Ignition System

Abstract

The present invention provides an ignition system. The ignition system is used to ignite a reaction gas in a reaction chamber of a plasma processing device, and includes: a first resistor and a second resistor connected in series, which are connected in parallel with an upper electrode plate and a lower electrode plate disposed in the reaction chamber, and are connected in series with a matcher; a voltage measurement module, which is used to detect the voltage on the first resistor electrically connected to the ground, send a first trigger signal when the measured voltage is zero, and send a second trigger signal when the measured voltage is a preset negative bias voltage; and a control module, which is used to control a radio frequency power supply to output ignition electrical energy to ignite the reaction gas, determine that the ignition is successful when receiving the second trigger signal, control the radio frequency power supply to re-ignite when receiving the first trigger signal, accumulate the number of ignition times and determine whether the number of ignition times reaches a preset number, if it reaches, determine that the ignition fails, otherwise continue to ignite and accumulate the number of ignition times. The present invention can improve the ignition success rate.

Description

Technical Field

[0001] The present invention relates to plasma processing equipment, and particularly to an ignition system. Background Art

[0002] Thin film / crystalline silicon heterojunction solar cells (hereinafter referred to as heterojunction solar cells, also known as HIT or HJT or SHJ solar cells) belong to the third generation of high-efficiency solar cell technology. It combines the advantages of crystalline silicon and silicon thin films, has characteristics such as high conversion efficiency and low temperature coefficient, and will gradually replace PERC (Passivated Emitter and Rear Cell) cells and become the mainstream of photovoltaic cells.

[0003] The core of a heterojunction solar cell is the formation of various amorphous silicon thin films, which are formed by corresponding PECVD processes in the reaction chamber of a plasma-enhanced chemical vapor deposition (PECVD) device. When igniting or igniting the reaction gas in the PECVD reaction chamber, first ensure that there is a properly proportioned reaction gas in the reaction chamber and at an appropriate pressure, and then feed an ignition power higher than the normal operating power to its upper and lower plates to perform RF ignition for about 0.3 - 1 second.

[0004] At present, after the PECVD reaction chamber is cleaned and multiple depositions are completed, its impedance has changed due to the thick film deposited on the inner wall, which may lead to RF ignition failure. After the RF ignition fails and enters the normal film-forming step (whose radio frequency power is less than the ignition power), the film-forming step is not the best ignition condition and will not make the ignition successful. Ignition failure requires manual intervention, which will cause a decrease in the production line operation time and a decrease in the product qualification rate.

[0005] Therefore, how to provide an ignition system to solve the problem that RF ignition is prone to failure after multiple film formations, improve the operation time of the production line, and improve product performance has become an urgent technical problem in the industry. Summary of the Invention

[0006] In view of the above problems of the prior art, the present invention proposes an ignition system for igniting the reaction gas in the reaction chamber of a plasma processing device. The plasma processing device includes a radio frequency power supply and a matcher. The ignition system includes:

[0007] A first resistor and a second resistor connected in series, which are connected in parallel with the upper plate and the lower plate arranged in the reaction chamber and are connected in series with the matcher;

[0008] A voltage measurement module for detecting the voltage on the first resistor electrically connected to the ground, sending a first trigger signal when the measured voltage is zero, and sending a second trigger signal when the measured voltage is a preset negative bias voltage; and

[0009] A control module, which is used to control the radio frequency power supply to output ignition energy to ignite the reaction gas, determines that the ignition is successful when receiving the second trigger signal, controls the radio frequency power supply to re-ignite when receiving the first trigger signal, accumulates the number of ignitions and determines whether the number of ignitions reaches a preset number. If it reaches, it determines that the ignition fails; otherwise, it continues to ignite and accumulates the number of ignitions.

[0010] In one embodiment, the matcher includes an inductor, a first capacitor, and a second capacitor. The first capacitor is connected in parallel with the radio frequency power supply, and the second capacitor is connected in parallel with the first capacitor after being connected in series with the inductor, a first resistor, and a second resistor.

[0011] In one embodiment, both the first capacitor and the second capacitor are adjustable capacitors, and their maximum capacitance values are both 200 picofarads (pF).

[0012] In one embodiment, the first resistor is 10 kΩ.

[0013] In one embodiment, the second resistor is 200 kΩ.

[0014] In one embodiment, the plasma processing device is a plasma enhanced chemical vapor deposition (PECVD) device.

[0015] In one embodiment, the capacitance value between the upper plate and the lower plate is 8 nanofarads (nF).

[0016] In one embodiment, the preset negative bias voltage is -10 to -40 V.

[0017] In one embodiment, the operating frequency of the radio frequency power supply is 13.56 MHz or 40 MHz, and the rated power is 6000 W.

[0018] In one embodiment, the preset number includes three times.

[0019] In one embodiment, the inductance value of the inductor is 700 nanohenries (nH).

