KR20110001800A - Tip and method of fabricating the solar cell using the tip - Google Patents

Abstract

PURPOSE: A tip and a method for manufacturing a solar cell using the same are provided to eliminate foreign materials remained in a contact pattern and a separate pattern by implementing scribing processes using tips with different shapes. CONSTITUTION: A plurality of rear-side contact electrode patterns(200) is formed on a substrate(100). A light absorbent layer(300) is formed on the substrate. A buffer layer(400) is formed on the light absorbent layer. A contact pattern passing through the light absorbent layer is formed by implementing a first scribing process using a first tip. A second scribing process is implemented using a second tip in order to foreign materials generated from the first scribing process.

Description

TIP AND METHOD OF FABRICATING THE SOLAR CELL USING THE TIP}

An embodiment relates to a tip and a method of manufacturing a solar cell using the same.

Recently, as the demand for energy increases, development of solar cells for converting solar energy into electrical energy is in progress.

In particular, CIGS-based solar cells, which are pn heterojunction devices having a substrate structure including a glass substrate, a metal back electrode layer, a p-type CIGS-based light absorbing layer, a high resistance buffer layer, an n-type window layer, and the like, are widely used.

At this time, when forming the CIGS-based solar cell, a scribing process, which is a mechanical method, performs a scribing process, which is a mechanical method, for dividing a contact pattern for connecting between electrodes and a separation pattern for unit cells. Impurities are generated and are left between the contact pattern and the separation pattern.

The foreign material thus left may interfere with the connection between the front electrode and the rear electrode, resulting in unstable connection, and may cause a defect of the device due to impurities.

The embodiment provides a tip capable of reducing impurities generated during solar cell manufacturing and a method of manufacturing the solar cell using the same.

A method of manufacturing a solar cell according to an embodiment includes forming a plurality of back electrode patterns spaced apart from each other on a substrate; Forming a light absorbing layer on the substrate on which the back electrode pattern is disposed; Performing a first scribing process using a first tip to form a contact pattern penetrating the light absorbing layer; Performing a second scribing process using a second tip to remove impurities generated during the first scribing process; Forming a front electrode on the light absorbing layer; And forming a separation pattern for dividing the unit cell into the front electrode and the light absorbing layer, wherein the front electrode is inserted into the contact pattern and electrically connected to the back electrode pattern.

The tip according to the embodiment is formed by combining the support and the contact portion, the width of the support portion and the contact portion includes, or the width of the contact portion is formed larger than the support portion, the bottom surface of the contact portion includes a flat.

According to an embodiment of the present disclosure, a tip and a method of manufacturing a solar cell using the same have two different scribing processes by using a tip having a different shape when forming a contact pattern and a separation pattern. The remaining impurities can be removed to prevent defects of the solar cell.

In the description of the embodiments, where each substrate, layer, film, or electrode is described as being formed "on" or "under" of each substrate, layer, film, or electrode, etc. , "On" and "under" include both "directly" or "indirectly" formed through other components. In addition, the upper or lower reference of each component is described with reference to the drawings. The size of each component in the drawings may be exaggerated for the sake of explanation and does not mean the size actually applied.

1 to 8 are cross-sectional views illustrating a method of manufacturing a solar cell according to an embodiment.

First, as shown in FIG. 1, the back electrode 201 is formed on the substrate 100.

The substrate 100 may be glass, and a ceramic substrate such as alumina, stainless steel, a titanium substrate, or a polymer substrate may also be used.

Soda lime glass may be used as the glass substrate, and polyimide may be used as the polymer substrate.

In addition, the substrate 100 may be rigid or flexible.

The back electrode 201 may be formed of a conductor such as metal.

For example, the back electrode 201 may be formed by a sputtering process using a molybdenum (Mo) target.

This is because of high electrical conductivity of molybdenum (Mo), ohmic bonding with the light absorbing layer, and high temperature stability under Se atmosphere.

In addition, although not shown in the drawing, the back electrode 201 may be formed of at least one layer.

When the back electrode 201 is formed of a plurality of layers, the layers constituting the back electrode 201 may be formed of different materials.

Subsequently, as shown in FIG. 2, a patterning process is performed on the back electrode 201 to form a back electrode pattern 200.

The back electrode pattern 200 may be formed such that the substrate 100 is exposed between the protection patterns 10.

In addition, the back electrode pattern 200 may be arranged in a stripe form or a matrix form and may correspond to each cell.

However, the back electrode pattern 200 is not limited to the above form and may be formed in various forms.

As shown in FIG. 3, the light absorbing layer 300 and the buffer layer 400 are formed on the back electrode pattern 200.

The light absorbing layer 300 includes an Ib-IIIb-VIb-based compound.

