JPH0897472A - Thermoelectric transducer and its manufacture - Google Patents

Abstract

PURPOSE: To provide a thermoelectric transducer which is small in size and thin in thickness and which facilitates the arrangement of a large number of thermoelectric material chips on a unit area. CONSTITUTION: A P-type (N-type) thermoelectric material wafer 40 is joined to a P-type (N-type) substrate 42 on which electrode wirings 43 are provided with a gap therebetween. By utilizing the gap, the unnecessary parts of the thermoelectric material wafer 40 joined to the substrate 42 are cut off and removed to obtained the substrate 42 on which thermoelectric material chips 45 are bonded. The substrate 42 on which the P-type thermoelectric material chips are bonded and the substrate 42 on which the N-type thermoelectric material chips are bonded are made to face each other and the tips of the chips are joined to the electrode wirings 43 on the substrates to form P-N junctions. A structure 44 which is used for the alignment in two joint processes and also used for blocking the flow of joint material is provided around the junction part of the substrate 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion element which enables temperature difference power generation (thermoelectric power generation) by the Seebeck effect and electronic cooling and heat generation by the Peltier effect, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A thermoelectric conversion element is manufactured by joining a P-type thermoelectric material and an N-type thermoelectric material through an electrically conductive electrode such as metal to form a PN junction pair. Since this thermoelectric conversion element generates a thermoelectromotive force based on the Seebeck effect by giving a temperature difference between the pair of junctions, it functions as a power generator. There are applications such as a cooling device and a precision temperature control device utilizing the so-called Peltier effect that generates heat.

Generally, a thermoelectric conversion element is used as a module in which a plurality of PN junction pairs are connected in series in order to improve its performance. The structure of this module is such that a P-type and N-type thermoelectric material piece (called a thermoelectric material chip) having a rectangular parallelepiped shape with a side of several hundred μm to several mm is an electrically insulating substrate such as alumina or aluminum nitride. The P-type thermoelectric material chip and the N-type thermoelectric material chip are PN-joined by electrodes made of a conductive material such as metal formed on the substrate, and at the same time, the thermoelectric material chips are connected in series. Connected to.

FIG. 15 shows a cross section of a conventional thermoelectric conversion element having such a structure (hereinafter, referred to as a thermoelectric conversion element including a module in which a plurality of thermoelectric material chips are arranged) in a direction parallel to a substrate. It is a figure showing the arrangement of the electrodes of the substrate and the thermoelectric material chips in the cross section of each part perpendicular to the substrate. FIG. 15A is a diagram showing the arrangement of electrode wirings and thermoelectric material chips on the substrate in a cross section in the direction parallel to the substrate of the conventional thermoelectric conversion element, in other words, the arrangement of electrodes and thermoelectric material chips from the top of the substrate. FIG. The electrode pattern shown by the solid line shows the electrode wiring 151 of the upper substrate, and the electrode pattern shown by the dotted line shows the electrode wiring 152 of the lower substrate. Also, the upper substrate electrode wiring 151
The shaded quadrangle inside the portion where the lower substrate electrode wiring 152 and the lower substrate electrode wiring 152 intersect is a P-type thermoelectric material chip 153.
And the N-type thermoelectric material chip 154 is shown. 15 (b), (c), and (d) are shown in FIG.
X1-X1 ', X2-X2' and Y1-Y in
It is a figure which shows each vertical cross section in 1 '. As can be seen from FIG. 15, the arrangement of the thermoelectric material chips in the conventional thermoelectric conversion element is arranged in a grid on the substrate, and each side of the grid (X direction and Y direction in FIG. 15A). In, the P-type thermoelectric material chips and the N-type thermoelectric material chips were arranged so that they always appeared alternately.

An outline of a conventional method for manufacturing a thermoelectric conversion element composed of a plurality of such thermoelectric material chips will be described below. FIG. 16 is a vertical sectional view showing an outline of processing of a thermoelectric material in manufacturing a conventional thermoelectric conversion element. FIG. 16A shows a thermoelectric material 1 processed into a plate shape or a rod shape.
A cross section of 61 is shown. Layers 162 for soldering Ni or the like are formed by plating on both surfaces of the thermoelectric material to be joined to the substrate (FIG. 16B).
Then, the thermoelectric material chip 163 having layers 162 for soldering on both sides by cutting this thermoelectric material
Are manufactured for P-type and N-type (FIG. 16C).

Next, each of the thermoelectric material chips thus produced is placed on a predetermined electrode wiring on the substrate by using a jig or the like and bonded to produce a thermoelectric conversion element. . FIG. 17 is a diagram showing a conventional manufacturing method for manufacturing a thermoelectric conversion element using a thermoelectric material chip and a substrate provided with wiring. FIG. 17A shows the state of the substrate 171 and the thermoelectric material chip 172 before joining. On the substrate 171, electrode wiring 173 for performing PN junction and a bonding material 174 for bonding the thermoelectric material chip 172 on the surface thereof are formed in layers. Thermoelectric conversion element 17 is formed by joining each part.
FIG. 17 (b) is a vertical cross-sectional view of the one manufactured as No. 5.

[0007]

The size of each thermoelectric material chip used as a thermoelectric conversion element is several hundred μm on a side.
Although it is a rectangular parallelepiped with a size of several tens to several hundreds of μm, it is said that a device having a size and a thickness of several tens to several hundreds of μm has higher performance in recent years. Is starting to appear. For example, IEICE Transactions C-II, Vol. J75-C-II, No. 8, p
p. This content is described in 416-424 and the like,
At the same time, he explains the importance of design to heat.

Further, the number of thermoelectric material chip pairs in one thermoelectric conversion element is at most several hundreds, and the density thereof is up to several tens of pairs / cm 2, but the number of thermoelectric material chip pairs is increased. This is one of the very important factors in improving performance and expanding its applications. Particularly in power generation using a small temperature difference, the electromotive force generated is proportional to the number of thermoelectric material chip pairs, so in order to extract a high voltage, the number of thermoelectric material chips connected in series within the thermoelectric conversion element should be increased as much as possible. Is desired. Furthermore, even when a thermoelectric conversion element is used as a cooling element or a temperature control element, if the number of thermoelectric material chips arranged in series is small, the current flowing through the element becomes large, and the wiring and power source are increased. Therefore, it is desired to arrange as many thermoelectric material chips as possible in series.

As described above, miniaturization, thinning, thermal design, and an increase in the number of thermoelectric material chip pairs connected in series in one thermoelectric conversion element lead to higher performance of the thermoelectric conversion element, and at the same time, the application It is becoming a point of expansion. However, when the thermoelectric conversion element having the conventional structure shown in FIG. 15 is manufactured by the manufacturing method shown in FIGS. 16 and 17, it is necessary to handle each thermoelectric material chip one by one, and thus workability and processing accuracy are improved. Considering this, there was a limit to reducing the size of the chip and the size of the device. Materials such as Bi-Te-based materials and Fe-Si-based materials, which are thermoelectric materials with particularly good performance, have low mechanical strength, so that the size of the thermoelectric material chip may be several hundred μm or less. When a thermoelectric conversion element having an extremely large number of chips is manufactured, it is difficult to handle the thermoelectric material, and it is difficult to manufacture the thermoelectric conversion element having the conventional structure by the conventional manufacturing method.

Therefore, an object of the present invention is to reduce the size of thermoelectric material chips and increase the number of thermoelectric material chips (chip density) per unit area, thereby providing a small and high-performance thermoelectric conversion element. It is to provide the manufacturing method.

[0011]

Therefore, according to the present invention, a new manufacturing method can be adopted by changing the arrangement of the thermoelectric material chip in the conventional thermoelectric conversion element on the substrate, and the size of the thermoelectric material chip can be increased. It is intended to obtain a thermoelectric conversion element having a reduced chip size and a high chip density.

According to the first aspect of the present invention, the electrode wiring is used.
A single substrate and at least a pair of chip-shaped P-type and N-type substrates sandwiched between them and PN-bonded via electrode wiring
A thermoelectric conversion element composed of a thermoelectric material chip, wherein the thermoelectric material chip has a quadrangular cross-sectional shape in a plane parallel to the substrate, and the thermoelectric material chip has a pair of P-type and N-type thermoelectric material chips. Make sure that the position / direction relationship between the straight line connecting the centers of the quadrangle and the four sides forming the quadrangle, which is the cross-sectional shape of each thermoelectric material chip forming this PN junction pair, is neither orthogonal nor parallel. It is a thermoelectric conversion element in which a thermoelectric material chip and an electrode for PN junction formed on a substrate are arranged.

The thermoelectric conversion element according to claim 2 is the thermoelectric conversion element according to claim 1.
In the thermoelectric conversion element described, PN which constitutes this element
In addition to the thermoelectric material chip having a joint, a dummy thermoelectric material chip that is not electrically connected is joined and arranged in the element. The thermoelectric conversion element according to claim 3 is the thermoelectric conversion element according to claim 1, wherein a plurality of thermoelectric material chips of the same type are formed on one electrode of the electrodes for forming the PN junction pair formed on the substrate. Has an electrode which is joined.

According to a fourth aspect of the present invention, the electrode wiring is used as the second wiring.
A single substrate and at least a pair of chip-shaped P-type and N-type substrates sandwiched between them and PN-bonded via electrode wiring
A thermoelectric conversion element composed of a thermoelectric material having a rectangular shape in cross section in a plane parallel to the substrate of the thermoelectric material chip, and the thermoelectric material chip having the cross sectional shape of the thermoelectric material chip on the substrate. The chips are arranged in a grid shape in the direction of the sides of the quadrangle, and the arrangement of chips forming one side of this grid arrangement is such that P-type thermoelectric material chips and N-type thermoelectric material chips are alternately arranged, and P-type thermoelectric material chips are formed on the other side. This is a thermoelectric conversion element in which rows in which only thermoelectric material chips or N-type thermoelectric material chips are arranged are alternately arranged.

A thermoelectric conversion element according to a fifth aspect is the fourth aspect.
In the thermoelectric conversion element described, PN which constitutes this element
In addition to a thermoelectric material chip having a joint, a dummy thermoelectric material chip that is not electrically connected is joined and arranged in the element. The thermoelectric conversion element according to claim 6,
The thermoelectric conversion element according to claim 4, wherein among the electrodes for forming the PN junction pair formed on the substrate, there is an electrode to which a plurality of thermoelectric material chips of the same type are joined on one electrode. There is something.

According to a seventh aspect of the present invention, an electrode wiring is used.
A thermoelectric conversion element composed of at least a pair of chip-shaped P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring, wherein the thermoelectric material chip has a cross-sectional shape. The width of the thermoelectric conversion element is different between the vicinity of the substrate and the center of the chip in the direction perpendicular to the substrate.

According to the present invention of claim 8, electrode wiring is used.
A thermoelectric conversion element composed of at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring, wherein the thermoelectric material chip and the substrate are bonded together. At least one of the
It is a thermoelectric conversion element in which a structure is provided on all or part of the surface of a substrate in the vicinity thereof.

The thermoelectric conversion device according to claim 9 is the thermoelectric conversion device according to claim 8.
In the thermoelectric conversion element described above, the structure provided on the substrate has a P-type thermoelectric material chip and an N-type on at least one substrate.
In the portion where the die thermoelectric material chip is arranged, the size,
Alternatively, the thermoelectric conversion elements have different shapes.

A thermoelectric conversion element according to a tenth aspect is the thermoelectric conversion element according to the eighth aspect, wherein the structure provided on the substrate is two substrates constituting the thermoelectric conversion element for the same thermoelectric material chip. , Thermoelectric conversion elements having different sizes or shapes. The thermoelectric conversion element according to claim 11 is the thermoelectric conversion element according to claim 8, wherein the material of the structure provided on the substrate is a polymer material.

A thermoelectric conversion element according to a twelfth aspect is the thermoelectric conversion element according to the eighth aspect, in which the structure provided on the substrate is formed by curing a photosensitive resin material. According to a thirteenth aspect of the present invention, two electrodes are wired.
A single substrate and at least a pair of chip-shaped P-type and N-type substrates sandwiched between them and PN-bonded via electrode wiring
A thermoelectric conversion element made of a thermoelectric material, wherein at least one of the two substrates forming the element is silicon.

A thermoelectric conversion element according to a fourteenth aspect is the thermoelectric conversion element according to the thirteenth aspect, in which the whole or a part of the surface of the silicon substrate constituting the element is covered with an insulating layer. . The invention according to claim 15 is
A thermoelectric conversion element comprising two substrates having electrode wiring, and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via the electrode wiring. In the bonding on at least one of the one substrate, the composition of the bonding material for bonding the thermoelectric material chip and the electrode formed on the substrate is different between the heterogeneous thermoelectric material chips. It is a thermoelectric conversion element.

According to a sixteenth aspect of the present invention, two substrates having electrode wiring are sandwiched between the two substrates, and at least a pair of chip-like P-type and N-type substrates which are PN-bonded via the electrode wiring.
A thermoelectric conversion element composed of a thermoelectric material of a die type, wherein a thermoelectric material chip and an electrode for forming a PN junction formed on a substrate are bonded via a projecting electrode.

