TWI623041B - Method and apparatus for processing workpieces - Google Patents

Abstract

The present invention discloses a method of processing a workpiece and an apparatus for processing the workpiece. Where A method of treating a workpiece includes performing a short heat treatment on the workpiece after it has been implanted with boron. This short heat treatment can be performed prior to placing the workpiece in the carrier. The short heat treatment can be performed using a laser, a heat lamp or a light emitting diode. In some embodiments, the heat source is disposed in the loading and unloading chamber and is actuated after the workpiece has been processed. In other embodiments, the heat source is disposed above the conveyor belt for moving the processed workpiece from the loading and unloading chamber to the loading/unloading station.

Description

Method and device for processing workpiece

Embodiments of the present invention relate to a system and method for improving the performance of a solar cell, and more particularly to a method of reducing the amount of boron diffused from a workpiece during an annealing process.

Semiconductor workpieces are often implanted with dopant species to produce the desired conductivity. For example, a solar cell can be implanted with a dopant to create an emitter region. This implantation can be performed using a number of different mechanisms. The generation of the emitter region enables the formation of a p-n junction in the solar cell. As the light strikes the solar cell, the electrons are excited, creating an electron-hole pair. A minority carrier generated by the energy from the incident light sweeps across the p-n junction in the solar cell. This produces a current that can be used to power an external load.

In some embodiments, boron is used to create a p-doped region in a solar cell. For example, in a passivated emitter (rear localized, PERL) solar cell, boron is implanted in the front surface. However, when the battery is subjected to annealing during manufacturing, boron has a diffusion out of the battery. trend. When the solar cell is annealed, the solar cell is typically placed in the carrier such that the front surface of one solar cell is adjacent to the back surface of the next solar cell. During annealing of the implanted boron, if boron at or near the front surface is not effectively bonded and driven into the workpiece, the boron may diffuse outward at high temperatures. Such outward diffusion of boron from the front surface of the solar cell in turn causes contamination of the rear surface of the solar cell or adjacent solar cell and causes severe degradation of surface passivation, which can result in reduced battery performance. Such outward diffusion of boron also reduces the doping concentration in the p-doped region.

Therefore, a protective layer is often deposited on the surface of the solar cell prior to annealing to reduce outward diffusion of boron from the front surface and diffusion of boron to the rear surface of adjacent solar cells. However, the deposition and subsequent removal of these protective layers increases the process, which increases the time and cost of the solar cell manufacturing process.

Accordingly, an apparatus and method for improving the manufacturing process associated with solar cells and, in particular, reducing contamination associated with boron outgrowth would be helpful.

Disclosed is an apparatus and method for processing a solar cell in which a short heat treatment is performed on the workpiece after the workpiece has been implanted with boron. This short heat treatment can be performed prior to placing the workpiece in the carrier. The short heat treatment can be performed using a laser, a heat lamp or a light emitting diode. In some embodiments, the heat source is disposed in the loading and unloading chamber and is actuated after the workpiece has been processed. In other embodiments, the heat source is disposed above the conveyor belt for moving the processed workpiece from the loading and unloading chamber Move to the loading/unloading station.

According to one embodiment, a method of processing a workpiece is disclosed. The method includes implanting boron into a first surface of the workpiece; exposing the workpiece to a short heat treatment while returning the workpiece to the carrier after the implanting; After exposure, the workpiece is subjected to an annealing process. In certain embodiments, oxygen is supplied to the surrounding environment during the exposure. In certain embodiments, the ambient environment is supplied with oxygen and at least one inert gas during the exposure. In some embodiments, the short heat treatment is performed using a laser. In certain embodiments, the short heat treatment is performed using one or more heat lamps. In some embodiments, the short heat treatment is performed using one or more light emitting diodes. In certain embodiments, the method includes implanting oxygen into the first surface of the workpiece prior to the exposing. In other embodiments, oxygen is implanted simultaneously with boron. In certain embodiments, the short heat treatment heats the workpiece to a temperature between 850 °C and 1450 °C.

