TWI405353B - Method for manufacturing photovoltaic element - Google Patents

Abstract

A method of manufacturing optoelectronic devices includes steps of: forming a sacrifice membrane on a substrate, and the sacrifice membrane including a plurality of channels connected to the surroundings; growing an optoelectronic semiconductor epitaxial membrane on the patterned sacrifice membrane; sticking a first substrate to the optoelectronic semiconductor epitaxial membrane; injecting etchant from the surroundings to the channels to etch the sacrifice membrane; and separating the substrate and the optoelectronic semiconductor epitaxial membrane. Because the channels are already made before the optoelectronic semiconductor epitaxial membrane is grown, the substrate can maintain complete and can be reused. Further, extra time for sticking works is excluded and the effect of fast etching and removing the sacrifice membrane can be maintained.

Description

Photoelectric element manufacturing method

The present invention relates to a semiconductor process method, and more particularly to a method of fabricating a photovoltaic element.

In the case of epitaxial fabrication of a light-emitting diode, sapphire having a relatively good lattice constant and a reasonable price is often used as a substrate for epitaxy. However, due to the poor heat dissipation capability of sapphire and non-conductivity, there are many limitations in the use of LED components.

In order to improve the performance of components, the current practice is to separate the optoelectronic semiconductor epitaxial film from the sapphire substrate by laser lift-off technology after epitaxial completion of an optoelectronic semiconductor epitaxial film, or to use mechanical polishing technology. The sapphire substrate is directly removed, and a heat-dissipating substrate with good thermal conductivity is replaced to improve the heat dissipation state of the optoelectronic semiconductor epitaxial film during operation, thereby achieving the purpose of excellent luminescence performance of the device.

In addition to the separation or removal of sapphire substrates by techniques such as laser lift-off, mechanical grinding, etc., for example, US Patent No. 2008/0038857 A1 discloses the formation of a sacrificial film between a sapphire substrate and an optoelectronic semiconductor epitaxial film, followed by wet etching. A method of separating a sacrificial film to separate a sapphire substrate from an optoelectronic semiconductor epitaxial film. However, the disadvantage of this technique is that the etching of the sacrificial film is only after the outer peripheral edge is contacted with the wet etchant, and then gradually etched toward the central portion. The area of the etchant contacting the sacrificial film is too small during the whole process, so that the etching rate is extremely slow. It takes too much work time.

In order to improve the etching rate, the method disclosed in US Pat. No. 5,073,230 is to increase the contact area of the sacrificial film with the etchant.

Referring to FIG. 1 and FIG. 2, the substrate 11, the sacrificial film 12, and the optoelectronic semiconductor epitaxial film 13 are sequentially prepared, and a temporary substrate 14 is bonded to the optoelectronic semiconductor epitaxial film 13. Referring to FIG. 3 and FIG. 4, a plurality of etch holes 15 are etched downward by the temporary substrate 14 to shield the predetermined position, and the etch holes 15 penetrate the optoelectronic semiconductor epitaxial film 13 and the sacrificial film 12, and reach the depth. The substrate 11 is. Referring to FIG. 5 and FIG. 6, by etching the holes 15, an etchant is introduced into the sacrificial film 12 during wet etching, and the sacrificial film 12 is etched away to remove the optoelectronic semiconductor epitaxial film 13 and The substrate 11 is separated. Referring to FIG. 7 and FIG. 8, the optoelectronic semiconductor epitaxial film 13 is finally attached to a permanent substrate 16 having a predetermined structure, and the temporary substrate 14 is removed.

However, the prior patents have to take time to fabricate the temporary substrate 14 to form the etched holes 15 at predetermined positions by the temporary substrate 14. Therefore, although the prior patent can speed up the removal rate of the sacrificial film 12, it takes other processes and costs to complete the fabrication of the photovoltaic element.

As can be seen from the above, the sacrificial film 12 helps to remove the sapphire substrate 11, but the manufacturing method of the prior patent still has the disadvantages of labor and cost, and therefore does not really solve the problem of removing the sapphire substrate 11 excessively. The shortcomings of working hours. For this reason, a photovoltaic element manufacturing method capable of quickly removing the sacrificial film 12 and saving process time and cost has yet to be paid attention to and researched by the industry and the academic community.

Accordingly, it is an object of the present invention to provide a method of fabricating a photovoltaic element that is process efficient.

Thus, the method for producing a photovoltaic element of the present invention comprises the following steps.

