TWI435461B - Method and system for obtaining the process history of the solar cell - Google Patents

Description

Method and system for recording solar wafer process history

The present invention relates to a method and system for recording a solar wafer process history, and more particularly to a process configuration for a tandem continuous production line.

In recent years, due to the rise of environmental awareness and the gradual depletion of other energy sources, the solar cell industry has gradually emerged, and how to improve the photoelectric conversion efficiency of solar cells has become the focus of current research. If advanced process control (APC) systems can be applied in the solar process, it will also help to improve the yield of solar cells.

In the process type of the conventional semiconductor integrated circuit, as shown in FIG. 1, only one wafer 10 is taken out from the wafer cassette 1 at a time, and then placed in the cavity 11 to fabricate components and components on the wafer 10. The circuit is connected between the wires. In order to increase the throughput and yield of the wafer 10, it has become very popular to use advanced process control systems to monitor the condition of the devices and wafers. For example, automatic detection of process parameter errors, process recipes are adjusted to eliminate or reduce the impact of interference factors such as parameter drift on the wafer, and record the process history of each wafer.

In addition, once the advanced process control system detects an abnormal condition of the device and causes the process parameters of the wafer to be out of the preset range, the wafer is marked. After all the integrated circuit processes are completed, The R&D personnel then analyze the process history of the wafer to analyze whether the abnormal condition affects the electrical measurement result.

Although advanced semiconductor process control technology is quite mature in the semiconductor industry, it has not yet been developed for the solar cell industry. The reason is that the output value of a solar chip is less than hundreds or even several times that of the integrated circuit wafer. If the advanced process control system used in the semiconductor integrated circuit is directly applied to the solar wafer process, the economic benefits of the overall process are not met. .

Also, in order to increase the production rate, the process pattern of the solar wafer tends to be in-line continuous production line. As shown in Fig. 2, a plurality of solar wafers 20 are placed on the conveyor belt 21 and continuously conveyed to different process stations 22, 23 for processing. Although such a process can have a large throughput, the solar wafers 20 placed on the conveyor belt 21 are close to each other, and the conventional advanced process control system is only suitable for each single wafer process, and is not applicable. Process type in tandem continuous production.

At present, in the solar wafer preparation process, although the condition of the device itself can be monitored, the process parameters of the device have no corresponding method to the solar wafer, and the solar wafer process history cannot be known. When the test result is not as expected, it is difficult to analyze the cause by the process parameters to eliminate the abnormal condition, and it is also difficult to further optimize the process parameters.

Therefore, for the process type of solar wafers, it is necessary to develop a method similar to an advanced process control system to know the process history of the solar wafer. And when the solar cell yield is reduced, by analyzing the relationship between the process parameters and the test results, the problem can be found and the photoelectric conversion efficiency of the solar wafer can be improved.

In view of the above problems, it is an object of the present invention to provide a method for recording a solar wafer process history, which is used in a tandem continuous production line of solar cells, and can also be used as an advanced process control technology for a solar wafer production line.

The method of the present invention includes: preset a plurality of process stations in a tandem continuous production line; preset at least one counter in the process stations or the process stations to enter and exit; calculating a time for the solar wafer to pass each of the counters, And according to the wafer count of the counter, the wafer serial number of each solar wafer is established to obtain the relationship between the serial number and the time of the wafer; the relationship between the process parameters of the processing station and the time is recorded; finally, the synchronization process parameters and the wafer serial number correspond to Time to get the process history of each solar wafer.

Another object of the present invention is to provide a system for recording a solar wafer process history for a tandem continuous production line of solar wafers, wherein the tandem continuous production line has a plurality of process stations, and the system includes: a wafer count The monitoring module comprises: a plurality of counters disposed at the processing stations to record the passed solar wafer counts, thereby establishing a wafer serial number of each solar wafer; and an output device for calculating the solar wafer passing through each counter Time, and output the relationship between the serial number of the solar wafer and the time; and a parameter monitoring module for outputting the relationship between the process parameters of the processing stations and the time, wherein the process parameters are synchronized by the process number and the wafer serial number Time to get the process history of each solar wafer.

The method and system of the present invention can be integrated into the original process, which is not only simple but also low in cost compared to the advanced process control methods used in conventional semiconductor integrated circuit processes. When there is a problem with the process parameters, the system of the present invention can automatically mark the solar cells with abnormal process parameters, so as to track whether the process parameters are the main cause of the decline in the yield of the solar wafer. Moreover, the tester can adjust the process parameters in a timely manner to optimize the quality of the solar cell.

