JP3350299B2 - Manufacturing method of thermoelectric converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric converter applicable to a cooling device, a heating device, a temperature control device having both devices for cooling and heating, and a power generation device utilizing a temperature difference between the two devices for cooling and heating. The present invention relates to a device manufacturing method.

[0002]

2. Description of the Related Art FIG. 11 shows a basic structure of a thermoelectric converter.
This will be described with reference to FIG. The thermoelectric conversion device 3 arranges a plurality of P-type semiconductor elements 1a and N-type semiconductor elements 1b for thermoelectric conversion alternately at a constant interval, and at one side of the P-type semiconductor element 1a and the N-type semiconductor element 1b, respectively. The electrode plates 2a and 2b are provided between the upper surfaces of adjacent semiconductor devices of opposite polarities and on the lower surface of the adjacent semiconductor devices of opposite polarity and solder 21 or the like is provided between the electrode plates 2a and 2b and the semiconductor device. And the P-type semiconductor elements 1a and the N-type semiconductor elements 1b are alternately and electrically connected in series. Further, the semiconductor element rows connected in this manner are supported and fixed by being sandwiched from above and below by an electrically insulating substrate 22 or the like.

When a voltage is applied to the two ends connected in series by the DC power supply 23, a heat absorbing action occurs in the heat exchanger 9a on the upper surface side of the thermoelectric converter 3 due to the Peltier effect.
The heat is transferred from the thermoelectric converter 3 to the lower-side heat exchanger 9b. The heat is absorbed by the heat exchanger 9b on the lower surface side of the thermoelectric conversion device 3. Therefore, when the heat of the heat exchanger 9b is efficiently radiated, the heat continuously moves from the heat exchanger 9a to the heat exchanger 9b.

Therefore, it is necessary to suppress the heat resistance of the heat exchangers 9a and 9b. Therefore, the heat exchangers 9a and 9b come into contact with the thermoelectric converter 3 via the heat conductive grease 16 or the like. are doing. Further, as a material of the heat exchangers 9a and 9b, a metal material such as a finned aluminum extruded material is used.

[0005] A plurality of P-type semiconductor elements 1a and N-type semiconductor elements 1b are alternately arranged at fixed intervals, and adjacent P-type semiconductor elements 1a and N-type semiconductor elements 1b are arranged.
A first electrode plate 2a is joined to the first surfaces of a pair of semiconductor elements 1a and 1b in common, and a pair of adjacent P-type and N-type semiconductors not joined in common on the first surface. Element 2
By bonding the second electrode plate 2b in common to the surface of
A thermoelectric converter 3 in which a P-type semiconductor element 1a and an N-type semiconductor element 1b are alternately connected in series is disclosed in, for example,
It is known in JP-A-99578 and JP-A-63-20465.

As a prior art in the assembling process of the thermoelectric conversion device 3, for example, as described in the above-mentioned Japanese Patent Application Laid-Open No. 58-199578, a single electrode plate is arranged on a ceramic substrate by an assembling jig or the like. How to do it,
Patent No. 65, which discloses a technique in which a copper plate is directly baked on a ceramic substrate and then etched and plated
There is a method using a C (direct bonding copper) substrate. Incidentally, although it is not an assembly process of the thermoelectric conversion device 3, as a conventional technology of etching process on a tape, an etching method of a copper foil attached by a TAB (tape automated bonding) tape used in an assembly process of a semiconductor LSI is used. There is processing.

[0007]

However, in the above-described method using a DBC substrate, the arrangement of the electrode plates can be simplified, but not only is the cost of the substrate high, but also the cost of ancillary equipment such as dies and jigs. Required. Further, the ceramic substrate has a thickness of about 0.6 to 0.8 mm, and the characteristics are deteriorated due to thermal resistance.

The above TA using a chemical-resistant adhesive
The tape for B (tape automated bonding) is incorporated as it is attached to the semiconductor LSI, but because it does not have high thermal conductivity, it is not suitable for use in thermal bonding to a heat exchanger as it is.

