TWI450411B - Method and apparatus for forming selective emitter of solar cell - Google Patents

Description

Method and apparatus for forming a selective emitter for a solar cell

The present invention relates to a method and apparatus for forming a selective emitter for a solar cell.

As environmental pollution problems have become more serious, there have been some recent studies on renewable energy sources that can reduce environmental pollution. In particular, a great deal of attention has been paid to solar cells capable of generating electric energy by using solar energy. However, in order to utilize solar cells in the actual industry, the photoelectric conversion efficiency of the solar cells must be sufficiently high, and the manufacturing cost of the solar cells must be low.
From the perspective of photoelectric conversion efficiency, since the theoretical efficiency limit of solar cells is not very high, there is a limitation in increasing the photoelectric conversion efficiency of actual solar cells, but world-renowned research groups have reported that germanium solar cells currently have 24% or higher. Photoelectric conversion efficiency.
However, in the case of mass production of solar cells, the actual average photoelectric conversion efficiency of solar cells is difficult to be higher than 17%. Therefore, there is a need for an efficient manufacturing method that can be applied to an automated high-volume production line having an annual production capacity of 30 MW or more.

The present invention provides a method and apparatus for forming a selective emitter for a solar cell, which method and apparatus can increase the photoelectric conversion efficiency of a solar cell by forming a selective emitter and can form the selective emitter by a stable manner .

The present invention provides a method and apparatus for forming a selective emitter for a solar cell, which method and apparatus can increase the photoelectric conversion efficiency of a solar cell by forming a selective emitter and can form the selective emission by a stable manner Device.

An aspect of the invention is characterized by an apparatus for forming a selective emitter of a solar cell, the apparatus comprising: a transfer device for transporting a substrate, a first emitter layer formed on an upper surface of the substrate, the first emission An n-type impurity is diffused in the layer; a stage is provided from the transfer device to the stage and the stage supports the supplied substrate; and a preheating device is used to perform the substrate supported by the stage Preheating; a laser radiation device positioned above the stage and spaced apart from the stage and configured to radiate a laser over a portion of the first emitter layer to form a second of which is further diffused and formed with n-type impurities Transmitter layer.

The preheating device can preheat the substrate through the stage.

The second emitter layer may include: a busbar layer formed at a position where the busbar electrode is to be formed; and a finger layer formed at a position where the finger electrode is to be formed. The laser radiation device may include: a first laser radiation device movable in a first direction to form a busbar layer; and a second laser movable in a second direction crossing the first direction to form a finger layer Radiation device.

The stage may include: a first stage and a second stage arranged in sequence, the first laser radiation device may be placed on the first stage and form a bus layer, and the second laser radiation device may be placed On top of the second stage and forming a finger layer.

The laser radiation device is movable in a first direction to form a busbar layer and in a second direction that intersects the first direction to form a finger layer.

The transfer device can include a conveyor belt on which the stage can be placed.

The apparatus for forming a selective emitter of a solar cell may further include a substrate sensor placed in front of the stage and sensing the transfer of the substrate, and controlling the operation of the conveyor such that the substrate is placed on the stage Go up and stop.

The apparatus for forming a selective emitter of a solar cell may further include an alignment sensor that senses an alignment state of the substrate placed on the stage and may be aligned according to the substrate The state corrects the position of the laser radiation device.

The alignment sensor can be placed on the bottom surface of the stage, and a transparent area can be placed on the stage so that the alignment sensor can sense the alignment of the substrate.

The alignment sensor may include: a first sensor for sensing a rear surface of the substrate; a second sensor for sensing a side of the substrate; and a third sensor for sensing a rotation state of the substrate.

Each of the first sensor, the second sensor, and the third sensor may include a lighting device and a camera.

In order to prevent the substrate placed on the stage from moving, a negative pressure hole for providing a negative pressure may be formed in the stage.

