JP2001168402A - Method for soldering thermoelectric semiconductor chip with electrode and thermoelectric semiconductor module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize variations in height, when a coated film thickness of solder is made uniform to fit a thermoelectric semiconductor chip on an electrode, and enhance an assembly property of the thermoelectric module in soldering the thermoelectric semiconductor chip with the electrode. SOLUTION: A cream solder is coated on an electrode plane of a substrate in a screen printing using a mesh screen 20. As using the mesh screen, this method is not affected by a deflection, etc., of a squeegee, and as a result, a thickness of a cream solder 41 to be coated on a predetermined plane of an electrode 14 is made uniform. Furthermore, in order to thin a coating film, a particle size of solder particles of the cream solder 41 is set as 15 to 50 μm, and the mesh size for a mesh plane 21 of the mesh screen 20 is set at 100 to 200 mesh.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for soldering a thermoelectric semiconductor chip and an electrode, a thermoelectric semiconductor module, and a jig for producing a thermoelectric semiconductor module. More specifically, the present invention relates to a thermoelectric semiconductor chip and an electrode. The present invention relates to thinning and uniforming of a solder coating film pressure at the time of soldering, a configuration of a thermoelectric module manufactured thereby, and a jig used at that time.

[0002]

2. Description of the Related Art As shown in FIG. 8, a thermoelectric module generally used at present has two insulating substrates (a heat-radiating substrate 101 and a heat-absorbing substrate 102) opposed to each other.
A plurality of electrodes patterned on the respective opposing surfaces of the insulating substrates 101 and 102 (a plurality of radiation-side electrodes 103 patterned on the radiation-side substrate 101 and a plurality of heat-absorption-side substrates 1).
Plural heat-absorbing electrodes 104 patterned in 02
And a plurality of P-type thermoelectric semiconductor chips 106 and N-type thermoelectric semiconductor chips 107 disposed between the heat radiation side substrate 101 and the heat absorption side substrate 102 and joined to the plurality of electrodes by solder 105. And the heat radiation side electrode 1
03, P-type thermoelectric semiconductor chips 106 and N-type thermoelectric semiconductor chips 107 are alternately and electrically connected in series via the heat-absorbing electrodes 104. In the figure, reference numeral 108 is a lead wire. With this configuration, when current is supplied from the lead wire 108, heat is radiated on the heat radiation side substrate 101 side and heat is absorbed on the heat absorption side substrate 102 side. Then, the heat absorption side substrate 102
Is brought into contact with the object to be cooled to perform electronic cooling.

[0003] As a method for soldering the thermoelectric semiconductor chip and the electrodes when the above-described thermoelectric module is manufactured, cream solder is applied to a predetermined surface of the electrode patterned on the substrate by screen printing, and the predetermined surface is coated. Heating the cream solder with the thermoelectric semiconductor chip placed on it melts the solder particles in the cream solder to form molten solder, volatilizes the flux, and then cools and solidifies the molten solder to separate the thermoelectric semiconductor chip and electrodes. A joining method may be employed. Conventionally, in screen printing when applying cream solder to a predetermined surface of an electrode, as shown in FIG. 8, a metal screen 108 having an open solder application portion is used, and this metal screen 108 is attached to the heat absorbing side substrate 102 (radiation side substrate). 101) is covered on the side on which the heat absorbing side electrode 104 (radiating side electrode 103) is patterned and a metal screen 108 is formed.
The cream solder applied on the top is leveled with a squeegee (not shown), and cream solder 1 is
09, the heat absorbing side electrode 104 patterned on the heat absorbing side substrate 102 (radiation side substrate 101).
The cream solder was applied to a predetermined surface of the (radiation side electrode 103).

[0004]

However, in the above-mentioned conventional soldering method, in screen printing for applying cream solder to a predetermined portion of an electrode, cream solder is applied using a metal screen having an open solder application portion. Since the opening of the metal screen is open to the leveling surface of the squeegee, the amount of cream solder introduced into the opening is affected by the deflection of the squeegee, and FIG.
As shown in (1), there is a problem that it is difficult to apply cream solder with a uniform thickness over the entire opening. If the cream solder cannot be applied with a uniform thickness, the thickness of the applied solder will vary, and then the height will vary when the thermoelectric semiconductor chip is attached to the electrodes. May not be possible. Also, the portion where the solder application thickness is the thinnest must be set as the required cream solder application thickness, so that the application amount of the cream solder becomes relatively large as compared with the case where the applied film thickness is uniform. When the applied amount of the cream solder is large, when the thermoelectric semiconductor chip is pressed against the electrode in a subsequent process, the excess solder flows due to the pressing force, and the solder thus flown is applied to the P-type and N-type thermoelectric semiconductors at the electrode. It collects in the portion between the chips and is heated and cooled as it is to complete the soldering. Then, as shown in FIG. 8, a large solder bump (A in the figure) is formed between the P-type and N-type thermoelectric semiconductors in each electrode. The thickness of the raised portion is about 300 to 400 μm in the conventional one.
It is about. The risk of contact between the thermoelectric semiconductor chip side surface and the raised portion of the solder increases as the raised portion increases. Normally, the thermoelectric semiconductor chip is coated with nickel plating or the like on the bonding surface with the electrode to prevent the diffusion of the solder component into the thermoelectric semiconductor chip, but the side surface portion is not subjected to the diffusion prevention treatment such as nickel plating. Therefore, when the side surface of the chip comes into contact with the raised portion of the solder, the solder component diffuses into the thermoelectric semiconductor chip. For this reason, the material characteristics of the thermoelectric semiconductor chip change, which causes a reduction in reliability and performance.

If the height of the raised portion of the solder is high, the following adverse effects are caused. That is, for example, if a swelling portion of the solder is formed on the heat-absorbing side electrode, the cold heat in the heat-absorbing side substrate is also transmitted to the swelling portion. Here, as the height of the raised portion is higher, the distance from the heat radiation side substrate becomes shorter, and the amount of cold heat transferred to the heat radiation side substrate by convection or radiation increases. For this reason, the cooling efficiency was also a factor.