In the case where the adhesive tape is attached to a heat conductive adhesive tape for etching and plating, the adhesive layer of the adhesive tape is exposed and the etched portion is exposed to an etching solution or a plating solution. Thermal conductive adhesive tapes that are not designed for etching use are not chemically resistant, so they are exposed to the etchant during the etching process, causing changes in the properties of the adhesive, and the residual etchant remaining in the adhesive. Effects on other materials over time (corrosion, etc.)
Is also a concern. For this reason, there is a method of applying a solid resist mask on the side of the copper plate to which the adhesive tape is attached. However, since this resist mask cannot be removed later, the thermal resistance of the bonding surface becomes a factor and the characteristics are reduced.

When a resist mask is formed on the side of the copper plate to which the adhesive tape is applied as a barrier property against chemicals, it is effective as a barrier against chemicals during etching. However, since the resist mask cannot be plated as it is after etching, it is necessary to wash and remove the resist mask on the copper plate surface before the plating step. At this time, the resist mask on the side of the copper plate to which the adhesive tape is attached is also removed, and the barrier property against chemicals is lost during plating.

Usually, a plurality of electrode plates are taken like an IC lead frame in order to improve production efficiency. However, in order to cut and divide on an adhesive tape after assembling, a space for cutting is formed in a cut portion. Is required, the yield (the number of products) is reduced, and a dedicated cutting device is also required. However, if the adhesive tape is cut before the assembling process, it becomes difficult to take a plurality of pieces.

Since the heat-conductive pressure-sensitive adhesive tape can be attached to the heat exchanger as it is, the process is simplified and the workability is improved. However, since the adhesive tape requires electrical insulation (DC current flows through the electrode plate), there is a limit to the heat conduction performance, and if the thickness is reduced to reduce the thermal resistance, the workability of the application will deteriorate. In addition, there is a limit in reducing the thickness itself.

An object of the present invention has been made in view of such a problem, and it is an object of the present invention to provide a method of manufacturing a thermoelectric converter which can simplify the assembly process of the thermoelectric converter and reduce the processing cost. is there. Another object of the present invention is to provide a method for manufacturing a thermoelectric conversion device having excellent barrier properties against chemicals during etching and plating. Further objects of the present invention are:
It is an object of the present invention to provide a method for manufacturing a thermoelectric conversion device that can simplify a plurality of devices. Still another object of the present invention is to provide a method for manufacturing a thermoelectric conversion device capable of improving heat exchange performance.

[0014]

According to the present invention, a plurality of P-type semiconductor elements and N-type semiconductor elements are alternately arranged at a fixed interval, and a first P-type / N-type semiconductor element pair adjacent to each other is formed. A first electrode plate is commonly bonded to the surfaces of the pair, and a second electrode plate is commonly shared to the second surfaces of a pair of adjacent P-type and N-type semiconductor elements that are not commonly bonded on the first surface. By joining
In a method of manufacturing a thermoelectric conversion device in which a P-type semiconductor element and an N-type semiconductor element are alternately connected in series, instead of arranging the first and second electrode plates one by one, a copper plate as an electrode base material is provided. A resist mask of an electrode pattern is formed by photo-etching or the like, and thereafter, the other adhesive surface of the double-sided adhesive tape 6 having a peelable separator 25 attached to one surface of the copper plate opposite to the surface on which the resist mask is formed. And the first electrode plate and the second electrode plate, which are two types of upper and lower electrode patterns, are collectively formed without being arranged. Next, the arranged first and second electrode plates adhered to the double-sided adhesive tape are directly subjected to electroless nickel plating. Next, solder printing is performed on each of the plated first and second electrode plates attached to the double-sided adhesive tape, and P-type semiconductor elements and N-type semiconductor elements are alternately arranged on the second electrode plate. The first electrode plate is placed on the upper surface, and reflow soldering is performed with the first electrode plate attached to the double-sided adhesive tape. Finally, the separator of the double-sided adhesive tape to which the first and second electrode plates are attached is peeled off, and the separator is directly attached to a heat exchanger for thermal connection.

