JP2009130118A - Semiconductor device, method for manufacturing the same, and solar battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device regarding which a connection interconnect is surely jointed to an element forming substrate on which predetermined elements are formed, and to provide a method for manufacturing the device, and a solar battery cell. <P>SOLUTION: A p electrode 4 and an n electrode 5 are prepared at the backside of a solar battery cell 1, and an electrode main body 6 of the p(n) electrodes 4 and 5 is exposed to an opening 9 formed in an insulating layer 8. On an interconnector 11, there are prepared crooked portions 16 in an extended portion 18 which extends in one direction. By having a laser beam irradiated on the crooked portions 16, the interconnector 11 is joined to the p(n) electrodes 4 and 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor device, a manufacturing method thereof, and a solar cell, a semiconductor device in which element forming substrates are connected to each other by a wiring member, a manufacturing method of such a semiconductor device, and a solar battery cell as such an element forming substrate. It is related with the solar cell containing.

  An example of a conventional semiconductor device is a solar cell. As one form of the solar battery, there is a solar battery in which a plurality of solar battery cells are electrically connected to each other by a predetermined metal wiring (interconnector). In this type of solar battery, a front electrode and a back electrode are respectively formed on the front surface (light receiving surface) and the back surface of each solar cell. This solar cell is manufactured as follows. First, as shown in FIG. 25, one end side of the interconnector 111 is connected to a surface electrode (not shown) of one solar battery cell 101. Next, as shown in FIG. 26, the other end side of the interconnector 111 is connected to a back electrode (not shown) of another solar battery cell 101. Next, as shown in FIG. 27, one end side of another interconnector 111 is connected to a surface electrode (not shown) of another solar battery cell 101. Hereinafter, similarly, a plurality of solar battery cells 101 are sequentially connected by the interconnector 111, whereby the solar battery 121 is manufactured.

  However, in such a light receiving surface of the solar cell 121, the region where the surface electrode is disposed does not contribute to power generation. For this reason, a structure has been proposed in which a front electrode is arranged on the back side in order to obtain a higher conversion rate. Patent Document 1 is one of documents that disclose such a solar cell. In the solar cell disclosed in Patent Document 1, a structure is proposed in which the front surface electrode is disposed on the back surface side by forming a through electrode in the solar cell without changing the basic configuration of the solar cell. .

  As shown in FIG. 28, in the solar battery cell 101, a through hole 103 penetrating the P type semiconductor layer 107 is formed, and an N type semiconductor layer 108 is formed on the surface of the P type semiconductor layer 107 including the side wall of the through hole 103. Is formed. An n-electrode 104 that contacts the N-type semiconductor layer 108 and fills the through hole 103 is formed so as to be exposed on the back surface side. A P + type semiconductor layer 106 is formed on the back side of the P type semiconductor layer 106, and a p-electrode 105 is formed on the P + type semiconductor layer 106. An antireflection film 109 is formed on the light receiving surface side of the N-type semiconductor layer 108.

  Thus, in the solar battery cell in which the front electrode is arranged as the n electrode 104 on the back surface side, it is necessary to electrically insulate the n electrode 104 from the back electrode (p electrode 105). In the solar cell shown in FIG. 28, a structure in which the n electrode 104 and the p electrode 105 are electrically insulated by an insulating layer 108 such as an organic insulating film is proposed.

  The manufacturing process of a solar cell is divided roughly into the first half process which produces a photovoltaic cell, and the latter half process which connects the photovoltaic cell in series and produces as a module. The subsequent half step includes a step of connecting the p electrode of one solar battery cell and the n electrode of another solar battery cell with an interconnector. In general, a copper-plated copper is applied as an interconnector. The interconnector and the p (n) electrode of the solar battery cell are joined by melting and soldering the solder while the interconnector is in contact with the p (n) electrode.

  However, when such soldering is performed, warpage due to a difference in thermal expansion coefficient between the thermal expansion coefficient of the solar battery cell 101 and the thermal expansion coefficient of the interconnector 111 may occur. When such warping occurs, there are problems such as difficulty in packaging with resin sealing and cracking of the solar battery cell 101. Such warping is caused by the fact that the entire solar battery cell 101 and the interconnector 111 are heated.

