JP2002294463A - Apparatus and method for forming film on large-scale substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus and a method for forming a film on a large- scale substrate with plasma CVD, which can accurately form a film having a uniform thickness and quality, by detecting factors directly correlating with distribution of plasma as a distribution on or around a plane of a substrate, and controlling the distribution of plasma into the optimum condition, on the basis of the information on the distribution. SOLUTION: This apparatus comprises a sealed housing which introduces high-frequency current fractionated by a high-frequency current fractionation means, through a high-frequency current fractionation point set on at least one of electrodes or the current feeding point, and converts high-frequency current into light by a photovoltaic device, an optical fiber cable which takes out optical signals from the sealed housing and leads them to an optical signal processing device, and the optical signal processing device which outputs plasma distribution signals of generated plasma according to the optical signals, to make the plasma distribution signals as the information for uniformizing the distribution of generated plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming a film on a large substrate by plasma CVD and a method for forming a film on a large substrate.

[0002]

2. Description of the Related Art A film forming apparatus for forming a film on a large substrate by plasma CVD generally includes a substrate holding means for holding a large rectangular substrate in a vacuum chamber, heating the substrate, and facing the large substrate. An electrode for generating plasma in the facing space, a high-frequency power supply connected to a feed point of the electrode via an impedance matching circuit, gas supply means for supplying a process gas into the vacuum chamber, and exhausting the vacuum chamber. A gas exhaust device for maintaining the set pressure is provided.The vacuum chamber is evacuated and maintained at the set pressure, and the large substrate is heated while supplying a process gas containing, for example, silane, and the power supply point of the electrode is provided. Is supplied with high-frequency power to generate plasma in the space between the electrode and the substrate, thereby forming a film such as silicon on the substrate.

In particular, in the case of film formation on a large substrate plane, it is important that the film thickness on the entire plane and the film quality are uniform, and for that purpose, the space where the substrate and the electrode face each other, that is,
The distribution of plasma generated on the substrate surface needs to be controlled uniformly. To do so, it is first necessary to detect a factor that directly correlates to the plasma distribution as a distribution on or near the plane. And, based on the distribution information,
What is necessary is just to control to the optimal plasma distribution state.

As is well known, in a film forming chamber, various chemical active species are present in a high temperature state and in an environment where a high-frequency high frequency is applied. Then, the film adheres to the observation window, and as the film forming time elapses, the light transmittance deteriorates, and eventually the measurement becomes impossible. Also, the field of view is restricted depending on the internal structure such as a film-forming electrode, and there are some points where measurement is impossible.

Further, if a probe or the like is inserted into the plasma existing area for electrical measurement, the generated plasma itself is disturbed and the uniformity of distribution is impaired.

Electrical means such as a voltage divider and a current detection coil are also affected by electromagnetic induction and have large errors due to the above-mentioned reasons.

Therefore, conventionally, plasma distribution information is obtained,
There has been no highly accurate apparatus or method capable of forming a uniform film thickness and quality by making the plasma distribution uniform.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and in a film forming apparatus and a method for a large substrate by plasma CVD, a factor directly correlating to plasma distribution is determined on the substrate plane or in the vicinity of the plane. And a high-precision film forming apparatus for large substrates capable of forming a film having a uniform film thickness and quality by controlling the plasma distribution to an optimum state based on the distribution information. It is an object to provide a membrane method.

[0009]

According to the present invention, there is provided a film forming apparatus for a large substrate, comprising a substrate holding means for holding and heating a large rectangular substrate in a vacuum chamber, and a facing space facing the large substrate. An electrode for generating a plasma, a high-frequency power supply connected to a feed point of the electrode via an impedance matching circuit, a gas supply unit for supplying a process gas into a vacuum chamber, and exhausting the vacuum chamber to maintain a set pressure. In a film forming apparatus for a large substrate having a gas exhaust device, a high-frequency current separated by high-frequency current collecting means is introduced using at least one of the electrodes or the feeding point as a high-frequency current separating point, and photoelectric conversion is performed. A sealed casing for converting a high-frequency current into light by the device, an optical cable for extracting an optical signal from the sealed casing and guiding the optical signal to an optical signal processor, and a plasma component generated by the optical signal. And an optical signal processor for outputting a signal, the plasma distribution signal, characterized in that the information to achieve uniformity of generated plasma distribution.