In more detail, the light absorbing layer 300 includes a copper-indium-gallium-selenide-based (Cu (In, Ga) Se ₂ , CIGS-based) compound.

Alternatively, the light absorbing layer 300 may include a copper-indium selenide-based (CuInSe ₂ , CIS-based) compound or a copper-gallium-selenide-based (CuGaSe ₂ , CIS-based) compound.

For example, to form the light absorbing layer 300, a CIG-based metal precursor film is formed on the back electrode pattern 200 using a copper target, an indium target, and a gallium target.

Thereafter, the metal precursor film is reacted with selenium (Se) by a selenization process to form a CIGS-based light absorbing layer 300.

In addition, during the process of forming the metal precursor film and the selenization process, an alkali component included in the substrate 100 may pass through the back electrode pattern 200, and the metal precursor film and the light absorbing layer ( 300).

An alkali component may improve grain size and improve crystallinity of the light absorbing layer 300.

In addition, the light absorbing layer 300 may form copper, indium, gallium, selenide (Cu, In, Ga, Se) by co-evaporation.

The light absorbing layer 300 receives external light and converts the light into electrical energy. The light absorbing layer 300 generates photo electromotive force by the photoelectric effect.

The buffer layer 400 is formed of at least one layer, and any one or a stack of cadmium sulfide (CdS), ITO, ZnO, and i-ZnO on the substrate 100 on which the light absorbing layer 300 is formed. Can be formed.

In this case, the buffer layer 400 is an n-type semiconductor layer, the light absorbing layer 300 is a p-type semiconductor layer. Thus, the light absorbing layer 300 and the buffer layer 400 form a pn junction.

The buffer layer 400 is disposed between the light absorbing layer 300 and the front electrode to be formed later.

That is, since the difference between the lattice constant and the energy band gap is large between the light absorbing layer 300 and the front electrode, a good junction may be formed by inserting the buffer layer 400 having a band gap between the two materials.

In the present exemplary embodiment, one buffer layer is formed on the light absorbing layer 300, but the present invention is not limited thereto, and the buffer layer may be formed of a plurality of layers.

Next, as shown in FIG. 4, a contact pattern 310 penetrating the light absorbing layer 300 and the buffer layer 400 is formed.

The contact pattern 310 may be formed by a mechanical method, and a portion of the back electrode pattern 200 is exposed.

The contact pattern 310 may be formed using the tip illustrated in FIG. 5.

First, the contact pattern 310 is formed by performing a first scribing process using the first tip 10.

In addition, a second scribing process is performed inside the contact pattern 310 using the second tip 20 to remove impurities generated during the first scribing process.

That is, foreign matters generated during the first scribing process and remaining in the contact pattern 310 may be removed.

In this case, the width W1 of the second tip 20 may be the same as the width W1 of the contact pattern 310, and the bottom surface may be formed in a plane.

In addition, the shape of the second tip 20 is not limited thereto, and a second tip 25 having a shape illustrated in FIG. 5C may be used.

The second tip 25 is formed to include a first support part 1 and a first contact part 2, and the first contact part 2 is inserted into the contact pattern 310.

In this case, the width W1 of the bottom surface 3 of the first contact portion 2 may be the same as the width W1 of the contact pattern 310, and the bottom surface 3 may be formed in a plane. Can be.

That is, the width W1 of the bottom surface 3 of the first contact portion 2 is the same as the width W1 of the contact pattern 310, so that impurities remaining in the contact pattern 310 are formed in the second portion. Can be removed by scribing process.

In this case, the width W1 of the second tip 20 and the width W1 of the bottom surface 3 of the first contact portion 2 may be 60 to 70 μm.

The second scribing process using the second tip 20 may be performed at the same time as the first scribing process using the first tip 10, and after finishing the first scribing process, The second scribing process may be performed.

6, a transparent conductive material is stacked on the buffer layer 400 to form the front electrode 500 and the connection wiring 700.

When the transparent conductive material is stacked on the buffer layer 400, the transparent conductive material may also be inserted into the contact pattern 310 to form the connection wiring 700.

The back electrode pattern 200 and the front electrode 500 are electrically connected to each other by the connection wiring 700.

The front electrode 500 is formed of zinc oxide doped with aluminum by performing a sputtering process on the substrate 100.

The front electrode 500 is a window layer forming a pn junction with the light absorbing layer 300. Since the front electrode 500 functions as a transparent electrode on the front of the solar cell, zinc oxide (ZnO) having high light transmittance and good electrical conductivity is provided. Is formed.

At this time, the aluminum oxide may be doped with aluminum to form an electrode having a low resistance value.

The zinc oxide thin film which is the front electrode 500 may be formed by a method of depositing using a ZnO target by RF sputtering, reactive sputtering using a Zn target, and organometallic chemical vapor deposition.

