KR20170033997A - Apparatus of fabricating thin film silicon substrate - Google Patents

Abstract

The present invention provides to an apparatus for fabricating a thin silicon substrate by which a thin silicon substrate having superior quality can be stably fabricated. The apparatus includes: a first reaction bath having a susceptor on which a silicon base material is mounted, in which the first reaction bath contains a plating solution to perform a plating process for forming a nickel layer on the silicon base material and provides a composite structure of the nickel layer and the thin silicon substrate wherein the composite structure is formed as the nickel layer and a thin silicon, which is a part of the silicon base material, are delaminated from the rest of the silicon base material due to cracks propagating caused by the difference in stress between nickel and silicon; and second reaction bath containing a nickel etching solution for forming the thin silicon substrate by removing the nickel layer from the composite structure; and a transfer device configured to lift and transfer the composite structure from the first reaction bath to the second reaction bath.

Description

[0001] Apparatus for fabricating thin film silicon substrates [0002]

The present invention relates to an apparatus for manufacturing a thin silicon substrate, and more particularly to a device capable of manufacturing a thin silicon substrate using a stripping process caused by a stress difference between silicon and metal.

As most of the energy consumption is used as fossil energy, greenhouse gas emissions such as carbon dioxide and methane are increasing, leading to global warming, sea level rise, smog phenomenon, greenhouse effect, etc. As time passes, fossil energy reserves Is at a supply crisis. In order to cope with these problems, the need to use and expand alternative energy has also been highlighted, and interest in alternative energy using natural energy without depleting dyestuffs has been increasing day by day, reducing dependence on fossil fuels and affecting the environment. From this point of view, the solar energy that can receive infinite energy from the sun among the many alternative energy sources is most interested in Korea, and the research is also actively carried out.

Photovoltaic power generation is a technology that converts unlimited, pollution-free solar energy directly into electric energy, and it can be classified into silicon system, compound system, organic system system depending on the material, and it can be classified into crystal system, thin film system, .

Now, solar energy is moving beyond the goal of high efficiency and low cost, making solar cells one step closer to commercialization. Most of the silicon solar cells, which account for more than 90% of the solar cell market, are made of monocrystalline ingots and used as wafers for cutting. In this case, thickness limit and Kerf-less are caused by cutting, resulting in high material cost. Therefore, it is necessary to develop technology for thinning and crystallization in order to lower the material cost by thinly separating the crystalline silicon material and realize high efficiency and low cost of the solar cell.

An object of the present invention is to provide an apparatus for manufacturing a thin silicon substrate capable of stably implementing a thin silicon substrate of good quality. However, these problems are exemplary and do not limit the scope of the present invention.

An apparatus for manufacturing a thin silicon substrate according to one aspect of the present invention is provided. The apparatus for manufacturing a thin silicon substrate includes a susceptor on which a silicon base material is mounted. The plating solution contains a plating solution for performing a plating process for forming a nickel layer on an upper surface of the silicon base material. A first reaction vessel capable of providing a composite structure of the nickel layer and the thin silicon by separating the nickel layer and the thin silicon as a part of the silicon base material from the rest of the silicon base material by crack propagation; A second reaction vessel containing a nickel etching solution for forming a thin silicon substrate by removing a nickel layer from the composite structure; And a transfer device configured to transfer the complex structure from the first reaction tank to the second reaction tank using gravity by its own weight.

The apparatus for manufacturing a thin silicon substrate may further include a laser device capable of forming a groove, which is a start region of crack propagation, in at least a part of a side surface of the silicon base material by a laser scribing process.

The apparatus for manufacturing a thin silicon substrate may further include a shaft connected to a lower portion of the susceptor to adjust a height of the susceptor. The shaft may be configured to be rotatable about an axial direction.

In the apparatus for producing a thin silicon substrate, the transfer device may include a guide plate extending from the first reaction vessel toward the second reaction vessel.

In the apparatus for producing a thin silicon substrate, the guide plate may be inclined such that the first reaction vessel side is higher than the second reaction vessel side.