In the method of forming a film on a large substrate of the present invention, the vacuum chamber is evacuated and maintained at a set pressure, and while supplying a process gas, a large rectangular substrate is held in the vacuum chamber and heated. By supplying high-frequency power to the feeding point of the electrode facing the large-sized substrate through an impedance matching circuit,
A plasma is generated in a space facing the electrode and the substrate, and in a large-size substrate deposition method for depositing a film on the substrate, the high-frequency current distribution point is defined as a high-frequency current distribution point on at least one electrode or the feeding point. The current is introduced into the sealed housing, the high-frequency current is converted to light, the optical signal is extracted from the sealed housing, guided to an optical signal processor, and the plasma signal of the generated plasma is output by the optical signal, It is characterized in that the generated plasma is made uniform.

[0011] Accordingly, the sorting means for sorting the high-frequency current from the sorting point is accessed from the rear of the electrode together with the cable connected to the closed casing into which the high-frequency current is to be introduced from the sorting means, so that the plasma is disturbed. Never. Further, the sorting means can be obtained by connecting a conducting wire directly to the electrode or the feeding line at the sorting point, but can also be taken out via an inductance or a conductance. As the simplest example, as shown in FIG. 2, the sorting cable 102 may be wound around the connection end of the power supply line 106 to the electrode 109, and the high-frequency current i generated by the induction of the current I to the electrode may be extracted.

The separated current is guided to a sealed casing 101 by a sorting cable 102, converted into light by a photoelectric conversion device 201 disposed in the casing, and converted into an optical cable 103.
As a result, the optical signal is taken out and inputted to the optical signal processor. The photoelectric conversion device can be constituted by an element that emits light by an electric signal, such as a semiconductor light emitting element or a neon tube. In an optical signal processor, one end usually converts an optical signal into an electric signal,
A plasma distribution signal is output according to the signal information.

By taking out and converting the signal in this way, it is not affected by magnetism, and the processing is performed in a closed casing. Therefore, there is no need to worry about the contamination of the functional part as described above.

Further, the film forming apparatus for a large substrate according to the present invention comprises a control unit for outputting an operation amount for operating an electrode attitude adjusting actuator by using a plasma distribution signal of a generated plasma output from an optical signal processor as an input signal. An electrode attitude adjusting actuator capable of adjusting the position and attitude of the electrode by an operation amount is provided to achieve uniform distribution of generated plasma.

Further, the method for forming a film on a large substrate according to the present invention is characterized in that the position and the posture of the electrode are adjusted by the plasma distribution signal of the generated plasma to make the generated plasma uniform. Since the plasma discharge changes greatly depending on the electrode position and the electrode parallelism, it is possible to perform control that is significantly more effective and precise than control of other elements.

The electrode attitude adjusting actuator can adjust the position and attitude of the electrode by using, for example, an air cylinder, a hydraulic cylinder, a step motor, or the like, with its operating end in contact with the electrode.

Further, the film forming apparatus for a large substrate according to the present invention is characterized in that there are a plurality of high frequency current sampling points, and the method of the present invention is characterized in that the high frequency current is sampled from a plurality of points.
That is, in order to detect the plasma distribution with high accuracy, it is preferable that the number of high-frequency current sampling points, which are sampling points, is large and the amount of information is large.

Further, the film forming apparatus for a large substrate according to the present invention is characterized in that the electrode posture adjusting actuator is constituted by a plurality of actuators. In order to control the attitude of the electrode more finely and responsively, it is preferable to provide actuators at the four corners of the electrode and control the attitude and distance.

