TW201526134A - Semiconductor processing device - Google Patents

Abstract

The present invention provides a system for obtaining a precise measurement signal in a radio frequency environment. The present invention makes use of an electrical signal detector electrically floating in a radio frequency environment to receive nearby weak electrical signals that are received by a plurality of probes. These electrical signals are processed to obtain the required engineering parameter data. Then, the engineering parameter data are converted into optical signals to be transmitted to the outside of the radio frequency environment so as to finally obtain precise measurement data and also prevent the radio frequency power from leakage, thereby saving the cost and space of a plurality of filters.

Description

Semiconductor processing device

The present invention relates to the field of semiconductor manufacturing technology, and in particular, to an electrical signal measuring system for a plasma processing apparatus.

Semiconductor processing processes for the fabrication of integrated circuits include chemical vapor deposition processes, plasma etching processes, and the like. In a plasma-assisted semiconductor processing apparatus, in order to generate a plasma, it is necessary to apply high-power radio frequency energy into the plasma reaction chamber, so that the entire reaction chamber space memory is in a large radio frequency electromagnetic field. As semiconductor processing precision increases, achieving more uniform processing results requires finer adjustment of various processing-related parameters, such as semiconductor substrate temperature. In order to more accurately control the substrate temperature, a method of placing a heating device in an electrostatic chuck (ESC) in which a wafer is placed is widely used in the industry. The heating device is placed in different areas of the electrostatic chuck to independently control the temperature of different areas to achieve a uniform temperature distribution. A heating device such as a resistance wire or the like requires a power input line to input electric energy to the heating device, and the input heating voltage is usually a low-frequency alternating current or a direct current heating voltage. The heating device is located in the electrostatic chuck that is radiated by the radio frequency, so an additional filter is required to prevent the RF signal from flowing backward from the power input line into the heating voltage source. In order to control the temperature of each zone in the electrostatic chuck, it is necessary to measure the temperature of each zone in order to determine how much power needs to be input to the heating device. There are two main types of temperature detection systems: one is as described in the 17th column of US Pat. No. 8,092,639, a probe is embedded in an electrostatic chuck, the temperature is converted into an optical signal, and the signal is transmitted through an optical fiber to a controller without external radio frequency interference. . Such a temperature detecting fiber is expensive and because the optical fiber is installed in a measurement area in the reaction chamber, it is easy to crush the fiber when the reaction chamber is cleaned or replaced, and maintenance is difficult. The other is to use a thermal coupler probe to measure temperature. Since the thermocouple probe is a conductor and the temperature generated by the potential signal is very weak, only the mv level, an additional filter is needed to couple the RF signal to the thermocouple probe. Filter out as much as possible. Figure 1 shows the structure of the reactor using the thermocouple temperature measurement method. The conventional reactor includes a reaction chamber 1 including a gas distribution device 40 at the top, and the gas distribution device 40 is connected to the gas source 50 through a pipe and a valve. The bottom of the reaction chamber includes a base 33 including a lower electrode to which a radio frequency power source is connected. An electrostatic chuck 34 is included above the lower electrode. A substrate 30 to be processed is placed over the electrostatic chuck. An edge ring 36 is also included around the electrostatic chuck and substrate 30. The electrostatic chuck includes a plurality of heating means, a centrally located heating means 60b and an edge heating means 60a surrounding the central heating means 60b. These heating devices receive heating power (not shown) through the power input line. The temperature detecting ends of the two thermocouples 104, 102 are respectively adjacent to the edge heating device 60a and the center heating device 60b to detect the respective temperatures of the two regions, respectively. Two filters 103 are respectively connected between the thermocouples 104, 102 and the temperature detector. The temperature detector processes the electrical signals from the thermocouple to obtain a temperature signal, and transmits the temperature signal to the process controller. The process controller determines the process parameters to be adjusted based on temperature signals and other parameters such as air pressure, RF power, processing time, and the like. The semiconductor processing apparatus also includes a gas extraction device 20 that exhausts the gas from the reaction chamber to achieve the desired low pressure.