According to a second embodiment, an apparatus for processing a workpiece is disclosed. The apparatus includes: a loading and unloading chamber; a chamber that houses the implant system and is in communication with the loading and unloading chamber; and a heat source disposed in the loading and unloading chamber to heat the workpiece after being processed by the implant system The workpiece. In certain embodiments, the loading and unloading chamber is supplied with oxygen while the heating source is actuated. In certain embodiments, the heating source comprises a heat lamp, a laser or a light emitting diode.

According to a third embodiment, an apparatus for processing a workpiece is disclosed. The apparatus includes: a loading/unloading station in which the workpiece is removed from the carrier; a loading and unloading chamber; moving the workpiece between the loading/unloading station and the loading and unloading chamber; a chamber accommodating the implant system and communicating with the loading and unloading chamber; and a heating source disposed on the conveying The belt is above to heat the workpiece as it is returned to the loading/unloading station after the workpiece has been processed by the implant system. In some embodiments, the heat source comprises a heat lamp, a laser or a light emitting diode. In some embodiments, the length of the beam directed toward the workpiece is greater than the first dimension of the workpiece.

10‧‧‧Workpiece

100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 210‧‧ ‧ processes

400, 500‧‧‧ devices

410, 510‧‧‧heat source

411‧‧‧Optical devices

420‧‧‧ loading and unloading room

421‧‧‧ first entry point

422‧‧‧ first entry point

430‧‧‧ implant system

440a‧‧‧First conveyor belt

440b‧‧‧Second conveyor belt

450‧‧‧Loading/Unloading Station

T1‧‧‧ stay cycle

T2‧‧‧ duration

T3‧‧‧ initial ramp up cycle

For a better understanding of the invention, reference is made to the accompanying drawings, in which FIG. 1 FIG. 1 shows a representative manufacturing flow of an n-type PERL solar cell in accordance with one embodiment.

2 is a representative manufacturing flow of an n-type PERL solar cell according to a second embodiment.

3A to 3C show heat distribution curves that can be used during a short heat treatment.

Figure 4 illustrates a first embodiment of an apparatus that can be used to implement the manufacturing flow illustrated in Figures 1-2.

Figure 5 illustrates a second embodiment of an apparatus that can be used to implement the manufacturing flow illustrated in Figures 1-2.

Implantable solar cells are very sensitive to surface conditions and processing sequences. Lift For example, the implanted boron can diffuse outward from the front surface of the solar cell during high temperature annealing. As described above, this reduces the concentration of the p-type dopant in the front surface. Furthermore, the diffused boron can then diffuse to the back surface that can be n-doped or not doped at all.

One way to prevent unwanted boron from contaminating the back surface of the solar cell is to remove boron from the surface of the workpiece prior to the annealing process. In some embodiments, this can be accomplished using a short heat treatment, such as a rapid thermal process (RTP), a flash anneal, or a laser anneal. Such short thermal treatment (STT) is intended to remove boron disposed at the surface of the solar cell and may result in or without emitter formation. In certain embodiments, the rate of boron removal can be varied by controlling the composition of the surrounding gas. For example, a short heat treatment can be performed in the surrounding environment containing a gas (eg, oxygen) to control the duration of surface boron removal.

Figure 1 illustrates a representative manufacturing process that can be used to reduce the outward diffusion of boron from the front surface and/or to reduce the diffusion of boron to the back surface.

First, as shown in process 100, the workpiece can be textured. Texturing increases the surface area of the front surface. In some embodiments, the workpiece can be an n-type crucible. As shown in process 110, a p-type dopant (e.g., boron) is then implanted into the front surface of the workpiece. Similarly, as shown in process 130, an n-type dopant (e.g., phosphorous) is implanted into the back surface of the workpiece. Although Figure 1 shows boron implanted into the front surface, it should be understood that in other embodiments, boron can be implanted into the back surface. Further, although FIG. 1 shows that phosphorus is implanted into the rear surface, the present invention is not limited to this embodiment. For example, other dopants can be implanted into the implanted boron table In the opposite surface of the surface. In other embodiments, the surface opposite the surface to which the boron is implanted may not be implanted at all. The processes described herein can be applied to any manufacturing process that includes implanting boron into at least one surface of a workpiece.

One or both of the implants can be a comprehensive implant implant in which the entire surface is implanted without the use of a mask. Alternatively, one or both of the implants can be a patterned implant, and a mask is used in the patterned implant to implant only a portion of the surface with dopant ions.