Another aspect of the invention is characterized by a method for forming a solar cell selective emitter, comprising: placing a substrate onto a stage, the upper surface of the substrate being formed with a first emitter layer, the first An n-type impurity is diffused in the emitter layer; the substrate placed on the stage is preheated; a portion of the first emitter layer is irradiated with a laser to form a portion in which the n-type impurity is further diffused and formed. Two emitter layers.

Preheating can be carried out through the stage.

The second emitter layer may include: a busbar layer formed at a position where the busbar electrode is to be formed; and a finger layer formed at a position where the finger electrode is to be formed. The radiation of the laser may be performed by means of: a first laser radiation device for moving in a first direction to form a busbar layer; and for moving in a second direction intersecting the first direction to form a finger a second layer of laser radiation.

The second emitter layer may include: a busbar layer formed at a position where the busbar electrode is to be formed; and a finger layer formed at a position where the finger electrode is to be formed. The radiation of the laser may be performed by a laser radiation device that is movable in a first direction to form a busbar layer and that is movable in a second direction that intersects the first direction to form a finger layer.

The radiation of the laser may be performed by a laser radiation device disposed above the substrate and separated from the substrate, and the method may further include: sensing an alignment state of the substrate placed on the stage; The alignment state of the substrate corrects the position of the laser radiation device.
The alignment state of the sensing substrate may include: illuminating the substrate; and taking a picture of the end of the substrate.

The alignment state of the sensing substrate may include: sensing the front surface of the substrate; sensing the side surface of the substrate; and sensing the rotation state of the substrate.

A negative pressure hole may be formed in the stage, and the method further includes providing a negative pressure to the substrate to fix the substrate placed on the stage.

A preferred embodiment of the present invention can improve the photoelectric conversion efficiency of a solar cell by forming a selective emitter, and can form a selective emitter in a stable manner.

Certain embodiments may be illustrated and described with reference to the drawings in the drawings. However, it is not intended that the invention be limited to the embodiments, and all modifications, equivalents and substitutions are included in the scope of the invention. In the entire description of the present invention, when it is decided to describe a certain technology without paying attention to the viewpoint of the present invention, the related detailed description will be omitted.

Terms such as "first" and "second" may be used to describe various elements, but the elements are not limited to the above terms. The above terms are only used to distinguish one element from another.

The terms used in the specification are only used to describe certain embodiments, and are not intended to limit the invention. Unless expressly stated otherwise, the singular expression includes the meaning of the plural. In the present specification, the expression "includes" or "includes" is intended to indicate a feature, quantity, step, operation, element, component, or combination thereof, and should not be construed as excluding any one or more other features or quantities. The existence or possibility of steps, operations, components, components, or combinations thereof.

Preferred embodiments of a method and apparatus for forming a selective emitter for a solar cell according to the present invention will be described in detail below with reference to the accompanying drawings. The same or corresponding elements will be given the same reference signs, and any redundant description of the same or corresponding elements will not be repeated.

Referring to Figures 1 through 11, a method for forming a selective emitter for a solar cell in accordance with an aspect of the present invention is described.

First, the substrate 10 is placed on the stage 200 (step S100 shown in FIG. 12), and the upper surface of the substrate 10 is formed with a first emitter layer 14 in which the first emitter layer 14 is diffused and formed. N-type impurity 12. The stage 200 supports the substrate 10, and the formation of the selective emitter on the substrate 10 is performed when the stage 200 supports the substrate 10. By performing the formation of the selective emitter while the substrate 10 is fixed on the stage 200, the selective emitter can be formed in a stable manner without vibrating the substrate 10.

The substrate 10 may be a p-type germanium substrate doped with boron ions, and the surface of the substrate 10 has been formed with the first emitter layer 14. That is, according to the present embodiment, the selective emitter (i.e., the second emitter layer 16) is formed by a different process from the process of forming the first emitter layer 14.

