formed at the center of the upper surface of the lower chuck 11, and the metal plate A is held on the upper surface of the projecting portion 11a. The protrusion 11a is formed to have a diameter that is approximately the same as that of the metal plate A, for example. For example, a suction port (not shown) is formed in the holding surface 11b on the upper surface of the protruding portion 11a, and the metal plate A can be adsorbed to the holding surface 11b by suction from the suction port.

  For example, a heater 21 is built in the lower chuck 11 to generate heat when power is supplied from the power source 20. The metal plate A on the lower chuck 11 can be heated by the heat of the heater 21. The lower chuck 11 is supported by a support base 22.

  The upper chuck 12 has, for example, a thick and substantially disk shape. At the center of the lower surface of the upper chuck 12, a downwardly protruding protrusion 12a is formed so as to face the protrusion 11a of the lower chuck 11, and the device B is held on the lower surface of the protrusion 12a. The projecting portion 12a is formed to have the same diameter as the device B, for example. For example, a suction port (not shown) is formed in the holding surface 12b on the upper surface of the protrusion 12a, and the device B can be adsorbed to the holding surface 12b by suction from the suction port. The upper chuck 12 can hold the device B so as to face the metal plate A of the lower chuck 11 with the bonding surface of the device B facing downward.

  Inside the upper chuck 12, a heater 31 is built in that generates heat when power is supplied from a power supply 30. For example, the device B held by the upper chuck 12 can be heated by the heat of the heater 31.

  The upper surface of the upper chuck 12 is supported by, for example, a cylinder 40 that is driven up and down. Accordingly, the upper chuck 12 can be moved up and down, and the device B held by the upper chuck 12 can be pressed against the metal plate A on the lower chuck 11 to be pressurized.

  For example, the control of the operation of the cylinder 40 is performed by, for example, the control unit 50. The upper chuck 12 is moved up and down by the control unit 50, and the device B and the metal plate A can be joined at a predetermined pressure with a predetermined pressure. The control unit 50 also controls the power sources 20 and 30 of the heaters 21 and 31. The controller 50 can supply a predetermined amount of heat to the lower chuck 11 and the upper chuck 12 and heat the metal plate A and the device B to a predetermined temperature. The control unit 50 is, for example, a general-purpose computer, and can execute a heat diffusion bonding process between the metal plate A and the device B by executing a program that realizes the bonding method according to the present embodiment, for example.

  Next, the joining method according to the present embodiment will be described. In the present embodiment, a rectangular metal plate A having an opening C formed at the center as shown in FIG. 2, and a rectangular device B having an electronic circuit region D formed at the center as shown in FIG. An example of joining these will be described. In this embodiment, the metal plate A is made of stainless steel. The device B is a MEMS having a function of a flow sensor, for example, one side having a dimension of 10 mm or less. Sapphire is used as the base material of the device B.

  First, the metal plate A is plated with a protruding metal frame 60 so as to surround the opening C as shown in FIG. As shown in FIG. 5, the metal frame 60 is formed to have a thickness of 5 to 10 μm, preferably 10 μm (condition (1)). In addition, as shown in FIG. 6, the device B is plated with a protruding metal frame 71 with a chromium layer 70 interposed, for example, so as to surround the electronic circuit region D. As shown in FIG. 7, the metal frame 71 has a thickness of 1 to 5 μm, preferably 5 μm (condition (2)). Further, the chromium layer 70 is formed to have a thickness of about 0.02 to 0.04 μm, for example. The arithmetic surface roughness Ra of the metal frames 60 and 71 is set in the range of 0.01 to 0.2 μm. These plating processes are performed by a plating apparatus such as an electroforming apparatus. A material having better adhesion to non-metals may be used.

  The plated metal plate A and device B are carried into the bonding apparatus 1 and subjected to a bonding process. FIG. 8 is a graph showing the temperature and pressurization pressure of the metal plate A and device B in this joining process.

The metal plate A and the device B carried into the bonding apparatus 1 are sucked and held by the lower chuck 11 and the upper chuck 12 so as to face each other as shown in FIG. Next, the upper chuck 12 is lowered, and the metal frame 71 of the device B is brought into contact with and aligned with the metal frame 60 of the metal plate A as shown in FIG. At this time, the pressurizing pressure between the metal plate A and the device B is maintained at 0.2 kg / mm ² or less to such an extent that the contact between the metal frame 60 of the metal plate A and the metal frame 71 of the device B is maintained. . For example, at the same time when the metal frame 60 of the metal plate A and the metal frame 71 of the device B are brought into contact with each other, the metal plate A and the device B are brought into, for example, room temperature (for example, the normal temperature (for example, 23 ° C.) to 250 to 350 ° C., preferably 300 ° C. (condition (3)). The speed of temperature rise at this time is set to about 80 to 90 ° C./min. Further, the in-plane uniformity of the temperature of the metal plate A and the device B is set within ± 0.5 ° C.