[0020] Compared with the prior art where RF ignition failure is likely to occur after multiple depositions, the ignition system of the present invention includes a first resistor and a second resistor connected in series, a voltage measurement module, and a control module. The first resistor and the second resistor are connected in parallel with the upper plate and the lower plate disposed in the reaction chamber and are connected in series with the matcher. The control module is configured to control the RF power supply to output ignition energy to ignite the reaction gas. It determines that the ignition is successful when it receives a second trigger signal sent by the voltage measurement module indicating that the measured voltage is a preset negative bias voltage. When it receives a first trigger signal sent by the voltage measurement module indicating that the measured voltage is zero, it controls the RF power supply to re-ignite, accumulates the number of ignitions, and determines whether the number of ignitions reaches a preset number. If it reaches the preset number, it determines that the ignition fails; otherwise, it continues to ignite and accumulates the number of ignitions.

[0021] The present invention can solve the problem of RF ignition failure caused by multiple film depositions, improve the operation time of the production line, and improve the product performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0023] Figure 1 It is a schematic structural diagram of the composition of the ignition system of the present invention. SPECIFIC EMBODIMENTS

[0024] The following provides a detailed description of the present invention in conjunction with the drawings and specific embodiments to better understand the purpose, features, and advantages of the present invention. It should be understood that the aspects described below in conjunction with the drawings and specific embodiments are merely exemplary and should not be construed as imposing any limitation on the protection scope of the present invention. Unless the context clearly indicates otherwise, the singular forms "a" and "the" include plural referents. It should be noted that in this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0025] See Figure 1 which shows a schematic structural diagram of the composition of the ignition system of the present invention. As Figure 1As shown, the ignition system 1 is used to ignite the reaction gas in the reaction chamber 24 of the plasma processing equipment. The plasma processing equipment includes a radio frequency power supply 20, a matcher 22, and a reaction chamber 24. The ignition system 1 includes a first resistor R1 and a second resistor R2 connected in series, a voltage measurement module 10, and a control module 12. The ignition system 1 is disposed outside the reaction chamber 24. Each component of the ignition system 1 will be described in detail below.

[0026] The first resistor R1 and the second resistor R2 are connected in series and are connected in parallel with the upper electrode plate C30 and the lower electrode plate C32 disposed in the reaction chamber 24. The first resistor R1 and the second resistor R2 are also connected in series with the matcher 22. One end of the first resistor R1 that is not connected to the second resistor R2, the lower electrode plate C32, and one end of the radio frequency power supply 20 are all electrically connected to the ground G. In this embodiment, the capacitance value between the upper electrode plate C30 and the lower electrode plate C32 is 8 nF; the first resistor R1 is 10 kΩ; the second resistor R2 is 200 kΩ.

[0027] The matcher 22 includes an inductor L1, a first capacitor C1, and a second capacitor C2. The first capacitor C1 is connected in parallel with the radio frequency power supply 20. The second capacitor C2 is connected in parallel with the first capacitor C1 after being connected in series with the inductor L1, the first resistor R1, and the second resistor R2. In this embodiment, both the first capacitor C1 and the second capacitor C2 are adjustable capacitors, and their maximum capacitance values are both 200 picofarads pF; the inductance value of the inductor L1 is 700 nanohenries nH.

[0028] The voltage measurement module 10 is used to detect the voltage on the first resistor R1 that is electrically connected to the ground G, and sends a first trigger signal when the measured voltage is zero, and sends a second trigger signal when the measured voltage is a preset negative bias voltage.

[0029] The control module 12 is used to control the radio frequency power supply 20 to output ignition energy to ignite the reaction gas in the reaction chamber 24, and determines that the ignition is successful when it receives the second trigger signal sent by the voltage measurement module 10. When the control module 12 receives the first trigger signal sent by the voltage measurement module 10, it controls the radio frequency power supply 20 to re-ignite, accumulates the number of ignition times and determines whether the number of ignition times reaches a preset number. The preset number includes three or more other numbers. If the number of ignition times reaches the preset number, it is determined that the ignition fails; otherwise, the ignition continues and the number of ignition times is accumulated. In this embodiment, the preset negative bias voltage is -10 to -40 V. More specifically, the preset negative bias voltage can be -10 to -20 V.

[0030] The matcher 22 includes an inductor L1, a first capacitor C1, and a second capacitor C2. The first capacitor C1 is connected in parallel with the RF power supply 20. The second capacitor C2 is connected in series with the inductor L1, a first resistor R1, and a second resistor R2, and then connected in parallel with the first capacitor C1. Both the first capacitor C1 and the second capacitor C2 are adjustable capacitors, and their maximum capacitance values are both 200 picofarads (pF). The inductance value of the inductor L1 is 700 nanohenries (nH).