Here, the first emitter layer 14 corresponds to an n layer which is diffused and formed with impurities 12 such as phosphorus. In order to prepare such a substrate 10, a solution containing an impurity 12 such as phosphorus may be applied onto the surface of the ruthenium substrate 10 (as shown in FIGS. 2 and 3), and then energy E1 may be applied to the surface of the ruthenium substrate 10. (as shown in Figure 4). When energy E1 is applied to the surface of the germanium substrate 10, ions of the impurity 12 may diffuse into the germanium substrate 10 to form a first emitter layer 14 (as shown in Fig. 5).

Then, as shown in Fig. 6, the substrate 10 placed on the stage 200 (as shown in Fig. 12) is preheated (as shown in step S200), and then radiated to a portion of the first emitter layer 14. The laser light L forms a second emitter layer 16 in which the n-type impurity 12 is further diffused and formed (as shown in step S300). In other words, after energy is applied to the entire substrate 10, the portion L of the first emitter layer 14 to which the n-type impurity 12 has been diffused is irradiated with the laser light L.

Here, in order to form the second emitter layer 16 in a specific portion of the first emitter layer 14, the sum of the energy E3 applied to the substrate 10 by preheating and the energy E2 applied by the laser L must be greater than The energy E1 (E2+E3>E1) forming the first emitter layer 14 is formed. If only the laser L is used to apply energy greater than the energy E1 used to form the first emitter layer 14, it is necessary to concentrate the excessively intense laser light L onto a specific portion of the substrate 10, which may be on the substrate 10. Damage is caused at specific parts, such as surface ablation.

In order to solve this problem, in the present embodiment, by performing a preheating process separately from the radiation of the laser light L, a certain amount of energy E3 is applied to the entire substrate 10 by preheating, and the energy E3 supplied by the preheating will be used. The required energy E2 is provided by laser radiation. As a result, it is possible to prevent the energy difference between the region irradiated by the laser light L and the remaining region from being excessively large, thereby preventing the substrate 10 from being damaged. Here, the preheating process and the laser irradiation process can be carried out continuously or simultaneously.

When energy E2+E3 larger than the energy E1 for forming the first emitter layer 14 is applied to a portion of the first emitter layer 14 by preheating and laser irradiation as described above, the n-type impurity 12 is further diffused to the In that portion of the laser L radiation, the result is that a second emitter layer 16 is formed in that portion of the first emitter layer 14 (as shown in Figure 7). This principle will be described in more detail below.

When the atomic concentration in the solid is not uniform, the atoms in the solid diffuse from the high concentration region to the low concentration region by thermal motion until the atomic concentration in the entire solid becomes uniform. This diffusion phenomenon based on Fick's first law, which is proportional to the concentration gradient, can be expressed by the following formula.

【Formula 1】


In [Formula 1], J is the amount of diffusion (i.e., the amount of diffusion material per unit area), D is the diffusion coefficient, C is the concentration of the diffusion material, and x is the moving distance of the diffusion material on the Y-axis.

Here, the diffusion coefficient increases remarkably with an increase in temperature, which can be expressed by the following formula.

[Formula 2]

In [Formula 2], D0 is a constant that is insensitive to temperature, k is a Boltzmann constant, and T is a temperature. Q is called the starting energy, which has a value between 2 and 5 eV depending on the material. The variation of the diffusion coefficient with temperature according to [Formula 2] is illustrated in the graphs shown in Figs. 8 and 9. For example, when Q=2eV and D0=8×10-5 m2/sec, D is about 10-38 m2/sec at 300°K, but D increases significantly to 10-11 m2 when T=1500°K. /sec.

Therefore, as shown in Fig. 8, if it is assumed that the energy E1 and the energy E2+E3 are respectively supplied to the two different points of the tantalum substrate 10 having different temperatures from each other, since the diffusion coefficients of the two points are respectively different from each other, D1 and D2, so the level reached by the impurity 12 also becomes different (i.e., the diffusion coefficient increases with increasing temperature), so that the second emitter layer 16 is formed in a specific portion of the first emitter layer 14, and the two emitters are formed The layers are distinguished from each other, as shown in Figure 7.