[0006] Therefore, the present invention has been made in view of the above circumstances, and in the case of soldering a thermoelectric semiconductor chip to an electrode, a case where the thermoelectric semiconductor chip is attached to the electrode by equalizing the thickness of the solder coating. A first technical problem is to minimize the height variation and improve the assemblability of the thermoelectric module. A second technical problem is to reduce the coating film thickness as much as possible and to prevent a decrease in the reliability or performance of the thermoelectric semiconductor chip due to an increase in the amount of solder applied.

[0007]

According to the first aspect of the present invention, there is provided an application step of applying cream solder to a predetermined surface of an electrode patterned on a substrate by screen printing. A heating step of heating the cream solder while pressing the thermoelectric semiconductor chip against the predetermined surface to which the cream solder has been applied to melt the solder particles in the cream solder to form a molten solder and volatilize the flux; In a method of soldering a thermoelectric semiconductor chip and an electrode including a cooling and solidifying step of joining the thermoelectric semiconductor chip and the electrode by cooling and solidifying the molten solder after the heating step, the screen printing uses a mesh screen. And a method of soldering a thermoelectric semiconductor chip and an electrode.

According to the first aspect of the present invention, in a method of soldering a thermoelectric semiconductor chip to an electrode, when cream solder is applied by screen printing to a predetermined surface of an electrode patterned on a substrate, a conventional metal solder is used. Screen printing is performed using a mesh screen instead of a screen.

According to the first aspect of the present invention, since screen printing is performed using a mesh screen as in the above configuration,
When the cream solder on the mesh screen is leveled by the squeegee, the mesh is interposed between the squeegee and the opening. For this reason, the opening does not come into direct contact with the squeegee, and the cream solder leveled by the squeegee is introduced into the opening via the mesh. I will not receive it. For this reason, variation in the thickness of the cream solder introduced into the opening can be suppressed, and the thickness of the cream solder applied to the predetermined surface of the electrode becomes uniform.

According to the first aspect of the present invention, since the thickness of the cream solder applied to a predetermined surface of the electrode is made uniform by the above-described operation, the height variation when the thermoelectric semiconductor chip is attached to the electrode after that is suppressed. And the assemblability of the thermoelectric module can be improved.

According to a second aspect of the present invention, in the first aspect, the cream solder contains solder particles having a particle size of 15 to 50 μm, and the mesh screen has a mesh size of 100 to 200 mesh. A feature is a method of soldering a thermoelectric semiconductor chip and an electrode.

Usually, the particle size of the solder particles contained in the cream solder is about 60 μm. When screen printing is performed by a mesh screen using ordinary cream solder mainly containing such large solder particles, the coating film thickness can be made uniform, but the film thickness is substantially 100 μm or more. However, it is impossible to reduce the thickness of the applied film. Therefore, in the invention of claim 2, screen printing is performed by a mesh screen using cream solder containing solder particles having a particle size of 15 to 50 μm. For this reason, the thickness of the solder coating can be reduced to about 70 μm or less, and not only can the coating thickness of the cream solder be made uniform, but also the coating thickness can be reduced. If the particle size of the solder particles is 15 μm or less, the amount of solder applied is not stable, and blurring occurs. In addition, the mesh size of the screen mesh is set to 100 to 200 mesh because solder particles of 50 μm or less need to be passed through the mesh.

According to the second aspect of the present invention, the thickness and thickness of the cream solder applied can be reduced by the above configuration and operation. For this reason, the flow amount of the cream solder flowing due to the pressing force when pressing the thermoelectric semiconductor chip against the electrode in the subsequent process is reduced, and the swelling portion of the solder after the completion of the soldering can be reduced. Therefore, the danger of the raised portion coming into contact with the side surface portion of the thermoelectric semiconductor chip is reduced, and the diffusion of the solder component into the chip due to the contact between the solder and the thermoelectric semiconductor chip can be prevented. It is possible to prevent a decrease in reliability and performance due to the change. Further, since the swelling portion of the solder can be reduced, the distance between the swelling portion and the substrate on the side facing the swelling portion can be increased, and deterioration of the cooling efficiency due to the short distance can be prevented.

[0014] In order to solve the above-mentioned technical problem, the invention of claim 3 provides two opposing insulating substrates,
A plurality of electrodes patterned on respective opposing surfaces of the two insulating substrates; and a plurality of Ps disposed between the two insulating substrates and soldered to the plurality of electrodes.
A thermoelectric module comprising a thermoelectric semiconductor chip and an n-type thermoelectric semiconductor chip, wherein the p-type thermoelectric semiconductor chip and the n-type thermoelectric semiconductor chip are alternately and electrically connected in series via the electrodes. And the thickness of the solder interposed between the N-type thermoelectric semiconductor chip and the electrode is 10 μm or more.
30 μm, and a thickness of solder applied to a portion between the P-type thermoelectric semiconductor chip and the N-type thermoelectric semiconductor chip in each of the plurality of electrodes is 150 μm or less. It is.

