TWI458114B - Method of manufacturing solar cell - Google Patents

Description

Solar cell manufacturing method

The present invention relates to a method of fabricating a solar cell, and more particularly to a method of fabricating a solar cell using a hard mask in combination with reactive ion etching to form a wire.

Conventional solar cells must have wires formed on the front and back to collect electrical charge to generate electrical energy. These wires are usually printed on the front and back sides of the solar cell by screen printing, and then sintered to electrically connect the wires to the germanium substrate of the solar cell. Since the sintering process is required to allow the material of the wire to penetrate the antireflection layer, the process time is long and considerable energy is consumed.

Since the material of these wires is electrically connected to the ruthenium substrate through the anti-reflection layer, the electrical connection effect is not very satisfactory, that is, the contact resistance value cannot be effectively reduced.

An object of the present invention is to provide a method of manufacturing a solar cell which can reduce the contact resistance value.

A method of manufacturing a solar cell, comprising the steps of: providing a substrate assembly comprising a germanium substrate, an oxide layer on the germanium substrate, and an anti-reflective layer on the oxide layer, the germanium substrate comprising a first type a layer and a second type of germanium layer, the oxide layer is located on the second type of germanium layer; a first hard mask is disposed on the anti-reflective layer, and the first hard mask has a a first pattern to expose a portion of the anti-reflective layer; an exposed portion of the anti-reflective layer and a portion of the oxide layer to form a plurality of first trenches in the anti-reflective layer and the oxide layer; removing the first hard mask And forming a plurality of first metal wires in the first trenches.

In order to make the above description of the present invention more comprehensible, a preferred embodiment will be described below in detail with reference to the accompanying drawings.

1 shows a flow chart of a method of manufacturing a solar cell according to the present invention. 2 to 9 are structural views showing respective steps of a method of manufacturing a solar cell according to the present invention.

The method for producing a solar cell of the present invention comprises the following steps.

First, in step S1, a substrate assembly 10 is provided. The germanium substrate assembly 10 includes a germanium substrate 11, an oxide layer 13 on the germanium substrate 11, and an anti-reflective layer 12 on the oxide layer 13. The germanium substrate 11 includes A first type of germanium layer 11A and a second type of germanium layer 11B, the oxide layer 13 is located on the second type of germanium layer 11B. The material of the anti-reflection layer 12 contains tantalum nitride (SiNx). The material of the oxide layer 13 contains cerium oxide (SiO ₂ ).

In one example, the first type of germanium layer 11A is a p-type germanium layer, and the second type of germanium layer 11B is an N type germanium layer.

Then, in step S2, a first hard mask 20 is placed on the anti-reflection layer 12. The first hard mask 20 has a first pattern 21 to expose a portion of the anti-reflection layer 12, as shown in FIG. The exposed portion of the anti-reflective layer and a portion of the oxide layer 13 can be etched by, for example, reactive ion etching. Reactive ion etching uses fluorocarbon (CxFy) to make.

Next, in step S3, the exposed portion of the anti-reflective layer 12 and a portion of the oxide layer 13 are etched to form a plurality of first trenches 12A in the anti-reflective layer 12 and the oxide layer 13, and the first trench 12A is penetrated. The reflective layer 12 and the oxide layer 13 are as shown in FIG.

Then, in step S4, the first hard mask 20 is removed, as shown in FIG.

Next, in step S5, a plurality of first metal wires 30 are formed in the first trench 12A, as shown in FIG. The first metal wire 30 can be formed by, for example, electroplating.

It should be noted that after step S5, the germanium substrate assembly 10, the oxide layer 13, the anti-reflective layer 12, and the first metal wires 30 may be annealed to improve the characteristics of the solar cell.

Then, as shown in FIG. 6, the first type germanium layer 11A is composed of a p-type germanium layer 11A1 and a p+ type germanium layer 11A2, and the p+ type germanium layer 11A2 is farther from the anti-reflective layer 12 than the p-type germanium layer 11A1. It is to be noted that the P-type germanium layer 11A1 and the P+ type germanium layer 11A2 can be formed at any point of time, for example, before the condition of FIG. Then, a dielectric layer 40 is formed on the back side of the anti-reflective layer 12 of the germanium substrate 11.

Next, a second hard mask 50 is placed on the back side of one of the dielectric layers 40. The second hard mask 50 has a second pattern 51 to expose a portion of the dielectric layer 40.

Then, as shown in FIG. 7, the exposed portion of the dielectric layer 40 is etched to form a plurality of second trenches 42 in the dielectric layer 40.

Next, as shown in Figure 8, the second hard mask 50 is removed; Then, as shown in FIG. 9, a plurality of second metal wires 60 are formed in the second trenches 42 while a reflective layer 70 is formed on the back surface of the dielectric layer 40. These second metal wires 60 are formed by electroplating.

The material of the dielectric layer 40 is tantalum nitride (SiNx) or hafnium oxide (SiO ₂ ). Therefore, the material of the dielectric layer 40 and the anti-reflection layer 12 may be tantalum nitride (SiNx). The exposed portion of the anti-reflective layer 12 and the exposed portion of the dielectric layer 40 are etched by reactive ion etching. Reactive ion etching is achieved by using a fluorocarbon (CxFy).

