Patent Description:
Currently, PERC solar cells are among the solar cells that have been put to extensive commercial use; during the production of a PERC solar cell, after a wafer of the solar cell undergoes the sintering procedure, a process occurs in a natural state in which light attenuates and then recovers. This process takes a certain period of time. In order to shorten this period, after the sintering procedure, a wafer of a solar cell is optically processed so that the wafer of the solar cell may complete a process of attenuating and then recovering within a relatively short time. In the current production of solar cell wafers, pipelining processing is always adopted, in which, after undergoing the sintering procedure, a wafer is optically processed to effectively increase the production efficiency.

<CIT> relates to a thermal processing system for processing silicon wafers for photovoltaic cells.

The present application provides a wafer optical processing device, for optically processing a sintered wafer, comprising: a wafer support device, said wafer support device comprising a support piece, said support piece being provided with an upper surface and a lower surface that are disposed facing each other, said support piece being hollowed out in a direction from the upper surface to the lower surface, said support piece being configured to be capable of supporting said wafer above said upper surface; an upper light source device, said upper light source device being disposed above said wafer support device and configured to provide a light source that illuminates the upper surface of said support piece; and a lower light source device, said lower light source device being disposed below said wafer support device and configured to provide a light source that illuminates the lower surface of said support piece.

The above-described wafer optical processing device is provided, said wafer optical processing device comprising a conveyor belt, said conveyor belt forming said support piece.

The above-described wafer optical processing device is provided, wherein a separation piece is disposed on said conveyor belt, said separation piece being configured to be capable of separating said wafer and the upper surface of said conveyor belt by a specific gap.

The above-described wafer optical processing device is provided, wherein said upper light source device and said lower light source device respectively comprise a plurality of light source modules, and one or more of said plurality of light source modules may be started when a wafer is optically processed.

The above-described wafer optical processing device is provided, wherein said light source module provides an LED light source.

The above-described wafer optical processing device is provided, wherein the maximum light energy that said upper light source device is capable of providing per unit of time is greater than the maximum light energy that said lower light source device is capable of providing per unit of time.

The above-described wafer optical processing device is provided, said wafer optical processing device further comprising: an upper transparent baffle plate, said upper transparent baffle plate being located between said upper light source device and said wafer support device and separated from said upper light source device, a plurality of holes being disposed in said upper transparent baffle plate; and a lower transparent baffle plate, said lower transparent baffle plate being located between said lower light source device and said wafer support device and separated from said lower light source device.

The above-described wafer optical processing device is provided, said wafer optical processing device further comprising: an upper cooling device, said upper cooling device being disposed above said upper light source device to cool said upper light source device, and a lower cooling device, said lower cooling device being disposed below said lower light source device to cool said lower light source device.

The above-described wafer optical processing device is provided, said wafer optical processing assembly further comprising: a housing, said upper light source device and said lower light source device being both located in said housing, said housing comprising air inlets and air outlets, said air inlets being located above said housing, said air outlets being located below said housing, so that an airflow may flow in through said air inlets and flow out through said air outlets.

The present application provides a sintering furnace, said sintering furnace comprising: a wafer sintering processing device; and the above-described wafer optical processing device, said wafer optical processing device being disposed downstream of said wafer sintering processing device.

A wafer optical processing device in the present application can, while guaranteeing an optical processing effect, process the front face and rear face of a wafer at the same time, thus increasing the processing efficiency greatly.

Specific embodiments of the present invention will be described below with reference to drawings that constitute part of the Description. It should be understood that although terms for indicating directions, such as "front", "rear", "upper", "lower", "left", and "right", are used herein to describe each demonstrative structural part and component of the present application, use of these terms herein is only intended for convenience of explanation, and these terms are determined on the basis of the demonstrative orientations shown in the drawings. Embodiments disclosed by the present application may be disposed in different directions, and so these terms indicating directions are only illustrative, instead of being construed as limiting.