In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, the method and system for recording a solar wafer process history according to the present invention will be described in detail with reference to the accompanying drawings. The same elements will be described with the same element symbols as follows.

The method for recording a solar wafer process history of the present invention is to set a plurality of counters, wherein the number of wafers of each solar wafer can be established by counting the solar wafers recorded by the counter, and by estimating the time when the solar wafer passes the counter, The relationship between the wafer serial number and time is obtained. After synchronizing the process parameters of the respective process stations and the time corresponding to the wafer serial number, the process history of the solar wafer can be further known.

As mentioned above, the process pattern of the solar wafer belongs to a tandem continuous production line and includes multiple processes. In this embodiment, only two of the processes are taken as an example, so that those having ordinary knowledge can understand the spirit of the present invention.

Referring to FIG. 3, an embodiment in which the system 3 for recording the solar wafer process history is applied to a partial process is shown. The figure shows that the solar wafer 20 is placed on a conveyor belt 21 and sequentially transported to the first process station 6 and the second process station 7 for heat treatment. The system 3 for recording the solar wafer process history includes a wafer count monitoring module 33 and a parameter monitoring module 34.

The chip count monitoring module 33 includes an output device 330 and a plurality of counters 331-333. The number and position of the counters 331~333 can be set in the process station or the entry and exit end of the process station according to requirements. In the embodiment of the present invention, the first to third counters 331 to 333 are respectively disposed at the entry and exit ends of the first process station 6 and the second process station 7.

Since the distance between the counters and the transfer rate of the conveyor belt 21 are fixed, the time during which the solar wafer 20 passes each counter can be calculated. Moreover, when the solar wafer 20 passes through these counters, the recorded wafer count can be regarded as the wafer serial number of each solar wafer.

The output device 330 records the time each solar chip passes through each counter, and outputs the wafer serial number versus time, optionally in a list of listings and/or a relationship diagram. Among them, the list of the list is shown in the following Table 1.

In order to map the process parameters of the process station to the solar wafer 20, the parameter monitoring module 34 is used to monitor and record the process parameters of the first process station 6 and the second process station 7, and output the relationship between the process parameters and time. The way of recording or outputting can be expressed by one of a group of words, a list of lists, a diagram, and any combination thereof.

In the embodiment of the present invention, the relationship between the process parameters and time of different process stations is as shown in FIG. 4 . 4 shows that the first process station 6 and the second process station 7 record the parameter tables 410-412 and 420-422 in sequence at different times. Wherein P ₁₁ , P ₁₂ ... P _1n and P ₂₁ , P ₂₂ ... P _2n respectively represent process parameters of the first process station 6 and the second process station 7, and according to different process stations, the recorded parameters are also different. In the embodiment of the present invention, since the first and second process stations are used for the heat treatment process, the process parameters include temperature, pressure, temperature holding time, atmosphere to be introduced, and the like. However, if it is in the roughening process station, the process parameters are changed to record the type and concentration of the chemical solution, the time of wafer immersion, and so on.

When recording the relationship between process parameters and time, you can preset a longer period, for example, set every ten minutes or half an hour to record, as shown in parameter table 420~422 in Figure 4. When the parameter monitoring module 34 detects an abnormal condition, such as the originally set process parameter, exceeds a preset range, the record is added at the time point when the abnormal condition occurs, or is changed to a shorter period record until the abnormality is eliminated, such as The parameter tables 411 to 412 in Fig. 4 are shown.

The parameter monitoring module 34 automatically records and marks the event occurrence time area. Referring to FIG 4, at the time 10:00:25 to 10:00:35, system temperature parameter is assumed that the first process station 6. P ₁₁ due tube rupture, the heat treatment temperature is decreased from a predetermined 500 ± 5 ℃ 400 ℃, The parameter monitoring module 34 will mark the time segment and the abnormal parameters in a different color or font manner. Of course, the annotation methods that can be thought of by the ordinary knowledge can be used.

Finally, the process parameters output by the parameter monitoring module 34 and the time corresponding to the wafer serial number are synchronized to obtain a process history of each solar chip. For example, comparing Table 1 above with FIG. 4, it can be seen that the process parameters of the solar wafer of the serial number "1" at the first process station 6, that is, the parameters listed in the parameter table 411 in FIG. 4, and so on.