According to the third aspect of the present invention, the two opposing
A plurality of insulating substrates, a plurality of electrodes patterned on respective opposing surfaces of the two insulating substrates, and a plurality of P-types disposed between the two insulating substrates and soldered to the plurality of electrodes. A thermoelectric module comprising a thermoelectric semiconductor chip and an N-type thermoelectric semiconductor chip, wherein a P-type thermoelectric semiconductor chip and an N-type thermoelectric semiconductor chip are alternately and electrically connected in series via electrodes. The thickness of the solder interposed between the thermoelectric semiconductor chip and the electrode is 10 μm to 30 μm
m, and the thickness of the solder applied to the portion between the P-type thermoelectric semiconductor chip and the N-type thermoelectric semiconductor chip in each of the plurality of electrodes is 150 μm or less. The thickness of the solder interposed between the P-type and N-type thermal semiconductor chips and the electrodes is 10 μm.
Since the thickness of the solder film is as thin as m to 30 μm, the amount of solder used can be reduced. In addition, the thickness of the solder (the thickness of the swelled portion of the solder) applied to the portion between the P-type thermoelectric semiconductor chip and the N-type thermoelectric semiconductor chip in each of the plurality of electrodes is 150 μm or less, which is about 30 μm or less.
0 to 400 μm), the danger of contact with the side surface of the thermoelectric semiconductor chip is reduced, and the solder component is prevented from diffusing into the thermoelectric semiconductor chip due to this contact, and the material property change of the thermoelectric semiconductor chip is reduced. Prevention, and eventually reliability and performance degradation,
The distance from the counterpart substrate can be increased, and heat transfer due to convection, radiation, or the like can be reduced, thereby preventing deterioration in cooling efficiency.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration of the thermoelectric module manufactured in this embodiment will be described with reference to FIG. In FIG. 1, a thermoelectric module 10 includes two opposing insulating substrates (a heat-radiating substrate 11 and a heat-absorbing substrate 12). A plurality of heat radiation side electrodes 13 are patterned on one surface of the heat radiation side substrate 11, and a plurality of heat absorption side electrodes 14 are patterned on one surface of the heat absorption side substrate 12. The surface of the heat-dissipating substrate 11 on which the heat-dissipating electrodes 13 are patterned and the surface of the heat-dissipating substrate 12 on which the heat-absorbing electrodes 14 are patterned face each other.

A solder layer 15 is provided on the surface of each of the electrodes 13 and 14.
Are formed. The P-type thermoelectric semiconductor chip 16 and the N-type thermoelectric semiconductor chip 17 are joined to the surface of the solder layer 15. By such bonding, each electrode 1
P-type and N-type thermoelectric semiconductor chips 16 and 17
Are joined. As shown in the figure, only one thermoelectric semiconductor chip is provided on the electrodes at both ends (in this example, the heat-absorbing electrodes 14 at both ends). (Only one semiconductor chip 16 and only one N-type thermoelectric semiconductor chip 17 on the heat absorbing side electrode at the left end in the figure)
The P-type thermoelectric semiconductor chip 16 is joined to the other electrodes.
The N-type thermoelectric semiconductor chip 17 and the N-type thermoelectric semiconductor chip 17 are joined at a predetermined interval.
The P-type thermoelectric semiconductor chips 16 and the N-type thermoelectric semiconductor chips 17 are alternately and electrically connected in series via.
In the drawing, reference numeral 18 is a lead wire.

The thermoelectric module 10 is configured as described above, and when electricity is supplied from the lead wire 18, heat is radiated on the heat radiation side substrate 11 side and heat is absorbed on the heat absorption side substrate 12 side. Then, the heat absorption side substrate 12 is brought into contact with the object to be cooled, thereby removing heat from the object to be cooled and performing electronic cooling.

FIG. 2 is a partially enlarged sectional view of FIG. As shown in FIG. 2, the solder layer 15 includes a P-type thermoelectric semiconductor chip 16 and an N-type
14, the thickness of the joint surface t1, which is the solder thickness of the joint surface with
The intermediate portion thickness t2 which is the solder thickness of the portion between the type thermoelectric semiconductor chip 16 and the N-type thermoelectric semiconductor chip 17 has a different thickness, and the intermediate portion thickness t2 is larger than the bonding surface thickness t1. , The center of the solder layer 15 is slightly raised. In the thermoelectric module 10 of the present example,
As the thickness of the solder layer 15, the joining surface thickness t1 is 10 μm.
m to 30 μm, and the thickness t2 of the intermediate portion is 10 to 150 μm
Range.

As shown in the above configuration, the configuration of the thermoelectric module in this embodiment is such that the heat radiation side substrate 11 and the heat absorption side substrate 12 facing each other, and a plurality of electrodes (radiation side) patterned on the respective opposing surfaces of these insulating substrates. The heat-dissipating electrode 13 patterned on the side substrate 11 and the heat-absorbing electrode 14 patterned on the heat-absorbing substrate 12) and a plurality of electrodes 13 disposed between the two insulating substrates 11 and 12.
P-type thermoelectric semiconductor chips 16 solder-bonded to
And an N-type thermoelectric semiconductor chip 17.
In the thermoelectric module 10 in which the P-type thermoelectric semiconductor chips 16 and the N-type thermoelectric semiconductor chips 17 are alternately and electrically connected in series through the PDP 4, the P-type and N-type thermoelectric semiconductor chips 16, 17 and the electrodes 13, The thickness (joint surface thickness) t1 of the solder interposed between the P-type thermoelectric semiconductor chip 17 and the N-type thermoelectric semiconductor chip 17 in each of the plurality of electrodes 13 and 14 is 10 μm to 30 μm. Thickness (middle part thickness) t of the raised part of the applied solder
2 is 150 μm or less. The thickness t1 is 10 μm or more
Since the solder film is as thin as 30 μm, the amount of solder used can be reduced. The thickness t2 is 15
0 μm or less, which is smaller than the conventional one (300 to 400 μm), the risk of contact between the thermoelectric semiconductor chips 16 and 17 and the bulging portion of the solder is reduced, and the solder component diffuses into the thermoelectric semiconductor chip due to this contact. To prevent changes in material properties of thermoelectric semiconductor chips,
As a result, the reliability and performance can be prevented from deteriorating, and the distance (illustrated distance L1) from the counterpart substrate can be increased, so that heat transfer due to convection, radiation, or the like can be reduced to prevent deterioration in cooling efficiency. .

Next, a method of soldering the thermoelectric semiconductor chips 16 and 17 and the electrodes 13 and 14 in the procedure for manufacturing the thermoelectric module 10 having the above configuration will be described.

In the present embodiment, the main steps of the method for soldering the thermoelectric module 10 are the following five steps.

(1) Cream solder application step (2) Intermediate assembly heating step (3) Intermediate assembly cooling / solidification step (4) Final assembly heating step (5) Final assembly cooling / solidification step The cream solder applying step (1) corresponds to the applying step in the present invention, the intermediate assembly heating step (2) and the final assembly heating step (4) correspond to the heating step in the present invention, and the intermediate assembly (3). The cooling and solidifying step and the final assembly cooling and solidifying step (5) correspond to the cooling and solidifying step in the present invention, respectively.

Hereinafter, each step will be described in order.