Additionally, boron ion implantation (process 110) can be performed to amorphize the front surface. However, in other embodiments, the energy and duration of boron ion implantation may not completely amorphize the front surface. Boron ion implantation can use a variety of ionic species including, but not limited to, B, BF, BF ₂ , BF ₃ , or B ₂ F ₄ .

Traditionally, since boron diffuses outward from the front surface, a protective layer has been applied to the front and/or back surface of the solar cell prior to the annealing process. Although the protective surface does reduce out-diffusion, the cost of protecting the surface is high in terms of the number of processes. Specifically, the protective coating is first deposited on the front and/or back surface of the solar cell. These protective layers are removed after the annealing process is completed.

In the process shown in Figure 1, no protective layer was deposited. Specifically, a short heat treatment (shown in process 120) is performed after boron ion implantation (process 110). This short heat treatment can be 10 seconds or less in some embodiments, and can be performed using laser annealing, rapid annealing, or rapid thermal processing. The short heat treatment is designed to intentionally diffuse boron outward from the surface of the workpiece. In some embodiments, at work The piece is placed on its rear surface while performing a short heat treatment. For example, after the workpiece is implanted with boron, a laser beam in the form of a pulse or continuous wave can be directed toward the front surface of each workpiece. A short heat treatment will cause boron near the surface of the workpiece to diffuse out of the workpiece. However, since the workpiece can be placed on its rear surface, little contamination of the rear surface can occur during a short heat treatment. Thus, a short heat treatment can be performed after the workpiece has been implanted and before the workpiece is returned to the carrier that is typically used to hold the plurality of workpieces.

Although FIG. 1 illustrates the implantation of phosphorus (process 130) after boron implantation (process 110) and short heat treatment (process 120), other embodiments are also within the scope of the present invention. For example, implantation of phosphorus (process 130) can be performed prior to implantation of boron (process 110). In another embodiment, the implantation of phosphorus (process 130) can be performed prior to a short heat treatment (process 120). In all of these embodiments, a short heat treatment (process 120) is performed after boron implantation (process 110) and prior to the annealing process (process 140).

Next, as shown in process 140, an annealing process is performed. In some embodiments, the cleaning process can be performed prior to the annealing process. The purpose of the annealing process is to drive the implanted dopant into the workpiece, repair any damage caused by the implant and activate the dopant. In some embodiments, the annealing process is performed while placing a plurality of workpieces in a carrier that can be made of quartz. The carrier can stack the workpieces such that the front surface of one workpiece is near the rear surface of the adjacent workpiece. However, since boron diffuses outward during a short heat treatment, the back surface of the workpiece may be uncontaminated during the annealing process.

Next, as shown in process 150, a passivation layer is formed on the front and back surfaces of the solar cell. As shown in process 160, an anti-reflective coating (ARC) is then applied to the front and/or back surface. This anti-reflective coating can be tantalum nitride (SiN), but other materials can also be used. As shown in process 170, the metal contacts are then applied using screen printing (SP). The metal paste is typically fritted to ensure good contact with the solar cell through the anti-reflective coating. As shown in process 180, the substrate is then fired to cause the metal to bond and diffuse into the substrate. The resulting solar cells were then tested and classified as shown in process 190. Although process 150 through process 190 illustrate a particular set of processes, it should be understood that other or different processes may be performed after the annealing process (process 140).

Figure 2 illustrates another embodiment of a manufacturing process that may be used. In the present embodiment, as used in FIG. 1, the same process is given the same reference indicator. The embodiment shown in Figure 1 assumes that only boron is implanted into the front surface during process 110.

However, in the embodiment shown in FIG. 2, in process 210, oxygen is also implanted with boron. In certain embodiments, such as in a non-mass analyzed system, oxygen can be implanted with boron. In other words, a first supply gas containing boron and a second supply gas containing oxygen may be introduced into the ion source to produce a first ion containing boron and a second ion containing oxygen. The number of oxygen ions can be determined based on the gas flow rate, the power applied to the ion source, or other parameters relative to the number of boron ions. The oxygen ions may be in the form of O ions or O ₂ ions. In other embodiments, oxygen can be implanted in a separate implant. For example, an implanted energy between 2 kv and 20 kv can be implanted with oxygen ions. In either embodiment, the concentration of oxygen implanted into the workpiece can be between 1 x 10 ¹⁴ cm ^-2 and 5 x 10 ¹⁵ cm ^-2 .