Therefore, in order to suppress such warpage, for example, Patent Document 2 discloses a method of soldering the p (n) electrode of the solar battery cell and the interconnector by locally heating using a laser beam. Proposed.
Japanese Patent Laid-Open No. 2-51282 JP 2004-134654 A

  However, the conventional solar cell described above has the following problems. In the solar cell in which the p-electrode 105 and the n-electrode 104 are provided on the back surface of the solar battery cell 101, as shown in FIG. 28, there are irregularities associated with the formation of the insulating layer 108 on the back surface of the solar battery cell 101. . On the other hand, as shown in FIG. 29, the interconnector has a light absorption layer 114 and a low melting point metal layer 113 formed on each surface of a core material 112 extending substantially linearly in one direction. Therefore, when the interconnector 111 is brought into contact with the p (n) electrodes 104 and 105 and joined, a gap is generated between the interconnector 111 and the p (n) electrodes 104 and 105, and the joining by soldering is ensured. There was a problem that it was not done.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a semiconductor device in which connection wiring is reliably bonded to an element formation substrate on which a predetermined element is formed. An object of the present invention is to provide a method of manufacturing such a semiconductor device, and yet another object is to provide a solar cell including such a semiconductor device, and to provide a method of manufacturing the same. That is.

  The semiconductor device according to the present invention includes an element formation substrate, an electrode, a material layer, and connection wiring. A predetermined element is formed on the element formation substrate. The electrode is provided on the element formation substrate and is electrically connected to the element. The material layer has a predetermined thickness and is formed on the element formation substrate to expose the electrode. The connection wiring is joined to the electrode. The connection wiring includes a contact portion that contacts the electrode in a manner that compensates for the difference in height between the surface of the material layer and the electrode, and joins the electrode.

  According to this configuration, the contact portion that electrically connects the electrode and the connection wiring is formed so as to contact the electrode in a manner that compensates for the height difference between the surface of the material layer and the electrode. Electrical connection between the electrode and the connection wiring can be reliably performed.

  Specifically, in order to ensure electrical connection between the electrode and the connection wiring, the material layer has an opening that exposes the electrode, and the connection wiring is disposed along the surface of the insulating layer. It is preferable that the extended portion includes a bent portion that is provided in the extended portion as a contact portion and bends toward the electrode side to contact the electrode.

  More specifically, the height from the extended portion of the bent portion is preferably set higher than the height corresponding to the distance from the upper surface of the material layer to the surface of the electrode.

  Furthermore, it is preferable that the bent portion is formed with a curved portion that is curved toward the electrode side.

  The connection wiring preferably includes a first metal layer serving as a core and a second metal layer formed on one surface of the first metal layer and made of a material different from that of the first metal layer.

  As such a 1st metal layer, it is preferable that the 1st metal layer is formed from the material in any one of gold | metal | money, silver, copper, and these alloys.

  Further, as the second metal layer, the second metal layer is preferably formed of a material having a melting point lower than the melting point of the first metal layer.

  Further, as such a second metal layer, the second metal layer is preferably formed of solder containing any of tin and lead alloys, tin and lead.

  Accordingly, it is possible to melt only the second metal layer without melting the first metal layer of the connection wiring and to join the electrode and the connection wiring.

  Further, it is preferable that a light absorption layer that absorbs light of a predetermined wavelength is formed on the other surface of the first metal layer.

  In this case, when the connection wiring is connected to the electrode by the laser beam, the energy of the laser beam is efficiently absorbed.

  As such a light absorption layer, the light absorption layer is preferably formed of the same material as the second metal layer.

  The solar cell according to the present invention has a solar cell substrate, a material layer, an electrode, and a connection wiring. A predetermined power generation element is formed on the solar cell substrate. The material layer has a predetermined thickness and is formed on the solar cell substrate. The electrode is exposed at a position lower than the position of the upper surface of the material layer. The connection wiring is arranged along the upper surface of the material layer. The connection wiring includes a contact portion that is elastically contacted and joined to the exposed electrode.

  According to this configuration, the connection wiring includes the contact portion that is elastically contacted and joined to the exposed electrode, so that the laser beam is irradiated while the contact portion is in contact with the electrode. Thus, the connection wiring and the electrode can be reliably bonded.

  Specifically, the material layer is provided with an opening, the electrode is exposed in the opening, and the connection wiring extends along the surface of the material layer, and the extension extends as a contact portion. And a bent portion that bends toward the electrode and contacts the electrode.

  A method for manufacturing a semiconductor device according to the present invention is a method for manufacturing a semiconductor device in which a connection wiring provided with a contact portion bonded to an electrode exposed at a position lower than the position of the upper surface of a material layer having a predetermined thickness is connected. Thus, a contact process and a connection process are provided. In the contact step, the contact portion of the connection wiring is brought into contact with the electrode. In the connection step, the contact portion is bonded to the electrode by irradiating a predetermined laser beam toward the connection wiring in a state where the contact portion is in contact with the electrode.

  According to this method, the connection wiring can be reliably bonded to the electrode by irradiating the predetermined wiring with the laser beam toward the connection wiring while the contact portion is in contact with the electrode.