As shown in Fig. 9, the graph shown in Fig. 8 can be redrawn in a graph showing the reciprocal relationship between the logarithmic function and the temperature. The following formula is a logarithmic function corresponding to the graph shown in Fig. 9 expressed by [Formula 2].

[Formula 3]

As shown in FIG. 10, the second emitter layer 16 selectively formed on the first emitter layer 14 may include a bus bar layer 16a and a finger layer 16b formed on the bus bar electrode 13a where the solar cell is to be formed. The position of the finger (as shown in Fig. 11); and the finger layer 16b is formed at a position where the finger electrode 13b is to be formed (as shown in Fig. 11). In order to form all of the bus bar layer 16a and the finger layer 16b, the above-described laser irradiation process may be divided into a first process for forming the bus bar layer 16a and a second process for forming the finger layer 16b.

Here, it should be understood that the first process and the second process may be performed by one laser radiation device or two laser radiation devices. The structure of a specific device for performing these processes will be described later. Fig. 11 shows that the finger electrodes 13b are formed on the finger layer 16b and the bus bar electrodes 13a are formed on the bus bar electrodes 16a. An anti-reflection film 11 is formed in a region where the finger electrode 13b and the bus bar electrode 13a are formed.

Heretofore, a method for forming a selective emitter of a solar cell according to an aspect of the present invention has been described, and an apparatus for forming a selective emitter of a solar cell according to another aspect of the present invention will be described hereinafter. The above described method for forming a selective emitter of a solar cell can be carried out by the same or similar device as that used to form the solar cell selective emitter described below. Accordingly, it should be understood that the description of the operation of each of the devices to be described below can also be applied to the above-described method for forming a selective emitter of a solar cell.

As shown in Fig. 12, an apparatus for forming a selective emitter of a solar cell according to another aspect of the present invention is mainly constituted by the following members: transfer means 100a, 100b, 100c for transporting the substrate 10 (together "100 together" ”) (as shown in FIG. 16), a first emitter layer 14 (shown in FIG. 7) is formed on the substrate 10; a stage 200 for supporting the provided substrate 10; Preheating device 300 for preheating; and laser radiation device 400 for forming a second emitter layer in which an n-type impurity is further diffused and formed by irradiating a laser over a portion of the first emitter layer 14. 17 (as shown in Figure 7).

The transfer device 100 performs a function of supplying the stage 200 with the substrate 10 on which the first emitter layer 14 has been formed. Although a robot (not shown) can be used for such a transport device 100, the present embodiment proposes a conveyor belt that facilitates continuous manufacture. By performing the flow method of transporting the substrate 10 using the transport belt as in the present embodiment, continuous processing can be performed, and productivity can be improved.

The stage 200 supports the substrate 10 provided by the transfer device 100, and when the substrate 10 is supported by the stage 200, the second emitter layer 17 is selectively formed on the substrate 10. By selectively forming the second emitter layer 16 when the substrate 10 is fixed on the stage 200, the selective emitter can be formed in a stable manner without the substrate 10 vibrating.

As shown in Fig. 16, the above-described conveying device 100 and stage 200 may be constructed in the form of a single element, and this single element form is referred to herein as a conveying element 1000. The specific structure of the transporting element 1000 will be described later.

The substrate 10 provided by the transfer device 100 onto the stage 200 may be a p-type germanium substrate doped with boron ions and having the first emitter layer 14 formed on its surface. The process of preparing the substrate 10 on which the first emitter layer 14 is previously formed is the same as the foregoing description, and thus a detailed description will not be provided herein.

The preheating device 300 performs a function of preheating the substrate 100 supported by the stage 200. A certain amount of energy E3 is applied to the entire substrate 10 by the preheating device 300 (as shown in FIG. 6) and the energy E2 required by the energy E3 provided by the preheating is provided by the laser radiation device 400 (as shown in FIG. 6). As shown, it is possible to prevent the energy difference between the area irradiated by the laser L and the area not irradiated by the laser L from being excessive. Thus, as described above, it is possible to prevent the relevant region of the substrate 10 from being damaged due to the excessively intense radiation laser concentrated on the relevant region of the substrate 10.