When the metal plate A and the device B are heated to 300 ° C., for example, the metal plate A and the device B are maintained at this temperature. Further, the upper chuck 12 is slightly lowered, and the metal frame 71 of the device B is pressed against the metal frame 60 of the metal plate A, for example, 5.0 to 7.0 kg / mm ² , preferably 6.48 kg / mm ² ( The pressure is applied under the condition (4)). In this pressurized state, it is maintained for, for example, 15 to 70 minutes, preferably 60 minutes (condition (5)). Thus, the metal plate A and the device B are heat diffusion bonded.

For example, after 60 minutes have elapsed, the upper chuck 12 is slightly raised, and the applied pressure between the metal plate A and the device B is returned to a low pressure of 0.2 kg / mm ² or less. For example, the heating pressure of the heater 21 of the lower chuck 11 and the heater 31 of the upper chuck 12 is stopped at the same time as the pressurization pressure of the metal plate A and the device B is returned to a low pressure. It is naturally cooled at a speed slower than the temperature fluctuation speed.

  When the temperatures of the metal plate A and the device B are returned to room temperature, the adsorption of the device B of the upper chuck 12 is released and the upper chuck 12 is raised. In this way, the joining process of the metal plate A and the device B is completed, and the joining unit U composed of the metal plate A and the device B is formed.

Here, the sealing performance when the metal plate A and the device B are joined under the above conditions (1) to (5) will be verified. FIG. 10 shows an outline of the configuration of an experimental apparatus 100 that verifies this sealing performance by a built-up method. The experimental apparatus 100 includes a container 101 whose upper surface is open, and a pipe line 103 communicating with a vacuum pump 102 is connected to a side wall of the container 101. A valve 104 and a pressure gauge 105 are connected to the conduit 103. In the experiment, the joining unit U is fixed to the opening on the upper surface of the container 101 by the bolt 106, and the opening of the container 101 is closed by the joining unit U. Next, the inside of the container 101 is evacuated by the vacuum pump 102. Thereafter, the valve 104 is closed and the pressure rise in the container 101 is measured by the pressure gauge 105. FIG. 11 shows three joint units U joined under the above conditions (1) 10 μm, (2) 5 μm, (3) 300 ° C., (4) 6.48 kg / mm ² , (5) 60 minutes. It is a graph which shows a pressure measurement result. The vertical axis is the pressure in the container 101, and the horizontal axis is the elapsed time. From this graph, the leak rate of the joint of each joint unit U is calculated to be 3.17 × 10 ⁻⁹ , 3.49 × 10 ⁻⁹ , and 2.32 × 10 ⁻⁹ Pa · m ³ / sec. From this result, it is understood that when the joining is performed under the above conditions (1) to (5), the leak rate between the metal plate A and the device B is 3.5 × 10 ⁻⁹ Pa · m ³ / sec or less. .

Further, in the experimental apparatus 100, as shown in FIG. 12, a He leak detector 110 is provided instead of the vacuum pump 102, and a He gas nozzle 111 is provided outside the upper surface of the container 101 to detect He gas passing through the joining unit U. When the He leak rate was measured, a He leak rate of 1 × 10 ⁻¹¹ Pa · m ³ / sec or less was obtained for each of the three junction units U.

  According to the inventor's knowledge, the sealing performance improves as the thickness of the metal frame 60 of the metal plate A and the metal frame 71 of the device B increases. On the other hand, if it is too thick, the surface of the metal frame becomes rough, and the (joining strength) may decrease. From such a viewpoint, it can be estimated that the same effect as the above-described experimental condition can be obtained when the thickness of the metal frame 60 of the metal plate A in the condition (1) is in the range of 5 to 10 μm. Moreover, it can be estimated that the effect equivalent to the above-mentioned experiment condition is acquired in the thickness of the metal frame 71 of the device B of the condition (2) in the range of 1 to 5 μm.

Further, according to the inventor's knowledge, the heating temperature of the condition (3) is in the range of 250 to 350 ° C., and the pressurizing pressure of the condition (4) is in the range of 5.0 to 7.0 kg / mm ^2. Even if the pressurization time of (5) is in the range of 15 to 70 minutes, the same sealing performance can be obtained.

According to the above embodiment, the conditions (1) to (5) are adjusted, the metal frame A is plated with the metal frame 60 of 5 to 10 μm, and the device B is provided with the metal frame 71 of 1 to 5 μm. After that, the metal plate A and the device B are heated to 250 to 350 ° C., and the metal frame 60 of the metal plate A and the metal frame 71 of the device B are 15 with a pressure of 5.0 to 7.0 kg / mm ^2. Since the bonding is performed by pressurizing for ~ 70 minutes, a sealing property with a He leak rate of 1 × 10 ⁻¹¹ Pa · m ³ / sec or less can be obtained. In this case, since the gold plating process and the heating and pressurization at the time of joining are sufficient, it is possible to perform joining with high sealing performance by using a simpler apparatus than in the past. In addition, in the conventional thermal diffusion bonding that does not use an electron beam or the like, it is necessary to raise the heating temperature to 400 ° C. or higher, which may cause damage to the device. Since device B can be joined, damage to device B due to heat can be prevented.