The implantation of oxygen changes the rate at which boron diffuses out of the front surface of the workpiece.

3A through 3C illustrate various embodiments of a short heat treatment. In these embodiments, the temperature of the short heat treatment process reaches a plateau. At this elevated zone, the maximum temperature _Tmax can be between 850 °C and 1450 °C, although other temperature ranges are also possible. The workpiece remains at this high temperature zone for a duration t2, which may be between 1 nanosecond and 10 seconds, although other durations are also possible.

Fig. 3A shows the first embodiment. In this embodiment, the temperature ramps up from its ambient temperature to the _Tmax high zone. In all embodiments, the temperature may ramp up at or near a rate of 1450 ° C/s, although other rates are also possible. The rate of ramp up may depend on the pulse duration of the heat source and the input power.

At an intermediate temperature T _dwell which may be between 150 ° C and 850 ° C but less than T _max , the temperature ramp is stopped to allow the workpiece to stay at this intermediate temperature T _dwell .

The workpiece may stay at this temperature for a dwell period t1, which may be between 0 and 60 seconds, although other durations are also possible. The use of an intermediate residence temperature minimizes thermal shock and prevents cracking of thin workpieces.

When the workpiece is at T _dwell , oxygen can be supplied to the surrounding environment. In one embodiment, oxygen is supplied throughout the residence period. In another embodiment, oxygen is supplied at the beginning of the dwell period and the oxygen is turned off before the end of the dwell period. In another embodiment, oxygen is supplied after the start of the dwell period and the oxygen is turned off at the end or end of the dwell period. In yet another embodiment, oxygen may be supplied during a plurality of time intervals during the dwell period. The duration of supply of oxygen during the dwell period can also vary. For example, oxygen may be supplied throughout the residence period t1 or any portion thereof. Moreover, if oxygen is supplied over a plurality of time intervals, these time intervals may or may not have equal durations.

Oxygen is supplied at any flow rate at the maximum flow rate that can be obtained. In addition, the total amount of oxygen supplied can also vary.

Although FIG. 3A shows that the temperature remains constant during the dwell period t1, other embodiments are possible. For example, the temperature does not stay at a constant temperature, but the slope of the temperature ramp can be made gentle so that the temperature rises much more slowly during the dwell period than during the initial temperature ramp. For example, the initial temperature ramp can be 1450 ° C / s. Once the temperature reaches _Tdwell , this rate can be slowed down to a rate as low as 1 °C/min during the dwell period. After the dwell period, the temperature ramp up may return to its initial rate, or may remain at a lower rate. Thus, the dwell period is defined as a time period at a temperature or temperature range that is less than the maximum temperature that is used to adapt the workpiece to an elevated temperature. As noted above, this dwell period can be at a constant temperature as shown in Figure 3A, or can be a duration with a reduced temperature ramp.

After the dwell period, the temperature can ramp up again until it reaches _Tmax . As before, the rate of temperature change can approach 1450 ° C / s, which is similar to the initial rate, but other rates are also possible. In some embodiments, the workpiece can be maintained at this maximum temperature _Tmax for a duration t2, where t2 is less than 10 seconds. During this time period, oxygen can also be supplied to the surrounding environment. As described above for the residence period, oxygen may be supplied during the duration t2 of this elevated zone or any portion thereof. Additionally, oxygen may be supplied during one time interval or during multiple time intervals. As is the case during the dwell period, the flow rate of oxygen can vary and the total volume can also vary. In some embodiments, oxygen can be provided as the sole ambient gas. In other embodiments, oxygen may be mixed with other gases or mixtures of gases such as, but not limited to, nitrogen and argon.

After the duration of the high temperature zone has elapsed, the temperature can be ramped down to ambient temperature at any desired rate.

Figure 3B shows a second embodiment that does not have a defined dwell period during the initial temperature ramp. In this embodiment, oxygen may be supplied to the surrounding environment during the duration t2 of reaching the maximum temperature _Tmax . In some embodiments, oxygen is supplied once the workpiece reaches a maximum temperature. In other embodiments, oxygen may be supplied at a later time during this high zone. As before, oxygen may be supplied during the duration t2 of the entire temperature ramp zone or during any portion thereof. Additionally, oxygen may be supplied in a plurality of time intervals, which may be equal or different durations. As in the above case, the flow rate of oxygen can vary and the total volume of oxygen introduced can also vary.

