JP2015119103A - Vacuum processing apparatus and method for adjusting film thickness distribution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniform the thickness distribution of a film deposited easily and for a short time by optimizing the selection of supply conditions of high frequency power in subjecting a substrate to film deposition treatment.SOLUTION: A thin film manufacturing device for forming plasma by high frequency power includes: a high frequency power source 31 outputting high frequency power; a phase modulator 33 modulating a phase of the high frequency power; a counter electrode; a plurality of discharge electrodes 3 to which the high frequency power is supplied and which form plasma between the discharge electrodes and the counter electrode; and an RF monitor 34 measuring a phase residence time distribution of the high frequency power on the discharge electrodes 3 and a voltage distribution on the discharge electrodes 3. In the thin film manufacturing device, at least one of the phase residence time distribution and the voltage distribution is adjusted so that the product of the phase residence time distribution and the voltage distribution is within a predetermined range.

Description

  The present invention relates to a vacuum processing apparatus and a film thickness distribution adjusting method, and more particularly, to a vacuum processing apparatus that performs processing by generating plasma by applying high power.

In recent years, a plasma enhanced chemical vapor deposition (PCVD) method has been used to form a material such as silicon on a substrate having a large area (for example, a size of 1 m or more in length and 1 m or more in width). A plasma CVD apparatus is used.
In Patent Document 1, in order to perform uniform film formation, high-frequency power is supplied to the discharge electrode from two power supply systems that are both left and right ends in the longitudinal direction of the discharge electrode, and the phase difference is temporally changed. To move a standing wave and obtain a uniform film thickness distribution in time integration.

Japanese Patent Laid-Open No. 2001-257098

However, in the film thickness distribution adjustment method disclosed in Patent Document 1, high-frequency power supply adjustment for changing the high-frequency phase modulation angle and high-frequency power supplied to the discharge electrode and confirmation of the film formation result are repeated. Therefore, it is necessary to select the supply conditions of the high frequency power that makes the film thickness distribution uniform. Such repeated adjustments required time for selecting the supply conditions of the high-frequency power, and also required resources such as substrates, source gases, and electric power.
Further, when the film forming conditions such as the film forming pressure, the gas flow rate, and the distance between the substrate powers are changed, the reflected power accompanying the change in the impedance of the discharge electrode as a load changes. For this reason, even when the film forming conditions are changed, the optimum conditions for making the film thickness distribution uniform change, and it is necessary to select the supply conditions of the high frequency power again. Further, it is necessary to select the film forming conditions and the high-frequency power supply conditions every time the apparatus is maintained.

  The present invention has been made in view of such circumstances. When a film forming process is performed on a substrate, the selection of a high-frequency power supply condition is optimized and the film is formed easily and in a short time. An object of the present invention is to provide a vacuum processing apparatus and a film thickness distribution adjusting method capable of making the film thickness distribution uniform.

  In order to solve the above problems, the vacuum processing apparatus and the film thickness distribution adjusting method of the present invention employ the following means.

  A vacuum processing apparatus according to a first aspect of the present invention is a vacuum processing apparatus for forming plasma by high-frequency power, and a high-frequency power source that outputs high-frequency power, a phase modulator that modulates the phase of the high-frequency power, A discharge electrode that is supplied with the high-frequency power and forms plasma between the counter electrode, a residence time distribution at each phase difference of the high-frequency power in the discharge electrode, and a voltage distribution in the discharge electrode Measuring means for measuring one of them, and adjusting at least one of the stay time distribution and the voltage distribution so that a product of the stay time distribution and the voltage distribution falls within a predetermined range.

  The vacuum processing apparatus according to this configuration forms plasma by high-frequency power, and is a high-frequency power source that outputs high-frequency power, a phase modulator that modulates the phase of high-frequency power, a counter electrode, and a counter electrode by high-frequency power. A discharge electrode that forms plasma between the electrode and the electrode. Further, at least one of the stay time distribution and the voltage distribution at each phase difference of the high-frequency power supplied to the discharge electrode is measured by the measuring means.

Here, as a result of performing analysis from various aspects of the film formation conditions, the inventors have determined that the film thickness distribution formed on the substrate is the residence time distribution at each phase difference of the high frequency supplied to the discharge electrode. We have discovered a new high-frequency power supply condition that is proportional to the product of the voltage distribution.
Therefore, at least one of the stay time distribution and the voltage distribution at each phase difference is controlled so that the product of the stay time distribution and the voltage distribution is within a predetermined range. For example, the lower the voltage is at a certain phase difference, the longer the stay time at the phase difference, and the product of the stay time distribution and the voltage distribution is within a predetermined range. Thereby, the film thickness distribution formed on the substrate becomes constant by adjusting the two parameters of the stay time distribution and the voltage distribution at each phase difference.

  Therefore, this configuration can optimize the selection of the supply condition of the high frequency power when performing the film forming process on the substrate, and can make the film thickness distribution uniform in a short time.