  Since the metal frame 71 is plated on the surface of the base material of the device B with the chromium layer 70 interposed, the non-metal surface of the device B and the metal frame 71 can be appropriately bonded with high bonding strength. In addition, instead of chromium as an intermediate material, a material having good adhesion to nonmetals such as titanium may be interposed between the nonmetallic surface of the device B and the metal frame 71.

  In the above embodiment, the metal frame 60 having the same width as the metal frame 71 of the device B is formed on the metal plate A. However, the metal plate A is wider than the metal frame 71 as shown in FIG. A metal frame 60 having a width may be formed. At this time, the metal frame 60 may be formed on the entire surface of the metal plate A other than the opening C.

  The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the spirit described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs. For example, in the above embodiment, the heated metal plate A and device B are naturally cooled, but a cooling gas is supplied from the nozzle or a cooling body is built in the chucks 11 and 12 to forcibly. It may be cooled. In the above embodiment, the base material on the surface of the device B is sapphire, but the same sealing property can be obtained even if other materials such as non-metallic silicon, quartz, and ceramics are used. Further, although the metal plate A is stainless steel, the same sealing performance can be obtained even if other metal such as Ni steel or Cr steel is used. Furthermore, the member to be bonded to the device B may be made of a nonmetal such as silicon. The device B is a flow sensor, but may be another sensor such as a pressure sensor, a temperature sensor, or a strain sensor. Device B is a MEMS, but it may be another device.

  INDUSTRIAL APPLICABILITY The present invention is useful when a device and a member to be bonded are bonded using a simple device and a high sealing performance is realized.

It is explanatory drawing of the longitudinal cross-section which shows the outline of a structure of the joining apparatus in this Embodiment. It is a perspective view of a metal plate. It is a perspective view of a device. It is a perspective view of the metal plate which formed the metal frame. It is a longitudinal cross-sectional view of the metal plate in which the metal frame was formed. It is a perspective view of the device which formed the metal frame. It is a longitudinal cross-sectional view of the device which formed the metal frame. It is a graph which shows the temperature of a device at the time of a joining process, and a metal plate, and a pressurization pressure. (A) is explanatory drawing of the longitudinal cross-section which shows the state which has arrange | positioned the device and the metal plate facing each other. (B) is explanatory drawing of the longitudinal cross-section which shows the state which joined the device and the metal plate. It is explanatory drawing which shows the outline of a structure of an experimental apparatus. It is a graph which shows the experimental result which evaluates the sealing performance of a joining unit. It is explanatory drawing of the experimental apparatus which measures He leak rate. It is a longitudinal cross-sectional view of the metal plate which formed the metal frame with a width | variety.

Explanation of symbols

1 Joining device 60 Gold frame 71 Gold frame A Metal plate B Device U Bonding unit

Claims (14)

A method of joining a device and a member to be joined,
A step of plating the device with gold in a frame shape;
A process of plating gold in a frame shape on the members to be joined;
Heating the gold-plated device and the member to be joined, and pressurizing and bonding parts of the metal frame of the device and the member to be joined together,
The He leak rate at the joint between the device and the member to be joined is 1 × 10 ⁻¹¹ Pa · m ³ / sec or less,
(1) The thickness of the metal frame of the member to be joined,
(2) Device metal frame thickness,
(3) The heating temperature of the device and the member to be joined,
(4) Pressurization pressure between the device and the member to be joined,
(5) Pressurization time between device and member to be joined,
The joining method characterized by adjusting the conditions of The joining method according to claim 1, wherein (1) is adjusted to 5 to 10 μm. The joining method according to claim 1, wherein (2) is adjusted to 1 to 5 μm. The joining method according to claim 1, wherein (3) is adjusted to 250 to 350 ° C. The joining method according to claim 1, wherein (4) is adjusted to 5.0 to 7.0 kg / mm ² . The joining method according to claim 1, wherein (5) is adjusted to 15 to 70 minutes. A method of joining a device and a member to be joined,
A step of plating the device into a frame having a thickness of 1 to 5 μm;
A step of plating gold on a member to be joined in a frame shape having a thickness of 5 to 10 μm;
The gold-plated device and the member to be bonded are heated at 250 to 350 ° C., and the metal frame portions of the device and the member to be bonded are bonded to each other at a pressure of 5.0 to 7.0 kg / mm ² to 15 to And a step of joining by pressing for 70 minutes. The device has a non-metallic surface;
The device is plated with gold with an intermediate material on the non-metallic surface,
The joining method according to claim 1, wherein the intermediate material is chromium or titanium. The bonding method according to claim 8, wherein the surface material of the device is any one of silicon, sapphire, quartz, and ceramics. The joining method according to claim 1, wherein the member to be joined is made of metal. The joining method according to claim 10, wherein the member to be joined is stainless steel. The bonding method according to claim 1, wherein the device is a MEMS. The bonding method according to claim 1, wherein the device is any one of a flow sensor, a pressure sensor, a temperature sensor, and a strain sensor. A joining unit comprising a device joined by the joining method according to claim 1 and a member to be joined.

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