<FIG>, a stereoscopic view of a wafer optical processing device, is used to explain the external structure of a wafer optical processing device <NUM>. As shown in <FIG>, the wafer optical processing device <NUM> is provided with a housing <NUM> and a pair of conveyor passages 130a, 130b. The housing <NUM> is provided with a front part <NUM>, a rear part <NUM>, an upper part <NUM>, a lower part <NUM>, a left part <NUM>, and a right part <NUM>, and thus the housing <NUM> roughly forms a box. In the present application, a direction from the front part <NUM> to the rear part <NUM> is called a length direction, a direction from the upper part <NUM> to the lower part <NUM> is called a height direction, and a direction from the left part <NUM> to the right part <NUM> is called a width direction. The front part <NUM> is provided with a wafer inlet 162a, 162b, and the rear part <NUM> is provided with a wafer outlet. The wafer inlet 162a, 162b and the wafer outlet are in communication with an upstream device and a downstream device, respectively. The conveyor passages 130a, 130b are formed between the wafer inlet 162a, 162b and the wafer outlet. In other words, the conveyor passages 130a, 130b penetrate the front part <NUM> and the rear part <NUM> of the housing <NUM>. In the conveyor passages 130a, 130b, the wafer support devices 140a, 140b are disposed, for supporting and conveying a wafer <NUM> to be processed. The upper part <NUM> of the housing <NUM> is provided with air inlets 103a, 103b, and the lower part <NUM> of the housing <NUM> is provided with air outlets 104a, 104b, the air inlets 103a, 103b or the air outlets 104a, 104b being connected to a fan (not shown in the drawing), so that an airflow may flow into the housing <NUM> through the air inlets 103a, 103b and then flows out through the air outlets 104a, 104b. In the housing <NUM>, an airflow may take away part of the heat in the housing <NUM>, ensuring that the temperature in the housing <NUM> is kept within a preset range. The lower part <NUM> of the housing <NUM> comprises a base plate <NUM> and air outlet boxes 172a, 172b, and the four sides of the base plate <NUM> are respectively connected to the front part <NUM>, the rear part <NUM>, the left part <NUM>, and the right part <NUM> of the housing. The base plate <NUM> is provided with an opening; one end of the air outlet boxes 172a, 172b is in communication with the opening on the base plate <NUM>, and the air outlets 104a, 104b are formed at the other end thereof; thus, an airflow may pass through the air outlet boxes 172a, 172b through the opening in the base plate <NUM> and then flow out through the air outlets 104a, 104b.

<FIG> is a stereoscopic view of the front part and rear part of the wafer optical processing device in <FIG> with the housing removed, showing the internal components of the wafer optical processing device; <FIG> is a sectional view of <FIG>. In <FIG>, the front part <NUM> and the rear part <NUM> of the housing <NUM> are removed, and the internal components of the wafer optical processing device are visible. As shown in <FIG> and <FIG>, the wafer optical processing device <NUM> comprises two wafer processing assemblies 201a and 201b that are disposed side by side, wherein the wafer processing assemblies 201a and 201b have completely the same structures; in actual application, both of the wafer processing assemblies 201a and 201b may be used at the same time, or only one of them may be used, depending on need. In another embodiment, one or more wafer processing assemblies may also be disposed. The internal structure of the wafer processing assembly 201a will be described below; the structure of the wafer processing assembly 201b, which is the same as that of the wafer processing assembly 201a, will not be described again.