The calculation analysis and comparison of the data can be selectively performed by a processor 35. In addition, when an abnormal situation occurs in the process station, by referring to the wafer serial number, it is possible to track which solar wafer is under the abnormal process parameters.

4, when the time in the time 10:00:25 to 10:00:35, the process parameters of the first station 6 of abnormal P _11, table 1, that may be the serial number "2 to 4" There is a problem with the solar wafer process. The processor 35 records the solar chips of the serial number "2~4" so that the developer can track whether this factor causes a drop in yield after the entire batch of solar wafers is completed.

In order to facilitate querying the data of each solar chip, the processor 35 further includes a storage unit 350 for storing the serial number, the number of the wafer, the relationship between the process parameters and the time, and the process history of the solar wafer.

In the embodiment of the present invention, in order to determine whether the counters 331 333 333 are accumulatively counted, each of the counters 331 333 333 further includes a detector 3310 ～ 3330, and the detectors 3310 ～ 3330 can periodically transmit a pulse signal, and Whether or not the signal reflected by the solar wafer 20 is received is determined whether or not the solar wafer 20 passes through the counters 331 to 333.

Since the solar wafer 20 has a certain width, the detectors 3310 to 3330 receive dense reflection signals when passing through the counters 331 to 333. Referring to FIG. 5A, the relationship between the number of wafers passing through the counter 331 and the time is shown, and FIG. 5B shows the intensity of the reflected signal received by the detector at different time points.

As can be seen from FIG. 5B, when t=0 to t=t ₁ , the detector 3310 continuously receives the reflection signal of the solar wafer 5 times, and the solar wafer completely passes through the counter 331. At this time, the counter 331 is automatically accumulated. Counting, but during t=t ₁ to t=t ₂ , the detector can only receive the background signal.

In addition, if the solar wafer is removed during the process of being transferred, it can be discriminated from the relationship diagram. Referring to FIG. 5C and FIG. 5D, when the expected reflection signal is not present at time t=t ₂ to t=t ₃ , it can be determined that the solar wafer has been cleared, and the number of wafers passing through the counter will be larger than the original. The estimate is small. Further, from the time point and the illustration, it can be inferred which piece of the solar wafer has been removed. Therefore, when the wafer serial number corresponds to the process parameter, there is no problem that the process history of the solar wafer is confused.

An embodiment in which the method and system of the present invention are extended to the entire solar wafer process is shown in FIG. Generally, the process of the solar wafer is followed by texturing, diffusion doping 91, isolation 92, ARC deposition, screen printing, and sintering 95. (co-firing) and test class 96 (testing and sorting) and other process stations, and record the relationship between the process parameters P ₁ ~ P _{n of the} above process station and time.

In the foregoing manner, a plurality of counters are separately set in the process station, and the relationship between the serial number and the time of the wafer is recorded, and the process history of each of the solar wafers is obtained by synchronizing the process parameters and the time of the wafer serial number.

In summary, the method and system for recording a solar wafer process history provided by the present invention have the following advantages:

(1) Using only the setting counter and using the synchronization timing method, that is, solving the process type of the conventional tandem continuous production line, the problem of the solar wafer process parameters cannot be traced, and the effect is like the advanced control process of the tandem continuous production line. System (APC).

(2) Process parameter correction is easier. Since the process parameters of each solar wafer can be recorded and documented, and wafers with abnormal process parameters can also be marked. When the yield of the solar cell drops, the tester can analyze and confirm the problem, and can also adjust the process parameters in time to optimize the quality of the solar cell.

(3) The method is simple, the cost is low, and can be integrated into the original process to track the process parameters of the solar wafer to eliminate the abnormality or optimize the process. Compared with the advanced control process system in the semiconductor integrated circuit, the invention is less expensive.

The present invention has been described above by way of a preferred example, but it is not intended to limit the spirit of the invention and the inventive subject matter. Those who are familiar with the technology can easily understand and utilize other components or methods to produce the same effect. Modifications made without departing from the spirit and scope of the invention are intended to be included within the scope of the appended claims.