The preheating device 300 can preheat the substrate 10 through the overload stage 200. That is, the preheating device 300 can heat the stage 200 to preheat the substrate 10 by the heated stage 200. In this case, as shown in Fig. 12, a heating coil embedded in the stage 200 can be employed as the preheating means 300.

Although the substrate 10 is preheated via the stage 200 in the present embodiment, the present invention is not limited to the manner described in the embodiment, and it is possible to employ a non-contact capable of directly heating the substrate 10 independently of the stage 200. Type preheating device.

The laser radiation device 400 is spaced apart from the stage and located above the stage 200, and radiates the laser light L to a predetermined portion of the substrate 10 supported by the stage 200. At the portion that is irradiated by the laser, the impurities are further diffused to allow formation of the second emitter layer 16.

As previously described with reference to FIG. 10, the second emitter layer 16 selectively formed on the first emitter layer 14 may include a bus bar layer 16a and a finger layer 16b formed on a solar cell to be formed. The position of the bus bar electrode 13a (as shown in Fig. 11); and the finger layer 16b is formed at a position where the finger electrode 13b is to be formed (as shown in Fig. 11). In order to form all of the bus bar layer 16a and the finger layer 16b, the laser irradiation process may be divided into a first process for forming the bus bar layer 16a and a second process for forming the finger layer 16b.

Here, it should be understood that the first process and the second process may be performed by one laser radiation device 400 or two laser radiation devices 400a, 400b (as shown in Figs. 13 and 15). Figure 13 is a view showing the first laser radiation device 400a movable in one direction (e.g., the x-axis direction) for performing the first process and the other direction (e.g., the y-axis direction) for performing the second process. Moving second laser radiation device 400b.

Fig. 14 shows a laser irradiation device 400 which is movable in both the x-axis direction and the y-axis direction so that the first process and the second process can be performed.

As shown in Fig. 15, there may be two sequentially arranged transport elements 1000a, 1000b and two laser irradiation devices 400a, 400b to perform the first process and the second process. That is, the first process can be performed on the stage 200a of the front transport unit 1000a with the first laser radiation device 400a movable in the x-axis direction, and the second process can be performed on the stage 200b of the rear transport element 1000b. The upper laser radiation device 400b is movable in the y-axis direction.

Although FIG. 15 shows that the two transport assemblies 1000a, 1000b are separated by a predetermined distance, the two transport elements 1000a, 1000b should also be continuously arranged so that they can be continuously connected by a conveyor belt disposed between the two stages. Transfer the substrate.

The structure of the conveying member 100 will be described in more detail below with reference to Figs. 16 to 19. Since the two transport elements 1000a, 1000b shown in Fig. 15 are identical, these two elements will not be separately described herein.

The transport element 1000 is configured to receive the substrate 10, support the substrate at the time of laser radiation, and transfer the substrate 10 that has completed the laser radiation to the following process. Fig. 16 shows a transport assembly 100 comprising: a generally pallet-shaped carrier gantry 500; a front conveyor 100a placed on the carrier gantry 500; a stage element TA; and a rear conveyor 100b.

The front transfer device 100a performs a function of supplying the substrate 10 to the stage element TA, and the post transfer device 100b performs a function of transferring the substrate 10 that has completed the laser irradiation to the lower process. The stage element TA is supplied with the substrate 10 from the front transfer device 100a, and performs a function of supporting the substrate 10 when irradiating a laser to the substrate 10. Here, the center conveyor 100c is provided on the stage element TA.

In the present embodiment, a conveyor belt is used for the front conveyor 100a, the rear conveyor 100b, and the center conveyor 100c. By implementing the type of flow using the conveyor belt, for continuous processing purposes, and increasing throughput. The center transfer device 100c places the substrate 100 on the stage 200, and can couple the center transfer device 100c to a belt frame 260 (shown in Fig. 17) having a roller 240 (shown in Fig. 17) or the like. The center conveyor 100c is operated.

