TWI397190B - Method of manufacturing metal wrap through solar cell - Google Patents

Description

Method for manufacturing metal through solar cell

The present invention relates to a method of fabricating a solar cell, and more particularly to a method of fabricating a metal wrap through solar cell.

The metal-through solar cell is a busbar that guides the current collected by the front finger electrode to the back surface by using a plurality of through holes on the front and back sides of the tantalum wafer on the tantalum wafer, which not only increases the front light The area, the reduction of the series resistance, and the simple packaging process are one of the future development trends of the crystal solar cell.

Generally, a metal-through solar cell is generally a p-type germanium substrate, and a n-type dopant is diffused on the front surface to form a pn junction. One of the technical focuses is how to prevent the front negative electrode (n-type semiconductor side electrode) in the through hole. The hole wall and the back surface are short-circuited with the p-type semiconductor substrate. At present, the metal through-type solar cell has a technique in which an n-type semiconductor diffusion region or an insulating layer is formed between the negative electrode metal of the hole wall and the back surface bus electrode to prevent short-circuit therebetween.

Since the metal electrode of the conventional twinned solar cell is prepared by printing and coating the metal paste, it is cured by high temperature sintering, and during the sintering process, the lead glass in the metal compound is combined with the tantalum substrate, tantalum nitride, The reaction of ruthenium oxide or the like destroys the tantalum nitride film and the ruthenium oxide film, and is embedded in the ruthenium substrate to form a bond. Moreover, the insulating layer or the n-type semiconductor layer in the through-hole wall is usually thin, so in the above-mentioned high-temperature sintering to form the via electrode, the metal compound often reacts excessively with the ruthenium substrate, tantalum nitride, ruthenium oxide, and the like. The tantalum nitride, hafnium oxide, or n-type semiconductor layer is destroyed to cause a short circuit with the substrate.

For the formation of such a short circuit, the recently proposed solution is to use different metal compounds on the front finger electrode and the hole-filling metal, and use different penetration properties of the two rubber materials to control. It is necessary to have a special rubber material selection, not only the material is not easy to obtain, but the process range of co-sintering of different rubber materials is narrow, and production control is difficult.

The invention provides a method for manufacturing a metal through solar cell to prevent excessive reaction between the metal compound and the tantalum substrate.

The present invention further provides a method of manufacturing a metal-through solar cell capable of preventing a short circuit between the n-type semiconductor layer and the substrate.

The invention further provides a method for manufacturing a metal through-type solar cell, which can accurately align the through holes and can prevent the metal glue used for the front and back electrodes from being mistakenly filled into the through holes.

The present invention further provides a method of fabricating a metal-through solar cell in which an additional laser insulating step is required on the back side of the germanium substrate.

The invention provides a method for manufacturing a metal through solar cell, which comprises first providing a substrate having a front side and a back side. Then, a plurality of through holes are formed in the crucible substrate, and the through holes penetrate through the front and back surfaces thereof. Next, the ruthenium substrate is structured on the surface, and the ruthenium substrate is subjected to an n-type dopant diffusion process to form an n-type diffusion layer at least on the front and back surfaces of the ruthenium substrate. Thereafter, an anti-reflection layer is formed on the front surface of the germanium substrate, and the n-type diffusion layer on the back surface of the germanium substrate is removed. Then, first and second metal glue layers are respectively formed on the back surface and the front surface of the germanium substrate, and then a co-sintering process is performed to make the second metal glue layer pass through the anti-reflection layer to contact the n-type diffusion layer, and make the first And the second metal glue layer becomes the first and second electrodes. Finally, a via electrode is formed in each of the through holes in the germanium substrate, wherein the temperature at which the via electrode is formed needs to be lower than 600 °C.