[0015] In this case, an array of electrode plates can be formed on the double-sided adhesive tape by etching and plating into an array pattern of the electrode plates while the copper plate is adhered to the double-sided adhesive tape. A thermoelectric conversion device can be assembled on a double-sided adhesive tape by solder paste printing on a plate, alternate mounting of P-type / N-type semiconductor elements by a chip mounter or the like, and reflow soldering.

As the double-sided adhesive tape to be attached to the copper plate prior to the etching process, a tape having both solder heat resistance and thermal conductivity is used. Thereby, it can be thermally joined with a heat exchanger without peeling off the double-sided adhesive tape.

In the electrode pattern of the resist mask formed on the copper plate as the electrode substrate, a resist mask having a reversible pattern is formed on the non-etched surface side of the copper plate with respect to the resist mask pattern on the etched surface of the copper plate. Are used.
As a result, after the etched portion of the copper plate is removed, the adhesive surface of the double-sided adhesive tape is covered and protected by the resist mask on the non-etched surface side, so that the double-sided adhesive tape has an excellent barrier property against an etchant chemical.

In the resist mask formed on the copper plate as the electrode base material, the resist mask on the non-etching side of the copper plate to which the double-sided adhesive tape is applied is not a resist agent for etching, but a resist for plating or soldering. Use agent. Thus, when removing the resist mask on the etched surface side of the copper plate after the etching process, the resist mask on the non-etched surface side can be left without being removed, and the double-sided adhesive tape has excellent barrier properties against plating solution chemicals.

To obtain a plurality of electrode patterns on the double-sided pressure-sensitive adhesive tape, the double-sided pressure-sensitive adhesive tape is partially cut into a plurality of electrode pattern outer dimensions by Thomson processing or the like to remove unnecessary portions other than the electrode patterns. Then, a soldering heat-resistant masking tape or the like is again adhered thereon to form a two-layer integrated tape.

In order to achieve a higher thermal conductivity than the above-mentioned double-sided adhesive tape, another thermal conductive grease which can be easily peeled off after reflow soldering and has a higher thermal conductivity, such as a silicone adhesive or an epoxy adhesive. As the double-sided adhesive tape, a heat-peelable tape having a function of reducing the adhesive strength by heating is used so that the material can be thermally bonded.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) A method for manufacturing a thermoelectric converter according to Embodiment 1 of the present invention will be described with reference to FIGS. 1A to 1E show the order of the manufacturing process. First, as shown in FIG. 1A, the other adhesive surface of the double-sided adhesive tape 6 having a peelable separator 25 attached to one surface is attached to the back surface of the copper plate 4. On the front side of the copper plate 4, a resist mask 5a of a first electrode plate pattern corresponding to the arrangement of the first electrode plates 2a illustrated in FIG. 2 (corresponding to the arrangement of the second electrode plates 2b illustrated in FIG. 3). In the case of the second electrode plate pattern shown in FIG. As the double-sided adhesive tape 6, for example, a tape having both solder heat resistance and heat conductivity such as Sumitomo 3M tape 9885 is used.

Next, an etching process is performed as shown in FIG. Then, the resist mask 5a of the copper plate 4
-The part not covered with 5b is dissolved and removed. Then, as shown in FIG.
After removing and cleaning b, electroless nickel plating is performed to form a nickel film 24 on the surface of the copper plate 4. Next, solder printing 8 is performed on the nickel film 24 of the first electrode plate 2a and the second electrode plate 2b thus obtained, and the first electrode is formed as shown in FIG. A P-type semiconductor element 1a is mounted on a solder print 8 on
And the N-type semiconductor elements 1b are alternately arranged. Next, as shown in (E) of the figure, the second electrode plate 2b is combined and pressed onto the first electrode plate 2a in which the P-type semiconductor element 1a and the N-type semiconductor element 1b are arranged, and reflow soldering is performed. Finally, the separator 25 of the double-sided adhesive tape 6 is peeled off, and directly adhered to the heat exchangers 9a and 9b as shown in FIG.