The wafer processing assembly 201a comprises an upper plate <NUM>, a lower plate <NUM>, a left plate <NUM>, and a right plate <NUM>; the upper plate <NUM>, the lower plate <NUM>, the left plate <NUM>, and the right plate <NUM> form a ring creating a cylindrical space <NUM>. The air inlet 103a is disposed in the upper plate <NUM>, and the air outlet box 172a is connected to the lower plate <NUM>. A guide rack <NUM> is disposed below the air inlet 103a; the guide rack <NUM> extends in the length direction shown in <FIG>; the length of the guide rack <NUM> in the length direction is greater than the diameter of the air inlet 103a and smaller than the length of the upper plate <NUM> in the length direction. The guide rack <NUM> is provided with a base plate <NUM> and lateral plates <NUM>, <NUM> that are formed extending upwards from both sides of the base plate <NUM> in the width direction (namely, the left-right direction shown in <FIG>), the upper ends of the lateral plates <NUM>, <NUM> being connected to the upper plate <NUM> of the wafer processing assembly 201a; thus, the guide rack <NUM> and the upper plate <NUM> of the wafer processing assembly 201a form a ring creating a guide passage <NUM>, of which both ends are provided with openings, the guide passage <NUM> guiding the circulation of an airflow in the housing <NUM>. An airflow that has flowed in through an air inlet <NUM> flows along the guide passage <NUM> and flows out through the openings at the front and rear ends of the guide passage <NUM>. In the cylindrical space <NUM>, the wafer support device 140a, the upper optical processing assembly <NUM>, and the lower optical processing assembly <NUM> are disposed. Both sides of the upper optical processing assembly <NUM> are respectively connected to the left plate <NUM> and the right plate <NUM> by the corresponding support rack, and the upper optical processing assembly <NUM> is located above the wafer support device 140a and separated from the wafer support device 140a by a specific gap. Likewise, both sides of the lower optical processing assembly <NUM> are respectively connected to the left plate <NUM> and the right plate <NUM>, and the lower optical processing assembly <NUM> is located below the wafer support device 140a and separated from the wafer support device 140a by a specific gap. The upper optical processing assembly <NUM> and the lower optical processing assembly <NUM>, respectively, optically process the front face and rear face of the wafer <NUM> placed on the wafer support device 140a, wherein the front face of the wafer <NUM> faces the upper optical processing assembly <NUM> and the rear face of the wafer <NUM> faces the lower optical processing assembly <NUM>.

<FIG> is a stereoscopic view of the upper optical processing assembly <NUM>, the wafer support device 140a, and the lower optical processing assembly <NUM>; as shown in <FIG>, the wafer support device 140a comprises a conveyor belt <NUM> and a pair of quartz rods <NUM>, the conveyor belt <NUM> being supported by the pair of quartz rods <NUM>. The conveyor belt <NUM> constitutes a support piece for supporting the wafer <NUM>. Driven by an external force, the conveyor belt <NUM> moves relative to the quartz rods <NUM>, thereby driving the wafer <NUM> placed on the conveyor belt <NUM> to move together, so that the wafer <NUM> enters the wafer optical processing device <NUM> through a wafer inlet 162a, 162b in the front part <NUM> and then leaves the wafer optical processing device <NUM> through a wafer outlet in the rear part <NUM>. Note that the drawings in the present application show only the conveyor belt <NUM> in the wafer optical processing device <NUM>, but not any conveyor belts outside the wafer optical processing device <NUM>. In the apparatus comprising the wafer optical processing device <NUM>, the conveyor belt <NUM> penetrates the wafer optical processing device <NUM> and relevant devices upstream and downstream of the wafer optical processing device <NUM>; in other words, after being processed on the conveyor belt <NUM> by devices upstream of the wafer optical processing device <NUM>, the wafer <NUM> enters the wafer optical processing device <NUM> via the conveyor belt <NUM>; when moving through the wafer optical processing device <NUM>, the wafer <NUM> is first optically processed by the upper optical processing assembly <NUM> and the lower optical processing assembly <NUM> and then is conveyed by the conveyor belt <NUM> to the downstream device in order to be processed in the next procedure.

The upper optical processing assembly <NUM> and the lower optical processing assembly <NUM> may each produce light having a certain intensity, thereby, respectively, optically processing the front face and rear face of the wafer <NUM> to accelerate the process of light attenuation. The conveyor belt <NUM> is a meshed structure having a hollowed-out portion, and thus light from the lower optical processing assembly <NUM> may penetrate the hollowed-out portion on the conveyor belt <NUM> to optically process the rear face of the wafer <NUM>.