According to one embodiment of the present invention as described above, it is possible to provide a thin silicon substrate manufacturing apparatus capable of stably implementing a thin silicon substrate of good quality. However, these problems are exemplary and do not limit the scope of the present invention.

FIGS. 1 to 7 are views sequentially illustrating a process of manufacturing a thin silicon substrate using an apparatus for manufacturing a thin silicon substrate according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, at least some of the components may be exaggerated or reduced in size for convenience of explanation. Like numbers refer to like elements throughout the drawings.

It is to be understood that throughout the specification, when an element such as a layer or a region is referred to as being "on" another element, the element may be directly "on" It will be understood that there may be other intervening components. On the other hand, when an element is referred to as being "directly on" another element, it is understood that there are no other elements intervening therebetween.

FIGS. 1 to 7 are views sequentially illustrating a process of manufacturing a thin silicon substrate using an apparatus for manufacturing a thin silicon substrate according to an embodiment of the present invention.

Referring to FIG. 1, a silicon base material 10 is disposed in a first reaction tank 100. The nickel plating solution 150 may be contained in the first reaction tank 100. The silicon base material 10 may be placed on the susceptor 110, which is a position adjusting pedestal.

Referring to FIG. 2, a nickel layer 20 of a silicon base material 10 is formed in a first reaction vessel 100 by a plating process. Table 1 shows the thermal expansion coefficient (unit: μK ^-1 ) of silicon and nickel. The difference in thermal expansion coefficient between nickel and silicon is an important characteristic in the peeling process because it causes difference in thermal stress in the subsequent process.

400K 500K 600K 700K 800K silicon 3.25 3.61 3.84 4.01 4.15 nickel 0.133 0.139 0.142 0.148 0.153

3, at least a part of the silicon base material 10 on which the nickel layer 20 is formed is moved over the surface of the nickel plating solution 150 using the susceptor 110 and the shaft 120. That is, the susceptor 110 and the shaft 120 can be understood as devices for adjusting the position of the silicon base material 10 and the nickel layer 20. As a result of the movement, at least a part of the silicon base material 10 and the nickel layer 20 are exposed on the surface of the nickel plating solution 150.

Referring to FIG. 4, a groove 70 is formed in at least a part of a side surface of the base material 10. The groove 70 has any shape including a concave portion and may be understood as other terms such as a hole, a trench or a cavity. The groove 70 may be a start region where a crack propagates due to a stress difference between nickel and silicon.

In one embodiment, the groove 70 may be formed only on a portion of the side of the silicon base material 10, and in a modified embodiment, the groove 70 may be formed continuously along the side of the base material 10 to form a closed loop.

The groove 70 may be implemented, for example, by a laser scribing process. When controlling the thickness of silicon stripped in the silicon stripping process, it is easy to control the thickness by scribing with a laser.

The groove 70 is formed in a region having a predetermined distance from the nickel layer 20, and the distance can determine the thickness of the thin silicon substrate 30a (FIG. 7) finally realized. For example, the grooves 70 may be formed from 10 탆 to 30 탆 below the nickel layer 20, and the thickness of the thin silicon substrate embodied therefrom may be about 20 탆.

On the other hand, in order to form the groove 70 at a uniform position, the laser can be irradiated while the silicon base material 10 is rotated by the rotation of the shaft 120 while the laser device 130 is fixed.

The present inventors confirmed that the stress induced by controlling the scribing depth formed by the laser scribing process can be controlled by interlocking. For example, when the scribing depth was 0.625 탆, 1.25 탆, and 2.5 탆, the stress was averaged on the average when the scribing depth was 0.625 탆, regardless of the temperature interval, and the scribing depth was 1.25 탆 At 2.5 μm, the stress was slightly smaller when the scribing depth was 1.25 μm. Furthermore, it was confirmed that as the thinning of the thinning thickness and the shallow depth of the laser processing are performed, the thermal energy received per unit area becomes larger when the laser processing width is fixed and constant heat energy is received, so that the thermal stress is further increased.

5A to 5C, cracks propagate from the groove 70 due to a difference in stress between nickel and silicon, so that the nickel layer 20 and the thin silicon 10a, which is a part of the silicon base material 10, 10 and the remainder 10b.