In the variant of Figure 3B, oxygen may be supplied to the surrounding environment during a portion of the initial ramp up period t3. In one embodiment, oxygen may be supplied at some point after the temperature has reached a particular temperature (eg, at least 550 °C). In another embodiment, the temperature ramp may be less than the maximum available to enable oxygen to be supplied during an extended period of time.

As noted above, in certain embodiments, oxygen may be supplied during at least a portion of the short heat treatment. The presence of oxygen in the surrounding environment can affect the rate at which boron diffuses out of the workpiece.

In yet another embodiment shown in FIG. 3C, the temperature profile may be similar to the temperature profile shown in FIG. 3B, however, the high zone at _Tmax appears to resemble a sawtooth pattern. In this embodiment, heat can be supplemented with a short pulse instead of a constant power supply to maintain a high zone temperature (i.e., maximum temperature _Tmax ). This approach produces lower overall power consumption.

FIG. 4 illustrates an exemplary apparatus that can be used to perform the sequence shown in FIGS. 1 and 2. Device 400 can include a loading/unloading station 450. In some embodiments, the loading/unloading station 450 can include a Front Opening Universal Pod (FOUP). In some embodiments, a plurality of workpieces are disposed in the carrier. The workpieces can be individually removed from the carrier and placed on the first conveyor belt 440a. The first conveyor belt 440a can move the workpiece 10 from the loading/unloading station 450 to the loading and unloading chamber 420. The first conveyor belt 440a can move the workpiece 10 at a speed between 10 cm/s and 20 cm/s, although other speeds can be used.

The loading and unloading chamber 420 generally includes a sealable chamber having a first entry point 421 and a second entry point 422. The workpiece 10 can be placed in the loading and unloading chamber 420 by opening the first entry point 421 and placing the workpiece 10 in the sealable chamber. The sealable chamber is then pumped down to near vacuum conditions. The second entry point 422 is then opened and the workpiece 10 is typically removed by a substrate handling robot disposed in a chamber containing the implant system 430. Workpiece 10 leaves The process of housing the chamber of implant system 430 operates in the opposite manner.

Implant system 430 is not limited by the invention. For example, implant system 430 can be a beam line ion implanter. The beamline ion implanter has an ion source that produces an ion beam. This ion beam is directed towards the workpiece. In some embodiments, the ion beam is mass analyzed such that only ions having the desired mass/charge are directed toward the workpiece. In other embodiments, the ion beam is not mass analyzed so that all ions can be implanted into the workpiece. The ion beam energy can be controlled by using an electrode for accelerating or decelerating the ion beam in the path of the ion beam as desired. The ion beam can be in the form of a ribbon beam in which the width of the ion beam is much greater than its height. In other embodiments, the ion beam can be a spot beam or a scanned ion beam. The ion source can be a Bernas ion source, or inductive or capacitive coupling can be used to generate the desired ions.

Alternatively, implant system 430 can be a plasma chamber in which the workpiece is disposed in the same chamber that produces the plasma. Plasma can be generated using a RF source, but other techniques are also possible. A bias is then applied to the workpiece to attract ions from the plasma toward the workpiece to implant the desired ions into the workpiece. Other types of devices can also be used to perform these ion implantation processes.

After the implant system 430 completes the implantation process, the workpiece 10 is removed from the chamber using the loading and unloading chamber 420. As described above, after the workpiece 10 is placed in the loading and unloading chamber 420, the second entry point 422 is closed and gas is introduced into the loading and unloading chamber 420 to return the sealable chamber to atmospheric conditions. After reaching atmospheric conditions, the first entry point 421 is opened and the workpiece 10 can be removed. The workpiece 10 is returned to the loading by the second conveyor belt 440b Loading/unloading station 450. As in the case of the first conveyor belt 440a, the workpiece 10 can be moved at a speed of 10 cm/s to 20 cm/s.