A thermoelectric conversion element according to a seventeenth aspect is the thermoelectric conversion element according to the sixteenth aspect, wherein a projecting electrode for joining the thermoelectric material chip and the electrode formed on the substrate is formed on the thermoelectric material chip. It is a thermoelectric conversion element. The thermoelectric conversion element according to claim 18 is the thermoelectric conversion element according to claim 16, wherein a projecting electrode for joining the thermoelectric material chip and the electrode formed on the substrate is formed on the thermoelectric material chip. It is a thermoelectric conversion element which is a projecting electrode having.

According to a nineteenth aspect of the present invention, two substrates having electrode wiring and at least a pair of chip-like P-type and N-type substrates sandwiched between these substrates and PN-bonded via the electrode wiring are provided.
A method for manufacturing a thermoelectric conversion element composed of a thermoelectric material, comprising plate-shaped or rod-shaped P-type and N-type thermoelectric materials (hereinafter
The plate-shaped or rod-shaped thermoelectric material is called a wafer-shaped thermoelectric material or a thermoelectric material wafer. 2) is separately bonded to two substrates provided with predetermined electrode wiring for forming a PN junction. Next, the joined thermoelectric material wafers are cut and removed as necessary so that the electrodes to which the different types of thermoelectric material chips are to be joined appear. At this time, a part of the substrate or the electrode wiring is also cut if necessary. By these steps, the P-type thermoelectric material chip is bonded to the predetermined electrode, and the electrode to which the N-type thermoelectric material chip is to be bonded is exposed on the surface, and the N-type thermoelectric material chip is connected to the predetermined electrode. Two substrates are produced which have electrodes on their surfaces which are to be joined and to which the P-type thermoelectric material chips are to be joined. Next, with respect to these two substrates, the surfaces on which the thermoelectric material chips are bonded are opposed to each other, the thermoelectric material chips and the substrate electrodes are aligned with each other at predetermined positions, and the tips of the thermoelectric material chips and the substrate are placed on each other. The thermoelectric conversion element is completed by forming a thermoelectric conversion element by forming a PN junction pair through an electrode made of metal or the like by joining the PN junction electrode with the PN junction electrode.

A method for manufacturing a thermoelectric conversion element according to a twentieth aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein a gap is provided between the thermoelectric material wafer and the substrate when joining the thermoelectric material wafer and the substrate. In the next step, which is the next step of cutting and deleting the thermoelectric material in unnecessary parts, this gap is used to cut and delete only the thermoelectric material wafer without damaging the substrate and electrodes, and the thermoelectric material chip is bonded. It is the one that makes up the printed circuit board.

A method for manufacturing a thermoelectric conversion element according to a twenty-first aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein a step of forming predetermined electrode wiring on the surface of the substrate and a surface of the thermoelectric material wafer are included. Solder having a predetermined shape and arrangement pattern on at least one surface to be joined to the substrate,
A step of forming bumps of gold, silver, copper, nickel, etc.,
And a step of joining the substrate and the thermoelectric material through the bumps.

A method for manufacturing a thermoelectric conversion element according to a twenty-second aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein in joining the thermoelectric material wafer and the substrate, the thermoelectric material wafer and the substrate are joined together. This is a method for manufacturing a thermoelectric conversion element in which a gap is provided in the gap and the gap is formed by a bump.

A method for manufacturing a thermoelectric conversion element according to a twenty-third aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein in joining the thermoelectric material wafer and the substrate, the thermoelectric material wafer and the substrate are joined together. A method for manufacturing a thermoelectric conversion element, in which a gap is provided in the substrate and the gap is formed by a structure provided on the substrate.

The method of manufacturing a thermoelectric conversion element according to claim 24 is the method of manufacturing a thermoelectric conversion element according to claim 19, wherein after the thermoelectric material wafer and the substrate are bonded, the surface of the thermoelectric material wafer bonded to the substrate. Among these, it is a method for manufacturing a thermoelectric conversion element, which is produced by forming bumps on the surface opposite to the surface bonded to the substrate.

A method for manufacturing a thermoelectric conversion element according to a twenty-fifth aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein at least one of the surfaces of the thermoelectric material wafer is bonded before the bonding of the thermoelectric material wafer and the substrate. This is a method for manufacturing a thermoelectric conversion element, in which all or part of the surface is processed so that the joint with the substrate or the portion in the vicinity of the joint becomes convex.

A method for manufacturing a thermoelectric conversion element according to a twenty-sixth aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein at least one of the surfaces of the thermoelectric material wafer is bonded before the bonding of the thermoelectric material wafer and the substrate. It is a method for manufacturing a thermoelectric conversion element, which has a step of grooving all or part of the surface.

A method of manufacturing a thermoelectric conversion element according to a twenty-seventh aspect is the method of manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein bonding is performed to bond the thermoelectric material wafer to the substrate before bonding the thermoelectric material wafer to the substrate. A method for manufacturing a thermoelectric conversion element, which comprises a step of grooving all or a part of at least one surface of a thermoelectric material wafer having a material or a layer of material for assisting bonding formed on at least one surface.

A method for manufacturing a thermoelectric conversion element according to a twenty-eighth aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, in which the thermoelectric material wafer and the substrate are bonded to each other before the first bonding. A step of grooving at least one of all or part of the surface of the thermoelectric material wafer on which the bumps are formed on the surface, and the grooving is performed between the bumps. It is a method of manufacturing an element.

A method for manufacturing a thermoelectric conversion element according to a twenty-ninth aspect is the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, wherein at least one surface of the thermoelectric material wafer is before the first bonding of the thermoelectric material wafer and the substrate. Has a step of grooving all or part of it, and the width of the groove formed in the thermoelectric material wafer by this grooving and the cutting in the subsequent step of cutting / removing unnecessary parts of the thermoelectric material wafer. A method for manufacturing a thermoelectric conversion element, in which the widths of the deleted portions are different.

[0035]

In the thermoelectric conversion element according to claim 1, the positional relationship between the P-type thermoelectric material chip and the N-type thermoelectric material chip, and
Because of the directional relationship between the P-type and N-type thermoelectric material chips and the PN junction electrodes, the degree of freedom in designing a thermoelectric conversion element having a plurality of PN junctions can be increased and the degree of freedom in the manufacturing method can be increased. It is possible to manufacture a thermoelectric conversion element including a thermoelectric material chip having a thickness of several hundreds μm or less.

In the thermoelectric conversion element according to the second aspect, since the electrically isolated thermoelectric material chip is bonded to the substrate, the mechanical strength of the thermoelectric conversion element can be increased. In the thermoelectric conversion element according to claim 3, since the thermoelectric material chip of the same type is bonded to one electrode for the PN junction, the mechanical strength is increased, and even if one is damaged, the function as an element is achieved. I can fulfill.

In the thermoelectric conversion element according to the fourth aspect, the degree of freedom in designing the thermoelectric conversion element having a plurality of PN junctions can be increased by the positional relationship between the P-type thermoelectric material chip and the N-type thermoelectric material chip and the relationship between them. Since the degree of freedom of the manufacturing method can be increased at the same time as the temperature is increased, it is possible to manufacture a thermoelectric conversion element composed of a thermoelectric material chip of several hundreds μm or less.

In the thermoelectric conversion element according to the fifth aspect, since the electrically isolated thermoelectric material chip is bonded to the substrate, the mechanical strength of the thermoelectric conversion element can be increased. In the thermoelectric conversion element according to claim 6, since the thermoelectric material chips of the same type are joined to one electrode for PN junction, the mechanical strength is increased, and even if one is broken, it functions as an element. I can fulfill.

In the thermoelectric conversion element according to the seventh aspect, the location where Joule heat is generated by energization can be defined by the cross-sectional shape when the Peltier effect is used. Further, in this method for manufacturing a thermoelectric conversion element, a thermoelectric conversion element composed of a thermoelectric material chip having a thickness of several hundred μm or less can be manufactured, and the yield can be improved.

In the thermoelectric conversion element according to the eighth aspect, the structure near the bonding portion on the substrate prevents the flow of the bonding material such as solder at the time of bonding the substrate and the thermoelectric material, and at the same time, prevents the thermoelectric material from flowing to the substrate. Makes alignment easier. In the thermoelectric conversion element according to claim 9, the size and shape of the structure in the vicinity of the joint on one substrate are different in the portion where the P-type thermoelectric material chip and the N-type thermoelectric material chip are arranged. Thereby, it is possible to join the thermoelectric materials without making a mistake. In addition, when a P-type thermoelectric material chip and an N-type thermoelectric material chip are first bonded to different substrates and then facing each other to perform PN bonding, when manufacturing a thermoelectric conversion element, positioning is performed at the first bonding. By using a smaller structure, the positioning accuracy of the joint can be improved, and by increasing the structure used for positioning in the second joint (PN joint), a margin can be provided for positioning and the joint can be performed at the same time. The flow of material can be prevented.

In the thermoelectric conversion element according to the tenth aspect, the structure provided on the substrate is the same thermoelectric material chip, and the two substrates constituting the thermoelectric conversion element have different sizes or shapes. By doing so, it is possible to join the thermoelectric materials without making a mistake. In addition, when a P-type thermoelectric material chip and an N-type thermoelectric material chip are first bonded to different substrates and then facing each other to perform PN bonding, when manufacturing a thermoelectric conversion element, positioning is performed at the first bonding. By using a smaller structure, the positioning accuracy of the joint can be improved, and by increasing the structure used for positioning in the second joint (PN joint), a margin can be provided for positioning and the joint can be performed at the same time. The flow of material can be prevented.

In the thermoelectric conversion element according to the eleventh aspect, since the structure near the joint on the substrate is made of a polymer material, the heat conduction is poor, so that the heat from the high temperature end to the low temperature end of the thermoelectric conversion element is not transferred. The flow is suppressed and the performance of the device is not deteriorated. In the thermoelectric conversion element according to claim 12, since the structure in the vicinity of the bonding portion on the substrate is made of cured photosensitive resin, it can be miniaturized by a photolithography method. When manufacturing a thermoelectric conversion element composed of the thermoelectric material chip, it works effectively as a structure.

In the thermoelectric conversion element according to the thirteenth aspect, fine processing can be performed by using silicon for the substrate. Therefore, it is possible to manufacture a thermoelectric conversion element composed of thermoelectric material chips of several hundred μm or less. . In addition, the thermal conductivity of silicon is not only higher than that of ceramics such as alumina, but also higher than that of metals such as aluminum at low temperatures, which makes it possible to efficiently absorb and release heat from the substrate. Therefore, the performance of the thermoelectric conversion element can be improved.

In the thermoelectric conversion element according to the fourteenth aspect, by providing the insulating layer on the silicon of the substrate, the electrical insulation between the substrate and the thermoelectric material chip can be completed. In the thermoelectric conversion element according to the fifteenth aspect, after the P-type thermoelectric material chip and the N-type thermoelectric material chip are respectively bonded to different substrates, bonding can be easily performed in bonding for forming a PN junction pair. .

In the thermoelectric conversion element according to the sixteenth aspect, since the PN junction can be easily formed by the projecting electrode, a method for producing a thermoelectric conversion element composed of a thermoelectric material chip with a size of several hundreds μm. Can be adopted. In the thermoelectric conversion element according to claim 17, since the projecting electrode is formed on the thermoelectric material, the alignment with the substrate for producing the PN junction can be easily performed.
A thermoelectric conversion element including a thermoelectric material chip with a size of several hundreds of μm can be easily manufactured.

In the thermoelectric conversion element according to claim 18, since the projecting electrodes have a solder bump structure formed on the thermoelectric material, the P-type thermoelectric material chip and the N-type thermoelectric material chip because the solder melts at the time of joining. Even if the heights are different, the difference in height can be offset by the solder, and the thermoelectric conversion element can be easily manufactured.

In the method of manufacturing a thermoelectric conversion element according to claim 19, the P-type and N-type thermoelectric material wafers are separately provided on two substrates provided with predetermined electrode wirings in order to previously form a PN junction. After joining, a predetermined portion of the joined thermoelectric material wafer is cut and removed to obtain a thermoelectric material chip joined to the substrate. At this time, the electrodes to which the different types of thermoelectric material chips are to be joined are exposed. The P-type thermoelectric material chip thus produced is joined to the substrate, and the N-type thermoelectric material chip is joined to the substrate, and they are joined at a predetermined position to produce a thermoelectric conversion element. can do.

In the method of manufacturing a thermoelectric conversion element according to the twentieth aspect, since there is a gap between the substrate and the bonded thermoelectric material wafer, when a predetermined portion of the thermoelectric material is cut / deleted by a device used for cutting / deletion. , It can be done at this gap. This makes it possible to cut / delete unnecessary portions of the thermoelectric material without breaking or damaging the electrode wiring on the substrate.

In the method of manufacturing a thermoelectric conversion element according to claim 21, an electrode for performing PN junction is formed on the substrate, and bumps of solder, gold, silver, copper, nickel or the like are formed on at least one surface of the thermoelectric material wafer. The step of forming and the step of joining the substrate and the thermoelectric material through the bumps can achieve miniaturization, so that the arrangement and spacing of thermoelectric material chips with a size of several hundred μm or less can be achieved. A thermoelectric conversion element can be manufactured.

In the method for manufacturing a thermoelectric conversion element according to the twenty-second aspect, since the gap is provided between the substrate and the thermoelectric material wafer by the bump formed on the surface of the thermoelectric material chip,
It is possible to cut and remove unnecessary portions of the thermoelectric material without breaking or damaging the electrode wiring on the substrate.