  Specifically, the connection wiring includes an extended portion disposed along the surface of the material layer, and a bent portion that is provided in the extended portion as a contact portion and bends toward the electrode to contact the electrode. In the contact step, the bent portion whose height from the extended portion of the bent portion is higher than the height corresponding to the distance from the upper surface of the material layer to the surface of the electrode is brought into contact with the electrode. The bent portion is preferably bonded to the electrode by irradiating a predetermined laser beam toward the connection wiring in a state where the bent portion is in contact with the electrode.

  Hereinafter, a semiconductor device and a method for manufacturing the semiconductor device according to the present invention will be specifically described by taking a solar cell as an example of the semiconductor device.

Embodiment 1
Here, each of the solar battery cells and the connection wiring constituting the solar battery will be described.

(Solar cell)
FIG. 1 shows a cross-sectional structure of p (n) electrodes 4 and 5 and the vicinity thereof in a solar cell 1 in which a p-electrode and an n-electrode are arranged on the back surface of a solar cell substrate 2 on which a pn junction is formed. Is. As shown in FIG. 1, an insulating layer 8 as a material layer for insulating the electrodes 4 and 5 is formed on the back surfaces of the solar cells (substrates) 1 and 2. An opening 9 is formed in the insulating layer 8, and the electrode body 6 of the p (n) electrodes 4 and 5 is exposed. The electrode body 6 is formed so as to fill the through hole 3 penetrating the solar cell substrate 2.

  Next, the arrangement (layout) of the p electrode and the n electrode on the back surface of the solar battery cell 1 will be described. FIG. 2 shows a layout in which electrodes 4 and 5 having the same polarity are arranged in the row direction, and p electrodes 4a to 4c and n electrodes 5a to 5c are arranged alternately in the column direction. FIG. 3 shows a layout in which the p electrodes 4 and the n electrodes 5 are alternately arranged in the row direction, and the electrodes 4a to 4f and 5a to 5f having the same polarity are arranged in the column direction.

  In any of the layouts of FIGS. 2 and 3, it is desirable that the p-electrode 4 or the n-electrode 5 arranged in the column direction be arranged on the same straight line. This is because the p electrode 4 and the n electrode 5 are formed along a straight line when the p (n) electrodes 4 and 5 and the interconnector (not shown) are joined by irradiating a laser beam. This is because the laser beam can be easily and quickly scanned.

  In addition, as the p electrode and the n electrode, the electrode body 6 exposed in the opening formed in the insulating layer 8 covering the back surface of the solar battery cell 1 is described as an example, but the electrode body 6 is formed in a material other than the insulating layer 8. The electrode body may be exposed at the opening, for example, and may be a silver electrode as a connection terminal exposed at the opening of the aluminum electrode layer.

(Interconnector)
Next, an interconnector as a connection wiring for electrically connecting solar cells to each other will be described. The interconnector includes an extending portion that extends in a predetermined direction for electrically connecting solar cells adjacent to each other, and a bent portion that contacts an electrode of the solar cells. The bent portion is provided in the extending portion and is bent toward the electrode side.

  First, a first example of an interconnector is shown in FIG. As shown in FIG. 4, the interconnector 11 is connected to the connection portion 15 connected to the electrode in the extending portion 18 extending in one direction, toward the electrode side of the solar battery cell (downward toward the paper surface). A bent portion 16 is provided. The bent portion 16 has a convex shape when viewed from the electrode side, and has a concave shape when viewed from the opposite side. As shown in FIG. 5, the height h of the bent portion 16 from the extending portion 18 is slightly higher than the height t corresponding to the distance from the upper surface of the insulating layer 8 of the solar battery cell 1 to the electrode body 6. Is formed. In this case, the portion of the bent portion 16 that contacts the electrode body 6 is substantially flat. In other words, the bent portion 16 as a connecting portion is formed in the interconnector 11 so as to compensate for the difference in height between the surface (upper surface) of the insulating layer 8 and the electrode.

  As shown in FIG. 4 or FIG. 5, the shape of such an interconnector 11 is mainly made of a core material 12. A light absorption layer 14 that absorbs a laser beam having a predetermined wavelength is continuously formed on one surface of the core material 12. A low melting point metal layer 13 is formed on the other surface of the core material 12. The material of the core material 12 is preferably a material having high electrical conductivity and high thermal conductivity, such as copper. The light absorption layer 14 is made of, for example, a solder material.

  A second example of an interconnector is shown in FIG. As shown in FIG. 6, the bent portion 16 of the interconnector 11 is formed with a curved portion 17 that is curved toward the electrode side. By forming the curved portion 17, when the interconnector 11 is pressed and the bent portion 16 is brought into contact with the electrode, the curved portion 17 can be brought into contact more stably by an elastic effect. A light absorption layer 14 is continuously formed on one surface of the core material 12 of the interconnector 11, and a low melting point metal layer 13 is formed on the other surface of the core material 12.

