JP2008270262A - Positioning tool and mounting method of element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning tool and a mounting method of an element for mounting the element at a predetermined position on a curved insulating substrate without causing a position gap. <P>SOLUTION: The positioning tool 1 is provided with a protrusion 6 protruding from the lower surface of a planar body 2 toward the insulating substrate 32 side at a part close to the outer circumferential edge thereof by making a level difference 5 in the lower surface of the planar body 2 within a range including a part of each positioning hole 4. Since the protrusion 6 provided on the lower surface of the planar body 2 touches or approaches the upper surface of the insulating substrate 32 close to the outer circumferential edge thereof when the positioning tool 1 is arranged on the insulating substrate 32 curved upward, a solder foil 31a and a heating element 31 in each positioning hole 4 are positioned such that movement in each positioning hole 4 is regulated by the protrusion 6 and mounted at a predetermined position. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a positioning jig and mounting method for an element mounted on an insulating substrate brazed on a cooler in a power module.

  As shown in FIG. 1, in a power module 30 in which a heating element (power MOSFET, IGBT, etc.) 31 such as a power semiconductor switching element is mounted on an insulating substrate 32, a structure for radiating heat from the heating element 31 is important. It becomes. For this reason, the power module 30 generally has a structure in which a cooler (heat sink) 34 is brazed 33 to the back surface of the insulating substrate 32 to dissipate heat from the heating element 31.

Therefore, when manufacturing the power module 30 described above, first, a plurality of insulating substrates 32 are welded to the cooler 34 by brazing 33 as shown in FIG. Thereafter, as shown in FIG. 2, each heating element 31 is mounted on an insulating substrate 32 using a conventional positioning jig 50.
By the way, the cooler 34 is made of aluminum, and the insulating substrate 32 is made of ceramic and has different linear expansion coefficients. When the cooler 34 and the insulating substrate 32 are brazed 33 at a high temperature, FIG. 4 shows. Thus, the phenomenon in which the insulating substrate 32 warps in a convex curve shape due to the difference in the respective linear expansion coefficients.

  However, as shown in FIG. 9, the conventional positioning jig 50 is made of carbon, covers the insulating substrate 32, and has a plate-like main body 52 having positioning holes 51 for positioning the solder foil 31 a and the heating element 31. And leg portions 53 suspended from the outer peripheral edge of the plate-like main body 52. Even if the solder foil 31a and the heating element 31 are disposed in the positioning hole 51, the insulating substrate 32 is convexly curved. Due to the warpage, the heating element 31 could not be mounted at a predetermined position on the insulating substrate 32.

That is, as shown in FIG. 9, when the conventional positioning jig 50 is arranged on the insulating substrate 32 in a convexly curved shape, the lower end inner wall portion 56 of the positioning hole 51 of the plate-like main body 52 and the positioning hole A large gap 55 appears between the upper surface of the insulating substrate 32 closest to the outer peripheral edge at 51.
Therefore, even if the solder foil 31a and the heating element 31 are disposed in the positioning hole 51, the solder foil 31a and the heating element 31 move so as to slide in the direction of the arrow along the curved upper surface of the insulating substrate 32. However, the heating element 31 could not be mounted at a predetermined position on the insulating substrate 32 due to the outside of the positioning hole 51 from the gap 55.
Therefore, in order to eliminate the positional deviation of the heating element 31 as described above, the thickness of the solder foil 31a can be increased compared to the conventional case. However, a measure to increase the thickness of the solder foil 31a from the viewpoint of cost. Is not preferred.

In Patent Document 1, a metal layer made of copper is joined to the back surface of a ceramic insulating substrate by silver brazing, while the heat sink is made of copper and copper oxide particles. It is disclosed that the Cu metal layer on the back surface of the insulating substrate and the heat sink are metal-bonded.
JP 2001-217363 A

  As described above, in the invention of Patent Document 1, the metal layer made of copper is joined to the back surface of the ceramic insulating substrate by silver brazing, and the heat sink is made of copper and copper oxide particles. The thermal expansion coefficient difference between the metal layer and the heat sink can be reduced, and the warpage of the ceramic insulating substrate can be reduced, but the warpage is not completely eliminated, so it is mounted on the ceramic insulating substrate. It is not possible to fundamentally solve the positional deviation of the generated heating element.