As shown in Figure 1, when there are many temperature zones that need to be independently controlled, such as the 2 zones in the figure, at least 2 filters are required to filter the RF signals separately, and the weak electrical signals are transmitted to the temperature detector, so the filtering is performed. It is very difficult to debug the device. Moreover, the plurality of filters are not only bulky, but also affect the arrangement of the mechanisms within the semiconductor processing apparatus. Since the temperature detector must be placed outside the RF radiation zone, the thermocouples 104, 102 require a long line to reach the temperature controller, which is determined by the material characteristics of the thermocouple. Longer thermocouples will cause an increase in heat capacity, further The response speed caused by the temperature measurement is reduced, and the rapidly changing temperature cannot be measured.

In order to solve the above problems, there is a need in the industry for a new system that enables accurate and rapid measurement of temperature in multiple heating zones in a radio frequency environment.

The problem to be solved by the present invention is to provide a semiconductor processing apparatus capable of detecting the temperature of a support disk having a plurality of temperature control regions at low cost and with reliability. The semiconductor processing device of the present invention comprises: a reaction chamber, the reaction chamber includes a base, the base is provided with an insulating material support disk, the support disk is provided with a substrate to be processed, a radio frequency generating device, a radio frequency electromagnetic field is generated and applied to the reaction chamber The bottom and side walls of the reaction chamber include an electric field mask conductor covering an electric field in the reaction chamber; the support disk includes a first heating device to heat the first region of the support disk, and a second heating device surrounds the first portion Heating a second area of the support disk around the device, the first thermocouple includes a detecting end disposed in the first area, and further comprising a second end connected to a temperature detector; the second thermocouple including a detecting end setting The second region further includes a second end connected to the temperature detector; the temperature detector receiving and processing the electrical signals from the first thermocouple and the second thermocouple and obtaining the first region and the second region The temperature signal transmits the temperature signal through a transmission fiber to a process controller located outside the mask conductor.

The temperature detector is connected to the DC power source outside the mask conductor through a filter, and can provide a stable power supply for the temperature detector. The filter is installed inside the mask conductor to prevent the RF electric field from leaking into the reaction chamber. outer.

Wherein the first and second heating devices are connected to the first heating power source and the second heating power source through the first heating filter and the second heating filter, respectively. The process controller controls the power output of the first heating power source and the second heating power source according to the temperature signals of the first region and the second region to implement temperature feedback control.

The invention also provides a semiconductor processing apparatus comprising: a reaction chamber, the reaction chamber includes a base, the base is provided with an insulating material support disk, the support disk is provided with a substrate to be processed, and a radio frequency generating device generates a radio frequency electromagnetic field And applied to the reaction chamber, the bottom of the reaction chamber and the sidewall include an electric field mask conductor to cover the electric field in the reaction chamber, an electrical signal detector is located in the reaction chamber, and the electrical signal detector includes at least one signal input end. The signal input terminal is connected to the signal output end of a process parameter probe, and the process parameter probe further comprises a detecting end disposed on the base or the support disk, and the electrical signal detector processes the signal from the process parameter probe to obtain the process parameter. Data, the electrical signal detector converts the process parameter data into an optical signal and outputs it through an optical signal output; a transmission fiber is connected to the optical signal output end of the electrical signal detector and is located in the electric field mask conductor Between the outer process controllers.

The electrical signal detector is in an electrically floating state to ensure that the RF signal does not interfere with the detection of the process parameter signal.

The process parameter is the support plate temperature or the potential of the substrate or the leakage current of the support disk, which can realize the detection of the process parameters more comprehensively.