(1) Coating Step First, a predetermined surface of an electrode patterned on a substrate is
The cream solder is applied by screen printing using a screen printer 50 as shown in FIG. The screen used for screen printing is a mesh screen 20 as shown in FIG. The mesh screen 20 is configured by overlapping a mesh surface 21 formed of a fine wire of stainless steel, tetron or the like in a mesh shape with a resin plate 22. The mesh surface 21 and the resin plate 22 have a thickness of 70 μm and 30 μm, respectively.
A plurality of openings 22a penetrating from the front to the back are formed at predetermined locations. The mesh size of the mesh surface 21 is 150
It is a mesh. Using such a mesh screen 20, cream solder is applied to a predetermined surface of the electrode as shown in FIGS. 5 (a) to 5 (d). More specifically, first, as shown in FIG.
The mesh screen 20 is placed on the surface on which the electrode (2) (for example, the heat absorbing electrode 14) is patterned. At this time,
The resin plate 22 of the mesh screen 20 is
And the opening 22a of the resin plate 22 is a predetermined surface of the electrode 14 (the surface on which the solder is to be applied).
Adjust the position so that it faces and cover it. Next, FIG.
As shown in (b), the cream solder 41 is dropped on the mesh surface 21 of the mesh screen 20, and the squeegee 51
The cream solder 41 is leveled on the mesh surface 21 (see FIG. 3). The cream solder 41 used in this example includes solder particles and flux, and the solder particles are formed so that the particle size is 15 to 50 μm. Therefore, the cream solder 41 penetrates the mesh of the mesh surface 21 (mesh size 150 mesh, that is, the opening width of the mesh is 100 μm), and the cream solder 41 enters the opening 22a of the resin plate 22 as shown in FIG. 41 is led. Thereafter, as shown in FIG. 5D, when the mesh screen 20 is removed from the substrate 12, the cream solder 41 is applied to a predetermined surface of the electrode 14.

The above-described coating step is performed by
On the heat radiation side substrate 11. In this step, cream solder is applied to a predetermined surface of the heat absorption side electrode 14 patterned on the heat absorption side substrate 12 and a predetermined surface of the heat radiation side electrode 13 patterned on the heat radiation side substrate 11.

As can be seen from the above description of the coating method, when the cream solder 41 is applied by screen printing to a predetermined surface of the electrode 14 patterned on the substrate 12, the mesh screen 20 is used as a screen used for screen printing. I have. Accordingly, the cream solder 41 hung on the mesh surface 21 of the mesh screen 20 is leveled by the squeegee 51, and the opening 22a of the resin plate 22 is formed.
When the squeegee 51 is introduced into the opening 22a, the mesh surface 21 is interposed between the opening 22a and the leveling surface of the squeegee 51.
The a and the squeegee 51 do not directly contact each other, and the cream solder 41 leveled by the squeegee is introduced into the opening 22 a through the mesh on the mesh surface 21. Therefore, the amount of the cream solder 41 introduced into the opening 22a is not affected by the deflection of the squeegee, and the thickness when the cream solder 41 is applied to a predetermined surface of the electrode 14 is substantially uniform. Therefore, it is possible to suppress a variation in height when the thermoelectric semiconductor chip is attached to the electrode 14 thereafter, and it is possible to improve the assemblability of the thermoelectric module.

The solder particles of the cream solder 41 used in the screen printing in this embodiment have a particle size of 15 to 50.
μm. Further, the thickness of the mesh surface 21 of the mesh screen 20 is 70 μm, the thickness of the resin plate 22 is 30 μm, and the mesh size of the mesh surface 21 is 150 mesh (the opening width is 100 μm).
μm). Therefore, the solder particles in the cream solder smoothed by the squeegee can pass through the mesh network, and the cream solder containing the solder particles is applied to the resin plate 22.
Is introduced into the opening 22a. Since the thickness of the opening 22a is 30 μm, which is the same as the thickness of the resin plate 22, the opening 22a having a thickness of 30 μm is filled with cream solder. Thereafter, the mesh screen 20 is removed. At this time, the cream solder accumulated in the mesh surface 21 is absorbed by the cream solder filled in the opening 22a to increase its thickness. In this method, a thin cream solder film having a thickness of about 70 μm is uniformly applied. As described above, the particle size of the solder particles contained in the cream solder 41 is made smaller than that of the conventional solder (in this example, 15 to 50 μm), and the solder particles can pass through the mesh size of the mesh surface 21 of the mesh screen 20. Set in this example (150 mesh in this example)
In addition, by forming the resin plate 22 of the mesh screen 20 with a predetermined thickness (30 μm in this example), a uniform and thin cream solder film can be applied on the electrode 14. When such a thin coating film is formed, the flow amount of the cream solder flowing due to the pressing force when pressing the thermoelectric semiconductor chip against the electrode in the subsequent process decreases, and the solder swelling portion after the soldering is completed (see FIG. 2, the solder at the portion indicated by the thickness t2)
Can be reduced. Therefore, the danger of the raised portion coming into contact with the side surface portion of the thermoelectric semiconductor chip is reduced, and the diffusion of the solder component into the chip due to the contact between the solder and the thermoelectric semiconductor chip can be prevented. It is possible to prevent a decrease in reliability and performance due to the change. Further, since the swelling portion of the solder can be reduced, the distance between the swelling portion and the substrate on the side facing the swelling portion can be increased, and deterioration of the cooling efficiency due to the short distance can be prevented.

The cream solder 41 used in the present application step preferably has a viscosity in the range of 250 to 350 Pa · S. If the viscosity is 350 Pa · S or more, there are disadvantages such as blurring of the solder at the time of applying the cream solder, and the inability to completely apply a predetermined shape. If the viscosity is 250 Pa · S or less, there is a problem such as dripping of cream solder after solder application.

(2) Intermediate Assembly Heating Step Next, the intermediate assembly heating step will be described.