The invention further provides a method for manufacturing a metal through solar cell, comprising first providing a substrate having a front side and a back side. Next, the ruthenium substrate is structured on the surface, and the ruthenium substrate is subjected to an n-type dopant diffusion process to form an n-type diffusion layer at least on the front and back surfaces of the ruthenium substrate. Thereafter, an anti-reflection layer is formed on the front surface of the germanium substrate, and the n-type diffusion layer on the back surface of the germanium substrate is removed. Then, first and second metal glue layers are respectively formed on the back surface and the front surface of the germanium substrate, and then a co-sintering process is performed to make the second metal glue layer pass through the anti-reflection layer to contact the n-type diffusion layer, and make the first And the second metal glue layer becomes the first and second electrodes. Then, a plurality of through holes penetrating the ruthenium substrate are formed in regions other than the first and second electrodes. Finally, a via electrode is formed in each of the through holes in the germanium substrate, wherein the temperature at which the via electrode is formed needs to be lower than 600 °C.

In the first and second embodiments of the present invention, the method of removing the n-type diffusion layer on the back side includes polishing the back surface of the germanium substrate to form a plane.

The invention further provides a method for manufacturing a metal through solar cell, comprising first providing a substrate having a front side and a back side. Next, the germanium substrate is structured on the surface, and a barrier layer is formed on the back surface of the germanium substrate. Then, an n-type dopant diffusion process is performed on the germanium substrate to form an n-type diffusion layer on the front surface of the germanium substrate. Thereafter, the barrier layer is removed, and an anti-reflection layer is formed on the front surface of the germanium substrate. Then, a first metal glue layer and a second metal glue layer are respectively formed on the back surface and the front surface of the germanium substrate, and then a co-sintering process is performed to make the second metal glue layer pass through the anti-reflection layer to contact the n-type diffusion layer. And making the first and second metal glue layers into the first and second electrodes. Then, a plurality of through holes penetrating through the substrate are formed in regions other than the first and second electrodes, and a via electrode is formed in each of the through holes in the substrate, wherein the temperature at which the via electrodes are formed needs to be lower than 600 °C.

The invention further provides a method for manufacturing a metal-through solar cell, comprising first providing a substrate having a front surface and a back surface, and then forming a plurality of through holes in the germanium substrate, the through holes penetrating through the front surface and the back surface. Next, the ruthenium substrate is structured on the surface, and a barrier layer is formed on the back surface of the ruthenium substrate. Then, an n-type dopant diffusion process is performed on the germanium substrate to form an n-type diffusion layer on the front surface of the germanium substrate. Thereafter, the barrier layer is removed, and an anti-reflection layer is formed on the front surface of the germanium substrate. Then, a first metal glue layer and a second metal glue layer are respectively formed on the back surface and the front surface of the germanium substrate, and then a co-sintering process is performed to make the second metal glue layer pass through the anti-reflection layer to contact the n-type diffusion layer. And making the first and second metal glue layers into the first and second electrodes. Then, a via electrode is formed in each of the through holes in the germanium substrate, wherein the temperature at which the via electrode is formed needs to be lower than 600 °C.

In the third and fourth embodiments of the present invention, the barrier layer is, for example, a tantalum nitride layer.

In the third and fourth embodiments of the present invention, the method of removing the above barrier layer is, for example, removed using hydrofluoric acid.

In various embodiments of the present invention, the step of forming the through-hole electrode includes first filling a through-hole compound in each through-hole and drying it, and then performing a sintering process to make the hole-filling compound become the above-mentioned pass. Hole electrode.

In various embodiments of the invention, the temperature of the sintering process is between about 400 ° C and 500 ° C.

In various embodiments of the invention, the step of forming the via electrodes includes filling a solder into each of the through holes using a torch.

In various embodiments of the invention, the temperature of the co-sintering process is greater than the temperature of the sintering process.

In various embodiments of the invention, the first metal glue layer comprises an aluminum glue, and the second metal glue layer comprises a silver glue.

Based on the above, the present invention employs a secondary sintering method in the production of the electrode, thereby preventing the electrode from reacting with the ruthenium of the substrate due to the excessive temperature at the time of fabricating the via electrode, and preventing the short circuit between the electrode and the substrate. Moreover, the present invention does not have an n-type diffusion layer on the back side of the substrate, so there is no need for an additional laser insulation step. In addition, the present invention can form the through holes after the front and back electrodes of the substrate are completed, so that the alignment can be accurately aligned and the defects of the metal paste used for the front and back electrodes can be prevented from being mistakenly filled into the through holes.