As described above, if a conveyor belt is employed as the conveying device 100 for placing the substrate 10 on the stage 200, the stage 200 can be disposed at a predetermined position below the center conveying device 100c (i.e., the conveyor belt). However, the present invention is not limited thereto, and the position of the stage 200 may be changed according to the configuration of the conveying device 100.

As shown in FIG. 16, the substrate sensor 110 that transmits the sensing substrate 10 can be placed in front of the stage 200. The substrate sensor 110 can perform a function of stopping the substrate 10 at a precise position by sensing the substrate 10 being transferred to the stage 200. In order to perform this function, the substrate sensor 110 can detect the transfer of the substrate 10 and then stop the operation of the transfer belt 100 after a predetermined time (for example, 1.5 seconds) elapses.

The upper surface of the stage 200 may be formed with an insertion groove 230 (as shown in Fig. 17) so that the conveyor belt 100c can be inserted into the groove 230. By the insertion groove 230 formed in the stage 200, it is possible to prevent the substrate 10 and the stage 200 from being unnecessarily separated by the conveyor belt 100c, so that the stage 200 can support the substrate 10 in a more stable manner.

The apparatus for forming a solar cell selective emitter according to the present embodiment may include alignment sensors 222a, 222b, 222c (as shown in FIG. 18) that are placed on the stage 200 inductively. The alignment state of the substrate 10 above. In order to ensure matching between the laser irradiation device 400 and the substrate 10, the alignment sensor 222 detects an alignment state of the substrate 10 placed over the stage 200. The detected alignment state of the substrate 10 is transmitted to the above-described laser irradiation devices 400, 400a, 400b, and the position of the laser irradiation devices 400, 400a, 400b can be corrected based on the alignment state of the substrate 10.

For the alignment sensor 222, the present embodiment proposes a camera and illumination device placed under the stage 200. To this end, the stage 200 can have transparent regions 220a, 220b, 220c (collectively "220", as shown in FIG. 17) such that the camera can sense the alignment of the substrate 10. Here, it should be understood that the transparent region 200 does not necessarily mean completely transparent, but may be sufficiently transparent to optically sense the alignment state of the substrate 10. The transparent region 220 of this embodiment is provided in quartz.

The alignment sensor 222 may include: a first sensor 222a for sensing the rear of the substrate 10; a second sensor 222b for sensing the side of the substrate 10; and a third for sensing the rotation state of the substrate 10. Sensor 222c. Therefore, the alignment errors in the X-axis and Y-axis directions can be determined by sensing the back and side edges with the first sensor 222a and the second sensor 222b, and the rotation alignment error can be made with the third sensor 222c. to make sure.

Once the alignment of the substrate 10 is sensed, the stage 200 and the substrate 10 placed over the stage 200 can be lifted by the overload stage elevator 250 (as shown in FIG. 17). The stage elevator 250 performs a function of raising and lowering the stage 200 by a predetermined height. While the substrate 10 is lifted by the stage elevator 250, laser radiation can be performed on the substrate 10.

The stage elevator 250 may include a plurality of support legs 251 disposed apart from each other along the outer edge of the stage 200 and vertically extendable; a cylinder 252 for vertically moving the belt carrier 260. Each support leg 251 can be secured to the support frame 253 for better assembly. Other power transfer structures that may be used for the stage lift 250 may include linear actuators (not shown) and gear trains (not shown).

A negative pressure hole 210 may also be formed in the stage 200 to prevent the substrate 10 placed on the stage 200 from moving. By forming the negative pressure hole 210 in the stage 200 and providing a negative pressure to the bottom surface of the substrate 10, for example, by a pump (not shown), the substrate 10 becomes closely attached to the stage 200, preventing alignment of the substrate 10. The state is in chaos.

Heretofore, the device structure for forming a selective emitter of a solar cell according to another aspect of the present invention has been described, and the operation of the device according to an embodiment of the present invention will be described below.