First, as shown in FIG. 6A, the P-type thermoelectric semiconductor chip 16 and the N-type thermoelectric semiconductor chip 17 are mounted on predetermined positions of the heat absorbing electrode 14 patterned on the heat absorbing substrate 12. In this case, since the cream solder 41 is applied to the predetermined surface of the heat-absorbing electrode 14 in the above-described application step, the chips 16 and 17 are mounted on the cream solder 41. In addition, since the cream solder 41 is in a flowing state, in order to fix the positions of the chips 16 and 17, as shown in FIG. Position 17 is fixed. Next, the assembled body in this state (hereinafter, an intermediate assembly) is set on the heating jig 30 as shown in FIG.

Here, the heating jig 30 will be described.
As shown in FIG. 6C, the heating jig 30 includes a cylinder block 31, a base block 32, and an intermediate plate 33 sandwiched between the cylinder block 31 and the base block 32.

As shown in the figure, the cylinder block 31 is formed with a cylinder hole 31a which is open at the center in the lower part, and a plunger 34 is formed in the cylinder hole 31a.
Is housed. One end of a spring 35 is connected to the bottom surface 31b of the cylinder hole 31a. The other end of the spring 35 is inserted into a concave portion 34c formed on the back surface 34b of the plunger 34 and connected to the bottom thereof. Therefore, the plunger 34 is elastically supported by the spring 35 in the cylinder hole 31a, and is configured to be able to reciprocate in the cylinder hole 31a while receiving the elastic force from the spring 35.

The base block 32 is arranged to face the opening surface of the cylinder hole 31a of the cylinder block 31.

The intermediate plate 33 is formed in a square frame shape with a through opening 33a formed at the center thereof, and is interposed between the cylinder block 31 and the base block 32 as described above. In addition, the intermediate plate 33
As shown in the figure, a step 33b is provided on one piece (right side in the figure) of the through opening 33a,
The opening area of 3c is larger than the opening area of the illustrated step upper portion 33d. The shape of the opening of the step lower portion 33c is such that the heat-absorbing side substrate 12 can be accurately accommodated and its position is fixedly held, that is, the heat-absorbing side substrate 12 can be positioned.

The lower end face 31c of the cylinder block 31 and the upper end face 32c of the base block 32 are provided with a plurality of positioning holes 31d and 32d, respectively (two locations in the figure).
Is formed. The intermediate plate 33 has a plurality of (two in the figure) positioning pin insertion holes 33g formed from the upper end surface 33e to the lower end surface 33f. Then, a plurality of (two in the figure) positioning pins 36 are inserted into the respective positioning pin insertion holes 33g of the intermediate plate 33, and among the portions where the respective positioning pins 36 protrude from the respective insertion holes 33g, the illustrated upper projecting portions are The illustrated lower protruding portion is inserted into each positioning hole 32d formed in the upper end surface 32c of the base block 32 into each positioning hole 31d formed in the lower end surface 31c of the cylinder block 31. In this manner, the positioning is performed by the plurality of positioning pins 36, and the cylinder block 31, the base block 32, and the intermediate plate 3 are aligned.
3 is connected and fixed.

As can be seen from the figure, the plunger 3
The fourth side surface 34d is accommodated in the cylinder hole 31a with a predetermined clearance provided between the side surface 34d and the inner wall surface 31e of the cylinder hole 31a of the cylinder block 31. Therefore, when the plunger 34 reciprocates in the cylinder hole 31a in the vertical direction in the figure, the front surface 34a of the plunger 34 can be inclined or moved with a small degree of freedom in the three-dimensional direction.

The intermediate assembly is set in the through-opening 33a of the intermediate plate 33, as shown in FIG. Then, the plunger 34 is positioned directly above the intermediate assembly, and the plunger 3
4 receives the elastic force from the spring 35, and presses the intermediate assembly in the direction of arrow A by the elastic force and the own weight of the plunger 34 itself. With this pressing force, the P-type and N-type thermoelectric semiconductor chips 16 and 17 of the intermediate assembly are pressed and pressed against the heat absorbing side electrode 14 with a predetermined force. Therefore, each of the thermoelectric semiconductor chips 16 and 17 and the heat absorbing side electrode 1
The cream solder 41 flows between the P-type thermoelectric semiconductor chip 16 and the N-type thermoelectric semiconductor chip 17 at each electrode 14, and the swelling portion (portion B in the drawing) is formed. Form. However, the intermediate assembly is manufactured by the above-described coating process, and in this coating process, the cream solder 41 applied to the predetermined surface of the electrode 14 is applied as a thin uniform film having a thickness of 50 μm. Even if the pressing force from 34 acts, the height of the raised portion does not increase so much.

In this state, the entire heating jig 30 is externally heated by a heater 37 as heating means. By this heating, heat is transmitted to the intermediate assembly, the solder particles in the cream solder 41 are melted, and the flux component is volatilized.

(3) Intermediate Assembly Cooling and Solidifying Step In the above heating step, the heating from the heater 37 is stopped when the solder particles in the cream solder 41 are melted and the flux components are almost volatilized. The solid is removed from the heating jig 30 and allowed to cool naturally. The molten solder is cooled and solidified by the natural cooling to form the solder layer 15, and the solder bonding between the P-type and N-type thermoelectric semiconductor chips 16 and 17 and the heat-absorbing electrode 14 is completed.

(4) Final Assembly Heating Step The positioning jig is removed from the intermediate assembly which has been solder-joined in the intermediate assembly cooling and solidifying step, and heat is radiated in the coating step as shown in FIG. The heat-dissipation-side substrate 11 in which the cream solder 41 is applied to a predetermined surface of the side electrode 13 is placed on the unsoldered surface of each of the chips 16 and 17 of the intermediate assembly, and the configuration of the final assembly as shown in FIG. And next,
This final assembly is set on the heating jig 30 used in the intermediate assembly heating step, as shown in FIG. Then, the plunger 34 is positioned right above the final assembly, and the plunger 34 receives an elastic force from the spring 35, so that the final assembly is moved by the elastic force and the own weight of the plunger 34 itself as shown by an arrow A in the drawing. Press in the direction. The heat radiation side substrate 11 is pressed by this pressing force, and the chips 16 and 17 are pressed against the heat radiation side electrode 13 with a predetermined force. Therefore, the cream solder 41 between each of the thermoelectric semiconductor chips 16 and 17 and the heat radiation side electrode 13 flows by the pressing force, and the P-type thermoelectric semiconductor chip 16
And an N-type thermoelectric semiconductor chip 17 to form a swelled portion (portion B in the drawing). However, the final assembly is manufactured by the above-described coating process, and in this coating process, the cream solder 41 applied to the predetermined surface of the electrode 13 is applied as a thin uniform film of 50 μm. Even if the pressing force from 34 acts, the height of the raised portion does not increase so much.