The above described features and advantages of the present invention will be more apparent from the following description.

1A to 1J are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a first embodiment of the present invention.

Referring to FIG. 1A, a substrate 100 having a front side 100a and a back side 100b is provided.

Referring to FIG. 1B , a through hole 102 is formed in the ruthenium substrate 100 , and the through hole 102 penetrates the front surface 100 a and the back surface 100 b of the ruthenium substrate 100 . Although only one through hole is shown in the drawing, actually several through holes may be formed as needed.

Referring to FIG. 1C, the germanium substrate 100 is structured on the surface. At this time, the front surface 100a of the ruthenium substrate 100, the back surface 100b, and the surface 102a of the through hole 102 are roughened.

Referring to FIG. 1D, an n-type dopant diffusion process is performed on the germanium substrate 100 to form an n-type diffusion layer 104 at least on the front surface 100a and the back surface 100b of the germanium substrate 100. At this time, the n-type diffusion layer 104 is also generally formed on the surface 102a of the through hole 102.

Referring to FIG. 1E, an anti-reflection layer 106 is formed on the front surface 100a of the germanium substrate 100. At this time, the anti-reflection layer 106 may also be formed on the surface 102a of the through hole 102 due to the process relationship.

Referring to FIG. 1F, the n-type diffusion layer 104 on the back surface 100b of the germanium substrate 100 is removed. The removal method is, for example, polishing the back surface 100b of the ruthenium substrate 100 to make it a flat surface. In the present embodiment, since the back surface 100b has no n-type diffusion layer, an additional laser insulation step is required, and the fill factor (F.F.) is lowered.

Referring to FIG. 1G, a first metal paste layer 108 is formed on the back surface 100b of the germanium substrate 100. The first metal glue layer 108 described above includes an aluminum glue.

Referring to FIG. 1H, a second metal paste layer 110 is formed on the anti-reflective layer 106 of the front surface 100a of the germanium substrate. The second metal glue layer 110 includes silver paste.

Referring to FIG. 1I, a common sintering process is performed to pass the second metal paste layer (110 of FIG. 1H) through the anti-reflective layer 106 to contact the n-type diffusion layer 104, and the first metal glue layer (108 of FIG. 1H). And the second metal glue layer becomes the first electrode 112 and the second electrode 114. The temperature of the co-sintering process is greater than 600 ° C, such as above 700 ° C.

Referring to FIG. 1J, a via electrode 116 is formed in the through hole 102 in the germanium substrate 100, wherein the temperature at which the via electrode 116 is formed needs to be lower than 600 °C. For example, if the through-hole electrode 116 is formed by first filling a through-hole compound in the through-hole 102 and drying it, and then performing a sintering process to make the hole-filling compound into the through-hole electrode 116, the sintering is performed. The process temperature is between about 400 ° C and 500 ° C. Further, if the solder is filled into the through hole 102 using a welding torch, the through hole electrode 116 is formed at a temperature of about 180 °C. As can be seen from the figure, the via electrode 116 is connected to the second electrode 114 but not in contact with the first electrode 112.

In the first embodiment, since the secondary sintering method is employed in the production of the electrode, it is possible to avoid the conventional reaction of the via electrode 116 and the tantalum substrate 100 due to the excessive temperature at the time of fabricating the via electrode, and the metal can be utilized. The high resistance characteristic of the Shockley barrier between the semiconductor and the semiconductor prevents short circuits between the two.

2A to 2I are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a second embodiment of the present invention.

Referring to FIG. 2A, a substrate 200 is provided having a front surface 200a and a back surface 200b.

Referring to FIG. 2B, the germanium substrate 200 is surface structured. At this time, the front surface 200a and the back surface 200b of the ruthenium substrate 200 are roughened.

Referring to FIG. 2C, an n-type dopant diffusion process is performed on the germanium substrate 200 to form an n-type diffusion layer 202 on the front surface 200a and the back surface 200b of the germanium substrate 200.

Referring to FIG. 2D, an anti-reflection layer 204 is formed on the front surface 200a of the germanium substrate 200.