  A third example of an interconnector is shown in FIG. As shown in FIG. 7, in the interconnector 11, a light absorption layer 14 is intermittently formed on one surface of the core member 12 corresponding to the region irradiated with the laser beam. The structure other than this is the same as the structure of the interconnector 11 shown in FIG. A fourth example of an interconnector is shown in FIG. As shown in FIG. 8, in the interconnector 11, a light absorption layer 14 is intermittently formed on one surface of the core member 12 corresponding to the region irradiated with the laser beam. The structure other than this is the same as the structure of the interconnector shown in FIG.

Embodiment 2 (Solar cell manufacturing method)
Here, an example of a method for connecting a solar battery cell and an interconnector will be described as a method for manufacturing a solar battery. First, as shown in FIG. 9, the bent portion 16 of the interconnector 11 is positioned with respect to the p (n) electrodes 4 and 5 of the solar battery cell 1. Next, as shown in FIG. 10, the bent portion 16 of the interconnector 11 is brought into contact with the electrode body 6 of the p (n) electrodes 4 and 5. Next, the interconnector 11 is pressed against the solar cell 1 from above by the pressing jig 31.

  At this time, by setting the height h of the bent portion 16 to the above-described predetermined height (see FIG. 5), the surface of the low-melting-point metal layer 13 (bended) with the bent portion 16 in contact with the electrode body 6. The position of the interface between the portion 16 and the low melting point metal) is located slightly above the upper surface of the insulating layer 8, and the interconnector 11 is separated from the insulating layer 8 on the side opposite to the side where the insulating layer 8 is located. The bent portion 16 of the interconnector 11 is reliably brought into contact with the electrode body 6.

  Next, as shown in FIG. 11, a laser beam 32 is irradiated from above onto the interconnector 11 while the interconnector 11 is pressed by the pressing jig 31. The light energy of the laser beam 32 is absorbed by the light absorption layer 14 and is conducted as thermal energy from the core material 12 of the interconnector 11 to the bent portion 16 through the low melting point metal layer 13, and the low melting point metal layer 13 of the bent portion 16. Melts. Thereafter, the melted low melting point metal layer 13 is solidified to complete the joining of the interconnector 11 and the p (n) electrodes 4 and 5 as shown in FIG.

  At this time, the energy of the laser beam 32 is adjusted by adjusting the power so that the low melting point metal layer 13 or the electrode protrusion 7 is melted without melting the core material 12 of the interconnector 11. The damage to 1 is suppressed and good bonding becomes possible.

  Further, the energy loss of the laser beam 32 can be reduced by changing the output (power) of the laser beam 32 with time. FIG. 13 and FIG. 14 are graphs showing the time variation of the control waveform of the laser beam output and the temperature of the low melting point metal part. As shown in FIG. 13, pulse irradiation with a constant laser beam output may be used. More preferably, as shown in FIG. 14, a method of temporally changing the output of the laser beam may be employed. In the method shown in FIG. 14, compared to the method shown in FIG. 13, the temperature of the object to be joined can be increased in a short time, and joining with lower energy becomes possible.

  In the method shown in FIG. 13, the melting point Ta of the low melting point metal is reached after the lapse of ta from the start of the laser beam irradiation, whereas in the method shown in FIG. To reach. Although Ta = Tc, the time to reach the melting point corresponds to the power of the laser beam irradiated during that time, and ta> tc. Therefore, compared with the method shown in FIG. 13, the method shown in FIG. 14 can efficiently heat the object to be joined, and can suppress the loss of energy of the laser beam throughout the joining process.

  As a method of scanning the laser beam, two methods of scanning the laser beam using a galvano scanner or the like and scanning the laser optical head can be applied. The laser is not limited to a YAG laser, and is applied to welding and soldering, such as a semiconductor laser with a wavelength of 0.8 to 1 μm, a fiber laser with a wavelength of 1 to 1.5 μm, and a disk laser with a wavelength of around 1 μm. A laser that emits a laser beam having a wavelength in the near infrared region (wavelength 0.8 to 2.5 μm) can be used.

  Further, as a material for the core material of the interconnector, a material having a low electrical resistance and a high thermal conductivity is preferable, and a material having a high absorption rate of the laser beam having a wavelength in the near infrared region described above is particularly preferable. Moreover, as a material of a light absorption layer, the material which absorbs the laser beam which has a wavelength of the near infrared region mentioned above, especially a wavelength of 0.8-1.1 micrometers is preferable. In the manufacturing method described above, the interconnector 11 shown in FIG. 7 described above can also be applied as the interconnector 11.