First, a substrate for epitaxy is prepared, and a sacrificial film is formed from the substrate, and at least one of the substrate and the sacrificial film forms a plurality of channels communicating with the periphery, and the width of the channels is 1 μm to 50 μm. The height is between 0.5 μm and 5 μm. Next, an optoelectronic semiconductor epitaxial film is epitaxially grown from the sacrificial film. Successively, a first substrate is pasted on the epitaxial film of the optoelectronic semiconductor, and a wet etchant is introduced into the channels from the periphery to etch away the sacrificial film, and the substrate is epitaxially grown from the photo-semiconductor Membrane separation. The effect of the invention is that the fabrication of the channels is completed before the epitaxial film of the optoelectronic semiconductor is grown, so as to keep the substrate intact and can be reused, and the step of aligning with the permanent substrate with the structure is omitted. The work time is reduced while maintaining the effect of rapid etching to remove the sacrificial film.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of FIG.

Before the present invention is described in detail, it is noted that in the following description, similar elements are denoted by the same reference numerals.

Referring to Figures 9 and 10, a first preferred embodiment of the method of fabricating a photovoltaic element of the present invention comprises the following steps.

First, a substrate 2 for epitaxy is prepared. Then, a flat sacrificial film 5 is epitaxially grown on the substrate 2, and the predetermined area is shielded by the photoresist 4, and the sacrificial film 5 of the non-shielding region is etched and removed to complete a patterned sacrificial film 5. Wherein, a plurality of channels 5' communicating with the periphery of the wafer are formed on the sacrificial film 5, and since the channels 5' communicate with the periphery of the wafer, the etchant is etched inwardly from the periphery of the wafer to etch the sacrificial film 5.

Referring to FIG. 11, after the patterning of the sacrificial film 5 is completed, an optoelectronic semiconductor epitaxial film 6 having a P-N interface is grown from the patterned sacrificial film 5 side by side.

Referring to FIG. 12, FIG. 13, and FIG. 14, the channel 5' of the sacrificial film 5 may be interlaced, non-connected, and each connected to the periphery, or may be in a curved state. It is worth mentioning that The channel 5' may also be a sawtooth shape, a spiral shape, a branch shape (not shown), etc., but such pattern changes are generally known in the art and can be easily changed by those skilled in the art, and therefore will not be described again.

In further detail, the optoelectronic semiconductor epitaxial film 6 is reduced in the through-difference density by laterally epitaxial from the patterned sacrificial film 5, wherein the preferred width of the channels 5' is 1 μm. The preferred height range is ~50 μm and is between 0.5 μm and 5 μm, so that the sacrificial film 5 has the dual advantages of facilitating the passage of the wet etchant and reducing the defects of the optoelectronic semiconductor epitaxial film 6.

It is worth mentioning that if the optoelectronic semiconductor epitaxial film 6 is laterally epitaxially grown from the sacrificial film 5, when too much material is filled in the channels 5', the channel 5 needs to be reused by the laser. The optoelectronic semiconductor epitaxial film 6 in the 'vaporization is removed, so that the channels 5' are kept unblocked for subsequent etching to remove the sacrificial film 5. (all are not shown)

Referring to FIG. 15, a first substrate is formed on the optoelectronic semiconductor epitaxial film 6. In the preferred embodiment, the first substrate is a heat dissipation substrate 7. Finishing After the fabrication of the epitaxial film 6 of the optoelectronic semiconductor, a conductive film 8 is deposited on the epitaxial film 6 of the optoelectronic semiconductor, and the conductive film 8 is, for example, nickel gold (Ni/Au), indium tin oxide (ITO), or the like. The material is placed in a nitrogen gas at 500 ° C ~ 600 ° C for about 10 minutes to complete the high temperature annealing to form an ohmic contact, and the heat dissipation substrate 7 is, for example, 1 μm thick Au, 50 nm thick Cr and germanium substrate, and at 350 ° C ~ The conductive film 8 is bonded to the substrate at a high temperature and a high pressure of 450 ° C. A mirror metal film (not shown) may be added to the conductive film 8. The foregoing processes are well known to those skilled in the relevant art. Therefore, it will not be detailed.

Referring to FIG. 16, next, a wet etchant is introduced into the channels 5' from the periphery to etch away the sacrificial film 5, and the channel 5' etchant is quickly introduced into the sacrificial film 5, The entire wafer effectively increases the etch rate.