  The present invention has been made in view of the above points, and provides an element positioning jig and a mounting method capable of mounting an element at a predetermined position without causing a positional shift on a warped insulating substrate. The purpose is to do.

As means for solving the above-mentioned problems, firstly, the element positioning jig of the present invention has a positioning hole for positioning the element, and the lower surface covering the insulating substrate is close to the outer peripheral edge of the insulating substrate. And the convex part which protrudes in the said insulated substrate side is provided.
Second, the element mounting method according to the present invention includes a projecting portion formed on the lower surface of the positioning jig by placing the positioning jig for the element according to the first invention on an insulating substrate. It is characterized in that a solder foil and an element are placed in a positioning hole of the positioning jig after being brought into contact with or close to the upper surface of the insulating substrate near the outer peripheral edge, and the element is mounted on the insulating substrate.

Thereby, when the positioning jig is disposed on the insulating substrate in a warped state, the convex portion protruding to the insulating substrate side provided on the lower surface covering the insulating substrate contacts or approaches the upper surface near the outer peripheral edge of the insulating substrate. The movement of the solder foil and the element in the positioning hole is restricted, the element can be prevented from being displaced, and the element can be mounted at a predetermined position on the insulating substrate.
Various aspects of the element positioning jig and mounting method of the present invention and their functions will be described in detail in the following section (Invention Aspect).

(Aspect of the Invention)
In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. In addition, each aspect is divided into a term like a claim, it attaches | subjects a number to each term, and is described in the format which quotes another term as needed. This is for the purpose of facilitating the understanding of the claimable invention, and is not intended to limit the combinations of the constituent elements constituting the claimable invention to those described in the following sections. In other words, the claimable invention should be construed in consideration of the descriptions, embodiments, etc. attached to each section, and as long as the interpretation is followed, an aspect in which other constituent elements are added to the aspect of each section, In addition, an aspect in which the configuration requirements are deleted from the aspect of each item can be an aspect of the claimable invention. In each of the following items, each of items (1) to (3) corresponds to each of claims 1 to 3, and each of items (6) and (7) corresponds to claims 4 and 5 respectively. It corresponds to each of.

(1) An element positioning jig used for mounting an element on an insulating substrate welded on a cooler, and the positioning jig has a positioning hole for positioning the element. A positioning jig for an element, characterized in that a convex portion that protrudes toward the insulating substrate side is provided on a lower surface that covers the insulating substrate.
Therefore, in the element positioning jig of item (1), since the convex portion protruding on the insulating substrate side provided on the lower surface covering the insulating substrate is in contact with or close to the upper surface near the outer peripheral edge of the insulating substrate, The movement of the solder foil and the element is restricted, and the positional deviation of the element is prevented.

(2) The element positioning jig as set forth in (1), wherein the convex portion is provided by a stepped portion in which a lower surface of the positioning jig is recessed.
Therefore, in the element positioning jig of item (2), a convex portion that protrudes toward the insulating substrate and near the outer peripheral edge of the insulating substrate can be easily formed on the lower surface of the positioning jig.

(3) A plurality of positioning holes are formed in the positioning jig, and the stepped portion is formed on a lower surface of the positioning jig in a range including a part of the positioning holes. The positioning jig for the element according to item.
Accordingly, in the element positioning jig of item (3), even when a plurality of positioning holes are formed in the positioning jig, the lower surface of the positioning jig is near the outer periphery including a part of each positioning hole of the insulating substrate. And the convex part which protrudes in the insulated substrate side can be formed easily.

(4) The height of the convex portion is set to about ½ of the height difference of the upper surface of the warped insulating substrate, according to any one of (1) to (3), Element positioning jig.
Therefore, in the element positioning jig of the item (4), the movement of the solder foil and the element in the positioning hole can be reliably controlled.

(5) The element positioning jig according to any one of (2) to (4), wherein the stepped portion is formed in a rectangular or triangular range in plan view.
Therefore, in the element positioning jig of item (5), in particular, when the stepped portion is formed in a triangular range in plan view, when the insulating substrate warps in a convex spherical shape, the lower surface of the positioning jig The corners of the protrusions provided on the surface come into contact with the upper surface of the insulating substrate at three points, so that the positioning jig is stabilized.