  Examples of the material of the light absorption layer of the interconnector applied to this solar cell are shown in Table 1, examples of the material of the core material are shown in Table 2, and examples of the material of the low melting point metal layer are shown in Table 3. In particular, as a material for the low melting point metal layer, an alloyed low melting point alloy can be used in addition to the metals listed in Table 3, as represented by eutectic solder.

Embodiment 3 (Method for Manufacturing Solar Cell)
Here, as another example of a method for connecting a solar battery cell and an interconnector as a method for manufacturing a solar battery, a connection method using an interconnector in which a bending portion is provided at a bent portion will be described.

  First, as shown in FIG. 15, the bent portion 16 (curved portion 17) of the interconnector 11 is positioned with respect to the p (n) electrodes 4 and 5 of the solar battery cell 1. Next, as shown in FIG. 16, the bent portion 16 of the interconnector 11 is brought into contact with the electrode body 6 of the p (n) electrodes 4 and 5. Next, the interconnector 11 is pressed against the solar cell 1 from above by the pressing jig 31.

  At this time, by setting the height h of the bent portion 16 including the curved portion 17 to the above-described predetermined height (see FIG. 5), the low melting point metal in a state where the bent portion 16 is in contact with the electrode body 6. The position of the surface of the layer 13 (the interface between the bent portion 16 and the low melting point metal) is located slightly above the upper surface of the insulating layer 8, and the side of the interconnector 11 opposite to the side on which the insulating layer 8 is positioned. The bent portion 16 of the interconnector 11 is surely brought into contact with the electrode body 6.

  Next, as shown in FIG. 17, a laser beam 32 is irradiated from above onto the interconnector 11 while the interconnector 11 is pressed by the pressing jig 31. The light energy of the laser beam 32 is absorbed by the light absorption layer 14 and is conducted as thermal energy from the core material 12 of the interconnector 11 to the bent portion 16 through the low melting point metal layer 13, and the low melting point metal layer 13 of the bent portion 16. Melts. Thereafter, the melted low melting point metal layer 13 is solidified to complete the joining of the interconnector 11 and the p (n) electrodes 4 and 5 as shown in FIG.

  At this time, the energy of the laser beam 32 is adjusted so that the low melting point metal layer 13 is melted without melting the core material 12 of the interconnector 11, thereby causing damage to the solar cells 1. It is suppressed and good bonding becomes possible.

  Also in the connection method described above, as described in the third embodiment, the loss of energy of the laser beam 32 can be reduced by temporally changing the output (power) of the laser beam 32 (FIG. 13, FIG. 13). (See FIG. 14).

  As described above, as a method of scanning the laser beam, a method of scanning the laser beam using a galvano scanner or a method of scanning the laser optical head can be applied. In addition to the YAG laser, a laser that emits a laser beam having a wavelength in the near infrared region (wavelength 0.8 to 2.5 μm) can be used as the laser. Furthermore, as the interconnector 11, the interconnector 11 formed from each of the materials described above (see Tables 1 to 3) can be applied. As the interconnector 11, the interconnector 11 shown in FIG. 8 described above can also be applied.

Embodiment 4
Here, an example of a solar battery in which a plurality of solar battery cells are connected to each other by an interconnector will be described. First, FIG. 19 shows a planar shape of the interconnector 11. As shown in FIG. 19, in the interconnector 11, in addition to the extending part 18 extended linearly in one direction, the connection part 15 with the p (n) electrode of a photovoltaic cell is formed. The connecting portion 15 is formed so as to protrude in a direction orthogonal to one direction with respect to the extending portion 18. As the structure of the interconnector 11 including the connection part 15, the interconnector 11 shown in FIGS. 4 to 8 described above can be applied.

  When the interconnector 11 shown in FIGS. 4 and 7 is used, the process shown in FIGS. 9 to 12 is performed, and when the interconnector 11 shown in FIGS. 6 and 8 is used, FIGS. Through the steps shown in FIG. 18, solar cells (strings) in which a plurality of solar cells 1 are joined to each other by the interconnector 11 are formed.

  FIG. 20 shows an n−1th solar cell 1a, an nth solar cell 1b, and an n + 1th solar cell 1c among such solar cells 21, and interconnectors 11a to 11h that join these to each other. The plane structure containing is shown.

  As shown in FIG. 20, in each of the solar cells 1, electrodes 4 a to 4 c and 5 a to 5 c having the same polarity are arranged in the row direction, and p electrodes 4 a to 4 c and n electrodes 5 a to 5 c are alternately arranged in the column direction. Is arranged. The n-th electrodes 5a to 5c in the first row of the n-th solar cell 1b and the p-electrodes 4a to 4c in the first row of the (n + 1) th solar cell 1c are electrically connected by the first interconnector 11a. ing. Also, the n-th solar cell 1b in the second row of n-electrodes 5a to 5c and the n + 1-th solar cell 1c in the second row of p-electrodes 4a to 5c are electrically connected by the second interconnector 11b. It is connected.

