KR101543034B1

KR101543034B1 - Tip and method of fabricating the solar cell using the tip

Info

Publication number: KR101543034B1
Application number: KR1020090059505A
Authority: KR
Inventors: 김경암
Original assignee: 엘지이노텍 주식회사
Priority date: 2009-06-30
Filing date: 2009-06-30
Publication date: 2015-08-10
Also published as: KR20110001800A

Abstract

A method of manufacturing a solar cell according to an embodiment includes forming a plurality of rear electrode patterns spaced apart from each other on a substrate; Forming a light absorbing layer on the substrate on which the rear 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 in the first scribing process; Forming a front electrode on the light absorbing layer; And forming a separation pattern for dividing the front electrode and the light absorption layer into unit cells, wherein the front electrode is inserted in the contact pattern and electrically connected to the rear electrode pattern.

The tip according to the embodiment includes a support portion and a contact portion formed to be coupled to each other, wherein the support portion and the contact portion have the same width or the width of the contact portion is larger than the support portion, and the bottom surface of the contact portion includes a plane.

Solar cell

Description

TECHNICAL FIELD [0001] The present invention relates to a method for manufacturing a solar cell,

Embodiments relate to a tip and a method of manufacturing a solar cell using the same.

As demand for energy has increased recently, development of solar cells that convert solar energy into electrical energy is underway.

Particularly, a CIGS-based solar cell which is a pn heterojunction device having a substrate structure including a glass substrate, a metal back electrode layer, a p-type CIGS light absorbing layer, a high resistance buffer layer, and an n-type window layer is widely used.

During the formation of the CIGS-based solar cell, a contact pattern for connecting the electrodes and a separation pattern for dividing the unit cells into cells are subjected to a scribing process that is a mechanical method. In the scribing process, Impurities are generated and are left between the contact pattern and the separation pattern.

The foreign matter left behind may interfere with the connection between the front electrode and the rear electrode, so that the connection may become unstable and the device may be defective due to impurities.

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

The tip according to the embodiment and the manufacturing method of the solar cell using the tip according to the embodiment can perform the scribing process two times by using the tip having different shapes when forming the contact pattern and the separation pattern, The remaining impurities can be removed, and the defect of the solar cell can be prevented.

In the description of the embodiments, in the case where each substrate, layer, film or electrode is described as being formed "on" or "under" of each substrate, layer, film, , "On" and "under" all include being formed "directly" or "indirectly" through "another element". 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, a rear electrode 201 is formed on a substrate 100.

As the substrate 100, glass is used, and a ceramic substrate such as alumina, stainless steel, a titanium substrate, or a polymer substrate may be used.

As the glass substrate, sodalime glass can be used, and as the polymer substrate, polyimide can be used.

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

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

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

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

Further, although not shown in the drawings, the rear electrode 201 may be formed of at least one layer.

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

Next, as shown in FIG. 2, the rear electrode 201 is patterned to form a rear electrode pattern 200.

The rear electrode pattern 200 may be formed to expose the substrate 100 between the protection patterns 10.

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

However, the rear electrode pattern 200 is not limited to the above-described embodiment, and may be formed in various shapes.

3, a light absorption layer 300 and a buffer layer 400 are formed on the rear electrode pattern 200. [

The light absorption layer 300 includes a compound of the formula Ib-IIIb-VIb.

More specifically, the light absorption layer 300 includes a copper-indium-gallium-selenide (Cu (In, Ga) Se ₂ , CIGS) compound.

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

For example, in order to form the light absorption layer 300, a CIG-based metal precursor film is formed on the rear 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.

An alkali component contained in the substrate 100 may be injected into the metal precursor film and the light absorbing layer (not shown) through the rear electrode pattern 200 during the process of forming the metal precursor film and the C- 300).

The alkali component improves the grain size of the light absorbing layer 300 and improves crystallinity.

The light absorption layer 300 may be formed by co-evaporation of copper, indium, gallium, selenide (Cu, In, Ga, Se).

The light absorption layer 300 receives external light and converts it into electric energy. The photoabsorption layer 300 generates a photoelectromotive force by a photoelectric effect.

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

At this time, the buffer layer 400 is an n-type semiconductor layer and the light absorption layer 300 is a p-type semiconductor layer. Accordingly, the light absorption layer 300 and the buffer layer 400 form a pn junction.

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

That is, since the light absorption layer 300 and the front electrode have a large difference between the lattice constant and the energy band gap, the buffer layer 400 having the bandgap between the two materials can be inserted to form a good junction.

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

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

The contact pattern 310 may be formed by a mechnical method, and a part of the rear electrode pattern 200 is exposed.

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

First, a first scribing process is performed using the first tip 10 to form the contact pattern 310.

The second scribing process is performed inside the contact pattern 310 using the second tip 20 to remove impurities generated in the first scribing process.

That is, the foreign materials remaining in the contact pattern 310 generated during the first scribing process can be removed.