Further, the film forming apparatus for a large substrate according to the present invention is characterized in that the electrode is a ladder electrode. In order to have a function to send the process gas from the back side and reach the substrate surface, and to apply the high frequency power load effectively and uniformly,
This is because a ladder structure is preferable. The ladder structure is also suitable for current distribution and attitude / distance control according to the present invention.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be exemplarily described with reference to the drawings. However, the shapes, materials, dimensions, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the scope of the present invention thereto, unless otherwise specified, but are merely illustrative examples. Absent.

(Embodiment 1) FIG. 1 is a conceptual diagram illustrating an example of a film forming apparatus for a large substrate according to the present invention. In this example, the plasma distribution is known by measuring the current distribution, and the information is reflected on the electrode position adjusting function.

In FIG. 1, reference numeral 115 denotes a vacuum chamber for forming a film, and a substrate holding means 112 for holding and heating a large rectangular substrate 110 in the vacuum chamber and facing the large substrate. 109 for generating plasma on the surface
At the feed points by feeder lines 106a and 106b,
The high frequency power supply 104 is connected via the impedance matching circuit 107. A gas supply unit 111 for supplying a process gas 116 is provided in the vacuum chamber, and a gas exhaust device 114 for exhausting the vacuum chamber and maintaining the set pressure is provided in the exhaust port 1.
13 is connected.

The high-frequency current distribution cables 102a and 102b are connected to the end of the power supply line near the power supply point, and the other end is connected to the photoelectric conversion device in the closed casings 101a and 101b. Details of the sealed housing are shown in FIG. That is, the power supply line 10 near the power supply point on the electrode 109 for supplying the high-frequency current I
A high-frequency current distribution cable is wound around 6, and thereby a high-frequency current i is distributed. The high-frequency current i is guided to the photoelectric conversion device 201 and converted into an optical signal 202. The optical signal 202 is taken out of the housing by the optical cable 103. A semiconductor light emitting element was used for the photoelectric conversion device 201 in FIG. 2 of this example.

The optical signals converted by the photoelectric conversion devices in the closed casings 101a and 101b are transmitted to the optical cables 103a and 103b.
3b to the optical signal processor 108 connected by
The optical signal is converted into an electric signal, and the signal is input to the control unit 117 connected to the next stage, and outputs an operation amount for operating the actuator. Actuators 105a, 10
5b has its working end connected to the back surface of the electrode 109 so that the electrode can advance and retreat with respect to the substrate by the operation of the actuator.

Thus, the substrate 110 is set on the holding means 112, the inside of the vacuum chamber 115 is evacuated by the exhaust device 114, heating is started, and when the temperature reaches the set temperature, the process gas 116 is supplied while Electric power is supplied to generate plasma, and film formation proceeds.

With the above configuration, the actuator is operated by using the current distribution at the feeding point as plasma distribution information to control the position of the electrode and maintain a uniform plasma distribution.

(Embodiment 2) FIG. 3 is a perspective view for explaining an example in which a multi-point feeding, multi-point sorting, multi-point actuator system is applied to a ladder electrode in a large-sized substrate film forming apparatus of the present invention. In this example, in addition to feeding power to a plurality of portions of the electrode to make the current more uniform, the current distribution at multiple points is measured to know the plasma distribution with higher accuracy, and the information is obtained at the electrode positions at multiple points and parallelism of the electrodes. This is reflected in the adjustment function of the electrode posture including the degree.

In FIG. 3, a vacuum chamber for forming a film, a large rectangular substrate is held in the vacuum chamber, and the substrate holding means and the like are omitted. A ladder electrode 109 faces the large substrate and generates plasma in the facing space, and is supported by an electrode support frame 301. Feeding line 106 at feeding point
a, 106b, 106c and 106d through the impedance matching circuit 107
4 is connected.