Among them, the acidic etchant is HF (applicable temperature is room temperature ~ 70 ° C), H ₂ SO ₄ (room temperature ~ 200 ° C), H ₃ PO ₄ (room temperature ~ 200 ° C), HCl (room temperature ~ 200 ° C ), BOE (room temperature ~ 70 ° C), and its diluent or mixture. And in the first preferred embodiment, the wet etching comprises a vapor etch.

Referring to FIG. 17, after the sacrificial film 5 is etched and removed, the substrate 2 is separated from the optoelectronic semiconductor epitaxial film 6. At this time, since the structure of the substrate 2 is not broken, the substrate can be 2 reuse to save costs.

Referring to Fig. 18, finally, the optoelectronic semiconductor epitaxial film 6 is inverted, and the optoelectronic semiconductor epitaxial film 6 is formed into a plurality of photovoltaic elements by a semiconductor process. As shown in FIG. 18, a plurality of vertically-conducting light-emitting diodes can be formed, and a plurality of horizontally-conductive light-emitting diodes (not shown) can also be formed.

It is worth mentioning that the patterned sacrificial film 5 can also be epitaxially formed to form the flat sacrificial film 5, and then the sacrificial film 5 is etched out of the channel 5' by a laser process to complete the patterning sacrifice. Membrane 5.

Since the patterned sacrificial film 5 is completed before epitaxial growth of the optoelectronic semiconductor epitaxial film 6, the substrate can be kept intact and can be reused.

Referring to FIG. 19 and FIG. 20, the second preferred embodiment of the method for fabricating the photovoltaic device of the present invention is substantially the same as the first preferred embodiment member and the step, except that the first embodiment of the second preferred embodiment The substrate is a temporary substrate 9.

After the fabrication of the optoelectronic semiconductor epitaxial film 6 is completed, the photodiode epitaxial film 6 is formed into a horizontally-conducting light-emitting diode by a semiconductor process. It is worth mentioning that vertical conduction can also be made. Diode (not shown). Next, the temporary substrate 9 is adhered to the optoelectronic semiconductor epitaxial film 6, and the sacrificial film 5 is etched to separate the substrate 2 from the optoelectronic semiconductor epitaxial film 6. Referring to FIG. 21, a heat dissipation substrate 7 and the optoelectronic semiconductor epitaxial film 6 are finally formed, and the temporary substrate 9 is removed.

Referring to FIG. 22, it is worth mentioning that the patterned sacrificial film 5 can directly vaporize the sacrificial film 5 by using a laser process, in addition to shielding the predetermined area by the photoresist 4, forming the channels 5' to complete the sacrificial film. 5 production.

It is further noted that the positions of the channels 5' are not particularly limited to the photoelectric elements, that is, when the number of the channels 5' is reduced, the laser process for patterning the sacrificial film 5 can be saved. The man-hour can be reduced without affecting the rate at which the sacrificial film 5 is etched.

Referring to Figure 23, a third preferred embodiment of the method of fabricating a photovoltaic device of the present invention is substantially identical to the steps of the first preferred embodiment, except that the channel 5' of the third preferred embodiment is formed On the substrate 2.

After the channels 5' are formed on the substrate 2, the sacrificial film 5 is grown and the channels 5' are not filled, and the channels 5' can be removed when the sacrificial film 5 is removed. The etchant is quickly introduced to increase the rate at which the sacrificial film 5 is removed.

In summary, since at least one of the sacrificial film 5 and the substrate has the channels 5 ′, the etching removal rate of the sacrificial film 5 is accelerated, and before epitaxial growth of the optoelectronic semiconductor epitaxial film 6 The process of the sacrificial film 5 is completed, so that it is not necessary to separately prepare the patterned temporary substrate 9 (not shown), the process time is saved, and the structure of the substrate 2 is not destroyed for repeated use, so the invention can be achieved. The purpose.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2. . . Substrate

4. . . Photoresist

5. . . Sacrificial film

5’. . . aisle

6. . . Photoelectric semiconductor epitaxial film

7. . . Heat sink substrate

8. . . Conductive film

9. . . Temporary substrate

1 is a perspective view showing a conventional substrate, a sacrificial film and an optoelectronic semiconductor epitaxial film;

2 is a perspective view showing the lamination of a temporary substrate on the epitaxial film of the optoelectronic semiconductor;

Figure 3 is a perspective view showing the etching from the temporary substrate;

Figure 4 is a perspective view showing the continuous etching of the temporary substrate to a substrate;