Referring to FIG. 2E, the n-type diffusion layer 202 on the back surface 200b of the germanium substrate 200 is removed. The removal method is, for example, polishing the back surface 200b of the ruthenium substrate 200 to make it a flat surface. In this embodiment, there is no n-type diffusion layer on the back surface 200b of the germanium substrate 200, so there is no need for an additional laser insulating step.

Referring to FIG. 2F, a first metal paste layer 206, such as an aluminum paste, is formed on the back surface 200b of the germanium substrate 200. A second metal paste layer 208, such as silver paste, is formed on the anti-reflective layer 204 of the front side 200a of the germanium substrate.

Referring to FIG. 2G, a common sintering process is performed to pass the second metal paste layer (208 of FIG. 2F) through the anti-reflective layer 204 to contact the n-type diffusion layer 202, and the first metal glue layer (206 of FIG. 2F). And the second metal glue layer becomes the first electrode 210 and the second electrode 212. The temperature of the co-sintering process is greater than 600 ° C, for example, above 700 ° C

Referring to FIG. 2H, a through hole 214 penetrating the ruthenium substrate 200 is formed in a region other than the first electrode 210 and the second electrode 212. Although only one through hole 214 is shown in the drawing, actually several through holes may be formed as needed. Since the through hole 214 is formed after the first and second electrodes 210 and 212 of the substrate 200 are completed, the alignment can be accurately aligned and the metal glue used for the first and second electrodes 210 and 212 can be prevented from being mistakenly filled. The problem of entering the through hole 214.

Referring to FIG. 2I, a via electrode 216 is formed in the through hole 214 in the germanium substrate 200, wherein the temperature at which the via electrode 216 is formed needs to be lower than 600 °C. For example, if the through-hole electrode 216 is formed by first filling a through-hole 214 with a hole-filling compound and drying it, and then performing a sintering process to make the hole-filling compound into the through-hole electrode 216, the sintering is performed. The process temperature is between about 400 ° C and 500 ° C. Further, if the solder is filled into the through hole 214 using a welding torch to form the via electrode 216, the temperature is about 180 °C. As can be seen from the figure, the via electrode 216 is connected to the second electrode 212 but is not in contact with the first electrode 210.

Since the second embodiment uses the secondary sintering method in which the temperature of the first and second electrodes 210 and 212 is lower than that in the fabrication of the via electrodes 216, it is possible to avoid the conventionally high temperature when the via electrodes are formed. The problem of reacting the electrode with the germanium of the substrate, and the high resistance characteristic of the Schaucle barrier between the metal and the semiconductor, can prevent the occurrence of a short circuit.

3A to 3H are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a third embodiment of the present invention.

Referring to FIG. 3A, a tantalum substrate 300 having a front surface 300a and a back surface 300b is provided, and the tantalum substrate 300 has been surface structured, so that both the front surface 300a and the back surface 300b are roughened.

Referring to FIG. 3B, a barrier layer 302 is formed on the back surface 300b of the germanium substrate 300. The barrier layer 302 is, for example, a tantalum nitride layer or other suitable material. The barrier layer 302 can block the diffusion of the n-type dopant into the back surface 300b of the germanium substrate 300 during the subsequent n-type dopant diffusion process, so that the back surface 300b has no n-type diffusion layer, and no additional laser insulation is required after the electrode is completed. step.

Referring to FIG. 3C, an n-type dopant diffusion process is performed on the germanium substrate 300 to form an n-type diffusion layer 304 on the front surface 300a of the germanium substrate 300.

Referring to FIG. 3D, the barrier layer 302 is first removed, and the removal method is removed, for example, using hydrofluoric acid. Hydrofluoric acid is typically used to remove the vitreous during the fabrication of the metal through solar cell, so the step of removing the barrier layer 302 is not an additional addition, but a step compatible with conventional processes. Thereafter, an anti-reflection layer 306 is formed on the front surface 300a of the ruthenium substrate 300.

Referring to FIG. 3E, a first metal glue layer 308, such as an aluminum paste, is formed on the back surface 300b of the ruthenium substrate 300. A second metal paste layer 310, such as silver paste, is formed on the anti-reflective layer 306 of the front side 300a of the germanium substrate.