At the end of the power supply line near the power supply point, high-frequency current distribution cables 102a, 102b, 102c and 1
02d, and the other ends are sealed housings 101a, 101b,
It connects to the photoelectric conversion device in 101c and 101d. Details of the sealed housing are shown in FIG. That is, the power supply line 10 near the power supply point on the ladder electrode 109 for supplying the high-frequency current I
At the end of 6, a high-frequency current distribution cable 102 is wound so that a high-frequency current i is distributed. The high-frequency current i is guided to the photoelectric conversion device 201 and converted into an optical signal 202. The optical signal 202 is taken out of the housing by the optical cable 103. Photoelectric conversion device 2 in FIG. 2 of this example
For 01, a semiconductor light emitting device was used.

The sealed casings 101a, 101b, 101c,
The optical signal converted by the photoelectric conversion device in 101d is guided to an optical signal processor 108 connected by optical cables 103a, 103b, 103c, and 103d, and the optical signal is converted into an electric signal. Control unit 1 connected
17 and outputs an operation amount for operating the actuator. Actuators 105a, 105b, 10
Reference numerals 5c and 105d denote the operating ends of the electrodes 1 and 2 so that the electrodes can advance and retreat with respect to the substrate by the operation of the actuator.
09 is connected to the back of the electrode support frame 301 supporting the same.

In this embodiment, the current distribution at multiple points is measured by the above-described configuration to know the plasma distribution more accurately, and a plurality of actuators are operated based on the information,
By controlling electrode positions and electrode attitudes including electrode parallelism at multiple points, more uniform plasma distribution is maintained.

(Embodiment 3) FIG. 4 is a conceptual diagram for explaining an example for explaining the measurement of the plasma distribution of the ladder electrode in the apparatus for forming a large substrate according to the present invention. In this example, a high-frequency current distribution is measured at multiple points on a ladder electrode, and this is displayed on a display device as plasma distribution information.

In FIG. 4, reference numeral 115 denotes a vacuum chamber for forming a film, and a substrate holding means 112 for holding and heating a large rectangular substrate 110 in this vacuum chamber. A ladder electrode 109 for generating a plasma at a high-frequency power supply 104 via an impedance matching circuit 107 through a power supply line 106 at a power supply point.
Connect. A gas supply unit 111 for supplying a process gas 116 is provided in the vacuum chamber, and a gas exhaust device 114 that exhausts the vacuum chamber and maintains the set pressure is connected to an exhaust port 113.

A high-frequency current distribution cable 102a to 102n is connected to each of the plurality of portions of the ladder electrode, and the other end is connected to a photoelectric conversion device in the closed casings 101a, 101b, 101c to 101n.

The sealed housings 101a, 101b, 101c and so on
The optical signal converted by the photoelectric conversion device in 101n is guided to the optical signal processor 108 connected by the optical cables 103a to 103n, and the optical signal is converted into an electric signal, and the display is connected to the next stage by the signal. The device 117 is driven.

Then, the substrate 110 is set on the holding means 112, the inside of the vacuum chamber 115 is evacuated by the exhaust device 114, heating is started, and when the temperature reaches the set temperature, the process gas 116 is supplied while Electric power is supplied to generate plasma, and film formation proceeds.

With the above configuration, the current distribution at each point of the ladder electrode is displayed on the display device as plasma distribution information, and the plasma distribution state is observed.

[0038]

As described above, according to the present invention, in the apparatus and method for forming a large substrate by plasma CVD, a high-frequency current distribution directly correlated with the plasma distribution is detected, and based on the distribution information, By controlling the distribution state of the plasma to be optimal, it is possible to provide a large-scale substrate film forming apparatus and a large-size substrate film forming method capable of forming a film having a uniform thickness and quality.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating an example of a large substrate film forming apparatus of the present invention.

FIG. 2 is a conceptual diagram illustrating an example of a high-frequency current sampling unit and a closed casing in the large-sized substrate film forming apparatus of the present invention.

FIG. 3 is a perspective view illustrating an example in which a multi-point power supply, a multi-point sorting, and a multi-point actuator method are applied to a ladder electrode in the large-sized substrate film forming apparatus of the present invention.

FIG. 4 is a conceptual diagram illustrating an example for explaining measurement of plasma distribution of a ladder electrode in the large substrate film forming apparatus of the present invention.