In the method of manufacturing a thermoelectric conversion element according to the twenty-third aspect, since a gap is formed between the bonded substrate and the thermoelectric material wafer by the structure provided on the substrate, the electrode wiring on the substrate is formed. Unnecessary parts of thermoelectric material can be cut and deleted without breaking or damaging.

In the method for manufacturing a thermoelectric conversion element according to the twenty-fourth aspect, since the bumps are formed on the surface of the thermoelectric material bonded to the substrate, the bumps can be easily formed as compared with the case where the bumps are simultaneously formed on both surfaces of the thermoelectric material wafer. Can be formed. In the method for manufacturing a thermoelectric conversion element according to claim 25, all or a part of the surfaces to be bonded of the thermoelectric material wafer used for bonding with the substrate are processed so that the bonding portions or the vicinity of the bonding portions are convex. Therefore, after joining the substrate and the thermoelectric material wafer, a gap can be formed between the substrate and the thermoelectric material wafer. Further, the cross-sectional shape of the thermoelectric material chip can be changed in the height direction of the thermoelectric material chip by the width of cutting / deleting and the shape of the convex portion.

In the method of manufacturing a thermoelectric conversion element according to a twenty-sixth aspect, among the surfaces of the thermoelectric material wafer, at least one of the surfaces to be bonded to the substrate is wholly or partially formed by physical or chemical means, By performing the grooving process, it is possible to form a convex portion at or near the joint portion.
With this convex portion, a gap can be provided between the thermoelectric material wafer and the substrate after bonding. By utilizing this gap, unnecessary portions of the thermoelectric material can be cut / deleted without breaking or damaging the electrode wiring on the substrate. Further, the cross-sectional shape of the thermoelectric material chip can be changed in the height direction of the thermoelectric material chip depending on the width of cutting / deleting and the shape of the convex portion.

In the method of manufacturing a thermoelectric conversion element according to claim 27, at least one of the surfaces of the thermoelectric material wafer provided with a bonding material layer or a layer for assisting the bonding is bonded to the substrate. Alternatively, a convex portion can be formed in the joint portion or in the vicinity of the joint portion by performing a grooving process such as the groove 67 of FIG. 6B using a physical or chemical means for a part thereof. Therefore, since a gap can be provided between the thermoelectric material wafer and the substrate after bonding, unnecessary portions of the thermoelectric material can be cut / deleted without breaking or damaging the electrode wiring on the substrate. You can In addition, by taking into consideration the width of cutting / removal and the shape of the convex portion, in the cross-sectional shape of the thermoelectric material chip of the completed thermoelectric conversion element in the plane perpendicular to the substrate, it is You can change the width.

In the method of manufacturing a thermoelectric conversion element according to claim 28, of the surface of the thermoelectric material wafer on which bumps for bonding to a substrate are formed, at least one surface on which the bumps are formed is wholly or partially. By using a physical or chemical means to form a groove between the bumps, it is possible to form a convex portion at or near the joint portion. Since a gap can be provided between the electrode and the substrate, the unnecessary portion of the thermoelectric material can be cut / deleted without breaking or damaging the electrode wiring on the substrate. Further, the cross-sectional shape of the thermoelectric material chip can be changed in the height direction of the thermoelectric material chip by the width of cutting / deleting and the shape of the convex portion.

In the method of manufacturing a thermoelectric conversion element according to claim 29, at least one surface of the surface of the thermoelectric material wafer to be bonded to the substrate is entirely or partially formed by using a physical or chemical means, For example, grooves 93 and 94 of FIG.
By carrying out such grooving processing, it is possible to form a convex portion at or near the joint portion. With this convex portion, a gap can be provided between the thermoelectric material wafer and the substrate after bonding. By utilizing this gap, unnecessary portions of the thermoelectric material can be cut / deleted without breaking or damaging the electrode wiring on the substrate.
Further, by making the width of cutting / deletion different from the width of the groove, the cross-sectional shape of the thermoelectric material chip can be changed in the height direction. Further, by increasing the width of the gap at the time of joining, which is formed by the grooving process, the degree of freedom of positioning and accuracy of the cutting tool used in the cutting process is increased, so that the workability is improved.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail based on embodiments with reference to the drawings. [Example-1] FIG. 1 is a view showing the outer appearance of a thermoelectric conversion element according to the present invention. The basic configuration of the thermoelectric conversion element 11 shown in FIG. 1 is a substrate 12, a P-type thermoelectric material chip 13, N
The thermoelectric material chip 14 and the PN junction electrode 15 are included. FIG. 2A and FIG. 2B are cross-sectional views of the main part of AA ′ and BB ′ shown in the external view of the thermoelectric conversion element shown in FIG. 1, respectively. In the sectional view shown in FIG. 2, in addition to the main part of the thermoelectric conversion element, the structure 23 of the present invention is formed on the substrate 21 around the bonding part. 2 which is a sectional view of FIG. 1A-A '
In FIG. 2A, which is a cross-sectional view of FIG. 1B-B ′, the P-type thermoelectric material chip and the N-type thermoelectric material chip are alternately shown in FIG. Only thermoelectric material chips are visible. FIG. 3 is a view of the thermoelectric conversion element of FIG. 1 seen through from above, showing the positional relationship between the electrode wiring pattern on the substrate and the thermoelectric material chip. (FIG. 1, FIG. 2 and FIG. 3 are schematic diagrams / concepts, and the dimensions and the number of thermoelectric material chips are determined depending on the purpose.) In FIG. Among them, the solid line shows the electrode wiring pattern 32 of the upper substrate, and the dotted line shows the electrode wiring pattern 33 of the lower substrate. It is needless to say that the terms “upper substrate” and “lower substrate” used here are for convenience of description, and that both substrates can be placed vertically in the thermoelectric conversion element. Further, two kinds of slashed rectangles represent the P-type thermoelectric material chip 34 and the N-type thermoelectric material chip 35, respectively.

An example of the thermoelectric conversion element of the present invention having such a structure and a manufacturing method thereof will be described for a small thermoelectric conversion element having a thermoelectric material chip size of 100 μm. As the thermoelectric material, a sintered body of Bi-Te based material, which is a material having excellent performance at around room temperature, was used. The main characteristic of this thermoelectric material is the Seebeck coefficient 205 for the P type.
μV / deg, specific resistance 0.95 mΩcm, thermal conductivity 1.5 W / m · deg, Seebeck coefficient 170 for N type
It was μV / deg, the specific resistance was 0.75 mΩcm, and the thermal conductivity was 1.5 W / m · deg. As the substrate material, a silicon wafer having a thickness of 300 μm, which was electrically insulated by thermally oxidizing the surface, was used. Regarding the size of the element, the height of the thermoelectric material chip is 500 μm, the shape of the cross section of the thermoelectric material chip parallel to the substrate is square, and the length of one side is 100 μm as described above. Distance between die thermoelectric material chips is 200μm
(Center-to-center distance is 300 μm), and the distance between the closest heterogeneous thermoelectric material chips is 70 μm (center-to-center distance is 30 μm).
0 / √2 = about 210 μm), and the number of element pairs arranged in one element is 125 pairs in series.

FIG. 4 is a diagram showing an outline of steps for manufacturing the thermoelectric conversion element of this embodiment. As shown in FIG. 4, this manufacturing method is roughly divided into five steps. This will be described step by step. In the bump forming step (a), a photoresist having a thickness of 50 μm is applied to both surfaces of each of the P-type and N-type thermoelectric material wafers 40 made of a Bi—Te based sintered body having a thickness of 500 μm. By exposing and developing this photoresist, the opening diameter 90
A resist layer having a circular shape of μm and having openings such that the arrangement has a desired pattern is formed. In addition,
The desired pattern here is determined based on the above-mentioned dimensions so that the thermoelectric material chips in FIG. 3 are arranged. Next, this opening is washed with acid or the like, and then nickel plating of 40 μm is first applied by electroplating to form a so-called nickel bump. Next, similarly, solder plating was performed on nickel by electroplating to form a solder layer of 30 μm. Here, the solder plating was performed so that the composition ratio of tin and lead was 6: 4. Next, after removing the photoresist, a rosin-based flux is applied to the solder plating layer and a reflow process is performed at 230 ° C., so that spherical solder bumps 41 having a diameter of about 100 μm are formed on both surfaces of the thermoelectric material wafer 40. I was able to.

In the electrode wiring step (b), by thermal oxidation,
On the surface of a silicon wafer substrate 42 having a thickness of 0.5 μm and provided with an oxide layer of 0.5 μm on the surface, a film having a thickness of 0.1 μm, 3 μm, and 1 μm was formed from the substrate side in this order from the substrate side by chromium, nickel, and gold. Formed. Next, the electrode wiring 43 was formed on the upper and lower substrates by photolithography so as to have the electrode wiring pattern of FIG. Further, two types of donut-shaped structures 44 were produced by a photolithography method around a portion where the P-type thermoelectric material and the N-type thermoelectric material are joined by solder bumps by using a polyimide photoresist. The size of the structure 44 composed of this polyimide-based photoresist is the size of a donut shape at the position where the P-type thermoelectric material chip is arranged on one of the two substrates forming the thermoelectric conversion element. Has an inner diameter of 120 μm, an outer diameter of 150 μm, a height of 30 μm, an inner diameter of 140 μm, an outer diameter of 170 μm, and a height of 30 μm at the position where the N-type thermoelectric material chip is arranged, and at a position where the P-type thermoelectric material chip is arranged on the other substrate. Inner diameter 1
The inner diameter was 40 μm, the outer diameter was 170 μm, and the height was 30 μm. The inner diameter was 120 μm, the outer diameter was 150 μm, and the height was 30 μm at the position where the N-type thermoelectric material chip was arranged.

In the joining step (c), the thermoelectric material wafer 40 with the solder bumps 41 produced in the bump forming step (a), the electrode wiring 43 produced in the electrode wiring step (b), and the doughnut-shaped structure near the joining portion. After the substrate 42 having the 44 formed thereon was opposed to the substrate 42 and predetermined alignment was performed, the solder was melted to bond the thermoelectric material wafer 40 and the substrate 42. In addition, in joining the P-type thermoelectric material wafer and the substrate,
Solder bumps formed on the surface of a P-type thermoelectric material wafer have an inner diameter of 120 μm and an outer diameter of 150 μ formed on the substrate.
m and the height of 30 μm, the thermoelectric material wafer 40 and the substrate 4 are put inside the smaller donut-shaped structure.
Alignment with 2. Similarly, when joining an N-type thermoelectric material wafer to a substrate, solder bumps formed on the surface of the N-type thermoelectric material wafer are connected to a small donut having an inner diameter of 120 μm, an outer diameter of 150 μm, and a height of 30 μm. The thermoelectric material wafer 40 and the substrate 42 were aligned by being placed inside the mold structure. Here, the smaller one of the two doughnut-shaped structures formed on the substrate is used for bonding the thermoelectric material wafer 40 and the substrate 42 to ensure that the bonding position is correct. , To improve mutual alignment accuracy.

In the cutting / deletion step (d), the thermoelectric material wafer 40 bonded to the substrate 42 is cut and removed to form a thermoelectric material chip 45 bonded to the substrate 42. At this time, if necessary, the substrate 42
Alternatively, a part of the electrode wiring 43 may be cut / deleted at the same time. In this example, the cutting / deletion step (d) was performed using a dicing saw used for cutting a silicon semiconductor or the like. The blade used for cutting / deleting has a thickness of 200
The thing with a micrometer was used. The thickness of this blade is 100 when the length of one side of the thermoelectric material chip 45 having a square of this embodiment is 100.
The distance between the centers of the similar thermoelectric material chips closest to each other in μm is 300
μm, and selected because different types of thermoelectric material chips are bonded in the positional relationship shown in FIG. Unnecessary portions of the thermoelectric material are cut / deleted at the center between the solder bumps 41, and at the same time, the gap between the thermoelectric material wafer 40 and the substrate 42 made of nickel bumps having a height of 40 μm is used on the substrate. This was done by adjusting the height of the blade so as not to damage the electrode wiring 43. A substrate 42 to which substantially 125 thermoelectric material chips 45 were bonded was produced for each type of thermoelectric material by cutting and removing it vertically and horizontally with a dicing saw blade.

Here, the substrate 42 to which 125 thermoelectric material chips 45 are substantially bonded is the arrangement and configuration of the thermoelectric material chips in FIG. 3, and a rectangular thermoelectric material wafer is used, and solder bumps are formed vertically. 11 rows x 12 horizontal rows
This is because when formed as a row (total 132 pieces), 125 pieces are substantially involved in the PN junction due to the arrangement. In this case, some unnecessary peripheral chips will be deleted in the cutting / removing step without any problem unless some means for joining is taken, but this unnecessary chip will be removed from the substrate. Since it is possible to enhance the mechanical reinforcement and electrical reliability of the thermoelectric conversion element to be produced by joining it to and leaving it, it is possible to join it to the substrate and leave it by some means. Good. In this case, if it is intended to increase the strength of the thermoelectric conversion element to be produced, a dummy bonding pad that is electrically isolated on the substrate is previously produced at the time of producing the electrode wiring, and other dummy bumps are formed. In the same manner, the thermoelectric conversion element can be manufactured without any trouble in the process by joining them. Also, by bonding the bumps of the unnecessary chip part to the substrate on which the pads are pre-wired so as to short-circuit the nearby electrodes, this chip is left and the thermoelectric material chip at the outermost periphery is mechanically reinforced. It is possible to improve the reliability of electrical connection.