  Similarly, the n-rows 5a to 5c and the p-electrodes 4a to 4c in the third row of the solar cells 1b and 1c are electrically connected by the third interconnector 11c, and the n-electrode 5a in the fourth row. To 5c and the p electrodes 4a to 4c are electrically connected by the fourth interconnector 11d. Thus, the n electrodes 5a to 5c of the nth solar cell 1b and the p electrodes 4a to 4c of the (n + 1) th solar cell 1c are electrically connected by the nth interconnector group including the four interconnectors 11a to 11d. Connected.

  Similarly, four rows of n electrodes 5a to 5c of the n-1th solar cell 1a and four rows of p electrodes 4a to 4c of the nth solar cell 1b include four interconnectors 11e to 11e. Each column is electrically connected by an (n-1) th interconnector group consisting of 11h. Similarly, the n and p electrodes of other solar cells are also electrically connected by an interconnector.

  In the connection part (refer FIG. 11 or FIG. 17) of the interconnector 11 and the p (n) electrodes 4 and 5 in the solar cell 21, the low melting metal layer 13 of the interconnector 11 and the electrodes of the p (n) electrodes 4 and 5 Since the material constituting the main body 6 is basically different, an intermetallic compound layer (or alloy layer) is formed between the material of the low melting point metal layer that has been melted and solidified and the electrode main body 6. Become. By forming such an intermetallic compound layer (or alloy layer), the bonding strength between the interconnector 11 and the p (n) electrodes 4 and 5 is further increased. As a result, the reliability of the solar cell 21 can be ensured over a long period of time.

  Moreover, in the solar cell 21 mentioned above, a photovoltaic cell is used by using the interconnector 11 (refer FIG. 19) formed so that the connection site | part 15 may protrude in the direction orthogonal to one direction with respect to the extension part 18. FIG. It is possible to alleviate the problems caused by the difference between the thermal expansion coefficient of the connector and the thermal expansion coefficient of the interconnector. This will be described.

  After a solar cell (string) is formed by connecting a plurality of solar cells with an interconnector, the solar cell string is sealed with a resin (packaged). In this packaging process, a resin sheet, a solar cell string, and protective glass are integrally laminated at a temperature of about 150 ° C. to 200 ° C. At that time, due to the difference between the thermal expansion coefficient of the solar battery cell and the thermal expansion coefficient of the interconnector, a difference occurs between the extension amount of the solar battery cell and the extension of the interconnector. The distance between the electrodes (main body) when the connector is connected is different from the distance between the electrodes (main body) at a temperature of about 150 ° C. to 200 ° C. associated with packaging. For this reason, there is a possibility that the solar cell is warped, a load is applied to the connection portion between the interconnector and the electrode, and the soldered portion is peeled off or the solar cell is cracked. is there.

  In addition, due to the temperature change in the environment in which the battery is actually used, thermal stress acts on the joint between the electrode and the interconnector due to the difference in thermal expansion coefficient between the solar battery cell and the interconnector. This may be one of the factors that reduce the reliability of the system.

  FIG. 21 shows a state of the solar battery cell and the interconnector before such thermal stress is applied, and FIG. 22 shows a state of the solar battery cell and the interconnector to which the thermal stress is applied. As shown in FIG. 21 and FIG. 22, the connecting portion 15 of the interconnector 11 is deformed in accordance with the difference in the thermal expansion coefficient that the extension of the solar battery cell 1 becomes larger than the extension of the interconnector 11. Become. Thus, thermal stress is relieved by the deformation of the connection part 15, and the solar battery cell 1 is prevented from warping or cracking, or the soldered part is peeled off. Can be prevented in advance.

Embodiment 5
Here, another example of a solar battery in which a plurality of solar battery cells are connected to each other by an interconnector will be described. First, FIG. 23 shows a planar shape of the interconnector 11. As shown in FIG. 23, in the interconnector 11, a connection portion 15 to the p (n) electrode of the solar battery cell is formed in an extending portion 18 that extends linearly in one direction. As the structure of the interconnector 11 including the connection part 15, the interconnector 11 shown in FIGS. 4 to 8 described above can be applied.

  When the interconnector 11 shown in FIGS. 4 and 7 is used, the process shown in FIGS. 9 to 12 is performed, and when the interconnector 11 shown in FIGS. 6 and 8 is used, FIGS. Through the steps shown in FIG. 18, solar cells (strings) in which a plurality of solar cells 1 are connected to each other by the interconnector 11 are formed.

  FIG. 24 includes n−1th solar cell 1a, nth solar cell 1b and n + 1th solar cell 1c among such solar cells 21, and an interconnector 11 for connecting them to each other. It shows a planar structure.