Once the substrate 10 is provided onto the stage 200, the preheating device 300 provides thermal energy to the substrate 10. The supply of thermal energy can continue until the completion of the laser radiation.

The alignment sensor 222 senses the alignment state of the substrate 10 placed on the stage 200, and then lifts the stage 200 on which the substrate 10 is placed.

The detected alignment state of the substrate 10 is transmitted to the laser radiation device 400 separated from the stage 200 and placed on the stage 200, and the position of the laser irradiation device 400 is corrected in accordance with the alignment state of the substrate 10.

The position-corrected laser radiation device 400 radiates a laser to a predetermined location on the substrate 10 to selectively form a second emitter layer 16 (as shown in Figure 17).

Once the laser radiation is completed, the stage is lowered to its original position, and then the substrate 10 is transferred for the following process.

While the invention has been described with respect to the preferred embodiments of the present invention, it is understood that various modifications and changes may be made by those skilled in the art without departing from the scope of the invention.

It should also be understood that there are many other embodiments in the claims of the invention in addition to the embodiments described above.

S100, S200, S300. . . step

10. . . Substrate

11. . . Anti-reflection film

110. . . Substrate sensor

12. . . Impurity

13a. . . Bus bar electrode

13b. . . Finger electrode

14. . . First emitter layer

16. . . Second emitter layer

16a. . . Bus layer

16b. . . Finger layer

1000, 1000a, 1000b. . . Transfer component

100a, 100b, 100c. . . Conveyor

200, 200a, 200b. . . Stage

210. . . Negative pressure hole

220, 220a, 220b, 220c. . . Transparent area

222, 222a, 222b, 222c. . . Alignment sensor

230. . . Insert slot

240. . . Roller

250. . . Stage lift

251. . . Support leg

252. . . cylinder

253. . . Support frame

260. . . Conveyor frame

300. . . Preheating device

400, 400a, 400b. . . Laser radiation device

500. . . Carrier stand

E1, E2, E3. . . energy

L. . . Laser

TA. . . Stage component

1 is a flow chart of a method for forming a selective emitter of a solar cell on the one hand of the present invention.

Figures 2 and 3 show the application of impurities on the surface of the substrate.

Figure 4 is the application of energy to the substrate to form a first emitter layer.

Figure 5 is a cross-sectional view of a substrate on which a first emitter layer is formed.

Figure 6 is a radiation laser to form a second emitter layer.

Figure 7 is a cross-sectional view of a substrate on which a second emitter layer is formed.

Fig. 8 and Fig. 9 are graphs showing the diffusion coefficient as a function of temperature.

Figure 10 is a plan view of how the busbar layer and the finger layer are formed.

Figure 11 is a plan view of how the bus bar electrodes and the finger electrodes are formed.

Figure 12 is a side elevational view of an apparatus for forming a selective emitter for a solar cell in accordance with another aspect of the invention.

Figures 13 through 15 are perspective views of various embodiments of an apparatus for forming a selective emitter for a solar cell in accordance with another aspect of the present invention.

Figure 16 is a plan view of the transfer assembly.

Figure 17 is a perspective view of the stage assembly.

Figure 18 is a plan view showing the stage removed as shown in Figure 17.

Figure 19 is a side view of the stage assembly.

400a, 400b. . . Laser radiation device

1000. . . Transfer component

Claims (17)