[Explanation of symbols]

 101 Closed case 101a Closed case 101b Closed case 101c Closed case 101d Closed case 101n Closed case 102 High frequency current sorting cable 102a High frequency current sorting cable 102b High frequency current sorting cable 102c High frequency current sorting cable 102d High frequency Current distribution cable 102n High-frequency current distribution cable 103a Optical cable 103b Optical cable 103c Optical cable 103d Optical cable 103n Optical cable 104 High-frequency power supply 105 Electrode attitude adjustment actuator 105a Electrode attitude adjustment actuator 105b Electrode attitude adjustment actuator 105c Electrode attitude adjustment actuator 105d Electrode attitude adjustment actuator 106 Electric wire 106a Feed line 106b Feed line 106c Feed line 106d Feed line 107 Imp Nsu matching circuit 108 optical signal processor 109 electrode 110 substrate 111 gas supply means 112 substrate holding means 113 outlet 114 gas exhaust unit 115 vacuum chamber 116 process gas 117 controller 201 the photoelectric conversion device 202 the optical signal 301 electrode support frame 401 display

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G075 AA24 AA43 BC04 CA25 CA32 CA80 EB01 EC21 EC30 4K030 CA12 FA03 JA07 KA15 5F045 AA09 BB01 BB08 CA15 DP09 EB01 EH04 EH07 EH19 GB08

Claims (8)

[Claims] 1. A substrate holding means for holding and heating a large rectangular substrate in a vacuum chamber and facing the large substrate,
An electrode for generating plasma in the facing space, a high-frequency power supply connected to a feed point of the electrode via an impedance matching circuit, gas supply means for supplying a process gas into the vacuum chamber, and a set pressure for exhausting the vacuum chamber. In a large substrate film forming apparatus having a gas exhaust device to hold, at least one of the electrodes or the feeding point as a high-frequency current sampling point, introducing a high-frequency current separated by high-frequency current sampling means, A sealed casing for converting a high-frequency current into light by a photoelectric conversion device, an optical cable for extracting an optical signal from the sealed casing and leading it to an optical signal processor, and an optical signal processing for outputting a plasma distribution signal of generated plasma by the optical signal A film forming apparatus for a large substrate, wherein the plasma distribution signal is used as information for uniformizing the generated plasma distribution. 2. A control unit for outputting an operation amount for operating an electrode attitude adjustment actuator using a plasma distribution signal of generated plasma output from an optical signal processor as an input signal, and adjusting a position and an attitude of the electrode by the operation amount. A film forming apparatus for a large substrate, comprising: an electrode attitude adjusting actuator capable of controlling the generated plasma; 3. The film forming apparatus for a large substrate according to claim 1, wherein there are a plurality of high frequency current sampling points. 4. The film forming apparatus for a large substrate according to claim 2, wherein a plurality of electrode attitude adjusting actuators are formed. 5. The film forming apparatus for a large substrate according to claim 1, wherein the electrode is a ladder electrode. 6. A vacuum chamber is evacuated and maintained at a set pressure,
While supplying a process gas, a large rectangular substrate is held in a vacuum chamber, heated, and an electrode facing the large substrate is heated.
A high-frequency power is supplied to the power supply point via an impedance matching circuit to generate plasma in a space facing the electrode and the substrate, and the film is formed on the substrate. Alternatively, the feeding point is used as a high-frequency current sampling point, the separated high-frequency current is introduced into the sealed housing, the high-frequency current is converted into light, the optical signal is extracted from the sealed housing, and the optical signal is processed by the optical signal processor. A method for forming a film on a large substrate, comprising: outputting a plasma distribution signal of generated plasma by using the optical signal; 7. The method for forming a film on a large substrate according to claim 6, wherein the position and orientation of the electrode are adjusted by the plasma intensity distribution signal of the generated plasma to make the generated plasma uniform. 8. The method for forming a film on a large substrate according to claim 6, wherein a high-frequency current is collected from a plurality of points.