<FIG> is an exploded view of the upper optical processing assembly <NUM> in <FIG>; as shown in <FIG>, the upper optical processing assembly <NUM> comprises an upper cooling device <NUM>, an upper light source device <NUM>, and an upper transparent baffle plate <NUM>. The upper cooling device <NUM>, the upper light source device <NUM>, and the upper transparent baffle plate <NUM> are fixed together by a support rack <NUM>. The upper light source device <NUM> is used to provide a light source for illuminating the front face (namely, the upper surface) of the wafer <NUM>, the upper cooling device <NUM> is used to absorb the heat generated by the upper light source device <NUM>, and the upper transparent baffle plate <NUM> is used to block foreign substances in the conveyor passage 130a, so that they are not prone to adhere to the upper light source device <NUM>. The upper light source device <NUM> comprises a light source plate <NUM> that is integrated with a plurality of LED light sources, wherein the light source plate <NUM> is dividable into a plurality of LED light source modules, and some or all of the LED light source modules may be started as needed in actual application. When operating, the upper light source device <NUM> generates intense heat; in order to keep the temperature in the wafer processing assembly 201a within a suitable range, the upper cooling device <NUM> is used to absorb part of the heat generated by the upper light source device <NUM>. The upper cooling device comprises a cooling plate <NUM> and a coil pipe <NUM> that are made of a metallic material. The cooling plate <NUM> is roughly platelike and has a certain thickness, the lower surface <NUM> of the cooling plate <NUM> is roughly a smooth plane, and the light source plate <NUM> is connected to the lower surface of the cooling plate <NUM>. The cooling plate <NUM> is provided with a plurality of grooves formed by being dented inwards from the upper surface, the grooves having a shape that matches the shape of the coil pipe <NUM> and being used to accommodate the coil pipe <NUM>. The coil pipe <NUM> is embedded in the cooling plate <NUM>, and the area of contact between the coil pipe <NUM> and the cooling plate <NUM> is made as large as possible. The coil pipe <NUM> is provided with an inlet <NUM> and an outlet <NUM>, and cooling water flows into the coil pipe through the inlet <NUM> and then flows out through the outlet <NUM>. Heat generated by the upper light source device <NUM>, through the cooling plate <NUM> and the coil pipe <NUM>, is conveyed to the interior of the coil pipe <NUM> and subjected to heat exchange with the cooling water in the coil pipe <NUM>, so that the cooling water absorbs heat and its temperature increases; finally, the cooling water flows out through the outlet <NUM>, taking away part of the heat. The upper transparent baffle plate <NUM> is disposed below the upper light source device <NUM>, a plurality of holes <NUM> are disposed in the upper transparent baffle plate <NUM>, and the holes <NUM> facilitate the circulation of an airflow in a vertical direction around the upper optical processing assembly <NUM>, thus preventing partial overheating near the upper light source device <NUM>. The upper transparent baffle plate <NUM> is made of glass or another transparent material, capable of preventing, to a certain extent, foreign substances from coming into contact with the upper light source device <NUM>. When a certain amount of foreign substances have accumulated, the upper transparent baffle plate <NUM> may be wiped and cleaned.