(Embodiment 2) FIGS. 4 to 6 show Embodiment 2 of the present invention. As shown in FIG. 4, a resist mask 5 a (5 b) is applied to the etching surface, which is the surface of the copper plate 4, with an etching resist 12 a for an electrode pattern. A resist mask 18a (18b) is applied to the electrode pattern reversible with the pattern using a plating or solder resist agent 12b. In this case, as shown in FIG. 5, after the etched portion of the copper plate 4 is removed, the adhesive surface of the double-sided adhesive tape 6 is covered and protected by the reversible resist mask 18a (18b). The effect of the etchant chemical on the adhesive surface at the time can be prevented.
Next, as shown in FIG. 6, before the plating step, the resist mask 5a (5b) for etching the surface of the copper plate 4 is washed and removed. At this time, the resist mask 18a (18b) made of the plating or solder resist agent 12b is used. Remains without being removed by the cleaning agent for the resist mask 5a (5b), so that the adhesive surface of the adhesive tape is covered and protected during plating. Since the resist mask 18a (18b) does not intervene at the joint portion between the copper plate 4 and the double-sided adhesive tape 6, there is no fear that the resist mask 18a (18b) affects thermal resistance. Other configurations are the same as those in the first embodiment.

(Embodiment 3) FIGS. 7 and 8 show Embodiment 3 of the present invention. As shown in FIG. 7, in order to obtain a plurality of electrode patterns on the double-sided adhesive tape 6, a part of the double-sided adhesive tape 6 is partially cut into a plurality of electrode pattern outer dimensions by Thomson processing or the like, and the other than the electrode pattern is removed. The unnecessary portion 13 is removed. Next, as shown in FIG. 8, a masking tape 14 having solder heat resistance and the like are stuck thereon to form an integrated tape 15, and the separator 25 of the double-sided adhesive tape 6 is peeled off and stuck to the copper plate 4. At this time, the copper plate 4 has been subjected to the double-sided resist mask processing, and has a resist mask 18a (18) having a reversible electrode pattern with the electrode pattern on the etching surface.
b) The side is aligned with the integrated tape 15 and attached. Other configurations are the same as those in the second embodiment.

(Embodiment 4) FIGS. 9 and 10 show Embodiment 4 of the present invention. In order to achieve higher thermal conductivity than the double-sided adhesive tape 6, another thermal conductive grease 16 which can be easily peeled off after reflow soldering and has higher thermal conductivity.
As a double-sided adhesive tape 6, a heat-peelable tape 17 having a function of significantly reducing the adhesive strength when heated is used so that the material can be thermally bonded with a material such as (see FIG. 11). Such a heat-peeling tape 17 can be easily peeled off after soldering, and enables heat bonding to the heat exchangers 9a and 9b with a heat conductive grease 16 or the like to further suppress the heat resistance.
Other configurations are the same as those in the first embodiment.

[0026]

As described above, according to the first aspect of the present invention, in an efficient skeleton thermoelectric converter using only semiconductor elements and electrode plates that do not use an insulating substrate, the electrode plate assembling process is simplified. It is omitted, and ancillary equipment costs such as dies and jigs are not required, and processing costs can be reduced.

According to the second aspect of the present invention, it is possible to easily prevent the effect of the chemical at the time of etching on the adhesive surface of the double-sided adhesive tape.

According to the third aspect of the present invention, it is possible to prevent the effects of chemicals at the time of etching or plating on the adhesive surface of the double-sided adhesive tape, so that it is not necessary to develop a new chemical-resistant tape. Easy.

According to the fourth aspect of the present invention, it is not necessary to cut the double-sided adhesive tape by post-processing in order to take a plurality of pieces, and without preparing a dedicated tape cutting jig or the like, a plurality of pieces can be obtained. The assembly and separation of the thermoelectric converter can be easily performed.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of a thermoelectric conversion device according to a first embodiment.

FIG. 2 is a plan view of an arrangement pattern of first electrode plates of the thermoelectric conversion device according to the first embodiment.

FIG. 3 is a plan view of an arrangement pattern of a second electrode plate of the thermoelectric conversion device according to the first embodiment.