An apparatus for forming a selective emitter of a solar cell, comprising: a transfer device for transporting a substrate, a first emitter layer is formed on an upper surface of the substrate, and the first emitter layer is diffused and formed An n-type impurity; a stage provided by the transfer device to the stage and supporting the substrate provided by the stage; a preheating device for performing the substrate supported by the stage Preheating; a laser radiation device located above the stage and spaced apart from the stage, and configured to radiate a portion of the first emitter layer to form a second emitter layer, Further diffusing and forming an n-type impurity in the second emitter layer; and an alignment sensor sensing an alignment state of the substrate disposed on the stage, wherein the position of the laser radiation device is based Correcting an alignment state of the substrate, wherein the alignment sensor is disposed under one of the stages, and wherein a transparent area is disposed in the stage such that the alignment sensor senses the pair of the substrate Quasi-state. The apparatus of claim 1, wherein the preheating device preheats the substrate through the stage. The apparatus of claim 1, wherein the second emitter layer comprises: a busbar layer formed at a position where the busbar electrode is to be formed; and a finger layer formed at a position where the finger electrode is to be formed, wherein The laser radiation device includes: a first laser radiation device movable in a first direction to form the bus layer; The second laser radiation device is movable in a second direction crossing the first direction to form the finger layer. The apparatus of claim 3, wherein the stage comprises a first stage and a second stage sequentially arranged, wherein the first laser radiation device is placed in the first load An upper surface of the stage and used to form the bus layer, and wherein the second laser radiation device is placed on top of the second stage and used to form the finger layer. The apparatus of claim 1, wherein the second emitter layer comprises: a busbar layer formed at a position where the busbar electrode is to be formed; and a finger layer formed at a position where the finger electrode is to be formed, wherein The laser radiation device is movable in a first direction to form the busbar layer and is movable in a second direction that intersects the first direction to form the finger layer. The apparatus of claim 1, wherein the conveying device comprises a conveyor belt, and wherein the stage is placed under one of the conveyor belts. The device of claim 6, further comprising a substrate sensor disposed in front of the stage and sensing the transfer of the substrate and controlling the operation of the conveyor such that the substrate is placed and stopped at Above the stage. The device of claim 1, wherein the alignment sensor comprises: a first sensor for sensing a rear surface of the substrate; and a second sensor for sensing a side of the substrate And a third sensor for sensing the rotation state of the substrate. The device of claim 8, wherein the first sensor, the second sensor, and the third sensor comprise a lighting device and a camera. The apparatus of claim 1, wherein the stage is formed to be useful A negative pressure port of negative pressure is provided to prevent movement of the substrate disposed above the stage. A method for forming a selective emitter for a solar cell, comprising the steps of: placing a substrate on a stage on which a first emitter layer is formed, the first emitter layer diffusing Forming an n-type impurity; preheating the substrate placed on the stage; and radiating a portion of the first emitter layer to further form a second emitter that diffuses and forms one of the n-type impurities a layer; wherein the laser radiation is performed by a laser radiation device disposed above the substrate and separated from the substrate, and the method further comprises the step of: sensing an arrangement of the carrier using an alignment sensor An alignment state of the substrate above the stage; and correcting a position of the laser radiation device according to an alignment state of the substrate, wherein the alignment sensor is disposed under one of the stages, and wherein A transparent area is provided in the stage such that the alignment sensor senses the alignment state of the substrate. The method of claim 11, wherein the preheating is performed through the stage. The method of claim 11, wherein the second emitter layer comprises: a busbar layer formed at a position where the busbar electrode is to be formed; a finger layer formed at a position where the finger electrode is to be formed, and The radiation of the laser may be performed by: a first laser radiation device for moving in a first direction to form a busbar layer; and a second laser radiation device for crossing the first direction Move in the second direction Move to form a finger layer. The method of claim 11, wherein the second emitter layer comprises: a busbar layer formed at a position where the busbar electrode is to be formed; a finger layer formed at a position where the finger electrode is to be formed, and Wherein the radiation of the laser is performed by a laser radiation device that is movable in a first direction to form a busbar layer and the laser radiation device is in a second direction crossing the first direction Moved to form a finger layer. The method of claim 11, wherein sensing the alignment state of the substrate comprises the steps of: illuminating the substrate; and photographing the end of the substrate. The method of claim 11, wherein sensing the alignment state of the substrate comprises: sensing a rear surface of the substrate; sensing a side surface of the substrate; and sensing a rotation state of the substrate. The method of claim 11, wherein a negative pressure hole is formed in the stage, and the method further comprises: providing a negative pressure to the substrate to fix the substrate disposed on the stage .