In the assembling step (e), two substrates 42 to which thermoelectric material chips 45 of different types are bonded are faced to each other, and solder bumps 41 formed on the tips of the chips are formed on the substrates. The electrode wiring 43 being formed is aligned with the position to be joined, and heated by applying pressure to melt the solder, and the thermoelectric material chip 45 and the electrode wiring 43 on the substrate 42 are joined together. A thermoelectric conversion element having a PN junction could be completed on the substrate. In addition, the alignment at the time of joining is performed by the solder bumps 41 formed on the tips of the thermoelectric material chips 45 of the respective molds.
Of the structure 44 formed on the other type of substrate to be bonded to the inside of the remaining large one (inner diameter 140 μm, outer diameter 170 μm, height 30 μm) of a donut type structure. went. The reason why the doughnut-shaped structure is made larger at the time of this alignment is to facilitate the alignment of the thermoelectric material chip and the substrate electrode and to suppress the flow of solder. These effects were sufficiently obtained in combination with the small donut-shaped structure in the step (c).

The final external dimensions of the thermoelectric conversion element produced in this way are about 1.2 mm in thickness (the thickness of the thermoelectric material chip is 0.5 mm, the upper and lower substrates are 0.3 mm each, the total height of the bonding material and nickel bumps in the upper and lower bonding parts is 0.05 mm), and the size is 4 m according to the size of the lower substrate provided with the input / output electrodes.
m × 4 mm, and the electrical internal resistance was 120Ω. The size of the thermoelectric conversion element of this example having the position / arrangement of the PN junction electrode and the thermoelectric material chip shown in FIG. 3 manufactured by this manufacturing method is the same as the conventional manufacturing method. After that, it is a size that cannot be made by a method of sandwiching it between the upper and lower substrates to make a thermoelectric conversion element.

When the lead wires were connected to the input / output electrodes of such a thermoelectric conversion element and the respective characteristics were examined, the following results were obtained. As for the power generation performance based on the Seebeck effect, the release voltage at a temperature difference between the substrates of 2 ° C. is 90 mV,
When a load resistance of 1 KΩ was attached to the outside and a temperature difference of 2 ° C. was applied between the substrates, an output of 80 mV-70 μA was obtained.
When 16 thermoelectric conversion elements of 125 pairs of PN junctions were connected in series and put in a quartz resonator type electronic wrist watch and carried, the timepiece could be driven at a room temperature of 20 ° C.

Regarding the performance as a cooling / heating element based on the Peltier effect, an aluminum radiator plate was bonded to the substrate on the heating side with a silicone adhesive having high thermal conductivity, and a voltage of 6 V was applied between the input electrodes. , A current of about 50 mA flows, and the phenomenon of instantaneous freezing of water in the air occurs on the surface of the substrate on the heat absorption side, demonstrating that the performance of this thermoelectric conversion element as a Peltier element is extremely excellent. Was done.

[Embodiment 2] FIG. 5 is a view seen from the upper substrate for explaining the outline of the arrangement of the electrode wiring and the thermoelectric material chip on the substrate of the thermoelectric conversion element according to the second embodiment. In FIG. 5, among the lines representing the electrode wiring, the solid line shows the electrode wiring pattern 50 on the upper substrate, and the dotted line shows the electrode wiring pattern 51 on the lower substrate. It is needless to say that the terms “upper substrate” and “lower substrate” used here are for convenience of description, and that both substrates can be placed vertically in the thermoelectric conversion element. Further, two types of diagonally shaded squares represent the P-type thermoelectric material chip 52 and the N-type thermoelectric material chip 53, respectively. Further, a thermoelectric material chip (hereinafter referred to as a dummy chip) existing on the outer peripheral portion of the thermoelectric conversion element and not related to the PN junction is bonded and fixed to the upper substrate and the lower substrate by the upper substrate dummy electrode 54 and the lower substrate dummy electrode 55. Has been done. In FIG. 5, the dummy chip is bonded to the dummy electrode on one substrate and is bonded to the electrode for PN bonding on the other substrate, but it may be a dummy electrode on both substrates. In any case, the dummy chip mechanically reinforces the thermoelectric conversion element composed of the small thermoelectric material chip manufactured in this example. As shown in FIG. 5, the arrangement of the thermoelectric material chips in the thermoelectric conversion element of the present embodiment is such that when a certain row is viewed in the X direction, only the P-type thermoelectric material chips or the N-type thermoelectric material chips form a row. The rows of the P-type thermoelectric material chips and the rows of the N-type thermoelectric material chips are alternately arranged. On the other hand, in the Y direction, when one row is viewed, the P-type thermoelectric material chips and the N-type thermoelectric material chips are arranged side by side.

In this example, the thermoelectric conversion element having this structure and the arrangement of the thermoelectric material chips has a size of 500 μm and a height of 5 in the cross section parallel to the substrate.
00 μm, the distance between the centers of the closest thermoelectric material chips is 10
The number of thermoelectric material chips (including dummy chips) was 64, including P type and N type.

As the thermoelectric material, a sintered body of Bi-Te series material, which is a material having excellent performance around room temperature as in Example-1, was used. The main characteristics of this thermoelectric material are the Seebeck coefficient of 205 μV / deg and the specific resistance of 0.9 for the P type.
5 mΩcm, thermal conductivity 1.5 W / m · deg, N-type Seebeck coefficient 170 μV / deg, specific resistance 0.75
It was mΩcm and the thermal conductivity was 1.5 W / m · deg. As the substrate material, alumina having a thermal conductivity of 20 W / m · deg was used.

FIG. 6 is a diagram showing an outline of steps for producing the thermoelectric conversion element. Hereinafter, each step will be described with reference to FIG. In the bonding layer forming step (a), nickel plating is performed by wet plating on both surfaces of the surface of the thermoelectric material wafer 60 having a thickness of 500 μm to be bonded to the substrate to form a nickel layer 61 having a thickness of 10 μm. . Next, one surface on which the nickel layer is formed is masked, and tin: lead =
Solder plating having a composition of 1: 9 is applied to form a solder layer 62 having a thickness of 30 μm. Next, this plating mask is removed, a solder layer 62 having a composition of tin: lead = 1: 9 is masked, and the other nickel layer 61 is wet-plated with a composition of tin: lead = 6: 4. Solder plating is performed to form a solder layer 63 having a thickness of 30 μm, and the plating mask is removed, so that tin: lead = 1: 1 on one surface.
9 has a solder layer 62 having a composition of 9 and tin: lead =
A thermoelectric material wafer having a solder layer 63 with a composition of 6: 4 is prepared. Next, a rosin-based flux was applied to the solder layers 62 and 63 on both surfaces, and the solder was reflowed at 350 ° C. to homogenize the solder layers and clean the surfaces. The reflow process may be performed after the grooving process, which is the subsequent process, because of the process.

In the grooving step (b), a dicing saw was used, but with a blade having a blade width of 1.5 mm, tin: lead = 1: 9.
90 from the surface of the nickel layer 61 on the solder layer 62 side of the composition
Groove vertically and horizontally to a depth of μm. The gap between the grooves of the blade at this time is 2 mm, that is, the interval between the convex portions formed between the grooves is 0.5 m, which is the size of the thermoelectric material chip.
I went to m. Here, the depth of the grooving is set to 90 μm from the surface layer of the solder is the depth of the groove for preventing the adjacent convex portions from being short-circuited in the bonding in the later step. It also serves as a gap between the thermoelectric material wafer and the substrate, which is required for chip formation by cutting / removing in a later step.

In the electrode wiring step (c), the thickness is 0.1 mm.
Of the 0.5 mm-thick alumina substrate 64 to which the copper plates of FIG. 5 are attached, the copper plate is photo-etched to form the electrode wiring 65 of the patterns of the upper substrate and the lower substrate shown in FIG.
Processed as. In the bonding step (d), the protrusion 68 of the thermoelectric material wafer 60 having the protrusion formed by grooving and the electrode wiring 65 on the substrate are aligned, and then the tin of the protrusion:
The solder layer 62 having a composition of lead = 1: 9 is melted to form the electrode wiring 6
2 and the thermoelectric material wafer 60 were joined. The bonding temperature at this time was 340 ° C.

In the cutting step (e), a dicing saw is used for cutting in the X direction shown in FIG. 5 with a blade having a blade width of 1.5 mm, and a cutting width in the Y direction is shown. The 0.5 mm blade cuts and deletes the electrode wiring 65 on the substrate 64 without damaging it. Therefore, the cutting edge is placed in the groove (recess) 67 formed in the grooving process to cut unnecessary portions. After that, the thermoelectric material chip 66 was manufactured.

In the assembly step (f), two substrates 64 to which thermoelectric material chips 66 of different types are bonded are faced to each other, and tin: lead = 6: 4 formed on the tips of the chips. The solder layer 63 having the composition described above and the electrode wiring 65 formed on the substrate 64 are aligned with the positions to be joined and heated while being pressurized to melt the solder, and the thermoelectric material chip 66 and the substrate 64 on the substrate 64. The thermoelectric conversion element having the PN junction was completed on the upper and lower substrates by joining with the electrode wiring 65. The temperature at the time of joining was 230 ° C., which is the temperature at which the solder having the composition of tin: lead = 1: 9, which was previously joined, did not melt. Therefore, the assembly process can be performed without causing the thermoelectric material chip to fall or shift without providing a structure around the joint.

The thermoelectric conversion element of this example also has essentially the same manufacturing method as the thermoelectric conversion element described in Example-1, but when the thermoelectric material chip is extremely small, The position / arrangement of the thermoelectric material chips and the electrode arrangement for PN junction by -1 are preferable, but in order to increase the density of the thermoelectric material chips in the thermoelectric conversion element, the position / arrangement of the thermoelectric material chips and the PN junction of this embodiment are used. Electrode placement is preferred. Also,
In order to suppress the amount of thermoelectric material to be removed by cutting and deleting, the thermoelectric conversion element and its manufacturing method according to the present embodiment are preferable.

The final external dimensions of the thermoelectric conversion element produced in this manner are about 1.5 mm in thickness and the size is 9 mm × 8 m, which is the size of the lower substrate provided with the input / output electrodes.
m, and electrically, the internal resistance was 1Ω. A lead wire was connected to the input electrode of such a thermoelectric conversion element, and the performance as a cooling / heating element based on the Peltier effect was investigated. A heat sink made of aluminum is bonded to the substrate on the heat generation side with a silicone adhesive with high thermal conductivity, and 1 is placed between the input electrodes.
When a voltage of V was applied, a current of about 1 A flowed, and abrupt cooling occurred on the endothermic substrate side. The ratio of the amount of heat absorbed to this input power, the so-called COP (coefficient of performance), is 2
It was 0.55 at 0 ° C., demonstrating that this thermoelectric conversion element has excellent performance. [Embodiment 3] In a thermoelectric conversion element having an electrode wiring structure similar to that of Embodiment 1, the size of the thermoelectric material chip is 50 μm.
The production of the small thermoelectric conversion element will be described.

As the thermoelectric material, a sintered body of Bi-Te based material, which is a material having excellent performance around the same room temperature as in Example-1, was used. The main characteristics of this thermoelectric material are the Seebeck coefficient of 205 μV / deg and the specific resistance of 0.9 for the P type.
5 mΩcm, thermal conductivity 1.5 W / m · deg, N-type Seebeck coefficient 170 μV / deg, specific resistance 0.75
It was mΩcm and the thermal conductivity was 1.5 W / m · deg. As the substrate material, a silicon wafer having a thickness of 300 μm, which was electrically insulated by thermally oxidizing the surface, was used. Regarding the size of the element, the height of the thermoelectric material chip is 500 μm, the shape of the cross section of the thermoelectric material chip parallel to the substrate is square, and the length of one side is 50 μm as described above. The distance between die-type thermoelectric material chips is 100 μm (150 μm in the center-to-center distance) and the distance between the closest heterogeneous thermoelectric material chips is 35 μm (in the center-to-center distance, 150 / √2 = about 110 μm) The number of element pairs arranged in series was 51 pairs in series.

FIG. 7 is a diagram showing an outline of steps for manufacturing the thermoelectric conversion element of this embodiment. As shown in FIG. 7, this manufacturing method is roughly divided into five steps. This will be described step by step. In the bump forming step (a), a photoresist having a thickness of 20 μm is applied to both surfaces of each of the P-type and N-type thermoelectric material wafers 70 made of a Bi—Te-based sintered body having a thickness of 500 μm. By exposing and developing this photoresist, the opening diameter 45
The resist pattern is formed so that μm is circular and the array has a desired pattern. The desired pattern here is determined based on the above-mentioned dimensions so that the thermoelectric material chips are arranged in FIG. Next, after cleaning this opening with an acid or the like,
First, 20 μm nickel plating is applied by electroplating to form a so-called nickel bump. Next, similarly, solder plating was performed on nickel by electroplating to form a solder layer of 30 μm. Here, the solder plating was performed so that the ratio of tin and lead was 6: 4. Next, after removing the photoresist, a rosin-based flux is applied to the solder plating layer and a reflow treatment is performed at 230 ° C., so that spherical solder bumps 71 having a diameter of about 50 μm are formed on both surfaces of the thermoelectric material wafer 70. I was able to.