As described above, the heating jig 30 used in the heating process (intermediate assembly heating process and final assembly heating process) of the present example includes the substrates 11, 12 on which the electrodes 13, 14 are patterned and the thermoelectric semiconductor chip. A pressing member (plunger 34) for pressing an assembly (intermediate assembly and final assembly) in which 16, 16 are assembled in a predetermined arrangement;
An elastic member (spring 3) for applying elastic force to the pressing member
5), wherein the thermoelectric semiconductor chip is pressed in a direction perpendicular to the surface of the electrode (the direction of arrow A in the figure) by the elastic force from the elastic member and the weight of the pressing member. For this reason, it is possible to prevent the thermoelectric semiconductor chip from moving due to the surface tension of the cream solder applied to the predetermined surface of the electrode, and as a result, it is possible to reduce assembly failure due to chip displacement. In addition, the pressing force is determined by the elastic force from the elastic member and the weight of the pressing member, and the assembly can be pressed with a constant pressing force each time, and the dispersion of the pressing force in each assembly can be reduced. Can be reduced.

Further, in the heating jig 10 of this embodiment, as described above, the side surface 34d of the plunger 34 is provided with a predetermined clearance between the side wall 34e of the cylinder block 31 and the inner wall surface 31e of the cylinder hole 31a. When the plunger 34 is reciprocated vertically in the drawing in the cylinder hole 31a, the front surface 34a of the plunger 34 is inclined or moved in the three-dimensional direction with some degree of freedom. be able to. Therefore, the plunger 34
Presses against the final assembly, the front 3 of the plunger 34
4a learns from the heat radiation side substrate 11. For this reason, the heat radiation side electrode 13 can be pressed against the thermoelectric semiconductor chips 16 and 17 by following the minute height variations of the thermoelectric semiconductor chips 16 and 17 well. On the other hand, if the predetermined clearance does not exist, the plunger 34 has its front surface 34a.
Is moved up and down in a state where the orientation of the chips is fixed (there is no degree of freedom), and the final assembly is pressed.
17 may not be able to follow the minute variation in height, and for example, there is a possibility that a defective connection between the chip and the electrode on one side of the thermoelectric module may occur. Normally, when such a jig is used, a member on the pressing side (corresponding to the plunger 34 in this example) and a receiving side are used in order to ensure the parallelism between the heat dissipation side substrate 11 and the heat absorption side substrate 12. (Corresponding to the base block 32 in this example) must be strictly controlled. However, in this example, since the plunger 34 as the pressing member learns from the substrate itself, a certain degree of parallelism can be secured without managing the parallelism between the pressing side member and the receiving side member. Therefore, the troublesome work of managing the parallelism of the jig can be omitted, and the workability is improved.

Also, as described above, the intermediate plate 33
Is formed in a rectangular frame shape with a through opening 33a formed in the center thereof. As shown in the drawing, the through-opening portion 33a of the intermediate plate 33 is provided with a step 33b on one piece (right side in the figure), and the opening area of the step lower portion 33c is larger than the opening area of the step upper portion 33d. ing. The shape of the opening of the stepped lower portion 33c is such that the heat-absorbing substrate 12 is accurately fitted and its position is fixedly held, that is, the heat-absorbing substrate 12 can be positioned. Upper step 3
The shape of the opening 3d is such that the heat radiation side substrate 11 can be accurately accommodated and its position is fixedly held, that is, the heat radiation side substrate 11 can be positioned. As described above, the heating jig 10 according to the present embodiment includes the holding means (the step upper portion 33 d of the intermediate plate 33) for fixedly holding the substrate.
And the opening at the stepped lower portion 33c), the substrate does not shift when the assembly is set on the heating jig. Can be reduced. Further, in this example, since both the heat radiation side substrate 11 and the heat absorption side substrate 12 are fixedly held with high accuracy, the relative displacement between the substrates 11 and 12 can be prevented.
It is also possible to reduce an improper assembly due to a relative displacement between the first and second positions.

With the final assembly set in the heating jig 30 having such a configuration, the entire heating jig 30 is externally heated by a heater 37 as heating means. By this heating, heat is transferred to the final assembly and the cream solder 4
As the solder particles in 1 melt, the flux component volatilizes. At this time, the solder on the heat-absorbing side substrate that has been cooled and solidified in the intermediate assembly cooling and solidifying step also remelts.

(5) Cooling and solidifying step of the final assembly In the heating step of the final assembly, the heating from the heater 37 is stopped upon observing that the solder particles in the cream solder 41 have melted and the flux components have almost completely volatilized. Then, the final assembly is removed from the heating jig 30 and allowed to cool naturally. By this natural cooling, the molten solder is cooled and solidified, and the P-type and N
Solder bonding between the thermoelectric semiconductor chips 16 and 17 and the heat-absorbing electrode 14 and between the P-type and N-type thermoelectric semiconductor chips 16 and 17 and the heat-radiating electrode 13 are completed.