  As shown in FIG. 24, in each of the solar cells 1a, 1b, and 1c, p electrodes 4a to 4f and n electrodes 5a to 5f are alternately arranged in the row direction, and electrodes 4a to 4f having the same polarity in the column direction. 5a-5f are arranged. The p-electrodes 4a to 4f in the first column of the n-th solar cell 1b and the n-electrodes 5a to 5f in the first column of the n-1th solar cell 1a are electrically connected by the first interconnector 11a. It is connected. Further, the second electrodes na to 5f in the second row of the nth solar cell 1b and the p electrodes 4a to 4f in the second row of the (n + 1) th solar cell 1c are electrically connected by the second interconnector 11b. It is connected.

  Further, the third electrodes pa 4a to 4f of the nth solar cell 1b and the n electrodes 5a to 5f of the third column of the (n-1) th solar cell 1a are electrically connected by the third interconnector 11c. Connected. The nth electrodes 5a to 5f in the fourth row of the nth solar battery cell 1b and the p electrodes 4a to 4f in the fourth row of the (n + 1) th solar battery cell 1c are electrically connected by the fourth interconnector 11d. It is connected.

  Thus, the p electrodes 4a to 4f of the nth solar battery cell 1b and the n electrodes 5a to 5f of the (n-1) th solar battery cell 1a are electrically connected by the two interconnectors 11a and 11c, and n The n electrodes 5a to 5f of the th solar cell 1b and the p electrodes 4a to 4f of the (n + 1) th solar cell 1c are electrically connected by two interconnectors 11b and 11d.

  In the solar cell 21, at the portion where the interconnector 11 and the p (n) electrodes 4 and 5 are connected, as described above, between the material of the low melting point metal layer that is melted and solidified and the electrode body 6. As a result, an intermetallic compound layer (or alloy layer) is formed. By forming such an intermetallic compound layer (or alloy layer), the bonding strength between the interconnector 11 and the p (n) electrodes 4 and 5 is further increased. As a result, the reliability of the solar cell 21 can be ensured over a long period of time.

  In each of the above-described embodiments, a solar battery including a solar battery cell has been described as an example, but a semiconductor including an element formation substrate on which an element having a predetermined function other than the solar battery cell is formed. The same applies to the apparatus. Moreover, although the solar cell in which the unevenness | corrugation by the height difference of the upper surface of the insulating layer as a material layer and the upper surface of an electrode main body was mentioned was mentioned as an example, the aluminum electrode layer as a material layer and its aluminum were demonstrated. The semiconductor device may include an electrode serving as a connection terminal exposed at the bottom of the opening of the electrode layer.

  The embodiment disclosed this time is an example, and the present invention is not limited to this. The present invention is defined by the terms of the claims, rather than the scope described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a fragmentary sectional view of the photovoltaic cell concerning Embodiment 1 of the present invention. In the same embodiment, it is the 1st top view which shows the layout of the electrode of a photovoltaic cell. In the same embodiment, it is the 1st top view which shows the layout of the electrode of a photovoltaic cell. FIG. 3 is a cross-sectional view showing a first example of an interconnector in the embodiment. In the same embodiment, it is a fragmentary sectional view for demonstrating the dimensional relationship between the bending part of an interconnector and an electrode. In the same embodiment, it is sectional drawing which shows the 2nd example of an interconnector. In the same embodiment, it is sectional drawing which shows the 3rd example of an interconnector. In the same embodiment, it is sectional drawing which shows the 4th example of an interconnector. It is a fragmentary sectional view which shows 1 process of the manufacturing method of the solar cell which concerns on Embodiment 2 of this invention. FIG. 10 is a partial cross-sectional view showing a step performed after the step shown in FIG. 9 in the same embodiment. FIG. 11 is a partial cross-sectional view showing a step performed after the step shown in FIG. 10 in the same embodiment. FIG. 12 is a partial cross-sectional view showing a step performed after the step shown in FIG. 11 in the same embodiment. In the same embodiment, it is the 1st graph which shows each time dependence of the output waveform of a laser beam, and the temperature change of a joined part. In the same embodiment, it is a 2nd graph which shows each time dependence of the output waveform of a laser beam, and the temperature change of a junction part. It is a fragmentary sectional view which shows 1 process of the manufacturing method of the solar cell which concerns on Embodiment 3 of this invention. FIG. 16 is a partial cross-sectional view showing a step performed after the step shown in FIG. 15 in the same embodiment. FIG. 17 is a partial cross-sectional view showing a step performed after the step shown in FIG. 16 in the same embodiment. FIG. 18 is a partial cross-sectional view showing a step performed after the step shown in FIG. 17 in the same embodiment. It is a top view which shows the interconnector applied to the solar cell which concerns on Embodiment 4 of this invention. In the same embodiment, it is a top view which shows the planar structure of a solar cell. In the same embodiment, it is a top view which shows the state of the photovoltaic cell and interconnector before a thermal stress acts. In the same embodiment, it is a top view which shows the state of the solar cell and interconnector which the thermal stress acted on. It is a top view which shows the interconnector applied to the solar cell which concerns on Embodiment 5 of this invention. In the same embodiment, it is a top view which shows the planar structure of a solar cell. It is a perspective view which shows 1 process of the manufacturing method of the conventional solar cell. FIG. 26 is a perspective view showing a step performed after the step shown in FIG. 25. FIG. 27 is a perspective view showing a process performed after the process shown in FIG. 26. It is a fragmentary sectional view which shows the electrode and its periphery in the conventional solar cell. It is sectional drawing which shows the interconnector in the conventional solar cell.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Solar cell, 2 Solar cell substrate, 3 Through hole, 4, 4a-4fp electrode, 5, 5a-5f n electrode, 6 Electrode main body, 8 Insulating layer, 9 Opening part, 11, 11a-11d Interconnector , 12 core material, 13 low melting point metal layer, 14 light absorption layer, 15 connection part, 16 bent part, 17 bent part, 18 extended part, 21 solar cell, 31 holding jig, 32 laser beam.