In the electrode wiring step (b), by thermal oxidation,
By sputtering on the surface of a silicon wafer substrate 72 having a thickness of 300 μm having an oxide layer of 0.5 μm on the surface, chromium, nickel, and gold are deposited in this order from the substrate to a thickness of 0.1 μm, 2 μm, and 1 μm, respectively. Formed. Next, the electrode wiring 7 is formed on the upper and lower substrates by photolithography so that the electrode wiring pattern shown in FIG. 3 is obtained.
Formed 3. Further, a structure 7 in which two types of circular joint portions are removed by a thick film photoresist around the portion where the P-type thermoelectric material and the N-type thermoelectric material are joined by solder bumps
4 was manufactured by the photolithography method. The structure 74 made of the thick film photoresist has a circular shape and size at the position where the P-type thermoelectric material chip is arranged on one of the two substrates forming the thermoelectric conversion element. The size of the removed portion was 60 μm, the diameter was 70 μm at the position where the N-type thermoelectric material chip was arranged, and the other portion was covered with a resist having a thickness of 40 μm. A structure is formed in which the diameter of the other substrate is 70 μm at the position where the P-type thermoelectric material chip is arranged, the diameter is 60 μm at the position where the N-type thermoelectric material chip is arranged, and the other portion is covered with a resist having a thickness of 40 μm. did. Here, the thickness of the resist is set to 40 μm in the following step (c) of joining the structure by this to the thermoelectric material wafer 70 and the substrate 72 and the following step (d) of cutting and deleting the thermoelectric material wafer 70. This is because it is used as a gap. Example-
In Example 1, this gap was formed by a nickel bump, but in Example-4, the gap between the thermoelectric material wafer 70 and the substrate 72 required in the cutting / removing step (d) was 30 μm or more, whereas This is because, when forming the bumps 71 on the thermoelectric material wafer 70 in the previous step, it is difficult to set the height of the nickel bumps forming the gap to 20 μm or more due to the limits of the photolithography technology and the plating technology.

In the joining step (c), the thermoelectric material wafer 70 with the solder bumps 71 produced in the bump forming step (a), the electrode wiring 73 produced in the electrode wiring step (b), and the structure 74 near the joint are formed. After performing a predetermined alignment with the formed substrate 72, the solder is melted and the thermoelectric material wafer 70 and the substrate 72 are joined. When the P-type thermoelectric material wafer is bonded to the substrate, the solder bumps formed on the surface of the P-type thermoelectric material wafer are put inside the bonding openings of the structure 74 having a diameter of 60 μm formed on the substrate. Thus, the thermoelectric material wafer 70 and the substrate 72 were aligned. Similarly, when joining the N-type thermoelectric material wafer and the substrate, the solder bumps formed on the surface of the N-type thermoelectric material wafer are bonded to each other with a diameter of 60 μm formed on the substrate.
The thermoelectric material wafer 70 and the substrate 72 were aligned by putting them inside the bonding opening of the structure 74. Here, the smaller bonding opening of the two bonding openings of the two structures 74 formed on the substrate is used for bonding the thermoelectric material wafer 70 and the substrate 72. And to improve mutual alignment accuracy.

In the cutting / deletion step (d), the thermoelectric material wafer 70 bonded to the substrate 72 is cut and removed to form a thermoelectric material chip 75 bonded to the substrate 72. At this time, if necessary, the substrate 72
A part of may be disconnected or deleted at the same time. In this example, the cutting / deletion step (d) was performed using a dicing saw used for cutting a silicon semiconductor or the like. The blade used for cutting / deleting had a thickness of 100 μm. The thickness of this blade is 50 μm on each side of the square thermoelectric material chip 75 of this embodiment, and the center distance between the closest thermoelectric material chips closest to each other is 100 μm. It was selected because it is joined in the positional relationship of. The unnecessary portion of the thermoelectric material is cut / deleted at the center between the solder bumps 71, and at the same time, the thermoelectric material wafer 70 and the substrate 7 made of the structure 74 having a height of 40 μm.
The height of the blade was adjusted so as to prevent the electrode wiring 73 on the substrate from being damaged by using the gap between the blades. By cutting and removing vertically and horizontally with the blade of a dicing saw,
For each type of thermoelectric material, a substrate 72 to which substantially 51 thermoelectric material chips 75 were bonded was produced.

Here, substantially 51 thermoelectric material chips 7 are provided.
The substrate 72 to which 5 is bonded is the arrangement and configuration of the thermoelectric material chips in FIG. When they are formed, because of the arrangement, 51 are each substantially involved in the PN junction. In this case, some unnecessary peripheral chips will be deleted in the cutting / removing step without any problem unless some means for joining is taken, but this unnecessary chip will be removed from the substrate. Since it is possible to enhance the mechanical reinforcement and electrical reliability of the thermoelectric conversion element to be produced by joining it to and leaving it, it is possible to join it to the substrate and leave it by some means. Good.
In this case, when the purpose is to increase the strength of the thermoelectric conversion element to be produced, a dummy bonding pad that is electrically isolated on the substrate is previously produced at the time of producing the electrode wiring, and is similar to other bumps. By joining to the thermoelectric conversion element, the thermoelectric conversion element can be manufactured without any trouble in the process. Also, by bonding the bumps of the unnecessary chip part to the substrate on which the pads are pre-wired so as to short-circuit the nearby electrodes, this chip is left and the thermoelectric material chip at the outermost periphery is mechanically reinforced. It is possible to improve the reliability of electrical connection.

In the assembling step (e), the two substrates 72 to which thermoelectric material chips 75 of different types are bonded are faced to each other, and the solder bumps 71 formed at the tips of the chips and the substrates are connected to each other. The formed electrode wiring 73
And the position to be joined, and by heating while applying pressure, the solder is melted and the thermoelectric material chip 75
And the electrode wiring 73 on the substrate 72 were joined together to complete the thermoelectric conversion element having the PN junction on the upper and lower substrates. In addition, the alignment at the time of joining is performed by the solder bumps 7 formed at the tips of the thermoelectric material chips 75 of the respective molds.
1 was put inside the remaining large one (diameter 70 μm) of the bonding opening of the structure 74 formed on the other type of substrate to be bonded. At the time of this alignment, the reason why the opening for bonding of the structure 74 is made larger is to facilitate alignment of the thermoelectric material chip and the substrate electrode and to suppress the flow of solder. Then, these effects were sufficiently obtained together with the small bonding opening of the structure 74 in the bonding step (c).

The final external dimensions of the thermoelectric conversion element thus produced are about 1.2 mm in thickness, and the size is 2 mm × 2 m, which is the size of the lower substrate provided with the input / output electrodes.
m, and electrically, the internal resistance was 180Ω. When the lead wire was connected to the input / output electrodes of such a thermoelectric conversion element and the respective characteristics were examined, the following results were obtained.

The power generation performance based on the Seebeck effect is that the release voltage at a temperature difference of 2 ° C. between the substrates is 35 mV,
When a load resistance of 1 KΩ was attached to the outside and a temperature difference of 2 ° C. was applied between the substrates, an output of 30 mV-30 μA was obtained.
In addition, the thermoelectric conversion element having this PN junction 51 pair is
When they were connected in series, put in a wristwatch and carried, they could drive the watch at room temperature of 20 ° C.

Regarding the performance as a cooling / heating element based on the Peltier effect, an aluminum radiator plate was bonded to the substrate on the heating side with a silicone adhesive having high thermal conductivity, and a voltage of 2 V was applied between the input electrodes. , A current of about 10 mA flows, and the phenomenon of instantaneous freezing of water in the air occurs on the surface of the substrate on the heat absorption side, demonstrating that the performance of this thermoelectric conversion element as a Peltier element is extremely excellent. Was done.

[Embodiment 4] In a thermoelectric conversion element having an electrode wiring structure similar to that of Embodiment 1, the cross sectional shape of the thermoelectric material chip is thick (70 μm) on one substrate side and thin on the other substrate side. Fabrication of a small thermoelectric conversion element having a (50 μm) structure will be described.

As the thermoelectric material, a sintered body of Bi-Te series material was used as well. The substrate material has a thickness of 300 which is electrically insulated by thermally oxidizing the surface.
A μm silicon wafer was used. Regarding the size of the element, the height of the thermoelectric material chip is 500 μm, the shape of the cross section parallel to the substrate of the thermoelectric material chip is square, and the length of one side is 50 μm as described above.
μm. The center-to-center distance between the closest similar-type thermoelectric material chips in FIG. 3 is 270 μm), and the center-to-center distance between the closest different-type thermoelectric material chips is 270 / √2 = about 190 μm.
m), the number of element pairs arranged in one element is 51 pairs in series. (This distance was calculated with the chip size of 70 μm.) FIG. 8 is a diagram showing an outline of the process for manufacturing the thermoelectric conversion element of the present Example-4. As shown in FIG. 3, this manufacturing method is roughly divided into six steps. This will be described step by step.

In the bump forming step (a), the thickness is 500 μm.
A photoresist having a thickness of 10 μm is applied to both surfaces of each of the P-type and N-type thermoelectric material wafers 40 made of a Bi-Te based sintered body of m. By exposing / developing this photoresist, a resist layer having a circular shape having an opening diameter of 40 μm on one surface and an opening diameter of 60 μm on the other surface, and having openings in which the arrangement has a desired pattern To form. It should be noted that the desired pattern referred to here is as shown in FIG.
The arrangement of the thermoelectric material chips is determined based on the above dimensions. Next, this opening is washed with an acid or the like, and then 10 μm of nickel is plated on both surfaces by electroplating to form a so-called nickel bump. Then, similarly by electroplating,
Solder plating on nickel, solder layer 30μm
Formed. Here, the solder plating has a tin to lead ratio of 6: 4.
I went to Next, after removing the photoresist, a rosin-based flux is applied to the solder plating layer,
When the reflow treatment was performed at 30 ° C., spherical solder bumps 81 having a diameter of about 50 μm on one surface and a diameter of 70 μm on the other surface could be formed on both surfaces of the thermoelectric material wafer 80.

In the grooving step (b), different grooving was performed on the P-type thermoelectric material wafer and the N-type thermoelectric material wafer. FIG. 9 is a view showing the width and depth of the grooving in the grooving step of this embodiment. As shown in FIG. 9, first, P
On the die thermoelectric material wafer, a dicing saw having a blade having a blade width of 160 μm was attached to the surface on which the solder bumps having a diameter of 70 μm were formed, and vertical and horizontal grooves having a depth of 150 μm were formed at the center between the solder bumps. This gives a width of 160
Since a groove is formed with a depth of 150 μm and a depth of 150 μm, a P-type thermoelectric material wafer in which a solder bump with a diameter of about 70 μm is formed on a convex portion with a side length of 70 μm and a height from the bottom of the groove of 150 μm is formed. Can be formed. On the surface of the N-type thermoelectric material wafer on which the solder bumps having a diameter of 50 μm are formed, a groove having a depth of 350 μm was vertically and horizontally grooved at the center between the solder bumps with a dicing saw having a blade having a blade width of 180 μm attached. This gives a width of 180 μm and a depth of 3
Since a groove of 50 μm is formed, a diameter of about 50 μm is formed on a convex portion with a side length of 50 μm and a height from the bottom of the groove of 350 μm.
It is possible to form an N-type thermoelectric material wafer having m solder bumps formed thereon. Such grooving was performed in order to form a gap between the thermoelectric material wafer and the substrate, which is required in the subsequent bonding step (d) and cutting / removing step (e) of FIG. In addition, by changing the cross-sectional shape of the thermoelectric material chip in the direction perpendicular to the substrate, when using the manufactured thermoelectric conversion element as a Peltier element, Joule heat due to energization is generated as much as possible on the heat dissipation substrate side to absorb heat. This is to prevent heat dissipation to the substrate side.

In the electrode wiring step (c) of FIG. 8, a thickness of 300 μm is obtained by forming an oxide layer of 0.5 μm on the surface by thermal oxidation.
A film was formed on the surface of a silicon wafer substrate 82 having a thickness of 0.1 m by sputtering from the substrate side in the order of 0.1 μm, 1 μm, and 0.1 μm of chromium, nickel, and gold, respectively. Next, the electrode wirings 83 were formed on the upper and lower substrates by photolithography so as to have the electrode wiring pattern shown in FIG. On one of the substrates, a doughnut-shaped structure 84 having an inner diameter of 80 μm, an outer diameter of 110 μm, and a height of 30 μm was formed by hardening a thick film photoresist around the portion to be joined by the solder bump by photolithography. On the other substrate, a doughnut-shaped structure 84 having an inner diameter of 60 μm, an outer diameter of 90 μm, and a height of 30 μm was formed around the portion to be joined by the solder bump by photolithography using a thick film photoresist.