FIG. 4 is a process chart of forming a resist mask of the thermoelectric conversion device according to the second embodiment.

FIG. 5 is an etching process diagram of the thermoelectric conversion device of the second embodiment.

FIG. 6 is a process chart of removing a resist mask of the thermoelectric conversion device according to the second embodiment.

FIG. 7 is a sectional view of a copper plate of the thermoelectric conversion device according to the third embodiment.

FIG. 8 is a sectional view of an etching tape of the thermoelectric conversion device according to the third embodiment.

FIG. 9 is a structural diagram of the thermoelectric conversion device of Embodiment 4 using a heat-peelable tape.

FIG. 10 is a cross-sectional view showing an example of assembling a thermoelectric conversion device according to a fourth embodiment using a heat-peelable tape.

FIG. 11 is a basic structural diagram of a conventional thermoelectric conversion device.

[Explanation of symbols]

1a P-type semiconductor element 1b N-type semiconductor element 2a first electrode plate 2b second electrode plate 3 thermoelectric converter 4 copper plate 5a resist mask (for first electrode plate) 5b resist mask (for second electrode plate) 6 Double-sided adhesive tape 8 Solder printing 9a Heat exchanger (heat absorbing side) 9b Heat exchanger (radiating side) 12a Etching resist 12b Resist for soldering (solder) 13 Unnecessary parts other than electrolytic pattern 14 Masking of solder heat resistance Tape 15 Integrated tape 16 Thermal conductive grease 17 Thermal peelable tape 18a Reversible resist mask (for first electrode plate) 18b Reversible resist mask (for second electrode plate) 24 Nickel film

Claims (4)

(57) [Claims] A plurality of P-type semiconductor elements and N-type semiconductor elements are alternately arranged at a constant interval, and adjacent P-type / N-type semiconductor elements are arranged.
A first electrode plate is jointed to the first surfaces of the pair of semiconductor elements in common, and adjacent Ps that are not jointly joined to the first surfaces are connected to each other.
In a method of manufacturing a thermoelectric conversion device in which a P-type semiconductor element and an N-type semiconductor element are alternately connected in series by joining a second electrode plate in common to the second surfaces of a pair of N-type and N-type semiconductor elements. A resist mask of an electrode pattern is formed on one side of a copper plate as an electrode substrate, and then a peelable separator is attached on one side to a surface opposite to the surface on which the resist mask is formed on the copper plate. A process of collectively forming a first electrode plate and a second electrode plate, which are two types of upper and lower electrode patterns, by attaching and etching an adhesive surface on the other side; A step of electroless nickel plating the attached first and second electrode plates as they are, and then performing solder printing on the first and second electrode plates attached to the double-sided adhesive tape, respectively. P type on board After alternately arranging the conductor elements and the N-type semiconductor elements, a first electrode plate is placed thereon and reflow soldering is performed with the first electrode plate adhered to a double-sided adhesive tape. Removing the separator of the double-sided adhesive tape attached to the electrode plate and directly attaching the electrode plate to a heat exchanger to thermally connect the electrode plate to the heat exchanger. 2. The method for manufacturing a thermoelectric conversion device according to claim 1, wherein a resist mask having a pattern reversible from the pattern of the resist mask formed on the etched surface of the copper plate is formed on the non-etched surface of the copper plate. 3. The thermoelectric device according to claim 2, wherein the resist mask on the etched surface of the copper plate 4 is formed of an etching resist, and the resist mask on the non-etched surface of the copper plate is formed of a plating or solder resist. A method for manufacturing a conversion device. 4. In order to obtain a plurality of electrode patterns on the double-sided adhesive tape, the double-sided adhesive tape is partially cut into a plurality of external dimensions of the electrode pattern by Thomson processing or the like to remove unnecessary portions other than the electrode pattern. 2. The method for manufacturing a thermoelectric conversion device according to claim 1, wherein the heat-resistant conversion tape is removed, and a masking tape having solder heat resistance is attached thereon to form an integrated tape.