The composite structure 30 composed of the nickel layer 20 and the thin silicon 10a which is a part of the silicon base material 10 may have a rolled form and the interface of nickel and silicon may be in a bonded state .

This peeling process starts from the groove 70, which is an initial crack origin, and is rolled up due to the stress difference between the peeled silicon and nickel, and cracks can be propagated. Since the thickness of the peeled silicon and nickel is thin, the composite structure 30 can be rolled up. For example, the composite structure 30 may be a 20 μm-thick silicon thin film substrate plated with nickel.

Separate heat treatment may be performed to facilitate separation of the nickel layer 20 and the thin silicon 10a, which is a part of the silicon base material 10, from the remainder 10b of the silicon base material 10 by separation. Thermal stress due to the difference in thermal expansion coefficient between nickel and silicon can contribute to the thin film peeling and separation process.

6, there is shown an example of a transfer device configured to transfer a composite structure 30 from a first reaction vessel 100 to a second reaction vessel 300 using gravity by its own weight. The transfer device includes a guide plate 210 extending from the first reaction vessel 100 toward the second reaction vessel 300. Furthermore, the guide plate 210 may be inclined such that the first reaction tank 100 side is higher than the second reaction tank 300 side. In this case, the composite structure 30 is transferred from the first reaction vessel 100 toward the second reaction vessel 300 by its own weight.

In a modified embodiment of the present invention, the guide plate 210 may be disposed while keeping the guide plate 210 horizontal without forming an inclination. In this case, in order for the composite structure 30 to be transferred from the first reaction vessel 100 to the second reaction vessel 300, the composite structure 30 is separated from the second reaction vessel 300 by a separate application unit (Not shown) may be introduced.

6 and 7, the composite structure 30 generated in the first reaction vessel 100 is moved to the second reaction vessel 300 containing the nickel etching solution 350 (A). When the composite structure 30 is immersed in the nickel etching solution 350, the nickel layer 20 constituting the composite structure 30 is removed from the composite structure 30 by the nickel etching solution 350. According to this, the composite structure 30 can be separated into the thin silicon substrate 30a and the nickel eluting portion 30b. The nickel eluting portion 30b is understood to be at least a part of the nickel layer 20 forming the composite structure 30, and may be integrally formed or may exist as a plurality of agglomerated or spaced lumps or flakes.

On the other hand, the above-described steps described above form a unit cycle, and such a unit cycle is continuously and repeatedly performed so that the thin silicon substrate 30a can be continuously mass-produced. In this case, the nickel eluting portion 30b separated from the composite structure 30 is moved (B) from the second reaction tank 300 to the first reaction tank 100 so as to be reused in the nickel plating process in the subsequent unit cycle . The nickel eluting portion 30b injected into the first reaction tank 100 is reused and the concentration of the nickel plating liquid 150 is maintained constant, thereby stabilizing the process and reducing the manufacturing cost.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (5)

And a susceptor on which the silicon base material is mounted. The plating solution is received to perform a plating process for forming a nickel layer on the upper surface of the silicon base material. The crack is propagated due to the difference in stress between nickel and silicon, And a thin silicon layer which is a part of the silicon base material is peeled off from the rest of the silicon base material to thereby provide a composite structure of the nickel layer and the thin silicon layer;
A second reaction vessel containing a nickel etching solution for forming a thin silicon substrate by removing a nickel layer from the composite structure; And
A conveying device configured to convey the composite structure from the first reaction tank to the second reaction tank using gravity by its own weight;
Wherein the thin silicon substrate is a silicon substrate. The method according to claim 1,
Further comprising a laser device capable of forming a groove as a start region of crack propagation in a laser scribing process on at least a part of the side surface of the silicon base material. The method according to claim 1,
And a shaft connected to a lower portion of the susceptor to adjust a height of the susceptor, wherein the shaft is configured to be rotatable about an axial direction. The method according to claim 1,
Wherein the transfer device includes a guide plate extending from the first reaction tank toward the second reaction tank. The method according to claim 1,
Wherein the guide plate is inclined such that the side of the first reaction vessel is higher than the side of the second reaction vessel.

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