Claims (14)

An element formation substrate on which a predetermined element is formed;
An electrode provided on the element formation substrate and electrically connected to the element;
A material layer having a predetermined thickness formed on the element formation substrate and exposing the electrode;
A connection wiring disposed on the surface of the material layer and bonded to the electrode;
The connection wiring includes a contact portion that contacts the electrode in a manner that compensates for a difference in height between the surface of the material layer and the electrode, and joins the electrode. The material layer is formed with a predetermined thickness,
An opening for exposing the electrode is formed in the material layer,
The connection wiring is
An extending portion disposed along the surface of the insulating layer;
The semiconductor device according to claim 1, further comprising: a bent portion that is provided as the contact portion in the extending portion and bends toward the electrode to contact the electrode.   The semiconductor device according to claim 2, wherein a height of the bent portion from the extended portion is set to be higher than a height corresponding to a distance from an upper surface of the material layer to a surface of the electrode.   The semiconductor device according to claim 2, wherein the bent portion is formed with a curved portion that is curved toward the electrode. The connection wiring is
A first metal layer as a core material;
The semiconductor device according to claim 1, further comprising: a second metal layer formed on one surface of the first metal layer and made of a material different from that of the first metal layer.   The semiconductor device according to claim 5, wherein the first metal layer is made of any material of gold, silver, copper, and alloys thereof.   The semiconductor device according to claim 5, wherein the second metal layer is made of a material having a melting point lower than that of the first metal layer.   The semiconductor device according to claim 7, wherein the second metal layer is formed of solder containing any one of an alloy of tin and lead, tin and lead.   The semiconductor device according to claim 5, wherein a light absorption layer that absorbs light of a predetermined wavelength is formed on the other surface of the first metal layer.   The semiconductor device according to claim 9, wherein the light absorption layer is made of the same material as the second metal layer. A solar cell substrate on which a predetermined power generation element is formed;
A material layer having a predetermined thickness formed on the solar cell substrate;
An electrode exposed at a position lower than the position of the upper surface of the material layer;
A connection wiring disposed along the upper surface of the material layer;
Have
The said connection wiring is a solar cell provided with the contact part joined in elastic contact with the said exposed electrode. The material layer is provided with an opening,
The electrode is exposed in the opening;
The connection wiring is
An extension disposed along the surface of the material layer;
The solar cell according to claim 11, further comprising: a bent portion that is provided in the extending portion as the contact portion, bends toward the electrode, and contacts the electrode. A method for manufacturing a semiconductor device in which a connection wiring provided with a contact portion bonded to an electrode exposed at a position lower than a position of an upper surface of a material layer having a predetermined thickness is connected,
A contact step of bringing the contact portion of the connection wiring into contact with the electrode;
A method of manufacturing a semiconductor device, comprising: a connecting step of joining the contact portion to the electrode by irradiating a predetermined laser beam toward the connection wiring in a state where the contact portion is in contact with the electrode. . The connection wiring is
An extension disposed along the surface of the material layer;
A bent portion that is provided in the extending portion as the contact portion, bends toward the electrode, and contacts the electrode;
In the contact step, the bent portion whose height from the extended portion of the bent portion is higher than the height corresponding to the distance from the upper surface of the material layer to the surface of the electrode is brought into contact with the electrode,
The semiconductor according to claim 13, wherein in the connecting step, the bent portion is joined to the electrode by irradiating a predetermined laser beam toward the connection wiring in a state where the bent portion is in contact with the electrode. Device manufacturing method.

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