(6) The element positioning jig according to (1), wherein the convex portion is provided by a curved concave portion or a polygonal pyramid concave portion having a concave bottom surface of the positioning jig.
Therefore, in the element positioning jig of item (6), the inner peripheral wall at the lower end of the positioning hole is inclined along the upper surface of the insulating substrate that is inclined downward in a curved shape, and the lower surface of the positioning jig is insulated. Since the convex portion that protrudes toward the insulating substrate side and closer to the outer peripheral edge of the substrate is formed, the positioning accuracy of the element is further improved.

(7) A mounting method for mounting an element on an insulating substrate welded on a cooler, the element positioning jig described in any one of (1) to (6) on the insulating substrate And the convex portion formed on the lower surface of the positioning jig is brought into contact with or close to the upper surface near the outer peripheral edge of the insulating substrate, and then the solder foil and the element are arranged in the positioning hole of the positioning jig. And mounting the element on an insulating substrate.
Therefore, in the element mounting method according to the item (7), when the element is mounted on the insulating substrate, the element positioning jig according to any one of the items (1) to (6) is provided on the insulating substrate. If it is arranged, the protrusion protruding toward the insulating substrate on the lower surface of the positioning jig contacts or is close to the upper surface near the outer peripheral edge of the insulating substrate, so that the movement of the solder foil and the heating element within the positioning hole is restricted. Then, the device is positioned, and the element is mounted at a predetermined position on the insulating substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the element positioning jig | tool and the mounting method which can mount an element in a predetermined position, without raise | generating a position shift on the insulated substrate of the curvature state can be provided.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 3, the power module 30 in which the heating element 31 is mounted on the insulating substrate 32 has a cooler 34 mounted on the back surface of the insulating substrate 32 in order to dissipate heat from the heating element 31. 33 is configured. Further, as shown in FIG. 2, when mounting each heating element 31 at a predetermined position on the insulating substrate 32, the positioning jigs 1, 1a, 1b according to the embodiment of the present invention are used.

The element positioning jigs 1, 1 a, 1 b according to the embodiment of the present invention have a convex curve as shown in FIG. 4 when the insulating substrate 32 is brazed 33 to the cooler 34. Even when the shape is warped, each heating element 31 is improved so that it can be mounted at a predetermined position on the insulating substrate 32.
As shown in FIGS. 5, 7, and 8, the positioning jigs 1, 1 a, and 1 b are made of carbon and cover the insulating substrate 32, and the outer periphery of the plate-like body 2. It is comprised with the leg part 3 suspended. A plurality of positioning holes 4 are formed in the plate-like main body 2 of the positioning jig 1 corresponding to the number of heating elements 31 arranged on the insulating substrate 32.

Next, the positioning jig 1 according to the first embodiment of the present invention will be described with reference to FIG.
In the positioning jig 1 according to the first embodiment, the plate-like main body 2 is formed in a rectangular shape, and two positioning holes 4 are formed side by side along the longitudinal direction thereof. Each positioning hole 4 is formed in a rectangular shape. Further, the lower surface of the plate-like main body 2 includes a substantially half region of the adjacent positioning hole 4 in the longitudinal direction, and a plane extending to the entire short side of the plate-like main body 2 in the short-side direction. A stepped portion 5 is formed in which a rectangular range (the shaded portion in FIG. 5) is provided. Due to the formation of the stepped portion 5, a convex portion 6 is formed on the lower surface of the plate-like main body 2 so as to protrude toward the insulating substrate 32 and close to the outer peripheral edge including substantially half of each positioning hole 4 of the insulating substrate 32.

  In addition, the height N of the convex part 6 provided in the lower surface of the plate-shaped main body 2 is 0.1-0.15 mm in height difference M of the upper surface of the insulating substrate 32 in the state which curved in the convex curve shape shown in FIG. Is set within a range of 0.05 to 0.075 mm. That is, the height N of the convex portion 6 is set to about ½ with respect to the height difference M of the upper surface of the insulating substrate 32 in a state of being curved in a convex curve. Therefore, the thickness of the solder foil 31a is approximately 0.1 mm, and the thickness of the heating element 31 is approximately 0.3 mm.