The aforementioned hard mask may be a carbon fiber board which can be repeatedly used, so that there is no waste and a problem of wasting manufacturing cost. That is, after forming a metal wire of a solar cell using the hard mask, the hard mask can be reused to form a metal wire of another solar cell. On the other hand, the patterning of the anti-reflective layer can be easily achieved with a hard mask without the need to use a laser source. In addition, the formed metal wire is directly in contact with the ruthenium substrate, so that the contact resistance can be effectively reduced and the efficiency of the solar cell can be improved. It is to be noted that the longitudinal and lateral metal wires of the front side of the solar cell may be formed by the method of the present invention. Furthermore, the metal wires on the front and back sides of the solar cell can be simultaneously formed by the method of the present invention, which makes the manufacturing process more simplified. In addition, the oxide layer can help enhance the anti-reflection effect of the anti-reflection layer and enhance the protection function for the germanium substrate.

The specific embodiments of the present invention are intended to be illustrative only and not to limit the invention to the above embodiments, without departing from the spirit of the invention and the following claims. The scope of the scope, the implementation of various changes, are the invention The scope.

S1-S5‧‧‧ method steps

10‧‧‧矽Substrate assembly

11‧‧‧矽 substrate

11A‧‧‧First type of layer

11A1‧‧‧P type layer

11A2‧‧‧P+ type layer

11B‧‧‧Second type

12‧‧‧Anti-reflective layer

12A‧‧‧first trench

13‧‧‧Oxide layer

20‧‧‧First hard mask

21‧‧‧ first pattern

30‧‧‧First metal wire

40‧‧‧ dielectric layer

42‧‧‧Second trench

50‧‧‧Second hard mask

51‧‧‧second pattern

60‧‧‧Two metal wires

70‧‧‧reflective layer

1 shows a flow chart of a method of manufacturing a solar cell according to the present invention.

2 to 9 are structural views showing respective steps of a method of manufacturing a solar cell according to the present invention.

S1-S5‧‧‧ method steps

Claims (16)

A method for manufacturing a solar cell, comprising the steps of: (a) providing a substrate assembly comprising a germanium substrate, an oxide layer on the germanium substrate, and an anti-reflection on the oxide layer a layer comprising a first type of germanium layer and a second type of germanium layer, the oxide layer being on the second type of germanium layer; (b) placing a first hard mask on the anti-reflective layer, The first hard mask has a first pattern to expose a portion of the anti-reflective layer; (c) etching the exposed portion of the anti-reflective layer and a portion of the oxide layer to the anti-reflective layer and the oxide layer Forming a plurality of first trenches, the first trenches penetrating the anti-reflective layer and the oxide layer; (d) removing the first hard mask; (e) forming a first trench in the first trench a plurality of first metal wires of the solar cell; and (f) utilizing the first hard mask and repeating steps (a) through (e) above to form a plurality of first metal wires of the other solar cell. The method for manufacturing a solar cell according to claim 1, further comprising the step of annealing the tantalum substrate assembly, the oxide layer, the anti-reflective layer, and the first metal wires. The method of manufacturing a solar cell according to claim 1, wherein the first metal wires are formed by electroplating. The method of manufacturing a solar cell according to claim 1, wherein the material of the antireflection layer comprises tantalum nitride (SiNx). The method of manufacturing a solar cell according to claim 1, wherein the material of the oxide layer comprises cerium oxide (SiO ₂ ). The method for manufacturing a solar cell according to claim 1, wherein the first type of germanium layer is a P type germanium layer, and the second type germanium layer is an N type germanium layer. The method for manufacturing a solar cell according to claim 6, wherein the first type of germanium layer is composed of a P-type germanium layer and a P+ type germanium layer, and the P+ type germanium layer is more than the P-type germanium layer. Keep away from the anti-reflection layer. The method of manufacturing a solar cell according to claim 1, wherein the exposed portion of the anti-reflective layer and a portion of the oxide layer are etched by reactive ion etching. The method for producing a solar cell according to claim 8, wherein the reactive ion etching is performed by using a fluorocarbon (CxFy). The method for manufacturing a solar cell according to claim 1, further comprising the steps of: forming a dielectric layer on a back surface of the germanium substrate away from the anti-reflective layer; and placing a second hard mask on the a back surface of one of the dielectric layers, the second hard mask having a second pattern to expose a portion of the dielectric layer; etching the exposed portion of the dielectric layer to form a plurality of second layers in the dielectric layer a trench; and removing the second hard mask; forming a plurality of second metal wires in the second trenches while forming a reflective layer on the back surface of the dielectric layer. The method of manufacturing a solar cell according to claim 10, wherein the material of the dielectric layer is tantalum nitride (SiNx). The method for manufacturing a solar cell according to claim 10, wherein the dielectric layer and the antireflection layer are made of tantalum nitride (SiNx). The method of manufacturing a solar cell according to claim 10, wherein the material of the dielectric layer is cerium oxide (SiO ₂ ). The method of manufacturing a solar cell according to claim 10, wherein the second metal wires are formed by electroplating. The method of manufacturing a solar cell according to claim 10, wherein the exposed portion of the anti-reflective layer and the exposed portion of the dielectric layer are etched by reactive ion etching. The method for producing a solar cell according to claim 15, wherein the reactive ion etching is achieved by using a fluorocarbon (CxFy).