1. . . Wafer box

10. . . Wafer

11. . . Cavity

20. . . Solar wafer

twenty one. . . conveyor

22, 23. . . Process station

3. . . System for recording solar wafer process history

33. . . Wafer count monitoring module

330. . . Output device

332. . . Second counter

331. . . First counter

3310~3330. . . Detector

333. . . Third counter

35. . . processor

34. . . Parameter monitoring module

6. . . First process station

350. . . Storage unit

7. . . Second process station

410, 411, 412. . . First process station parameter table

420, 421, 422. . . Second process station parameter table

90. . . Roughening process station

91. . . Diffusion doped process station

92. . . Insulation process station

93. . . Anti-reflective coating process station

94. . . Screen printing electrode processing station

95. . . Sintering process station

96. . . Test sorting station

P ₁ ~P _n , P ₁₁ ~P _1n , P ₂₁ ~P _2n . . . Process parameter

Figure 1 shows a process type of a conventional semiconductor integrated circuit;

Figure 2 shows the process type of the solar wafer;

3 shows an embodiment of a system for recording a solar wafer process history of the present invention applied to a partial process;

Figure 4 shows the relationship between process parameters and time for different process stations;

5A and 5C are diagrams showing the relationship between the wafer count of the counter and the time;

5B and FIG. 5D show the relationship between the intensity and time of the solar cell reflection signal detected by the detector;

6 shows an embodiment of a system for recording a solar wafer process history of the present invention applied to a full process of a solar wafer.

3. . . System for recording solar wafer process history

20. . . Solar wafer

330. . . Output device

twenty one. . . conveyor

33. . . Wafer count monitoring module

331. . . First counter

332. . . Second counter

333. . . Third counter

35. . . processor

3310~3330. . . Detector

6. . . First process station

34. . . Parameter monitoring module

7. . . Second process station

350. . . Storage unit

Claims (11)

A method for recording a solar wafer process history, wherein the tandem continuous production line for a solar cell comprises: preset a plurality of process stations in the tandem continuous production line; preset at least one counter at the process stations Or the ingress and egress of the processing stations; calculating the time for each solar chip to pass each of the counters, and establishing a wafer serial number of each solar wafer according to the wafer counts of the counters to obtain the serial numbers and times of the wafers Relationship; record the relationship between the process parameters of the process stations and time; and synchronize the process parameters of the process stations and the time corresponding to the wafer serial number to obtain a process history of each solar wafer. According to the method of claim 1, the time for each solar chip to pass each of the counters is calculated according to the distance of the counters and the delivery rate of the tandem continuous production line. For example, when the method of claim 1 is obtained, the relationship between the serial number and the time of the wafer is obtained, and the method further includes outputting by a list of lists and/or a relationship diagram. For example, when the method described in claim 1 of the patent application records the relationship between the process parameters of the process stations and the time, the method further includes selecting one of a group of characters, a list of lists, a relationship diagram, and any combination thereof. For example, when the method described in claim 1 is used to record the relationship between the process parameters of the process stations and the time, the system records once every longer period, and when an abnormal condition occurs, the time at which the abnormal condition occurs is generated. Increase the record, or record it in a shorter period until the abnormal condition is excluded. The method of claim 5, wherein the abnormal condition is that the process parameter is detected to exceed a predetermined range, and at this time, the time zone and the process for recording and marking the abnormal condition are further recorded and marked. parameter. The method of claim 6, after synchronizing the process parameters of the process stations and the time of the wafer serial number, further comprising an abnormal solar wafer that traces and marks the process parameters in the time zone. A system for recording a solar wafer process history for a tandem continuous production line of a solar wafer, wherein the tandem continuous production line has a plurality of process stations, the system comprising: a wafer count monitoring module comprising: a plurality of counters, One or more set in the process stations or the process station inlet and outlet ends to record the passed solar wafer counts, thereby establishing the wafer serial number of each solar wafer; an output device, calculating the solar wafer through each of the counters And outputting the relationship between the serial number of the solar wafers and the time; and a parameter monitoring module for outputting the relationship between the process parameters of the processing stations and the time, wherein by synchronizing the process parameters, and The time corresponding to the number of the wafers is obtained to obtain a process history of each of the solar wafers. According to the system of claim 8, the output device outputs the relationship between the serial number and the time of the wafer, and outputs the data in the form of a list and/or a relationship diagram. In the system of claim 8, each of the counters further includes a detector for determining whether the counter accumulates the count by receiving the number of times the solar wafer reflects the signal. The system of claim 8, wherein the system further comprises a processor to synchronize the process parameters, and the time corresponding to the wafer serial number, and mark the solar wafer with abnormal process parameters.