[0031] To further illustrate the principle and efficacy of the present invention, the following takes the plasma processing equipment as a plasma enhanced chemical vapor deposition (PECVD) equipment, and takes the deposition of an intrinsic amorphous silicon thin film in the PECVD equipment as an example for illustration. When using Figure 1 the ignition system 1 shown to ignite the reaction gas in the reaction chamber 24 of the PECVD equipment, at this time, a silicon wafer on which an intrinsic amorphous silicon thin film needs to be deposited is provided in the reaction chamber 24, and it is under a pressure suitable for performing the PECVD process (for example, 0.7 to 1.5 millibars), and silane, argon, and hydrogen with an appropriate ratio are passed through it. The control module 12 of the ignition system 1 controls the RF power supply 20 to supply ignition electrical energy to the upper electrode plate C30. If the ignition is successful, the voltage measurement module 10 will detect that the voltage on the first resistor R1 is a preset negative bias voltage and send a second trigger signal. After receiving the second trigger signal, the control module 12 determines that the ignition is successful. If the RF power supply 20 fails during the first ignition due to changes in the conditions in the reaction chamber 24, the voltage measurement module 10 detects that the voltage on the first resistor R1 is zero and sends a first trigger signal. After receiving the first trigger signal, the control module 12 controls the RF power supply 20 to perform a re-ignition, and the control module 12 accumulates the number of ignitions and determines whether the number of ignitions reaches a preset number (for example, 3 times). When the second ignition of the RF power supply 20 is successful, the voltage measurement module 10 can detect that the voltage on the first resistor R1 is a preset negative bias voltage and send a second trigger signal. After receiving the second trigger signal, the control module 12 determines that the ignition is successful. If the second ignition still fails, the control module 12 controls the RF power supply 20 to perform a third ignition. When the voltage measurement module 10 detects that the voltage on the first resistor R1 is a preset negative bias voltage, it sends a second trigger signal. After receiving the second trigger signal, the control module 12 determines that the ignition is successful. If the third ignition is still not successful, the control module 12 finally determines that the ignition fails.

[0032] The ignition system of the present invention includes a first resistor R1 and a second resistor R2 connected in series, a voltage measurement module 10, and a control module 12. The first resistor R1 and the second resistor R2 are connected in parallel with the upper electrode plate C30 and the lower electrode plate C32 disposed in the reaction chamber 24, and are connected in series with the matcher 22. The voltage measurement module 10 is configured to detect the voltage on the first resistor R1 electrically connected to the ground, and send a first trigger signal when the measured voltage is zero, and send a second trigger signal when the measured voltage is a preset negative bias voltage. The control module 12 is configured to control the RF power supply to output ignition energy to ignite the reaction gas. It determines that the ignition is successful when receiving the second trigger signal, controls the RF power supply 20 to re-ignite when receiving the first trigger signal, accumulates the number of ignition times, and determines whether the number of ignition times reaches a preset number. If it reaches, it determines that the ignition fails; otherwise, it continues to ignite and accumulates the number of ignition times.

[0033] The present invention can solve the problem of RF ignition failure caused by multiple film depositions, improve the running time of the production line, and improve the product performance.

[0034] The above embodiments are provided for those skilled in the art to implement or use the present invention. Those skilled in the art can make various modifications or changes to the above embodiments without departing from the inventive concept of the present invention. Therefore, the protection scope of the present invention is not limited by the above embodiments, but should be the maximum scope that conforms to the innovative features mentioned in the claims.

Claims

1. An ignition system for igniting reaction gas in a reaction chamber of a plasma processing apparatus, the plasma processing apparatus including a radio frequency power supply and a matcher, characterized in that, The ignition system includes: A first resistor and a second resistor connected in series, which are connected in parallel with the upper plate and the lower plate arranged in the reaction chamber and are connected in series with the matcher; A voltage measurement module, which is used to detect the voltage on the first resistor electrically connected to the ground, send a first trigger signal when the measured voltage is zero, and send a second trigger signal when the measured voltage is a preset negative bias voltage; and A control module, which is used to control the RF power supply to output ignition energy to ignite the reaction gas, determines that the ignition is successful when receiving the second trigger signal, controls the RF power supply to re-ignite when receiving the first trigger signal, accumulates the ignition times and judges whether the ignition times reach the preset times. If so, it determines that the ignition fails, otherwise continues to ignite and accumulates the ignition times.

2. The ignition system according to claim 1, characterized in that The matcher includes an inductor, a first capacitor and a second capacitor. The first capacitor is connected in parallel with the RF power supply, and the second capacitor is connected in parallel with the first capacitor after being connected in series with the inductor, the first resistor and the second resistor.

3. The ignition system according to claim 2, wherein Both the first capacitor and the second capacitor are adjustable capacitors, and their maximum capacitance values are both 200 picofarads (pF).

4. The ignition system according to claim 1, wherein, The first resistor is 10 kΩ, and the second resistor is 200 kΩ.

5. The ignition system according to claim 1 or 4, characterized in that, The plasma processing equipment is a plasma enhanced chemical vapor deposition (PECVD) equipment.

6. The ignition system according to claim 1, wherein, The capacitance value between the upper plate and the lower plate is 8 nanofarads (nF).

7. The ignition system according to claim 1, characterized in that, The preset negative bias voltage is -10 to -40 V.

8. The ignition system according to claim 1, characterized in that, The operating frequency of the RF power supply is 13.56 MHz or 40 MHz, and the rated power is 6000 W.

9. The ignition system according to claim 1, characterized in that, The preset times include three times.

10. The ignition system according to claim 2, characterized in that, The inductance value of the inductor is 700 nanohenries (nH).

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