The signal detector may include a plurality of signal input terminals, each of which is connected to a signal output end of a process parameter probe, and the detection ends of the plurality of signal probes are located in different areas of the base or the support plate for detecting Different process parameters. The detection ends of the plurality of process parameter probes may also be disposed in different areas of the support disk for detecting the temperature of different regions corresponding to the support disks, wherein different regions of the support disk are distributed in a grid shape, and the number of regions is greater than 8. The present invention can significantly reduce the number of filters and the space occupied when the number of temperature control regions is large.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of a semiconductor processing apparatus for measuring temperature by a thermocouple according to the present invention. The figure includes a reaction chamber 1. The reaction chamber 1 includes a gas distribution device 40 at the top, and the gas distribution device 40 is connected through a pipe and a valve. To the gas source 50. The bottom of the reaction chamber includes a base 33 including a lower electrode to which a radio frequency power source is connected. An electrostatic chuck 34 is included above the lower electrode. The RF power source can also be applied to the gas distribution device 40 as the upper electrode or to the inductor coil outside the reaction chamber 1. The electromagnetic field generated by the inductor coil enters the reaction chamber space through the insulating material window at the top of the reaction chamber to ionize the reaction chamber. Reaction gas. A substrate 30 to be processed is placed over the electrostatic chuck. An edge ring 36 is also included around the electrostatic chuck and substrate 30. The electrostatic chuck includes a plurality of heating means, a centrally located heating means 60b and an edge heating means 60a surrounding the central heating means 60b. These heating devices receive heating power from a heating power source (not shown) through a power input line, and a filter is connected in series between the heating power box heating devices. These filters are capable of filtering out RF signals on the reactive power input line, allowing only heating power (such as low frequency AC current or DC current) to pass through the power input line.

The bottom and side walls of the reaction chamber 1 of the semiconductor processing device include a grounded mask conductor that can cover the RF electric field so that the RF electric field is only present inside the mask conductor, ensuring that no RF electric field is present outside the mask conductor.

The temperature detecting ends of the two thermocouples 104', 102' are respectively adjacent to the edge heating device 60a and the central heating device 60b to respectively detect the respective temperatures in the two regions, while the detecting ends of the two thermocouples 104', 102' are respectively Connect to two inputs of a temperature detector. The temperature detector processes the electrical signal from the thermocouple to obtain the temperature data, and then converts the temperature data into an optical signal, and transmits the optical signal with the temperature data to the bottom of the reaction cavity through the transmission fiber 106, a process control The device receives the optical signal and decodes the temperature data, and then controls the power output of different heating power sources according to the temperature data or other process parameters such as air pressure, processing time, and RF power, and finally controls the temperature distribution of the central region and the edge region. The transmission fiber 106 of the present invention can also be connected to the process controller through a mask conductor laterally passing through the sidewall of the reaction chamber, and the specific structure can be adjusted according to design requirements. Any embodiment of the transmission fiber of the present invention can be implemented as long as the optical signal can pass from the radio frequency environment through the mask conductor to the area not interfered by the radio frequency electric field.

The temperature detector is located in an RF-hot area and is in an floating state such that the RF field has no significant voltage between the two thermocouples 104', 102' and the temperature detector. There is no significant RF current flowing from the thermocouple to the temperature detector that affects the accuracy of the detection. The potential (mv level) generated at the detection end is very weak and is highly susceptible to external signal interference. Even with the filter 103 to rate the wave as in the conventional technique shown in FIG. 1, it is not guaranteed that all interference signals are filtered out. Therefore, the measurement accuracy cannot be guaranteed. The award temperature detector of the invention is directly disposed near the temperature range to be measured, and has the same electromagnetic environment as the temperature range to be measured, can completely avoid the existence of these disturbances, and obtain high-precision temperature data.

The processing circuit or wafer operation in the temperature detector requires power supply. In the RF environment, the power input line for powering the heating device can be taken. Because the power input line has a filter before the RF environment, the temperature detection is performed. The RF electric field on the power supply line does not flow outside the reaction chamber, causing leakage of RF energy. It is also possible to specifically provide a detector power supply 107 as shown in Fig. 2 to supply power to the temperature detector through a dedicated filter 105. The detector power supply 107 can output a stable DC voltage of 5-12V, which is not only low in power compared to the power supply to the heating devices 60a, 60b, but also has a relatively constant power output, so the filter design is relatively simple and the footprint is small. So it does not create additional space or cost burden.