As described above, according to the method of soldering the thermoelectric semiconductor chip and the electrodes according to the present embodiment, the electrodes (radiation-side electrodes 13 and heat-absorption side) are patterned on the substrate (radiation-side substrate 11 and heat-absorption-side substrate 12). A coating step of applying a cream solder 41 to a predetermined surface of the electrode 14) by screen printing, and pressing the thermoelectric semiconductor chips 16 and 17 against the predetermined surface on which the cream solder 41 has been applied;
Is heated by a heater 37 to melt the solder particles in the cream solder 41 to form molten solder and volatilize the flux (intermediate assembly heating step and final assembly heating step), and after the heating step, the molten solder Is cooled and solidified to form thermoelectric semiconductor chips 16 and 17 and electrodes 13 and 14.
In the method of soldering a thermoelectric semiconductor chip and an electrode including a cooling and solidifying step (a cooling and solidifying step for an intermediate assembly and a cooling and solidifying step for a final assembly) for joining the electrodes, the screen printing in the applying step uses a mesh screen 20. Since the method for soldering the thermoelectric semiconductor chip and the electrodes is characterized in that the mesh is interposed between the squeegee 51 and the opening 22a, the opening 22a and the squeegee 5
1, the cream solder 41 leveled by the squeegee 51 is introduced into the opening through the mesh, so that the amount of the cream solder 41 introduced into the opening 22 a is affected by the bending of the squeegee 51 and the like. I will not receive it. For this reason,
Variations in the thickness of the cream solder 41 introduced into the openings 22a can be suppressed, and the thickness of the cream solder 41 applied to predetermined surfaces of the electrodes 13 and 14 becomes uniform. Therefore, height variations when the thermoelectric semiconductor chips 16 and 17 are attached to the electrodes 13 and 14 thereafter can be suppressed, and assemblability of the thermoelectric module can be improved.

The cream solder 41 has a particle size of 15 to 5
0 μm solder particles and mesh screen 2
0 indicates that the mesh size is 100 to 200 mesh, so that the solder coating film thickness of the cream solder 41 applied in the coating step is 50 μm or less, which not only makes the coating thickness of the cream solder uniform, but also Can be realized at the same time. For this reason, the amount of cream solder flowing due to the pressing force when pressing the thermoelectric semiconductor chips 16 and 17 against the electrodes 13 and 14 in the subsequent steps is reduced, and the swelling portion of the solder after the soldering is completed (in each electrode, The solder portion between the P-type thermoelectric semiconductor chip and the N-type thermoelectric semiconductor chip) can be reduced. Therefore, the danger of the raised portion coming into contact with the side surface portion of the thermoelectric semiconductor chip is reduced, and the diffusion of the solder component into the chip due to the contact between the solder and the thermoelectric semiconductor chip can be prevented. It is possible to prevent a decrease in reliability and performance due to the change. Further, since the swelling portion of the solder can be reduced, the distance between the swelling portion and the substrate on the side facing the swelling portion can be increased, and deterioration of the cooling efficiency due to the short distance can be prevented.

(Supplementary Note) The following technical ideas can be understood from the present embodiment.

(1) When soldering a thermoelectric semiconductor chip to an electrode patterned on a substrate, the cream solder applied to a predetermined surface of the electrode is heated to melt the solder particles in the cream solder and flux. A heating jig for volatilizing the heating jig,
A pressing member (plunger 34) for pressing an assembly (intermediate assembly and final assembly) in which the substrate on which the electrodes are patterned and the thermoelectric semiconductor chip are assembled in a predetermined arrangement; An elastic member (spring 35) for applying an elastic force to the thermoelectric semiconductor chip is pressed in a direction perpendicular to the surface of the electrode by the elastic force from the elastic member and the weight of the pressing member. And heating jig.

(2) In the above (1), the heating jig 10 is provided with holding means for fixedly holding the substrate (an opening in the lower step 33c and an opening in the upper step 33d of the intermediate plate 33). A heating jig characterized by performing.

(3) In the above (1) or (2),
The heating jig 10 includes a cylinder member (cylinder block 31) having a cylinder hole 31a, and the pressing member is housed in the cylinder hole of the cylinder member and is reciprocally movable in the cylinder hole. A heating jig, wherein a clearance is provided between the pressing member and an inner wall 31e of the cylinder hole.

According to the above (1), the thermoelectric semiconductor chip receives a load in a direction perpendicular to the electrode surface due to the elastic force from the elastic member and the weight of the pressing member. For this reason, it is possible to prevent the thermoelectric semiconductor chip from moving due to the surface tension of the cream solder applied to the predetermined surface of the electrode, and as a result, it is possible to reduce assembly failure due to chip displacement. In addition, the pressing force is determined by the elastic force from the elastic member and the weight of the pressing member, and the assembly can be pressed with a constant pressing force each time, and the dispersion of the pressing force in each assembly can be reduced. Can be reduced.

According to the above (2), when the assembly is set on the heating jig, the substrate is fixedly held by the holding means, so that the substrate is not displaced, and as a result, It is possible to reduce assembly failure due to displacement of the substrate.

According to the above (3), the pressing member is accommodated in the cylinder hole of the cylinder member, and the clearance is provided between the pressing member and the inner wall of the cylinder hole.
When the pressing member presses the assembly, the pressing surface of the pressing member (the front surface 34a of the plunger 34) learns from the portion of the assembly that contacts the pressing member (radiation side substrate 11). For this reason, the assembly can be pressed by appropriately following the dimensional variation of the assembly (small height variation of the thermoelectric semiconductor chip). On the other hand, if the clearance is not provided, the pressing member reciprocates and presses the assembly in a state where the direction of the pressing surface is fixed (there is no degree of freedom). It is not possible to follow the variation, and for example, there is a possibility that a defective connection between the chip and the electrode on one side of the thermoelectric module may occur.

(Other Embodiments) In the above embodiment,
As the application step, screen printing using a mesh screen has been described, but there is another method of applying solder to the electrode surface of the substrate using sheet-like solder. For this, a sheet-like solder is placed on the surface of the substrate on which the electrodes are patterned, and heating is performed in this state. Then, the sheet-like solder is melted by heat. At this time, the solder covering the portion other than the electrode surface is absorbed by the molten solder on the electrode surface portion, and as a result, the molten solder is applied only to the predetermined surface of the electrode. Becomes

When the solder is applied in this manner, the nonuniformity of the applied film thickness which occurs when screen printing is performed using a conventional metal screen does not occur, and the cream solder is uniformly applied to the predetermined surface of the electrode. Can be applied.
In addition, by using a thin solder having a thickness of about 10 μm to 30 μm as the sheet-like solder, the thickness of the solder coating after being applied to the predetermined surface of the electrode is about 50 μm to 70 μm, and the coating thickness can be reduced.