In the joining step (d) of FIG. 8, the thermoelectric material wafer 80 with the solder bump 81 produced in the bump forming step (a) and the electrode wiring 8 produced in the electrode wiring step (c) are used.
3 Further, after performing a predetermined alignment with the substrate 82 on which the doughnut-shaped structure 84 is formed in the vicinity of the bonding portion, the solder is melted and the thermoelectric material wafer 80 and the substrate 82 are bonded. At the time of this bonding, the solder bumps on the grooved surface of the thermoelectric material wafer 80 and the donut-shaped structure 84 on the substrate 82 are combined, and heating / bonding is performed while pressing the substrate 82 from the outside. A P-type thermoelectric material wafer has an inner diameter of 80 μm, an outer diameter of 110 μm, and a height of 30 μ due to solder bumps with a diameter of 70 μm formed on the grooved surface.
m wafer is bonded to the substrate on which the structure is formed, and the N-type thermoelectric material wafer has an inner diameter of 60 μm by a solder bump having a diameter of 50 μm formed on the grooved surface.
It will be bonded to a substrate on which a structure having an outer shape of 90 μm and a height of 30 μm is formed.

In the cutting / deleting step (e) of FIG.
The thermoelectric material wafer 80 bonded to 2 is formed into the thermoelectric material chip 85 bonded to the substrate 82 by cutting and removing a part of the thermoelectric material wafer. At this time, if necessary, a part of the substrate 82 may be cut / deleted at the same time.
Also in this example, similarly to Example-1, this cutting / deleting step (e) was performed using a dicing saw used for cutting a silicon semiconductor or the like. The blade used for cutting / deleting has a blade thickness of 180 for cutting / deleting P-type thermoelectric material wafers.
A blade having a blade thickness of 160 μm was used for cutting and removing the N-type thermoelectric material wafer. In the P-type thermoelectric material wafer, a groove having a width of 160 μm has already entered 150 μm from the substrate side in the grooving process. Therefore, in the cutting / removing process (e), the remaining portion is the blade having a blade thickness of 180 μm. The thermoelectric material wafer is cut and removed to a depth of 350 μm from the surface of the thermoelectric material wafer on the side opposite to the side where a groove having a width of 160 μm and a depth of 150 μm is formed. In the N-type thermoelectric material wafer, a groove of 180 μm width has already been formed on the substrate side by the grooving process.
Since it contains 50 μm, in this cutting / deleting step (e), the surface of the thermoelectric material wafer on the side opposite to that when the remaining 150 μm with the 160 μm blade is provided with the groove having the width of 180 μm and the depth of 350 μm. Disconnect / delete from. FIG. 10 is a cross-sectional view of the substrate to which the thermoelectric material chip produced by this operation is joined, taken in a direction perpendicular to the substrate. As shown in FIG. 10, in the P-type thermoelectric material chip, one side is 70 μm up to 150 μm from the substrate side,
The remaining 150 μm to 500 μm is 50 μm on a side
In the N-type thermoelectric material chip, one side is 50 μm up to 350 μm from the substrate side, and the remaining 3
From 50 μm to 500 μm, one side has a size of 70 μm.

In the assembling step (f) of FIG. 8, two substrates 82 to which thermoelectric material chips 85 of different types are bonded are faced to each other and solder bumps 81 formed at the tips of the chips are connected. The electrode wiring 83 formed on the substrate is aligned with the position to be joined and heated while being pressurized to melt the solder, thereby joining the thermoelectric material chip 85 and the electrode wiring 83 on the substrate 82. It was possible to complete the thermoelectric conversion element having the PN junction on the upper and lower substrates. The alignment at the time of bonding was performed by the structure 84 formed on the substrate of the other mold to which the solder bump 81 formed at the tip of the thermoelectric material chip 85 of each mold should be bonded.

FIG. 11 is a cross-sectional view showing an outline of a thermoelectric conversion element manufactured by this series of steps.
The structure of the element is the same as that of the element manufactured in Example-1, but the cross-sectional shapes of the P-type thermoelectric material chip 110 and the N-type thermoelectric material chip 111 are not simple rectangles but P-type and N-type.
Both of the molds are thick on one substrate 116 side and thin on the other substrate 113 side.

In order to investigate the performance of the thermoelectric conversion element of this Example-4, thermoelectric conversion elements having the same number of PN junctions and the same outer dimensions were prepared for the thermoelectric material chip sizes of 50 μm and 70 μm, respectively, and the performance as a Peltier element was confirmed. As a result of comparison by the three parties, the element of the present example at the same input power,
The COP of each of the comparative samples was about 10% higher, indicating the best performance.

In the Peltier element, Joule heat is generated due to energization in addition to heat generation on the heat dissipation substrate side due to heat transfer due to the Peltier effect. As is well known, Joule's heat is generated and heated most at the center when the cross section of a substance to be energized is uniform. In the thermoelectric conversion element of the present embodiment, Joule heat is generated mainly in the thin portion of the thermoelectric material chip by energizing the substrate on the side where the thermoelectric material chip is thin so as to serve as a heat dissipation substrate. Since this generated heat is smoothly conducted from the closer substrate, that is, the heat dissipation substrate, it is possible to prevent the flow of heat to the heat absorbing substrate on the opposite side, resulting in higher performance of the thermoelectric conversion element. ..

Although FIG. 11 shows a schematic sectional view of the thermoelectric conversion element of the present Example-4, the thermoelectric conversion element is easy to manufacture, particularly alignment in the assembly process and the thermoelectric material chip and the substrate. Considering the joining, the sectional shape shown in FIG. 12 is also effective. [Example-5] In the thermoelectric conversion element having the same electrode wiring structure as in Example-1, an example in which a small thermoelectric conversion element is manufactured by a method other than the solder bump method for joining the thermoelectric material and the substrate will be described. The size of the thermoelectric material chip, the number of PN junction pairs, the materials used, and the like were the same as in Example-1.

FIG. 13 is a diagram showing an outline of steps for manufacturing the thermoelectric conversion element of this embodiment. As shown in FIG. 13, this manufacturing method is roughly divided into five steps. This will be described step by step. In the projecting electrode forming step (a), P-type and N-type thermoelectric material wafers 1 each made of a Bi—Te-based sintered body having a thickness of 500 μm
A photoresist having a thickness of 50 μm is applied to both surfaces of 30. By exposing and developing this photoresist,
A resist layer is formed which has a circular shape with an opening diameter of 90 μm and has openings having a desired pattern. The desired pattern here is determined based on the above-mentioned dimensions so that the thermoelectric material chips are arranged in FIG. Next, this opening is washed with an acid or the like, and then nickel plating of 50 μm is first applied by an electroplating method to form a protruding nickel layer. Next, similarly, gold was plated on nickel by electroplating to form a gold layer of 1 μm. Next, the resist was peeled off to form the protruding electrodes 131 made of nickel-gold. Here, the gold layer is provided in order to prevent oxidation of the nickel surface and to facilitate soldering in a later step, so that this gold layer is not always necessary if there is no fear of oxidation.

In the electrode wiring step (b), by thermal oxidation,
By sputtering on the surface of a silicon wafer substrate 132 having a thickness of 300 μm and provided with an oxide layer of 0.5 μm on the surface, chromium, nickel, and gold are formed in order of 0.1 μm, 1 μm, and 0.1 μm from the substrate side. A film was formed. Next, the electrode wirings 133 are formed on the upper and lower substrates by photolithography so as to have the electrode wiring pattern of FIG. 3, and solder paste is printed on the electrode wirings 133 to form the electrode wirings 133. completed.

In the joining step (c), the thermoelectric material wafer 130 with the protruding electrodes 131 prepared in the protruding electrode forming step (a) and the electrode wiring 1 prepared in the electrode wiring step (b) are used.
After performing a predetermined alignment with the substrate 132 on which 33 is formed, the solder is melted and the thermoelectric material wafer 130 and the substrate 132 are bonded. (However, the terms “upper part” and “lower part” are used for convenience as described above, and there is no upper or lower side of the substrate of the thermoelectric conversion element.) In the cutting / deletion step (d), the thermoelectric material wafer 130 bonded to the substrate 132 is removed. By cutting and removing a part of the thermoelectric material wafer 130, the thermoelectric material chip 134 bonded to the substrate 132 is formed. At this time, if necessary, a part of the substrate 132 may be cut / deleted at the same time. In this example, the cutting / deletion step (d) was performed using a dicing saw used for cutting a silicon semiconductor or the like. The blade used for cutting and deleting had a thickness of 200 μm. Regarding the thickness of this blade, the length of one side of the thermoelectric material chip 134 having a square shape of the present embodiment is 100 μm, the center-to-center distance between the closest thermoelectric material chips is 300 μm, and the thermoelectric material chips of different types are shown in FIG. It was selected because it is joined in the positional relationship of. The unnecessary portion of the thermoelectric material is cut / deleted at the center between the protruding electrodes 131, and at the same time 50
The height of the blade is adjusted so as not to damage the electrode wiring 133 on the substrate by utilizing the gap between the substrate 132 and the thermoelectric material wafer 130 made of the protruding electrodes 131 having a height of μm. It was A substrate 132 to which substantially 125 thermoelectric material chips 134 were bonded was prepared for each type of thermoelectric material by cutting and removing it vertically and horizontally with a dicing saw blade.

In the assembling step (e), the two substrates 13 to which the thermoelectric material chips 134 of different types are bonded respectively.
2 facing each other, aligning the protruding electrode 131 formed at the tip of each chip and the electrode wiring 133 formed of a solder layer formed on the substrate to a position to be joined, and heating while applying pressure. Melts the solder, and the thermoelectric material chip 134 and the electrode wiring 1 on the substrate 132 are melted.
It was possible to complete the thermoelectric conversion element having the PN junction on the upper and lower substrates by performing the joining with 33.

The final external dimensions of the thermoelectric conversion element thus manufactured are about 1.2 mm in thickness, and the size is 4 mm × 4 m in terms of the size of the lower substrate provided with the input / output electrodes.
m, electrically, the internal resistance was 120Ω, and the basic characteristics were the same as those of the thermoelectric conversion element produced in Example-1.

[Embodiment 6] In a thermoelectric conversion element having an electrode wiring structure similar to that of Embodiment 1, a small thermoelectric conversion element is manufactured by a method using a solder bump method and a conductive adhesive for joining a thermoelectric material and a substrate. An example will be described. The size of the thermoelectric material chip, the number of PN junction pairs, the materials used, and the like were the same as in Example-1.

FIG. 14 is a diagram showing an outline of steps for manufacturing the thermoelectric conversion element of this embodiment. As shown in FIG. 14, this manufacturing method is roughly divided into five steps. This will be described step by step. In the bump forming step (a), the P-type and N-type thermoelectric material wafers 140 made of a Bi—Te-based sintered body having a thickness of 500 μm are used.
A photoresist having a thickness of 50 μm is applied to one surface of the.
By exposing and developing this photoresist, a resist layer having openings having a circular shape with an opening diameter of 90 μm and having a desired pattern in its arrangement is formed.
The desired pattern here is determined based on the above-mentioned dimensions so that the thermoelectric material chips are arranged in FIG. Further, the surface not coated with the photoresist is coated with a plating resist. Next, the opening is washed with acid or the like, and then electroplating is performed to first apply 40 μm of nickel plating,
A so-called nickel bump is formed. Next, similarly, solder plating was performed on nickel by electroplating to form a solder layer of 30 μm. Here, the solder plating was performed so that the ratio of tin and lead was 6: 4. Next, after peeling off the photoresist and the plating resist, a rosin-based flux was applied to the solder plating layer and a reflow treatment was performed at 230 ° C., and a spherical solder bump 141 having a diameter of about 100 μm was formed on one surface of the thermoelectric material wafer 140. Could be formed.

In the electrode wiring step (b), by thermal oxidation,
A silicon wafer having a thickness of 300 μm and having an oxide layer of 0.5 μm formed on the surface is sputtered on the surface of the substrate 142 by sputtering, and chromium, nickel, and gold are deposited in the order of 0.1 μm, 1 μm, and 0.1 μm respectively. To form a film. Next, the electrode wiring 143 was formed on the upper and lower substrates by photolithography so as to have the same electrode wiring pattern as in FIG. Further, two types of donut-shaped structures 144 were formed by photolithography using a polyimide-based photoresist around the portion where the P-type thermoelectric material and the N-type thermoelectric material are joined by solder bumps. The structure 144 made of this polyimide-based photoresist has an inner diameter of 120 μm, an outer diameter of 150 μm, and a high outer diameter at a position where the P-type thermoelectric material chip is arranged on one of the two substrates forming the thermoelectric conversion element. 30μ
m, an inner diameter of 140 at the position where the N-type thermoelectric material chip is placed
μm, outer diameter 170 μm, and height 30 μm, and the other substrate has an inner diameter 140 μm, outer diameter 170 μm, and height 30 μm at the position where the P-type thermoelectric material chip is arranged.
Inner diameter 120μ at the position where the N-type thermoelectric material chip is placed
m, outer diameter 150 μm, and height 30 μm.