Figure 5 is a perspective view showing the introduction of a wet etchant in a plurality of etched holes;

6 is a perspective view showing a sacrificial film being etched away and separating the optoelectronic semiconductor epitaxial film from the substrate;

Figure 7 is a perspective view showing the alignment of the optoelectronic semiconductor epitaxial film with a permanent substrate;

Figure 8 is a perspective view showing the removal of the temporary substrate;

Figure 9 is a side elevational view showing a first preferred embodiment of a method of fabricating a photovoltaic element of the present invention;

Figure 10 is a side elevational view showing the etching of a plurality of channels in the first preferred embodiment;

Figure 11 is a side elevational view showing the epitaxial growth of an optoelectronic semiconductor epitaxial film on a patterned sacrificial film in the first preferred embodiment;

Figure 12 is a top plan view showing the channels interleaved in the first preferred embodiment;

Figure 13 is a top plan view showing the channels in parallel with each other in the first preferred embodiment;

Figure 14 is a top plan view showing the curved passages in the first preferred embodiment;

Figure 15 is a side elevational view showing the heat dissipation substrate formed in the first preferred embodiment;

Figure 16 is a side elevational view showing the first preferred embodiment in which a wet etchant is introduced into the channels to etch the sacrificial film;

Figure 17 is a side elevational view showing the optoelectronic semiconductor epitaxial film separated from the substrate in the first preferred embodiment;

Figure 18 is a side elevational view of the first preferred embodiment of the optoelectronic semiconductor epitaxial film into a plurality of vertical conduction of the light-emitting diode;

Figure 19 is a side elevational view showing a second preferred embodiment of a method of fabricating a photovoltaic element of the present invention;

Figure 20 is a side elevational view showing the second preferred embodiment in which a temporary substrate is attached to the optoelectronic semiconductor epitaxial film, and the sacrificial film is etched and removed;

Figure 21 is a side elevational view showing the optoelectronic semiconductor epitaxial film separated from the substrate in the second preferred embodiment, and removing the temporary substrate;

Figure 22 is a side elevational view showing the channel of the sacrificial film in the second preferred embodiment may also be formed by laser vaporization;

Figure 23 is a side elevational view showing a third preferred embodiment of a method of fabricating a photovoltaic element of the present invention.

2. . . Substrate

5. . . Sacrificial film

5’. . . aisle

6. . . Photoelectric semiconductor epitaxial film

7. . . Heat sink substrate

Claims (6)

A method for manufacturing a photovoltaic element, comprising: (a) preparing a substrate for epitaxy; (b) forming a sacrificial film from the substrate; (c) forming at least one of the substrate and the sacrificial film to form a plurality of and peripheral edges Connected channels having a width of 1 μm to 50 μm and a height of 0.5 μm to 5 μm; (d) epitaxial growth of an optoelectronic semiconductor epitaxial film from the sacrificial film; (e) epitaxy of the optoelectronic semiconductor Forming a first substrate on the film; and (f) passing a chemical etchant from the periphery into the channels to etch away the sacrificial film and separating the substrate from the optoelectronic semiconductor epitaxial film. According to the method of manufacturing a photovoltaic device according to the first aspect of the invention, in the step (c), the sacrificial film is patterned, a channel is formed between the sacrificial films, and the step (c) is performed in the step ( b) After. According to the method for manufacturing a photovoltaic device according to claim 2, in the step (c), a flat sacrificial film is first epitaxially formed, and the sacrificial film is etched out of the channels by a semiconductor process to complete the method. Sacrificial film patterning. According to the method for manufacturing a photovoltaic device according to claim 2, in the step (c), a flat sacrificial film is first epitaxially formed, and the sacrificial film is etched out of the channels by a laser process to complete The sacrificial film is patterned. According to the method of manufacturing a photovoltaic device according to the first aspect of the invention, the first substrate in the step (e) is a heat dissipation substrate, and further comprises a real After the step (g) after the step (f), the optoelectronic semiconductor epitaxial film is formed into a plurality of photovoltaic elements by a semiconductor process. According to the method of manufacturing a photovoltaic device according to the first aspect of the invention, the first substrate in the step (e) is a temporary substrate, and after the step (f) is completed, a heat dissipation substrate is formed and the temporary portion is removed. The substrate further includes a step (g) performed before the step (f), and the photo-electric semiconductor epitaxial film is formed into a plurality of photovoltaic elements by a semiconductor process.