Referring to FIG. 3F, a common sintering process is performed to bring the second metal paste layer (310 of FIG. 3F) through the anti-reflective layer 306 to contact the n-type diffusion layer 304, and to make the first metal glue layer (308 of FIG. 3F). And the second metal glue layer becomes the first electrode 312 and the second electrode 314. The temperature of the co-sintering process is greater than 600 ° C, such as above 700 ° C.

Referring to FIG. 3G, a through hole 316 penetrating the ruthenium substrate 300 is formed in a region other than the first electrode 312 and the second electrode 314. Although only one through hole 316 is shown in the drawing, actually several through holes may be formed as needed. In this embodiment, the through holes 316 are formed after the first electrode 312 and the second electrode 314 of the substrate 300 are completed, so that the alignment can be accurately aligned and the metal glue used for the first electrode 312 and the second electrode 314 can be prevented from being mistakenly filled. Into the through hole 316.

Referring to FIG. 3H, a via electrode 318 is formed in the through hole 316 in the germanium substrate 300, wherein the temperature at which the via electrode 318 is formed needs to be lower than 600 °C. For example, if the through-hole electrode 318 is formed by filling a through-hole 316 with a hole-filling compound and drying it, and then performing a sintering process to make the hole-filling compound into the through-hole electrode 318, the sintering is performed. The process temperature is between about 400 ° C and 500 ° C. Further, if the solder is filled into the through hole 316 by using a welding torch to form the via electrode 318, the temperature is about 180 °C. The via electrode 318 of FIG. 3H is connected to the second electrode 314 but is not in contact with the first electrode 312.

In the third embodiment, since the second sintering method is used in the fabrication of the first electrode 312, the second electrode 314, and the via electrode 318, it is possible to avoid the excessive temperature between the via electrode 318 and the germanium substrate 300 during the conventional co-firing. Short circuit.

4A to 4G are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a third embodiment of the present invention.

Referring to FIG. 4A, a germanium substrate 400 having a front surface 400a and a rear surface 400b is provided, and a through hole 402 is formed in the germanium substrate 400. The through hole 402 extends through the front surface 400a and the back surface 400b of the germanium substrate 400. Although only one through hole is shown in the drawing, actually several through holes may be formed as needed.

Referring to FIG. 4B, the germanium substrate 400 is surface structured. At this time, the front surface 400a of the ruthenium substrate 400, the back surface 400b, and the surface 402a of the through hole 402 are roughened. Then, a barrier layer 404 is formed on the back surface 400b of the germanium substrate 400. At this time, the barrier layer 404 may be formed on the surface 402a of the through hole 402 due to the process relationship. The barrier layer 404 is, for example, a tantalum nitride layer or other suitable material. The barrier layer 404 can block the diffusion of the n-type dopant into the back surface 400b of the germanium substrate 400 during the subsequent n-type dopant diffusion process, so that in the case where the back surface 400b has no n-type diffusion layer, the electrode is no longer completed. Additional laser insulation steps are required.

Referring to FIG. 4C, an n-type dopant diffusion process is performed on the germanium substrate 400 to form an n-type diffusion layer 406 on the front surface 400a of the germanium substrate 400.

Referring to FIG. 4D, the barrier layer 404 is first removed, and the removal method is removed, for example, using hydrofluoric acid. As mentioned above, this step of removing the barrier layer 404 is not additional. Thereafter, an anti-reflection layer 408 is formed on the front surface 400a of the germanium substrate 400. At this time, the anti-reflection layer 408 may be formed on the surface 402a of the through hole 402 because of the process relationship.

Referring to FIG. 4E, a first metal glue layer 410, such as an aluminum paste, is formed on the back surface 400b of the ruthenium substrate 400. A second metal paste layer 412, such as silver paste, is formed on the anti-reflective layer 408 of the front side 400a of the germanium substrate.

Referring to FIG. 4F, a common sintering process is performed to bring the second metal paste layer (412 of FIG. 4F) through the anti-reflective layer 408 to contact the n-type diffusion layer 406, and to make the first metal glue layer (410 of FIG. 4F). And the second metal glue layer becomes the first electrode 414 and the second electrode 416. The temperature of the co-sintering process is greater than 600 ° C, such as above 700 ° C.