Disposed over the second conveyor belt 440b can be a heating source 410 and its associated optics 411. Heating source 410 can include a laser that operates in a continuous wave or pulsed mode. In other embodiments, the heat source 410 can be one or more infrared lamps. In other embodiments, the heat source 410 can be one or more light emitting diodes. In some embodiments, heat source 410 and associated optics 411 produce a beam of light that extends and/or scans across the entire size of workpiece 10 as workpiece 10 moves over second conveyor belt 440b. In other words, the workpiece 10 can have a first size that extends perpendicular to the advancement direction of the second conveyor belt 440b (ie, extends into the page shown in FIG. 4) and a second size that is It extends in the moving direction of the second conveyor belt 440b. In some embodiments, the heat source 410 produces a light beam that is at least as long as the first dimension of the workpiece 10. The light beam produced by heat source 410 can have a width that is much smaller than the second dimension of workpiece 10. In some embodiments, the light beam generated by heat source 410 is pulsed such that all portions of workpiece 10 are exposed to the light beam. In other embodiments, the beam of light may be energized constantly.

In other embodiments, the heat source and associated optics produce a light beam that is less than the first dimension of the workpiece 10. In these embodiments, the associated optics 411 can scan the beam in a first direction (ie, a direction into and out of the page) as the workpiece 10 moves along the second conveyor belt 440b. The scanning can also be performed in the direction of movement of the belt. The focused heat from the heat source 410 can be used to raise the temperature of the workpiece 10 to the temperatures shown in Figures 3A-3C.

Thus, when the workpiece 10 that has been implanted with boron moves back from the implant system 430 along the second conveyor belt 440b to the loading/unloading station 450, the workpiece 10 undergoes a short heat treatment. Further, since the workpiece 10 is placed on the rear surface thereof on the second conveyor belt 440b, heat is guided to the front surface of the workpiece 10, and boron diffuses out of the front surface and leaves the workpiece 10.

Although FIG. 4 shows the first conveyor belt 440a carrying the workpiece 10 from the loading/unloading station 450 to the loading and unloading station 420, and the second conveyor belt 440b returning the workpiece 10 to the loading/unloading station 450, other embodiments are possible. of. For example, each conveyor belt can operate in both directions. For example, the first conveyor belt 440a may also be capable of returning the workpiece 10 to the loading/unloading station 450. Moreover, the number of conveyor belts is not limited by the invention. For example, one or more conveyor belts may be present. All of these conveyor belts or any subset of these conveyor belts can be capable of returning workpiece 10 from loading and unloading chamber 420 to loading/unloading station 450. In certain embodiments, each heating source 410 and its associated optics 411 are disposed above each of the conveyor belts that are capable of moving the workpiece 10 from the loading and unloading chamber 420 to the loading/unloading station 450. In other embodiments, each heating source 410 and its associated optics 411 are disposed above at least one conveyor belt that is capable of moving the workpiece 10 from the loading and unloading chamber 420 to the loading/unloading station 450.

FIG. 5 shows another embodiment of an apparatus 500 that may be used. The same elements as those used in FIG. 4 are given the same reference indicators and will not be described again. In this embodiment, the heat source 510 is disposed within the loading and unloading chamber 420 rather than disposed above the second conveyor belt 440b. The heat source 510 can be one or more heat lamps, or can be a laser or a plurality of light emitting diodes.

In operation, the workpiece 10 is placed in the loading and unloading chamber 420 after processing. In the present embodiment, the heat source 510 can be activated when the loading and unloading chamber 420 returns to atmospheric conditions with the implanted workpiece disposed therein. In certain embodiments, the loading chamber 420 is pumped with gas to return it to atmospheric conditions for a period of up to 10 seconds so that a short heat treatment can occur during this cycle. In certain embodiments, oxygen is pumped into the loading and unloading chamber 420 when the loading and unloading chamber 420 returns to atmospheric conditions. In other embodiments, oxygen and at least one other gas are pumped into the loading and unloading chamber 420 when the loading and unloading chamber 420 returns to atmospheric conditions. As a result, oxygen is introduced into the loading and unloading chamber 420 while the workpiece 10 is subjected to a short heat treatment.

Although the present invention illustrates the use of this method in the manufacture of n-type PERL solar cells, the method can be applied to a variety of workpieces, such as n-type PERT, IBC (wherein boron is implanted into at least one surface of the workpiece) Interdigitated back contact refers to cross-back contact and other high efficiency solar cells.