In the joining step (c), the thermoelectric material wafer 140 with the solder bumps 141 produced in the bump forming step (a) and the electrode wiring 1 produced in the electrode wiring step (b).
43 and the substrate 142 on which the doughnut-shaped structure 144 in the vicinity of the bonding portion is formed are opposed to each other and predetermined alignment is performed, and then the solder is melted to bond the thermoelectric material wafer 140 and the substrate 142. In the bonding of the P-type thermoelectric material wafer and the substrate, the solder bumps formed on the surface of the P-type thermoelectric material wafer have an inner diameter of 120 μm formed on the substrate.
The thermoelectric material wafer 140 and the substrate 142 were aligned by putting them inside the smaller donut-shaped structure 144 having an outer diameter of 150 μm and a height of 30 μm. Similarly, when joining the N-type thermoelectric material wafer to the substrate, solder bumps formed on the surface of the N-type thermoelectric material wafer are
120 μm inside diameter and 150 μm outside diameter formed on the substrate,
By inserting the thermoelectric material wafer 140 and the substrate 1 inside a small donut-shaped structure 144 having a height of 30 μm.
Alignment with 42 was performed. Here thermoelectric material wafer 1
The smaller one of the two doughnut-shaped structures formed on the substrate is used to bond the 40 and the substrate 142 to each other in order to ensure the bonding position and the mutual alignment accuracy. Is to raise.

In the cutting / deleting step (d), the thermoelectric material wafer 140 bonded to the substrate 142 is cut / deleted to form a thermoelectric material chip 145 bonded to the substrate 142. . At this time, if necessary, a part of the substrate 142 may be cut / deleted at the same time. In this example, the cutting / deletion step (d) was performed using a dicing saw used for cutting a silicon semiconductor or the like. The blade used for cutting / deleting has a thickness of 200μ
m was used. The thickness of this blade is such that the length of one side of the thermoelectric material chip 145 having a square of this embodiment is 100.
The distance between the centers of the similar thermoelectric material chips closest to each other in μm is 300
μm, and selected because different types of thermoelectric material chips are bonded in the positional relationship shown in FIG. The unnecessary portion of the thermoelectric material is cut / deleted at the center between the solder bumps 141, and at the same time, the gap between the thermoelectric material wafer 140 made of nickel bumps having a height of 40 μm and the substrate 142 is used.
This was done by adjusting the height of the blade so as not to damage the electrode wiring 143 on the substrate. A substrate 142 to which substantially 125 thermoelectric material chips 145 were bonded was produced for each type of thermoelectric material by cutting and removing it vertically and horizontally with a dicing saw blade.

In the assembly step (e), the two substrates 14 to which thermoelectric material chips 145 of different types are bonded
Regarding No. 2, silver particles and a conductive adhesive containing an epoxy resin as a main component are attached to the tip of the thermoelectric material chip 145 by stamping, and these are faced to each other to be formed on the tip of the thermoelectric material chip 145 and the substrate 142. By aligning with the electrode wiring 143 at the position to be joined and heating while applying pressure, the conductive adhesive is cured,
Thermoelectric material chip 145 and electrode wiring 143 on substrate 142
Was completed, and a thermoelectric conversion element having a PN junction on the upper and lower substrates could be completed. In addition, this joint is
This was done inside the remaining donut-shaped structure 144, but this donut-shaped structure 144 was able to prevent the conductive adhesive from protruding during bonding.

The final external dimensions of the thermoelectric conversion element thus manufactured are about 1.2 mm in thickness, and the size is 4 mm × 4 m in size of the lower substrate provided with the input / output electrodes.
m, electrically, the internal resistance was 120Ω, and the basic characteristics were the same as those of the thermoelectric conversion element produced in Example-1.

In this embodiment, since the plating resist is not formed on both sides by photolithography in the step of forming bumps on the thermoelectric material, it is necessary to apply the photoresist on both sides or use a double-side aligner / exposure machine. Therefore, it is possible to simplify equipment and processes.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to the above-mentioned embodiments, and can be applied to a wide range of applications. For example, in each embodiment, as the thermoelectric material, B
Although a sintered body of an i-Te-based thermoelectric material was used, it goes without saying that the present invention is not limited to this thermoelectric material.
It can also be applied to various thermoelectric materials such as —Si based materials, Si—Ge based materials, and Co—Sb based materials. Further, in each of the embodiments, the small thermoelectric conversion element and the manufacturing method thereof are described. However, according to the thermoelectric conversion element and the manufacturing method thereof of the present invention, after the thermoelectric material chip is manufactured, it is sandwiched between two substrates. It can also be applied to a relatively large thermoelectric conversion element manufactured by the method described above.

[0114]

As described above, according to the invention described in claims 1 to 29, the thermoelectric material wafer and the PN junction electrode on the substrate are bonded together due to the positional relationship between the thermoelectric material chip and the PN junction electrode. After that, the unnecessary parts of the thermoelectric material are cut and removed to produce thermoelectric material chips bonded on the substrate, and then the substrates to which the heterogeneous thermoelectric material chips are bonded are faced to each other, Since the PN junction is formed by joining the tip of the electrode to the PN junction electrode on the substrate, the size of the thermoelectric material chip is small, and a thermoelectric conversion element with a high density of the number of thermoelectric material chips per unit area is manufactured. There is an effect that you can.

According to the first and fourth aspects of the present invention, the thermoelectric material chip is arranged, and the position and arrangement relationship between the thermoelectric material chip and the PN junction electrode are taken into consideration.
Since the method of manufacturing a thermoelectric conversion element according to the invention described in 9, that is, the method of chipping a thermoelectric material after bonding it to a substrate can be adopted, it is not necessary to handle a thermoelectric material chip alone which is difficult to handle. It is possible to provide a small thermoelectric conversion element in which the size of the thermoelectric material chips is small and the density of the number of thermoelectric material chips per unit area is high.

Further, according to the invention of claim 2, claim 3, claim 5 or claim 6, a dummy thermoelectric element is provided at a portion corresponding to the outer peripheral portion of the thermoelectric conversion element which is susceptible to a mechanical shock from the outside. Since the material chip is fixed between the two substrates, there is an effect that the mechanical strength of the element is increased and the reliability is increased.

Further, according to the invention described in claims 7 and 29, when the thermoelectric conversion element utilizes the Peltier effect by changing the cross-sectional shape of the thermoelectric material chip in the direction perpendicular to the substrate, the thermoelectric conversion element is energized. Since the place where the Joule heat is generated can be limited, there is an effect of enhancing the cooling efficiency on the cooling surface. Moreover, since the alignment accuracy in the assembly process can be improved by changing the cross-sectional shape, it is possible to manufacture a thermoelectric conversion element composed of a thermoelectric material chip of several hundreds μm or less, and to improve the yield. There is an effect that you can.

According to the eighth, ninth, tenth, eleventh and twelfth aspects of the present invention, the structure is provided on the substrate in the vicinity of (around) the position where the thermoelectric material is to be joined. Is provided, there is an effect that the alignment accuracy at the time of joining can be improved and the flow of the joining material can be prevented.

According to the thirteenth and fourteenth aspects of the present invention, since silicon is used as the substrate material, surface processing can be easily performed by a photolithography method, and a small thermoelectric conversion element can be easily manufactured. There is an effect that can be. In addition, since the thermal conductivity of silicon is extremely high, especially at low temperatures, it is higher than that of metals such as aluminum, so the efficiency of heat absorption and heat dissipation in the manufactured thermoelectric conversion element is improved, and the performance as a thermoelectric conversion element is also improved. There is an effect.

According to the fifteenth aspect of the present invention, in the method of joining different types of thermoelectric material chips to different substrates, facing each other, and joining the thermoelectric material chips and the substrate to each other, the first joining is performed. By changing the composition of the bonding material used for and the bonding material used for the second time, the second bonding temperature can be lower than the first bonding temperature, so the thermoelectric conversion element can be installed without damaging the first bonding part. There is an effect that it can be manufactured.

According to the inventions of claim 16, claim 17, claim 18, claim 21, and claim 22, the bonding is carried out through a protruding electrode such as a bump, thereby improving the effect of the invention. In the method of manufacturing the thermoelectric conversion element described, that is, in addition to the effect of a bonding material in bonding the thermoelectric material wafer and the substrate, in the cutting / removing step after bonding,
There is an effect that it also serves as forming a gap for not damaging the electrode wiring on the substrate. Furthermore, by providing a protruding electrode of nickel or the like on the thermoelectric material side, the diffusion reaction between the bonding material such as solder and the thermoelectric material can be suppressed, so that the reliability of the manufactured thermoelectric conversion element is improved. be able to. This effect has a remarkable effect in the case of joining with a Bi-Te-based material solder whose diffusion reaction with the solder is remarkable.

According to the nineteenth aspect of the invention, since a method of chipping the thermoelectric material after bonding it to the substrate can be adopted, the thermoelectric material becomes difficult to handle when the size of the thermoelectric material chip becomes small. Since a single chip is not handled, it is possible to provide a small thermoelectric conversion element in which the size of the thermoelectric material chip is small and the density of the number of thermoelectric material chips per unit area is high.

According to the twentieth aspect of the invention, in the method of manufacturing a thermoelectric conversion element according to the nineteenth aspect, a gap is provided between the bonded thermoelectric material wafer and the substrate. By holding the cutting edge of a cutting tool or the like used in this gap in this gap, it is possible to produce a thermoelectric material chip bonded to the substrate without damaging the substrate or the electrode wiring provided on the substrate.

According to the invention described in Item 23, in the method for manufacturing a thermoelectric conversion element described in Item 19, the structure provided on the substrate is utilized to bond the bonded thermoelectric material wafer and substrate. Since a gap can be created between the two, the blade edge of the cutting tool used for cutting and removing can be held in this gap so that it can be bonded to the substrate without damaging the substrate or the electrode wiring provided on the substrate. There is an effect that a thermoelectric material chip can be manufactured. Further, the structure itself may serve as a gap.

According to the twenty-fourth aspect of the present invention, in the method of manufacturing a thermoelectric conversion element according to the nineteenth aspect, it is not necessary to previously provide bonding layers on both sides of the thermoelectric material wafer,
First joining is performed using the joining layer formed on only one side, and if it is after that, it is stamped on the tip of the thermoelectric material chip if it is a method such as printing, or if it is made into chips after cutting / deleting. There is an effect that the bonding material layer can be formed on the other surface by a simple method such as a method.

According to the twenty-fifth and twenty-sixth aspects of the present invention, in the method for manufacturing a thermoelectric conversion element according to the nineteenth aspect, at least the first bonding surface of the thermoelectric material wafer is the electrode on the substrate. Since a gap can be created between the joined thermoelectric material wafer and the substrate by making the portion to be joined with and the vicinity thereof convex, the cutting edge of a cutting tool used for cutting / removing can be kept in this gap. Thus, there is an effect that the thermoelectric material chip bonded to the substrate can be easily manufactured without damaging the substrate or the electrode wiring provided on the substrate. Regarding the method of forming the convex portion, in addition to a physical method using a cutting tool, a chemical method such as etching, when the thermoelectric material is a sintered body, a desired convex shape is obtained during sintering. There is also a method of manufacturing using such a mold.

According to the twenty-seventh aspect of the present invention, a groove is formed in the thermoelectric material wafer on the surface of which a bonding material layer for bonding with the substrate or a layer for assisting the bonding is formed. A convex portion is formed in the portion joined to and the vicinity thereof. As a result, the convex portion becomes a protruding electrode corresponding to a bump, and the layer formed at the tip thereof becomes a layer directly involved in bonding. Therefore, in the method of manufacturing a thermoelectric conversion element according to claim 19, a patterned bonding layer is formed, and a gap can be formed between the bonded thermoelectric material wafer and the substrate. By holding the cutting edge of a cutting tool or the like used for removal in this gap, it is possible to easily produce a thermoelectric material chip bonded to the substrate without damaging the substrate or the electrode wiring provided on the substrate. is there.

According to the twenty-eighth aspect of the present invention, by forming a groove between the bumps of the thermoelectric material wafer having bumps for bonding with the substrate formed on the surface, the bumps are formed on the convex portions. Located in. Therefore, claim 1
In the method for manufacturing a thermoelectric conversion element according to 9, since the bumps are small, after the bonding, cutting between the substrate and the thermoelectric material is performed.
When the gap required for the removal cannot be formed, a gap having a sufficient width can be formed between the bonded thermoelectric material wafer and the substrate by the protrusion and the bump. As a result, the cutting edge of a cutting tool or the like used for cutting / deleting can be held in this gap, and the thermoelectric material chip bonded to the substrate can be easily manufactured without damaging the substrate or the electrode wiring provided on the substrate. There is an effect.

According to the invention of claim 29, in the method of manufacturing a thermoelectric conversion element of claim 19, by changing the width of the groove inserted before the first joining and the width of cutting / removing, It is possible to manufacture a thermoelectric conversion element in which the cross-sectional shape of the thermoelectric material chip in the direction perpendicular to the substrate is different in the vicinity of the substrate and in the central portion, which is the invention of claim 7, thus providing a thermoelectric conversion element with excellent performance. There is an effect that can be.

Further, the small size manufactured in this way,
A thin thermoelectric conversion element having a large number of PN junction pairs of thermoelectric material chips exhibits a great effect in power generation at a small temperature difference. In Example-1, a thermoelectric conversion element having a number of PN junction pairs capable of producing an output of about 1 V or more is used,
Although an example in which an electronic wristwatch is driven has been shown, the number of elements can be significantly reduced by attaching a booster circuit or the like, or by lowering the voltage of the CMOS-IC.
The thermoelectric conversion element can be applied and developed not only to electronic wrist watches but also to many portable electronic devices. Further, the use of the small thermoelectric conversion element produced by the present invention as a cooling element also has a great effect. For example, in order to make the cooling performance the same, if the current density to flow per thermoelectric material chip is constant, the cross-sectional area of the thermoelectric material chip is small, many thermoelectric material chips can be arranged in series, The cooling capacity can be increased by increasing the voltage. For example, the cooling performance is determined by the electric power input to the thermoelectric conversion element, but in the conventional thermoelectric conversion element, since the cross-sectional area of the thermoelectric material chip is large,
Power supply becomes low voltage and large current. On the other hand, in the thermoelectric conversion element of the present invention, since the cross-sectional area of the thermoelectric material chip can be reduced, it becomes possible to supply electric power at a low current. This eliminates the need to make the input / output wiring thick and the power source used to have a large current type. Furthermore, because the electric wiring can be made thin,
It becomes possible to easily fabricate a so-called multi-stage element called a cascade type, and it is possible to achieve an extremely low temperature.