<FIG> is an exploded view of the lower optical processing assembly <NUM> in <FIG>; similar to the upper optical processing assembly <NUM> shown in <FIG>, the lower optical processing assembly <NUM> comprises a lower cooling device <NUM>, a lower light source device <NUM>, and a lower transparent baffle plate <NUM>. The lower cooling device <NUM>, the lower light source device <NUM>, and the lower transparent baffle plate <NUM> are fixed together by the support rack <NUM>. The lower light source device <NUM> is used to provide a light source for illuminating the rear face of the wafer <NUM>, the lower cooling device <NUM> is used to absorb the heat generated by the lower light source device <NUM>, and the lower transparent baffle plate <NUM> is used to prevent foreign substances in the conveyor passage 130a from adhering to the lower light source device <NUM>. The lower light source device <NUM> is formed by a plurality of light source modules <NUM>, wherein the light source modules <NUM> are LED light source modules, and some or all of the LED light source modules <NUM> may be started as needed in actual application. The plurality of light source modules <NUM> may be independent of one another and connected to the lower cooling device <NUM>, respectively. The power of the lower light source device <NUM> and that of the upper light source device <NUM> may be set to be the same or different, as determined by the processing requirements for the front face and rear face of the wafer <NUM>. In the present application, the optical processing requirement for the front face of the wafer <NUM> is greater than the optical processing requirement for the rear face of the wafer <NUM>, because the maximum light energy that the upper light source device <NUM> is capable of providing per unit of time is greater than the maximum light energy that the lower light source device <NUM> is capable of providing per unit of time. In the present application, a plurality of separate detachable light source modules are used as the lower light source device <NUM>, and an integrated light source module is used as the lower cooling device <NUM>. In another embodiment, a light source module in another form may also be used as needed. The structure of the lower cooling device <NUM> is the same as the structure of the upper cooling device <NUM>, but the lower cooling device <NUM> is placed in a direction different from the upper cooling device; the upper surface <NUM> of the lower cooling device <NUM> forms a roughly smooth plane, and the coil pipe <NUM> is mounted into the grooves of the cooling plate <NUM> from below the cooling plate <NUM> and thus located in the cooling plate <NUM>. In other words, the lower cooling device <NUM> and the upper cooling device <NUM> are disposed facing each other. The light source modules <NUM> of the lower optical processing assembly <NUM> are connected to the upper surface <NUM> of the cooling plate <NUM>. Heat generated by the lower light source device <NUM>, through the cooling plate <NUM> and the coil pipe <NUM>, is conveyed to the interior of the coil pipe <NUM> and subjected to heat exchange with the cooling water in the coil pipe <NUM>, so that the cooling water takes away part of the heat. The lower transparent baffle plate <NUM> is disposed above the lower light source device <NUM>; different from the upper transparent baffle plate <NUM>, the lower transparent baffle plate <NUM> is provided with no holes; the reason is that, because of the action of gravity and the roughly top-down circulation of an airflow in the housing <NUM>, foreign substances are relatively more prone to be deposited and accumulate on the lower transparent baffle plate <NUM>. The lower transparent baffle plate <NUM>, provided with no holes, is capable of preventing foreign substances from falling on the lower light source device <NUM> through a hole. The lower transparent baffle plate <NUM> is made of glass or another transparent material. When a certain amount of foreign substances have accumulated, the lower transparent baffle plate <NUM> may be wiped and cleaned. In the present application, heat generated by the lower light source device <NUM> is generally lesser than the heat generated by the upper light source device <NUM>; thus, though the lower transparent baffle plate <NUM> is provided with no holes, no partial overheating occurs near the lower light source device <NUM>.

<FIG> is a simplified view of the upper optical processing assembly <NUM>, the wafer support device 140a, and the lower optical processing assembly <NUM> in <FIG>, showing more clearly the relative position relationship among the above-mentioned components. As shown in <FIG>, the upper light source device <NUM> of the upper optical processing assembly <NUM> is pressed close to the lower surface of the upper cooling device <NUM>, so that the upper cooling device <NUM> may effectively absorb the heat generated by the upper light source device <NUM>. "Pressed close" mentioned herein means being close in distance, but there may also be a specific gap between the upper light source device <NUM> and the upper cooling device <NUM>. There is a specific gap <NUM> between the upper transparent baffle plate <NUM> and the upper light source device <NUM>; thus, in the length direction of the wafer optical processing device <NUM>, an opening <NUM> is formed between the upper transparent baffle plate <NUM> and the upper light source device <NUM> (see <FIG>). The gap <NUM> allows an airflow to flow between the upper transparent baffle plate <NUM> and the upper light source device <NUM>; then, the airflow flows out through the opening <NUM>, thereby taking away part of the heat and preventing partial overheating of the upper light source device <NUM>. In addition, a plurality of holes <NUM> are disposed in the upper transparent baffle plate <NUM>, the plurality of holes <NUM> further facilitating the circulation of an airflow so that the airflow may further flow out penetrating the holes <NUM> from top to bottom.

Similarly, the lower optical processing assembly <NUM> comprises the lower cooling device <NUM>, the lower light source device <NUM>, and the lower transparent baffle plate <NUM>, wherein the lower light source device <NUM> is pressed close to the lower surface of the lower cooling device <NUM>, so that the cooling device <NUM> may effectively absorb the heat generated by the lower light source device <NUM>. "Pressed close" mentioned herein means being close in distance, but there may also be a specific gap between the lower light source device <NUM> and the lower cooling device <NUM>. There is a specific gap <NUM> between the lower transparent baffle plate <NUM> and the lower light source device <NUM>; thus, in the length direction of the wafer optical processing device <NUM>, an opening <NUM> is formed between the lower transparent baffle plate <NUM> and the lower light source device <NUM> (see <FIG>). The gap <NUM> allows an airflow to flow between the lower transparent baffle plate <NUM> and the lower light source device <NUM>; then, the airflow flows out through the opening <NUM>, thereby taking away part of the heat and preventing partial overheating of the lower light source device <NUM>. As described above, the lower transparent baffle plate <NUM> is provided with no holes, in order to prevent foreign substances from falling on the lower light source device <NUM> through a hole.