Then, as shown in FIG. 2, when using the positioning jig 1 according to the first embodiment, each heating element 31 is mounted at a predetermined position on the upper surface of the insulating substrate 32 warped in a convex curve shape. As shown in FIG. 6A, the positioning jig 1 is arranged so as to cover the insulating substrate 32 from above.
Then, as shown in FIG. 6A, the inner surface of the leg portion 3 of the positioning jig 1 comes into contact with the outer surface of the insulating substrate 32. At the same time, the corners of the convex portions 6 provided on the bottom surface of the plate-like body 2 come into contact with or close to the top surface of the insulating substrate 32 in a state where the substantially central portion of the bottom surface of the plate-like body 2 of the positioning jig 1 is warped. The portion 12 contacts the upper surface near the outer peripheral edge of the insulating substrate 32, and the lower end inner peripheral wall 8 of each positioning hole 4 on the convex portion 6 side is limited to the upper surface closest to the outer peripheral edge of the insulating substrate 32 in each positioning hole 4. Not close. Note that the gap 10 between the lower end inner peripheral wall 8 of each positioning hole 4 on the convex portion 6 side and the top surface of the insulating substrate 32 in each positioning hole 4 closest to the outer peripheral edge is formed by the solder foil 31a and the heating element 31. It is not high enough to be inserted.

Thereafter, the solder foil 31 a and the heating element 31 are disposed in the positioning holes 4 of the positioning jig 1 disposed in the insulating element 32.
Then, the movement of the solder foil 31a and the heating element 31 in each positioning hole 4 in each direction is restricted by the convex portion 6 provided in the plate-like body 2 in the short side direction and the long side direction of the insulating substrate 32. Positioned. Thereafter, each heating element 31 is mounted at a predetermined position on the insulating substrate 32 by applying heat to each solder foil 31a.

Next, a positioning jig 1a according to the second embodiment will be described with reference to FIG.
As for the positioning jig 1a which concerns on 2nd Embodiment, the plate-shaped main body 2 is formed in square shape, and the four positioning holes 4 are formed. Further, on the lower surface of the plate-like main body 2, a stepped portion 5 is formed that is recessed in a triangular shape in plan view (shaded portion in FIG. 7) in a range including a part of all the positioning holes 4.
As a result, the lower surface of the plate-like main body 2 is close to the outer peripheral edge including a part of each positioning hole 4 of the insulating substrate 32 and on the insulating substrate 32 side, like the positioning jig 1 according to the first embodiment. A protrusion 6 (not shown in FIG. 7) is formed.

In the positioning jig 1a according to the second embodiment, depending on the shape of the warp of the insulating substrate 32, for example, if the insulating substrate 32 is warped in a convex spherical shape, the three points in FIG. At the position of the reference symbol P1), the corners of the convex portions 6 provided on the lower surface of the plate-like main body 2 (corresponding to the corner portions 12 shown in FIG. 6A) are in contact with the upper surface of the insulating substrate 32. The positioning jig 1a becomes stable.
In addition, about the other effect | action of the positioning jig 1a which concerns on 2nd Embodiment, since it is the same as the positioning jig 1 which concerns on 1st Embodiment, description here is abbreviate | omitted.

Next, a positioning jig 1b according to the third embodiment will be described with reference to FIG.
In the positioning jig 1b according to the third embodiment, a triangular pyramid-shaped concave portion 5a is provided on the lower surface of the plate-like main body 2 so that the inner peripheral wall at the lower end of each positioning hole 4 is inclined downward in a curved shape. Inclined so as to follow the upper surface of the insulating substrate 32, and on the lower surface of the plate-like main body 2 near the outer peripheral edge of the insulating substrate 32, similarly to the positioning jigs 1, 1 a according to the first and second embodiments. And the convex part 6 which protrudes in the insulated substrate 32 side is formed.
In the present embodiment, the triangular pyramid recess 5a is provided on the lower surface of the plate-like main body 2, but a curved recess may be provided.

  When the positioning jig 1b according to the third embodiment is disposed on the warped insulating substrate 32, the convex portion 6 formed on the lower surface of the plate-like main body 2 contacts the upper surface of the insulating substrate 32 near the outer peripheral edge. Or, since they are close to each other, the movement of the solder foil 31a and the heating element 31 disposed in each positioning hole 4 is restricted and positioned.