Although the size of the thermoelectric material chip is set to 500 μm or less in the embodiment, the present invention can be applied to a size of several hundred μm, which is a general rule, to a millimeter order. Needless to say. Furthermore, in the examples, the production of individual thermoelectric conversion elements was described, but by using a large-sized substrate or thermoelectric material wafer, a plurality of elements can be produced collectively, so that a small thermoelectric conversion element can be produced. In the case of manufacturing, the present invention has a great effect in terms of cost.

[Brief description of drawings]

FIG. 1 is a diagram showing an appearance of a thermoelectric conversion element according to the present invention.

FIG. 2 is a diagram showing a cross section of a main part of AA ′ and BB ′ shown in FIG.

FIG. 3 is a diagram showing the relationship between the arrangement of thermoelectric material chips and the electrode wiring of the thermoelectric conversion element shown in Example-1 of the present invention.

FIG. 4 is a diagram showing an outline of a process for manufacturing a thermoelectric conversion element according to Example-1 of the present invention.

FIG. 5 is a diagram showing a relationship between arrangement of thermoelectric material chips and electrode wiring of a thermoelectric conversion element according to Example-2 of the present invention.

FIG. 6 is a diagram showing an outline of a process for manufacturing a thermoelectric conversion element according to Example-2 of the present invention.

FIG. 7 is a diagram showing an outline of a process for producing a thermoelectric conversion element according to Example-3 of the present invention.

FIG. 8 is a diagram showing an outline of a process for manufacturing a thermoelectric conversion element according to Example-4 of the present invention.

FIG. 9 is a view showing a cross section of the thermoelectric material wafer after the grooving step in the step of manufacturing the thermoelectric conversion element according to Example-4 of the present invention.

FIG. 10 is a diagram showing a cross section of a main part after a cutting / deleting step in the step of manufacturing a thermoelectric conversion element according to Example-4 of the present invention.

FIG. 11 is a view showing a completed cross section of a thermoelectric conversion element according to Example-4 of the present invention.

FIG. 12 is a sectional view of a thermoelectric conversion element having a structure related to the thermoelectric conversion element of Example-4 of the present invention.

FIG. 13 is a diagram showing an outline of a process for manufacturing a thermoelectric conversion element according to Example-5 of the present invention.

FIG. 14 is a diagram showing an outline of a process for manufacturing a thermoelectric conversion element according to Example-6 of the present invention.

FIG. 15 is a diagram showing the relationship between the arrangement of thermoelectric material chips and electrode wiring of a conventional thermoelectric conversion element.

FIG. 16 is a vertical sectional view showing an outline of processing of a thermoelectric material in manufacturing a conventional thermoelectric conversion element.

FIG. 17 is a diagram showing a conventional thermoelectric conversion element manufacturing method for manufacturing a thermoelectric conversion element by using a thermoelectric material chip and a substrate provided with electrode wiring.

[Explanation of symbols]

11, 175 thermoelectric conversion elements 12, 21, 31, 42, 56, 72, 82, 102,
113, 116, 122, 123, 132, 142, ...
150, 171 substrate 13, 34, 52, 110, 120, 153 P-type thermoelectric material chip 14, 35, 53, 111, 121, 154 N-type thermoelectric material chip 15 PN bonding electrode 22 bonding material 23, 44, 74, 84, 104, 115, 144 structure 32, 50 upper substrate electrode wiring pattern 33, 51 lower substrate electrode wiring pattern 40, 60, 70, 80, 130, 140 thermoelectric material wafer 41, 81, 71, 91, 101, 112 , 141 solder bumps 43, 65, 73, 83, 103, 114, 133, 1
43, 173 Electrode wiring 45, 66, 75, 85, 134, 145, 163, 1
72 thermoelectric material chip 54 upper substrate dummy electrode 55 lower substrate dummy electrode 61 nickel layer 62, 63 solder layer 64 alumina substrate 67 groove 68 convex portion 90 P-type thermoelectric material wafer 92 N-type thermoelectric material wafer 105 N-type thermoelectric material 131 protrusion Electrode 151 Upper substrate electrode wiring 152 Lower substrate electrode wiring 161 Thermoelectric material 162 Layer for soldering 174 Bonding material

Claims (29)

[Claims] 1. A thermoelectric conversion element comprising two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. In, the chip-shaped thermoelectric material has a quadrangular cross-sectional shape in a plane parallel to the substrate, and a straight line connecting the centers of the quadrangle of the P-type and N-type thermoelectric materials forming an electrical pair and each thermoelectric material. A thermoelectric conversion element characterized in that the positional relationship with the four sides forming a quadrangle, which is the cross-sectional shape of the chip, is not orthogonal or parallel. 2. The thermoelectric conversion element according to claim 1, wherein the thermoelectric material chip sandwiched between two substrates has a thermoelectric material chip that is electrically separated and bonded to the substrates. Thermoelectric conversion element. 3. The thermoelectric conversion element according to claim 1, wherein the thermoelectric conversion element has an electrode in which a plurality of chips of the same type among thermoelectric material chips sandwiched between two substrates are arranged. 4. A thermoelectric conversion device comprising two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. In the element, the thermoelectric material chip has a quadrangular cross-sectional shape in a plane parallel to the substrate, and the thermoelectric material chips are arranged in a grid shape in the side direction of the quadrangular shape having the cross-sectional shape to form this grid-like arrangement. The P-type thermoelectric material chips and the N-type thermoelectric material chips are alternately arranged on one side, and the P-type thermoelectric material chips or only the N-type thermoelectric material chips are arranged alternately on the other side. A thermoelectric conversion element characterized by the above. 5. The thermoelectric conversion element according to claim 4, wherein the thermoelectric material chip sandwiched between two substrates has a thermoelectric material chip that is electrically isolated and bonded to the substrates. Thermoelectric conversion element. 6. The thermoelectric conversion element according to claim 4, wherein among thermoelectric material chips sandwiched between two substrates, the thermoelectric conversion element has an electrode on which a plurality of chips of the same type are arranged. 7. A thermoelectric conversion element comprising two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. A thermoelectric conversion element, wherein the cross-sectional shape of the thermoelectric material chip is changed in the height direction of the thermoelectric material chip. 8. A thermoelectric conversion element composed of two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. A thermoelectric conversion element, wherein a structure is provided in the vicinity of a portion where the chip-shaped thermoelectric material and the substrate are bonded via electrodes on the surface of both or one of the two substrates. 9. The thermoelectric conversion element according to claim 8, wherein the structure provided on the substrate has a size in at least a portion of the substrate where the P-type thermoelectric material chip and the N-type thermoelectric material chip are arranged, Alternatively, a thermoelectric conversion element having a different shape. 10. The thermoelectric conversion element according to claim 8, wherein the structure provided on the substrate has two substrates constituting the thermoelectric conversion element for the same thermoelectric material chip,
Alternatively, a thermoelectric conversion element having a different shape. 11. The thermoelectric conversion element according to claim 8, wherein the structure provided on the substrate is made of a polymer material. 12. The thermoelectric conversion element according to claim 8, wherein the structure provided on the substrate is one obtained by curing a photosensitive resin. 13. A thermoelectric conversion element composed of two substrates having electrode wiring, and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. 2. A thermoelectric conversion element, wherein both or one of the two substrates is silicon. 14. The thermoelectric conversion element according to claim 13, wherein
A thermoelectric conversion element, characterized in that the whole or part of the surface of the silicon substrate is covered with an insulating layer. 15. A thermoelectric conversion element composed of two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. In at least one of the substrates, the composition of the bonding material for bonding the thermoelectric material chip and the electrode formed on the substrate is different in the different type thermoelectric material chips. Thermoelectric conversion element. 16. A thermoelectric conversion element composed of two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. In the thermoelectric conversion element, the chip-shaped thermoelectric material chip and the electrode formed on the substrate are joined via a projection-shaped electrode. 17. The thermoelectric conversion element according to claim 16,
A thermoelectric conversion element, wherein a projecting electrode for joining a chip-shaped thermoelectric material and an electrode formed on a substrate is formed on the chip-shaped thermoelectric material. 18. The thermoelectric conversion element according to claim 16, wherein
A thermoelectric conversion element, wherein the projecting electrode for joining the chip thermoelectric material and the electrode formed on the substrate is a projecting electrode having a solder bump structure formed on the chip thermoelectric material. 19. A thermoelectric conversion element composed of two substrates having electrode wiring and at least a pair of chip-like P-type and N-type thermoelectric materials sandwiched between these substrates and PN-bonded via electrode wiring. In the manufacturing method of
A step of forming electrode wiring for joining (electrode wiring step), a step of joining P-type and N-type plate-shaped or rod-shaped thermoelectric materials and respective substrates (joining step), and a joined plate shape Alternatively, a step (cutting / deletion step) of manufacturing separate substrates to which the P-type and N-type thermoelectric material chips are joined by cutting / removing the rod-shaped thermoelectric material as necessary, and a P-type thermoelectric material The substrate to which the chip is bonded and N
Face the substrate on which the mold thermoelectric material chip is joined, join the electrode on the substrate and the tip of the thermoelectric material chip,
A method of manufacturing a thermoelectric conversion element, comprising the step of assembling a thermoelectric conversion element by forming a PN junction pair via electrode wiring (assembly step). 20. The method of manufacturing a thermoelectric conversion element according to claim 19, wherein after the substrate and the plate-shaped or rod-shaped thermoelectric material are bonded (bonding step), there is a gap between the substrate and the thermoelectric material. Method for manufacturing thermoelectric conversion element. 21. The method for manufacturing a thermoelectric conversion element according to claim 19, wherein a predetermined electrode wiring is provided on the surface of the substrate, and a predetermined shape and arrangement are provided on at least one surface of the plate-shaped or rod-shaped thermoelectric material. Solder with pattern,
A step of forming bumps of gold, silver, copper, nickel, etc.,
A method of manufacturing a thermoelectric conversion element, comprising a step of joining a substrate and a thermoelectric material via bumps. 22. The method of manufacturing a thermoelectric conversion element according to claim 19, wherein the substrate and the plate-shaped or rod-shaped thermoelectric material are joined to each other (joining step) on the surface of the thermoelectric material between the substrate and the thermoelectric material. A method for manufacturing a thermoelectric conversion element, characterized in that a gap is provided by bumps. 23. The method of manufacturing a thermoelectric conversion element according to claim 19, wherein the structure is formed on the substrate between the substrate and the thermoelectric material by joining (bonding step) the substrate and the plate-shaped or rod-shaped thermoelectric material. A method for manufacturing a thermoelectric conversion element, characterized in that a gap is provided by. 24. The method of manufacturing a thermoelectric conversion element according to claim 19, wherein after the substrate and the plate-shaped or rod-shaped thermoelectric material are bonded (bonding step), bumps are formed on the surface of the thermoelectric material that is not bonded to the substrate. A method for manufacturing a thermoelectric conversion element, comprising: 25. The method for manufacturing a thermoelectric conversion element according to claim 19, wherein all or a part of the surfaces to be bonded of the thermoelectric material wafer used for bonding with the substrate have a bonding portion or a bonding portion with the substrate. A method of manufacturing a thermoelectric conversion element, characterized in that processing is performed so that the vicinity is convex. 26. The method for manufacturing a thermoelectric conversion element according to claim 19, wherein, before joining, grooving is performed on all or part of at least one of the joining surfaces of the surfaces of the plate-like or rod-like thermoelectric material. A method of manufacturing a thermoelectric conversion element, comprising: 27. In the method for manufacturing a thermoelectric conversion element according to claim 19, a plate-like member having a bonding material layer for bonding with a substrate or a layer for assisting bonding, formed on the surface before bonding, or A thermoelectric conversion element, characterized by having a step of forming a convex portion at a portion to be a joint portion with a substrate and in the vicinity thereof by grooving all or a part of at least one surface on the surface of a rod-shaped thermoelectric material. Manufacturing method. 28. The method for manufacturing a thermoelectric conversion element according to claim 19, wherein at least one of the surfaces of a plate-shaped or rod-shaped thermoelectric material on the surface of which bumps for bonding with a substrate are formed before bonding. A method of manufacturing a thermoelectric conversion element, wherein grooving is performed between bumps in the step of grooving all or part of one surface. 29. The method for manufacturing a thermoelectric conversion element according to claim 19, comprising a step of grooving all or part of at least one surface of the plate-shaped or rod-shaped thermoelectric material before joining. And the width of the groove made by this grooving,
A method for manufacturing a thermoelectric conversion element, characterized in that the width of cutting / deletion in a step of cutting / deleting an unnecessary portion of a thermoelectric material, which is a subsequent step, is different.