In addition, a double structure in which an indium tin oxide (ITO) thin film having excellent electro-optical properties is laminated on a zinc oxide thin film may be formed.

Subsequently, as shown in FIG. 7, a separation pattern 320 penetrating the light absorbing layer 300, the buffer layer 400, and the front electrode 500 is formed.

The separation pattern 320 may be formed by a mechanical method, and a portion of the back electrode pattern 200 is exposed.

The separation pattern 320 may be formed using the tip illustrated in FIG. 8.

First, the separation pattern 320 is formed by performing a third scribing process using the third tip 30.

In addition, a fourth scribing process is performed inside the separation pattern 320 using the fourth tip 40 to remove impurities generated during the third scribing process.

That is, foreign matters generated during the third scribing process and remaining in the separation pattern 320 may be removed.

In this case, the width W2 of the fourth tip 40 may be the same as the width W2 of the separation pattern 320, and the bottom surface may be formed in a plane.

In addition, the shape of the fourth tip 40 is not limited thereto, and a fourth tip 45 having a shape illustrated in FIG. 8C may be used.

The fourth tip 45 includes a second support part 4 and a second contact part 5, and the second contact part 5 is inserted into the separation pattern 320.

In this case, the width W2 of the bottom surface 6 of the second contact portion 5 may be the same as the width W2 of the separation pattern 320, and the bottom surface 6 may be formed in a plane. Can be.

That is, since the width W2 of the bottom surface 6 of the second contact portion 5 is the same as the width W2 of the separation pattern 320, impurities remaining in the separation pattern 320 may be formed in the fourth portion. Can be removed by scribing process.

The fourth scribing process using the fourth tip 40 may be performed simultaneously with the third scribing process using the third tip 30. After finishing the third scribing process, The fourth scribing process may be performed.

The buffer layer 400 and the front electrode 500 may be separated by the separation pattern 320, and the cells C1 and C2 may be separated from each other by the separation pattern 320.

The front electrode 500 buffer layer 400 and the light absorbing layer 300 may be arranged in a stripe shape or a matrix shape by the separation pattern 320.

The separation pattern 320 is not limited to the above form and may be formed in various forms.

Cells C1 and C2 including the back electrode pattern 200, the light absorbing layer 300, the buffer layer 400, and the front electrode 500 are formed by the separation pattern 320.

In this case, each of the cells C1 and C2 may be connected to each other by the connection wiring 700. That is, the connection wiring 700 electrically connects the back electrode pattern 200 of the second cell C2 and the front electrode 500 of the first cell C1 adjacent to the second cell C2. do.

In the method of manufacturing a solar cell according to the above-described embodiment, two scribing processes are performed using a tip having a different shape when forming a contact pattern and a separation pattern. Impurities can be removed, and defects in the solar cell can be prevented.

Although described above with reference to the embodiment is only an example and is not intended to limit the invention, those of ordinary skill in the art to which the present invention does not exemplify the above within the scope not departing from the essential characteristics of this embodiment It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 to 8 are cross-sectional views illustrating a method of manufacturing a solar cell according to an embodiment.

Claims (8)

Forming a plurality of back electrode patterns spaced apart from each other on the substrate; Forming a light absorbing layer on the substrate on which the back electrode pattern is disposed; Performing a first scribing process using a first tip to form a contact pattern penetrating the light absorbing layer; Performing a second scribing process using a second tip to remove impurities generated during the first scribing process; Forming a front electrode on the light absorbing layer; And Forming a separation pattern on the front electrode and the light absorbing layer for dividing into unit cells; And the front electrode is inserted into the contact pattern and electrically connected to the back electrode pattern. The method of claim 1, The separation pattern, It is formed to penetrate the front electrode and the light absorbing layer using a third scribing process using a third tip, The method of manufacturing a solar cell comprising exposing the back electrode pattern by the third scribing process. 3. The method of claim 2, And after the third scribing process, performing a fourth scribing process using a fourth tip to remove impurities generated during the third scribing process. The method of claim 1, The width of the second tip is the same as the width of the contact pattern, The width of the fourth tip of the solar cell manufacturing method comprising the same as the width of the separation pattern. The method of claim 1, The second tip includes a first support portion and a first contact portion, And a bottom surface of the first contact portion of the second tip having the same width as the contact pattern. The method of claim 1, The fourth tip includes a second support portion and a second contact portion, And a bottom surface of the second contact portion of the fourth tip having the same width as that of the separation pattern. It is formed by combining the support and the contact, The width of the support portion and the contact portion is the same, It includes that the width of the contact portion is formed larger than the support portion, And a bottom surface of the contact portion is planar. The method of claim 7, wherein Tip of the bottom surface of the contact portion comprises a 60 ~ 70 μm.

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