Referring to FIG. 4G, a via electrode 418 is formed in the through hole 402 in the germanium substrate 400, wherein the temperature at which the via electrode 418 is formed needs to be lower than 600 °C. For example, if the through-hole electrode 418 is formed by first filling a through-hole compound in the through-hole 402 and drying it, and then performing a sintering process to make the hole-filling compound into the through-hole electrode 418, the sintering is performed. The process temperature is between about 400 ° C and 500 ° C. Further, if the solder is filled into the through hole 402 using a welding torch to form the via electrode 418, the temperature is about 180 °C. The via electrode 418 of FIG. 4G is connected to the second electrode 416 but is not in contact with the first electrode 414.

In the fourth embodiment, since the second electrode is used in the fabrication of the first electrode 414 and the second electrode 416 and the via electrode 418, it can be avoided that the conventional co-firing temperature is too high, resulting in a gap between the via electrode 418 and the germanium substrate 400. Short circuit.

Several examples are given below to demonstrate the effects of the present invention.

Example one

First, follow the steps below to make the metal through-type solar cell of Example 1:

Step 1. Drill holes on the p-type 矽 substrate with a laser.

Step 2. The ruthenium substrate was etched with potassium hydroxide (KOH), and surface structuring was performed on the ruthenium substrate.

Step 3. Diffusion of the surface of the germanium substrate into an n-type in a POCl ₃ gas atmosphere to produce a pn junction.

Step 4. Remove the phosphorus-containing cerium oxide (PSG) layer formed by diffusion with a buffer oxide etch (BOE) solution.

Step 5. Coating the anti-reflective layer on the front side of the p-type germanium substrate by plasma chemical vapor deposition (PECVD).

Step 6. Flatten the back surface of the p-type ruthenium substrate with sodium hydroxide (NaOH) to remove the n-type diffusion layer.

Step 7. Print the front silver grid electrode (silver glue) by screen printing and dry.

Step 8. Print on the back aluminum flat electrode (aluminum glue) by screen printing and dry.

Step 9. Sintering of the front and back electrodes was carried out in an infrared oven at a high temperature of about 700 °C.

Step 10. Printing the hole-filling compound (silver glue) from the front side of the substrate by screen printing and drying.

Step 11. Screen printing of the hole-filling compound (silver glue) and the back side bus bar from the back side of the substrate by screen printing, and drying.

Step 12. Sintering of the hole-filling compound and the backside bus electrode in an infrared oven at a lower temperature of about 400 °C.

Comparative example one

A metal-through solar cell of Comparative Example 1 was produced in accordance with the procedure of Example 1 except that the high-temperature sintering of the step 9 was changed to the step 12 and co-firing was performed.

The efficiency of the metal through solar cell of the first example and the first comparative example is as shown in Table 1 below.

As can be seen from Table 1, Example 1 can obtain very high F.F. and efficiency (η).

Example two

Follow the steps below to make the metal through solar cell of Example 2:

Step 1. Surface structuring on a p-type germanium substrate by acid etching.

Step 2. Depositing tantalum nitride on the back side of the germanium substrate by PECVD as a barrier layer.

Step 3. Since there is a barrier layer on the back surface, in the POCl ₃ gas environment, only the front surface of the germanium substrate will diffuse into an n-type to form a pn junction.

Step 4. The PSG layer formed during diffusion is removed simultaneously with the barrier layer in a BOE solution.

Step 5. Coating the front anti-reflective layer of the p-type germanium substrate by PECVD.

Step 6. Print the front silver grid electrode (silver glue) and the back aluminum plane electrode (aluminum glue) by screen printing and dry.

Step 7. Sintering the front and back electrodes in an infrared furnace at an ambient temperature of about 760 °C.

Step 8. Drill holes on the ruthenium substrate with a laser to form a plurality of through holes penetrating the front and back sides of the ruthenium substrate.

Step 9. Printing and drying the back-filling electrode (silver glue) on the front side of the substrate by screen printing and the back side bus electrode (silver glue) on the back side.