The apparatus and method of the present invention have a number of advantages. First, the method of the present invention avoids the need to apply a protective coating to the surface of the workpiece to avoid contamination of the outward diffusion of boron. This saves processing time, increases throughput and reduces costs. Furthermore, the method of the present invention can be conveniently incorporated into existing semiconductor devices. For example, the heated source can be placed in the loading and unloading chamber as the treated workpiece is removed from the chamber. Alternatively, the heat source can be placed over the conveyor belt that returns the treated workpiece to the loading/unloading station. In addition, the non-equilibrium nature of these processes can also yield further benefits such as process simplification and improvement. One aspect of boron implantation and downstream processing is the removal of implant-related defects. Since the short heat treatment uses a relatively high processing temperature (for example: maximum temperature T _max ), short heat treatment can eliminate defects associated with boron implantation and produce improved emitter performance, and thus improve, despite the short time. Solar cell performance.

The scope of the invention is not to be limited by the specific embodiments set forth herein. In addition, other various embodiments of the invention and modifications of the invention in addition to those described herein will be apparent to those of ordinary skill in the art. Accordingly, such other embodiments and modifications are intended to be within the scope of the invention. In addition, although the invention has been described herein for a particular purpose in the context of a particular embodiment in a particular context, one of ordinary skill in the art will recognize that the applicability of the invention is not limited thereto, and the invention It can be advantageously implemented for any number of purposes in any number of environments. Therefore, the claims above should be construed in consideration of the full scope and scope of the invention described herein.

Claims (15)

A method of processing a workpiece, comprising: implanting boron into a first surface of the workpiece; exposing the workpiece to a short while returning the workpiece to the carrier after the implanting Heat treatment; and after the exposing, subjecting the workpiece to an annealing process, wherein the workpiece and at least another workpiece are stacked in the carrier during the annealing process. A method of processing a workpiece according to claim 1, wherein oxygen is supplied to the surrounding environment during the exposure. The method of processing a workpiece according to claim 1, wherein the ambient is supplied with oxygen and at least one inert gas during the exposure. The method of processing a workpiece according to claim 1, wherein the short heat treatment is performed using a laser. The method of processing a workpiece according to claim 1, wherein the short heat treatment is performed using one or more heat lamps. The method of processing a workpiece according to claim 1, wherein the short heat treatment is performed using one or more light emitting diodes. The method of processing a workpiece of claim 1, further comprising implanting oxygen into the first surface of the workpiece prior to the exposing. A method of processing a workpiece according to claim 7, wherein the oxygen is implanted simultaneously with the boron. A method of processing a workpiece according to claim 1, wherein the short heat treatment heats the workpiece to a temperature between 850 ° C and 1450 ° C. A device for processing a workpiece, comprising: a loading and unloading chamber; a chamber accommodating the implant system and communicating with the loading and unloading chamber; a heating source disposed in the loading and unloading chamber for processing the workpiece through the implant system And heating the workpiece; and the carrier, wherein the workpiece is stacked in the carrier with at least one other workpiece after exiting the loading and unloading chamber, and wherein the workpiece and the at least one other workpiece are in the carrier The article is simultaneously subjected to an annealing process. The apparatus for processing a workpiece according to claim 10, wherein the loading and unloading chamber is supplied with oxygen while the heating source is actuated. The apparatus for processing a workpiece according to claim 10, wherein the heating source comprises a heat lamp, a laser or a light emitting diode. An apparatus for processing a workpiece, comprising: a loading/unloading station in which the workpiece is removed from a carrier; a loading and unloading chamber; a conveyor belt at the loading/unloading station and Moving the workpiece between the loading and unloading chambers; a chamber containing the implant system and communicating with the loading and unloading chamber; and a heating source disposed above the conveyor belt for processing the workpiece through the implant system The workpiece is then heated as the workpiece is returned to the loading/unloading station. The apparatus for processing a workpiece according to claim 13, wherein the heating source comprises a heat lamp, a laser or a light emitting diode. A device for processing a workpiece according to claim 13 wherein the length of the light beam directed toward the workpiece is greater than the first dimension of the workpiece.