At this time, the width W1 of the second tip 20 may be equal to the width W1 of the contact pattern 310, and the bottom may be flat.

In addition, the shape of the second tip 20 is not limited thereto, and the second tip 25 having the shape shown in Fig. 5C can be used.

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

The width W1 of the bottom surface 3 of the first contact portion 2 may be equal to the width W1 of the contact pattern 310 and the bottom surface 3 may be formed as a flat surface .

That is, the width W1 of the bottom surface 3 of the first contact portion 2 is equal to the width W1 of the contact pattern 310, and the impurity remaining in the contact pattern 310 is the second It can be removed by scribing process.

At this time, 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 first scribing step using the first tip 10 and the second scribing step using the second tip 20 may be performed at the same time. After the first scribing step is completed, The second scribing process may be performed.

As shown in FIG. 6, a front electrode 500 and a connection wiring 700 are formed by laminating a transparent conductive material on the buffer layer 400.

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

The rear electrode pattern 200 and the front electrode 500 are electrically connected by the connection wiring 700.

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

The front electrode 500 is a window layer that forms a pn junction with the light absorbing layer 300. The front electrode 500 functions as a transparent electrode on the entire surface of the solar cell. Therefore, zinc oxide (ZnO), which has high light transmittance and good electrical conductivity, .

At this time, an electrode having a low resistance value can be formed by doping the zinc oxide with aluminum.

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

In addition, a double structure in which an ITO (Indium Tin Oxide) thin film excellent in electro-optical characteristics is laminated on a zinc oxide thin film may be formed.

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

The separation pattern 320 can be formed by a mechnical method, and a part of the rear electrode pattern 200 is exposed.

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

First, a third scribing process is performed using the third tip 30 to form the separation pattern 320.

The fourth scribing process is performed inside the separation pattern 320 using the fourth tip 40 to remove impurities generated in the third scribing process.

That is, the foreign materials generated in the third scribing process and remaining in the separation pattern 320 can be removed.

At this time, the width W2 of the fourth tip 40 may be the same as the width W2 of the separation pattern 320, and the bottom may be flat.

In addition, the shape of the fourth tip 40 is not limited thereto, and the fourth tip 45 having the shape shown in Fig. 8C can be used.

The fourth tip 45 is formed to include a second support portion 4 and a second contact portion 5 and the second contact portion 5 is inserted into the separation pattern 320.

At this time, 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 as a flat surface .

That is, the width W2 of the bottom surface 6 of the second contact portion 5 is equal to the width W2 of the separation pattern 320, and the impurities remaining in the separation pattern 320 are the fourth It 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 the third scribing process is completed, The fourth scribing step may be carried out.

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 buffer layer 400 and the light absorbing layer 300 may be arranged in a stripe form or a matrix form by the separation pattern 320.

The separation pattern 320 is not limited to the above-described shape, but may be formed in various shapes.

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

At this time, the cells C 1 and C 2 may be connected to each other by the connection wiring 700. That is, the connection wiring 700 electrically connects the rear 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 manufacturing method of the solar cell according to the above-described embodiment, the scribing process is performed twice using the tips having different shapes when forming the contact pattern and the separation pattern, so that the contact pattern and the remaining Impurities can be removed, and defects of the solar cell can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

Forming a plurality of rear electrode patterns spaced apart from each other on a substrate;

Forming a light absorbing layer on the substrate on which the rear 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 in the first scribing process;

Forming a front electrode on the light absorbing layer; And

Forming a separation pattern for division into unit cells in the front electrode and the light absorption layer,

Wherein the front electrode is inserted into the contact pattern and electrically connected to the rear electrode pattern.

The method according to claim 1,

Wherein the separation pattern

And a third scribing step using a third tip, the second electrode being formed to penetrate the front electrode and the light absorbing layer,

And exposing the rear electrode pattern by the third scribing process.

3. The method of claim 2,

Further comprising performing a fourth scribing process using the fourth tip after the third scribing process to remove impurities generated in the third scribing process.

The method of claim 3,

The width of the second tip is equal to the width of the contact pattern,

Wherein a width of the fourth tip is equal to a width of the separation pattern.

The method according to claim 1,

Wherein the second tip includes a first support portion and a first contact portion,

Wherein a width of the contact pattern and a bottom surface of the first contact portion of the second tip are the same.

The method of claim 3,

The fourth tip includes a second support portion and a second contact portion,

Wherein a width of the bottom surface of the second contact portion of the fourth tip is the same as a width of the separation pattern.

delete

The method according to claim 1,

The second tip

A support portion and a contact portion are coupled and formed,

The width of the support portion and the width of the contact portion may be the same,

Wherein the width of the contact portion is larger than that of the support portion, and the bottom surface of the contact portion is planar.

10. The method of claim 9,

The second tip

And the width of the bottom surface of the contact portion is 60 to 70 占 퐉.