[0059]

As described above, according to the present invention,
In the soldering of the thermoelectric semiconductor chip and the electrode, the thickness of the applied solder can be made uniform so that the height variation when the thermoelectric semiconductor chip is attached to the electrode is minimized, and the assemblability of the thermoelectric module can be improved. Further, it is possible to make the coating film thickness as thin as possible, and to prevent the reliability and performance of the thermoelectric semiconductor chip from deteriorating due to an increase in the amount of solder applied.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a thermoelectric module according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 4 is a schematic sectional view of a mesh screen used in the embodiment of the present invention.

FIG. 5 is a diagram showing a coating step in the embodiment of the present invention.

FIG. 6 is a diagram showing an intermediate assembly heating step in the embodiment of the present invention.

FIG. 7 is a diagram showing a final assembly heating step in the embodiment of the present invention.

FIG. 8 is a schematic sectional view of a thermoelectric module according to the related art.

FIG. 9 is a diagram showing a state in which solder is applied to a predetermined surface of an electrode of a substrate using a metal screen.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Thermoelectric module 11 ... Heat dissipation side board (substrate) 12 ... Heat absorption side board (substrate) 13 ... Heat dissipation side electrode (electrode) 14 ... Heat absorption side electrode (electrode) 15 ... Solder 16: P-type thermoelectric semiconductor chip 17: N-type thermoelectric semiconductor chip 20: Mesh screen 21: Mesh surface 22: Resin plate, 22a: Opening 30: Heat treatment Tool 31: cylinder block, 31a: cylinder hole, 31b: bottom surface, 31c: lower end surface,
31d: positioning hole, 31e: inner wall surface 32: base block, 32c: upper end surface,
32d: positioning hole 33: intermediate plate, 33a: through opening,
33b: step, 33c: lower step, 33d
... upper step, 33e ... upper end face, 33f ...
・ Lower end face, 33g ・ ・ ・ Positioning pin insertion hole 34 ・ ・ ・ Plunger, 34a ・ ・ ・ Front face, 34b
... Back 35 ... Spring 36 ... Positioning pin 37 ... Heater (heating means) 41 ... Cream solder 50 ... Screen printing machine 51 ... Squeegee

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] January 20, 2000 (2000.1.2
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a thermoelectric module according to an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of FIG.

FIG. 3 is a schematic perspective view of a screen printing machine.

FIG. 4 is a schematic sectional view of a mesh screen used in the embodiment of the present invention.

FIG. 5 is a diagram showing a coating step in the embodiment of the present invention.

FIG. 6 is a diagram showing an intermediate assembly heating step in the embodiment of the present invention.

FIG. 7 is a diagram showing a final assembly heating step in the embodiment of the present invention.

FIG. 8 is a schematic sectional view of a thermoelectric module according to the related art.

FIG. 9 is a diagram showing a state in which solder is applied to a predetermined surface of an electrode of a substrate using a metal screen.

[Description of Signs] 10 ・ ・ ・ Thermoelectric module 11 ・ ・ ・ Heat radiation side substrate (substrate) 12 ・ ・ ・ Heat absorption side substrate (substrate) 13 ・ ・ ・ Heat radiation side electrode (electrode) 14 ・ ・ ・ Heat absorption side electrode (electrode) 15: solder 16: P-type thermoelectric semiconductor chip 17: N-type thermoelectric semiconductor chip 20: mesh screen 21: mesh surface 22: resin plate, 22a: opening 30 ... Heating jig 31 ... Cylinder block 31a ... Cylinder hole 31b ... Bottom face 31c ... Lower end face
31d: positioning hole, 31e: inner wall surface 32: base block, 32c: upper end surface,
32d: positioning hole 33: intermediate plate, 33a: through opening,
33b: step, 33c: lower step, 33d
... upper step, 33e ... upper end face, 33f ...
・ Lower end face, 33g ・ ・ ・ Positioning pin insertion hole 34 ・ ・ ・ Plunger, 34a ・ ・ ・ Front face, 34b
... Back 35 ... Spring 36 ... Positioning pin 37 ... Heater (heating means) 41 ... Cream solder 50 ... Screen printing machine 51 ... Squeegee

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masakazu Ishiguro 2-1-1 Asahi-cho, Kariya-shi, Aichi F-term (reference) in Aisin Seiki Co., Ltd. 5E319 AA03 AA07 AB05 BB05 CC44 CD29

Claims (3)

[Claims] An application step of applying cream solder to a predetermined surface of an electrode patterned on a substrate by screen printing, and heating the cream solder while pressing a thermoelectric semiconductor chip against the predetermined surface on which the cream solder is applied. A heating step of melting the solder particles in the cream solder into molten solder and volatilizing the flux,
In the method of soldering a thermoelectric semiconductor chip and an electrode including a cooling and solidifying step of joining the thermoelectric semiconductor chip and the electrode by cooling and solidifying the molten solder after the heating step, the screen printing includes a mesh screen. A method of soldering a thermoelectric semiconductor chip and an electrode, wherein the method is performed by using the method. 2. The thermoelectric semiconductor chip according to claim 1, wherein the cream solder includes solder particles having a particle size of 15 to 50 μm, and the mesh screen has a mesh size of 100 to 200 mesh. Soldering method with electrodes. 3. The two insulating substrates facing each other, a plurality of electrodes patterned on respective opposing surfaces of the two insulating substrates, and the plurality of electrodes arranged between the two insulating substrates and A plurality of P-type thermoelectric semiconductor chips and an N-type thermoelectric semiconductor chip soldered to each electrode are provided, and the P-type thermoelectric semiconductor chip and the N-type thermoelectric semiconductor chip are alternately and electrically connected in series via the electrodes. The thickness of the solder interposed between the P-type and N-type thermoelectric semiconductor chips and the electrodes is 10 μm to 30 μm, and the P-type thermoelectric semiconductor chips and the N-type A thermoelectric module, wherein the thickness of the solder applied to a portion between the thermoelectric semiconductor chip and the thermoelectric semiconductor chip is 150 μm or less.