As described above, in the positioning jigs 1, 1 a according to the first and second embodiments of the present invention, a part of the positioning holes 4 provided in the plate-like body 2 on the lower surface of the plate-like body 2. Is provided on the lower surface of the plate-like main body 2 near the outer peripheral edge including a part of each positioning hole 4 and projecting toward the insulating substrate 32. 6 is formed, when the positioning jigs 1 and 1a are arranged on the insulating substrate 32 in a convex curved shape, the convex portions 6 provided on the lower surface of the plate-like main body 2 become the positioning holes of the insulating substrate 32. 4 is in contact with or close to the upper surface near the outer peripheral edge including a part of 4.
Thereby, the solder foil 31a and the heating element 31 in each positioning hole 4 are positioned by the movement of each positioning hole 4 being restricted by the convex portion 6, and the heating element 31 is mounted at a predetermined position.

  Further, in the positioning jig 1a of the second embodiment, the insulating substrate 32 is warped in a convex spherical shape, in particular, by making the planar view shape of the stepped portion 5 in which the lower surface of the plate-like main body 2 is recessed into a triangular shape. In this case, the corners of the protrusions 6 (corresponding to the corners 12 shown in FIG. 6A) provided on the lower surface of the plate-like main body 2 come into contact with the upper surface of the insulating substrate 32 at three points. When mounting the solder foil 31a and the heating element 31 on the insulating substrate 32, the positioning jig 1a needs to be slightly pressed. By pressing the three contact positions, the positioning jig 1a can be held in a stable state. Can be maintained.

  Furthermore, in the positioning jig 1b according to the third embodiment, by forming the triangular pyramid concave portion 5a on the lower surface of the plate-like main body 2, the lower end inner peripheral wall of each positioning hole 4 is curved downward. A convex portion 6 is formed on the lower surface of the plate-like main body 2 so as to be along the upper surface of the inclined insulating substrate 32 and protrudes toward the insulating substrate 32 and closer to the outer peripheral edge of the insulating substrate 32. Thereby, the positioning accuracy of the solder foil 31a and the heating element 31 can be further improved.

1A and 1B show a power module, where FIG. 1A is a plan view and FIG. 1B is a side view. FIG. 2 is an exploded view in which the portion A of FIG. FIG. 3 is an enlarged view of a portion B in FIG. FIG. 4 is a side view showing a state in which the insulating substrate is warped. FIG. 5 shows a positioning jig according to the first embodiment of the present invention, where (a) is a plan view and (b) is a cross-sectional view. FIG. 6A is a cross-sectional view of the state in which the positioning jig according to the first embodiment is disposed on the insulating substrate, and FIG. 6B is a state in which the solder foil and the heating element are disposed in the positioning hole. It is sectional drawing. FIG. 7 is a plan view showing a positioning jig according to the second embodiment. FIG. 8 is a sectional view showing a positioning jig according to the third embodiment. FIG. 9 is a cross-sectional view showing a conventional positioning jig.

Explanation of symbols

1, 1a, 1b Positioning jig, 2 Plate body, 4 Positioning hole, 5 Stepped part, 5a Triangular pyramid recessed part, 6 Convex part, 12 Corner part, 30 Power module, 31 Heating element, 31a Solder foil, 32 Insulation Substrate, 33 brazing, 34 cooler,

Claims (5)

An element positioning jig used when mounting an element on an insulating substrate welded on a cooler,
The positioning jig is provided with a positioning hole for positioning an element, and a lower surface that covers the insulating substrate is provided with a convex portion that is close to the outer peripheral edge of the insulating substrate and protrudes toward the insulating substrate. An element positioning jig.   The element positioning jig according to claim 1, wherein the projecting portion is provided by a stepped portion in which a lower surface of the positioning jig is recessed.   The positioning jig according to claim 2, wherein a plurality of positioning holes are formed in the positioning jig, and the stepped portion is formed in a range including a part of each positioning hole on a lower surface of the positioning jig. Element positioning jig.   2. The element positioning jig according to claim 1, wherein the convex portion is provided by a curved concave portion or a polygonal pyramid concave portion having a concave bottom surface of the positioning jig. A mounting method for mounting an element on an insulating substrate welded on a cooler,
The element positioning jig according to any one of claims 1 to 4 is arranged on the insulating substrate, and the convex portion formed on the lower surface of the positioning jig is brought into contact with the upper surface near the outer peripheral edge of the insulating substrate. Alternatively, a method for mounting an element comprising placing a solder foil and an element in a positioning hole of the positioning jig and then mounting the element on an insulating substrate.

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