Still referring to <FIG>, the wafer support device 140a comprises the conveyor belt <NUM> and the quartz rods <NUM>. The two quartz rods <NUM> are respectively located on either side of the conveyor belt <NUM>. The conveyor belt <NUM> is provided with an upper surface <NUM> and a lower surface <NUM>, the lower surface <NUM> being roughly a plane and coming into contact with the two quartz rods <NUM>, and thus the two quartz rods <NUM> support the conveyor belt <NUM>. In the present application, the conveyor belt <NUM> forms a support piece for supporting the wafer <NUM>. A separation piece <NUM> is disposed on the upper surface <NUM> of the conveyor belt <NUM>, and two raised ribs 628a, 628b are formed extending in the extension directions of the conveyor belt <NUM> on the separation piece <NUM>. An inclined plane extending outwards and upwards is formed on the insides of the two raised ribs 628a, 628b, respectively. The two inclined planes are respectively provided with bottom sides 629a, 629b, and the distance between the bottom sides 629a, 629b is smaller than the width of the wafer <NUM>. Thus, when the wafer <NUM> is located on the conveyor belt <NUM>, two sides of the wafer <NUM> in the width direction come into contact with the inclined surfaces or with the tops of the raised ribs 628a, 628b; thus, a specific gap is created between the wafer <NUM> and the upper surface of the conveyor belt <NUM>, so that the lower surface of the wafer <NUM> does not come into contact with the conveyor belt, which is conducive to the formation of a smooth lower surface (namely, the rear face of the wafer) on the wafer <NUM>. In the present application, the conveyor belt <NUM> is a meshed structure; in other words, the conveyor belt <NUM> is provided with a hollowed-out portion that penetrates the upper surface and lower surface of the conveyor belt <NUM>. Therefore, light from the lower light source device <NUM> may penetrate the hollowed-out portion and illuminate the lower surface of the wafer <NUM>. In addition, the meshed conveyor belt <NUM> having a hollowed-out portion facilitates the circulation of airflows on both sides of the conveyor belt <NUM>. The separation piece <NUM> may be integrated with the meshed conveyor belt <NUM>, for example, being formed by folding upwards a plurality of metallic wires that form the upper part of the meshed conveyor belt, or may be a separately formed component that is connected to the upper surface of the conveyor belt <NUM>.

Claim 1:
A wafer optical processing device, for optically processing a sintered wafer, comprising:
wafer support devices (140a, 140b), said wafer support devices (140a, 140b) comprising a support piece, said support piece being provided with an upper surface (<NUM>) and a lower surface (<NUM>) that are disposed facing each other, said support piece being hollowed out in a direction from the upper surface (<NUM>) to the lower surface (<NUM>), said support piece being configured to be capable of supporting said wafer above said upper surface (<NUM>);
an upper light source device (<NUM>), said upper light source device (<NUM>) being disposed above said wafer support devices (140a, 140b) and configured to provide a light source that illuminates the upper surface of said support piece (<NUM>); and
a lower light source device (<NUM>), said lower light source device (<NUM>) being disposed below said wafer support devices (140a, 140b) and configured to provide a light source that illuminates the lower surface (<NUM>) of said support piece (<NUM>),
wherein said wafer optical processing assembly further comprises:
an upper transparent baffle plate (<NUM>), said upper transparent baffle plate (<NUM>) being located between said upper light source device (<NUM>) and said wafer support devices (140a, 140b) and separated from said upper light source device (<NUM>), a plurality of holes being disposed in said upper transparent baffle plate (<NUM>);
and a lower transparent baffle plate (<NUM>), said lower transparent baffle plate (<NUM>) being located between said lower light source device (<NUM>) and said wafer support devices (140a, 140b) and separated from said lower light source device (<NUM>), characterised in that the lower transparent baffle plate <NUM> is provided with no holes.