Step 10. Sintering of the hole-filling compound and the back side bus electrode in an infrared oven at a temperature of about 400 °C.

Example three

According to the procedure of Example 2, the metal through-type solar cell of Example 3 was fabricated, except that in step 9-10, the solder was directly filled into the through hole by using a welding torch.

The efficiency of the metal through-type solar cells of Example 2 and Example 3 above is shown in Table 2 below.

As can be seen from Table 1, Example 2 is close to F.F. of Example 3, and the resistance of Example 3 is 0.012 Ω close to 0.011 Ω of Example 2 (silver glue).

Comparative example two

A metal through-type solar cell of Comparative Example 2 was produced in accordance with the procedure of Example 2, except that the high-temperature sintering of the step 7 was changed to the step 10 for co-firing.

The efficiency of the metal through-type solar cells of the above Example 2 and Comparative Example 2 is shown in Table 3 below.

As can be seen from Table 3, if the sintering of the front and back electrodes (Step 7 of Example 2) and the sintering of the hole-filling compound and the back side bus electrode (Step 10 of Example 2) are carried out simultaneously, high-temperature sintering is necessary. As a result, a short circuit is formed between the through-hole wall and the back-side bus electrode, causing a decrease in F.F.

In summary, since the present invention produces an electrode by means of secondary sintering, it is possible to avoid the problem that the co-sintering temperature when the through-hole electrode is formed is too high, causing the electrode to react with the ruthenium substrate, and thus preventing the electrode from being Short circuit of the substrate. Therefore, the invention does not need to consider the selection of the rubber compound, and the general rubber compound can be used, so that the process has larger parameter adjustment space and process stability. Furthermore, the present invention does not have an n-type diffusion layer on the back surface of the substrate, so that an additional laser insulation step is required, which can greatly improve the filling factor and efficiency of the battery. In addition, the present invention can select the through holes to be formed after the front and back electrodes of the substrate are completed, so that the alignment can be accurately aligned and the metal glue used for the front and back electrodes can be prevented from being mistakenly filled into the through holes.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100, 200, 300, 400. . .矽 substrate

100a, 200a, 300a, 400a. . . positive

100b, 200b, 300b, 400b. . . back

102, 214, 316, 402. . . Through hole

102a, 402a. . . surface

104, 202, 304, 406. . . N-type diffusion layer

106, 204, 306, 408. . . Antireflection layer

108, 110, 206, 208, 308, 310, 410, 412. . . Metallic layer

112, 114, 210, 212, 312, 314, 414, 416. . . electrode

116, 216, 318, 418. . . Through hole electrode

302, 404. . . Barrier layer

1A to 1J are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a first embodiment of the present invention.

2A to 2I are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a second embodiment of the present invention.

3A to 3H are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a third embodiment of the present invention.

4A to 4G are schematic cross-sectional views showing a manufacturing process of a metal through-type solar cell according to a third embodiment of the present invention.

100. . .矽 substrate

102. . . Through hole

106. . . Antireflection layer

112, 114. . . electrode

116. . . Through hole electrode

Claims (12)