The isolation measuring system of the semiconductor processing apparatus of the present invention can be used for temperature detection of a grid-like partition as shown in FIG. 3, except that it can be used to detect the temperature of a plurality of partitions inside and outside as shown in FIG. In some applications, since the temperature distribution is not only related to the radius of the substrate, but also related to the orientation, even a plurality of discontinuous temperature uneven regions may occur, so the temperature control of the grid-like partition can be used to solve the temperature. Uneven problem. To better solve these problems, it is necessary to set as many temperature control areas as possible, as shown in Figure 3, including more than 8, or even more than 50 temperature control areas, each temperature control area 61 corresponding to a different base above The part of the piece. In this application, if a conventional thermocouple is used with a thermocouple, and each thermocouple is connected to a temperature detector outside the reaction chamber by a filter, a total of more than 50 filters are required, which is not only expensive. Moreover, a large amount of space is occupied, making it impossible to install other components, which is basically not feasible. Using the method of the present invention to achieve grid-like partition temperature control requires only one thermocouple per temperature control zone, and these thermocouples are connected to a uniform temperature detector in the radio frequency region, and the temperature detector will be different regions. The temperature signal is transmitted to the process controller outside the reaction chamber through a fiber 106 to finally achieve temperature control in multiple zones.

The detection system of the present invention can also be used to detect other weak electrical signals located in the radio frequency environment, such as during the plasma processing process, the charge on the substrate will gradually accumulate or the charge will be rapidly reduced during the de-chucking process. Therefore, the potential changes. These potential signals are important for the plasma processing and de-clamping process and need to be monitored. However, in the RF environment, these weak potential signals are difficult to detect after filtering by the filter. Other parameters are estimated. The same principle is also an important basis for detecting whether the clamping action is completed during the clamping and de-clamping process. It can also be realized by the isolation detection system provided by the present invention. FIG. 4 is a schematic diagram of a semiconductor processing apparatus for potential/current detection according to another embodiment of the present invention. In Fig. 4, a probe 108 has an upper end connected to the lower surface of the substrate and a lower end connected to the potential/current detector. The potential/current detector detector converts the received weak electrical signal into an optical signal and transmits it through the transmission fiber 106 to a process controller external to the reaction chamber. The process controller converts the received optical signals into measured potential/current signals and controls the process parameters based on these signals. The probe 108 may also be embedded inside a support disk structure such as an electrostatic chuck to detect leakage current flowing through the electrostatic chuck. The potential/current detector of the present invention can also be integrated with the temperature detector of the embodiment described in FIG. 2 to form an electrical signal detector, and the electrical signal detector can receive and process various temperature, potential, and current signals of the above embodiments. , converted into optical signal output to the process controller outside the RF environment.

The invention provides an electric floating signal detector in an RF environment, receives the weak electrical signals received by the various probes nearby, processes the electrical signals to obtain the required data, and converts the data into optical signals for transmission to the optical signal. Outside the RF environment (such as the reaction cavity cover conductor), accurate measurement data is finally obtained, and the leakage of RF power is avoided, which saves the cost and space of multiple filters.

Although the present invention has been disclosed above, the present invention is not limited thereto. Any changes and modifications may be made without departing from the spirit and scope of the invention, and the scope of the invention should be determined by the scope of the claims.

1‧‧‧reaction chamber
102‧‧‧ thermocouple
102'‧‧‧ Thermocouple
103‧‧‧ filter
104‧‧‧ thermocouple
104'‧‧‧ Thermocouple
105‧‧‧Filter
106‧‧‧Fiber
107‧‧‧Detector power supply
108‧‧‧ Probe
20‧‧‧Exhaust device
30‧‧‧Substrate
33‧‧‧Base
34‧‧‧Electrostatic chuck
36‧‧‧Edge ring
40‧‧‧ gas distribution device
50‧‧‧ gas source
60a‧‧‧heating device
60b‧‧‧ heating device
61‧‧‧temperature control area

1 is a schematic view of a semiconductor processing apparatus for measuring temperature by a thermocouple according to the prior art; FIG. 2 is a schematic view of a semiconductor processing apparatus for temperature measurement by a thermocouple of the present invention; FIG. 3 is a second embodiment of the present invention, wherein the electrostatic chuck has a plurality of temperatures. Schematic diagram of the control area. 4 is a schematic view of a third embodiment of the present invention for potential/current detection.