A method for manufacturing a metal through-type solar cell, comprising: providing a substrate having a front surface and a back surface; forming a plurality of through holes in the substrate, the through holes penetrating the front surface and the back surface; a germanium substrate; performing an n-type dopant diffusion process on the germanium substrate to form an n-type diffusion layer on the front surface and the back surface of the germanium substrate; forming an anti-reflection layer on the front surface of the germanium substrate; The n-type diffusion layer on the back surface of the germanium substrate; a first metal paste layer and a second metal paste layer are respectively formed on the back surface of the germanium substrate and the front surface; and a co-sintering process is performed to make the second metal The adhesive layer passes through the anti-reflective layer to contact the n-type diffusion layer, and the first metal adhesive layer and the second metal adhesive layer become a first electrode and a second electrode; and in the germanium substrate A through-hole electrode is formed in each of the through holes, wherein the temperature at which the through-hole electrode is formed is lower than 600 °C. A method for manufacturing a metal through solar cell, comprising: providing a germanium substrate having a front surface and a back surface; structuring the germanium substrate; and performing an n-type dopant diffusion process on the germanium substrate to at least the germanium substrate Forming an n-type diffusion layer on the front surface and the back surface; forming an anti-reflection layer on the front surface of the germanium substrate; removing the n-type diffusion layer on the back surface of the germanium substrate; and the back surface of the germanium substrate Forming a first metal glue layer and a second metal glue layer on the front side; performing a co-sintering process, so that the second metal glue layer passes through the anti-reflection layer to contact the n-type diffusion layer, and makes the first The metal glue layer and the second metal glue layer become a first electrode and a second electrode; a plurality of through holes penetrating the 矽 substrate are formed in a region other than the first electrode and the second electrode; and the 矽 substrate A through-hole electrode is formed in each of the through holes, wherein a temperature at which the through-hole electrode is formed is lower than 600 °C. The method of manufacturing a metal through-type solar cell according to claim 1 or 2, wherein the method of removing the n-type diffusion layer on the back surface of the germanium substrate comprises grinding the back surface of the germanium substrate, To form a plane. A method for manufacturing a metal-through solar cell, comprising: providing a substrate having a front surface and a back surface; structuring the surface of the substrate; forming a barrier layer on the back surface of the substrate; The ruthenium substrate is subjected to an n-type dopant diffusion process to form an n-type diffusion layer on the front surface of the ruthenium substrate; removing the barrier layer; forming an anti-reflection layer on the front surface of the ruthenium substrate; Forming a first metal glue layer and a second metal glue layer respectively on the back surface and the front surface; performing a co-sintering process, so that the second metal glue layer passes through the anti-reflection layer to contact the n-type diffusion layer, and The first metal glue layer and the second metal glue layer are made into a first electrode and a second electrode; and a plurality of through holes penetrating the 矽 substrate are formed in a region other than the first electrode and the second electrode; A via electrode is formed in each of the through holes in the germanium substrate, wherein a temperature at which the via electrode is formed is lower than 600 °C. A method for manufacturing a metal through-type solar cell, comprising: providing a substrate having a front surface and a back surface; forming a plurality of through holes in the substrate, the through holes penetrating the front surface and the back surface; a ruthenium substrate; a barrier layer is formed on the back surface of the ruthenium substrate; an n-type dopant diffusion process is performed on the ruthenium substrate to form an n-type diffusion layer on the front surface of the ruthenium substrate; and the barrier layer is removed; Forming an anti-reflection layer on the front surface of the substrate; forming a first metal paste layer and a second metal paste layer on the back surface of the germanium substrate; and performing a co-sintering process to make the second metal The adhesive layer passes through the anti-reflective layer to contact the n-type diffusion layer, and the first metal adhesive layer and the second metal adhesive layer become a first electrode and a second electrode; and in the germanium substrate A through-hole electrode is formed in each of the through holes, wherein the temperature at which the through-hole electrode is formed is lower than 600 °C. The method of manufacturing a metal through-type solar cell according to claim 4, wherein the barrier layer comprises a tantalum nitride layer. The method of manufacturing a metal-through solar cell according to claim 6, wherein the method of removing the barrier layer comprises removing with hydrofluoric acid. The method for manufacturing a metal through-type solar cell according to any one of the preceding claims, wherein the forming the through-hole electrode comprises: filling each of the through holes with a filling hole; a compound; drying the hole-filling compound; and performing a sintering process to make the hole-filling compound into the through-hole electrode. The method for manufacturing a metal through-type solar cell according to claim 8, wherein the temperature of the sintering process is between 400 ° C and 500 ° C. The method of manufacturing a metal-through solar cell according to any one of claims 1, 2, 4, or 5, wherein the step of forming the via electrode comprises filling a solder into each of the through holes using a welding torch. The method of manufacturing a metal-through solar cell according to any one of claims 1, 2, 4, or 5, wherein the temperature of the co-sintering process is greater than the temperature of the sintering process. The method for manufacturing a metal through-type solar cell according to any one of claims 1, 2, 4, or 5, wherein the first metal glue layer comprises aluminum glue, and the second metal glue layer comprises silver glue. .