1‧‧‧reaction chamber

102’‧‧‧ thermocouple

104’‧‧‧ Thermocouple

105‧‧‧Filter

106‧‧‧Fiber

107‧‧‧Detector power supply

20‧‧‧Exhaust device

30‧‧‧Substrate

33‧‧‧Base

34‧‧‧Electrostatic chuck

36‧‧‧Edge ring

40‧‧‧ gas distribution device

50‧‧‧ gas source

60a‧‧‧heating device

60b‧‧‧ heating device

Claims (11)

A semiconductor processing apparatus comprising: a reaction chamber, the reaction chamber includes a base, the base is provided with an insulating material support disk, the support disk is provided with a substrate to be processed, a radio frequency generating device, a radio frequency electromagnetic field is generated and applied to the reaction cavity The bottom and side walls of the reaction chamber include an electric field mask conductor covering an electric field in the reaction chamber; the support tray includes a first heating device for heating the first region of the support disk, and a second heating device surrounding the first portion A second region of the support disk is heated around the device, the first thermocouple includes a detecting end disposed in the first region, and further includes a second end connected to a temperature detector; the second thermocouple includes a detecting end setting The second region further includes a second end connected to the temperature detector; the temperature detector receiving and processing the electrical signals from the first thermocouple and the second thermocouple and obtaining the first region and the second region The temperature signal transmits the temperature signal through a transmission fiber to a process controller located outside the mask conductor. The semiconductor processing apparatus of claim 1, wherein the temperature detector is connected to a DC power source outside the mask conductor through a filter. The semiconductor processing apparatus of claim 2, wherein the filter is mounted inside the mask conductor. The semiconductor processing apparatus of claim 1, wherein the first and second heating means are connected to the first heating power source and the second heating power source through the first heating filter and the second heating filter, respectively. The semiconductor processing apparatus of claim 4, wherein the process controller controls power outputs of the first heating power source and the second heating power source according to temperature signals of the first area and the second area. A semiconductor processing apparatus comprising: a reaction chamber, the reaction chamber includes a base, the base is provided with an insulating material support disk, the support disk is provided with a substrate to be processed, and a radio frequency generating device generates a radio frequency electromagnetic field and is applied to the reaction chamber The bottom of the reaction chamber and the sidewall include an electric field mask conductor covering the electric field in the reaction chamber, an electrical signal detector is located in the reaction chamber, and the electrical signal detector includes at least one signal input end, and the signal of the detector The input end is connected to a signal output end of a process parameter probe, and the process parameter probe further comprises a detecting end disposed on the base or the support plate, and the electrical signal detector processes the signal from the process parameter probe to obtain process parameter data. The electrical signal detector converts the process parameter data into an optical signal and outputs it through an optical signal output end, and a transmission fiber is connected to the optical signal output end of the electrical signal detector and outside the electric field mask conductor. Between process controllers. The semiconductor processing device of claim 6, wherein the electrical signal detector is in an electrically floating state. The semiconductor processing apparatus of claim 6, wherein the process parameter is a support disk temperature or a potential of the substrate or a leakage current of the support disk. The semiconductor processing device of claim 6, wherein the electrical signal detector comprises a plurality of signal input terminals, each signal input end being connected to a signal output end of a process parameter probe, and the detection end of the plurality of signal probes Located in different areas of the base or support plate for detecting different process parameters. The semiconductor processing device of claim 6, wherein the electrical signal detector comprises a plurality of signal input terminals, each signal input end being connected to a signal output end of a process parameter probe, and the detecting of the plurality of process parameter probes The ends are disposed in different areas of the support tray for detecting the temperature of different areas corresponding to the support discs. The semiconductor processing apparatus of claim 10, wherein the different regions of the support disk are distributed in a grid shape, and the number of regions is greater than 8.