  In the first aspect, it is preferable that the stay time distribution is adjusted by adjusting a phase modulation waveform of the phase modulator.

  According to this configuration, the stay time distribution can be easily adjusted.

  In the first aspect, it is preferable that the adjustment of the voltage distribution is performed by adjusting at least one of an impedance of the high frequency power source and a phase angle change range of the phase modulator.

  According to this configuration, the voltage distribution can be easily adjusted.

  In the first aspect, the substrate held on the counter electrode by plasma is plasma treated, and the residence time distribution at each phase difference of the high-frequency power in the discharge electrode based on the film thickness distribution formed on the substrate It is preferable that at least one of the voltage distributions in the discharge electrode is finely adjusted.

  According to this configuration, the film thickness distribution can be easily made uniform.

  In the first aspect, the substrate held on the counter electrode by plasma is plasma-processed, the measuring unit measures the residence time distribution, and the voltage distribution is a film thickness distribution formed on the substrate. It is preferable to estimate based on this.

  According to this configuration, the measuring unit only needs to measure either one of the residence time distribution at each phase difference of the high-frequency power in the discharge electrode and the voltage distribution in the discharge electrode, so that the apparatus configuration can be further simplified.

  The film thickness distribution adjusting method according to the second aspect of the present invention includes a high-frequency power source that outputs high-frequency power, a phase modulator that modulates the phase of the high-frequency power, a counter electrode, and the high-frequency power supplied to the counter A vacuum comprising: a discharge electrode that forms plasma with the electrode; and a measurement unit that measures at least one of a residence time distribution at each phase difference of the high-frequency power in the discharge electrode and a voltage distribution in the discharge electrode In the processing apparatus, a film thickness distribution adjusting method for forming a film on the substrate by plasma, wherein the stay time distribution and the voltage distribution are set so that a product of the stay time distribution and the voltage distribution is within a predetermined range. Adjust at least one of

  According to the present invention, when a film forming process is performed on a substrate, it is possible to optimize the selection of high-frequency power supply conditions and to make the film thickness distribution uniform easily and in a short time. Have

It is the schematic which shows the structure of the thin film manufacturing apparatus which concerns on the 1st Embodiment of this invention. It is the schematic explaining supply of the electric power with respect to the discharge electrode which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the voltage distribution on the discharge electrode at the time of fixing a phase difference. It is a schematic diagram which shows phase difference distribution at the time of using a triangular wave for the phase modulation waveform of the high frequency electric power supplied to a discharge electrode. It is a schematic diagram which shows phase difference distribution at the time of using a sine wave for the phase modulation waveform of the high frequency electric power supplied to a discharge electrode. It is a figure which shows film thickness distribution at the time of using a triangular wave for the phase modulation waveform of the high frequency electric power supplied to a discharge electrode. It is a figure which shows film thickness distribution at the time of using a sine wave for the phase modulation waveform of the high frequency electric power supplied to a discharge electrode. It is a figure which shows the example of film thickness distribution at the time of forming into a film in the state which fixed the phase difference to 0 degree and +/- 180 degree. It is a figure which shows the example of the voltage value in each phase difference of the high frequency electric power supplied to a discharge electrode. It is a flowchart which shows the flow of the film thickness distribution adjustment process concerning this 1st Embodiment. It is a figure which shows the example of the voltage distribution in the discharge electrode concerning this 1st Embodiment. It is a figure which shows the example of phase residence time distribution according to the voltage distribution measured by the film thickness distribution adjustment process concerning this 1st Embodiment. It is a flowchart which shows the flow of the film thickness distribution adjustment process concerning this 2nd Embodiment.

  Hereinafter, an embodiment of a vacuum processing apparatus and a film thickness distribution adjusting method according to the present invention will be described with reference to the drawings.

[First Embodiment]
The first embodiment of the present invention will be described below.

  As a vacuum processing device, high-speed film-forming processing of films made of amorphous silicon, microcrystalline silicon, silicon nitride, etc. used for amorphous solar cells, microcrystalline solar cells, TFTs for liquid crystal displays (Thin Film Transistor), etc. A wide pressure range from vacuum to atmospheric pressure, such as thin film manufacturing equipment, sputtering equipment, dry etching equipment, plasma treatment equipment that performs substrate surface treatment, surface modification equipment and ozonizers that require large-area plasma treatment, etc. And the like. In the present embodiment, a thin film manufacturing apparatus that performs a film forming process on a substrate will be described as an example of a vacuum processing apparatus.

  FIG. 1 is a schematic configuration diagram showing a configuration of a thin film manufacturing apparatus used for forming a silicon thin film used for a solar cell panel. The thin film manufacturing apparatus 1 holds a film forming chamber 6 that is a vacuum container, a counter electrode 2 that is a conductive plate, a heat equalizing plate 5 that equalizes the temperature distribution of the counter electrode 2, a heat equalizing plate 5, and the counter electrode 2. A soaking plate holding mechanism 11, a discharge electrode 3 for generating plasma between the counter electrode 2, a deposition plate 4 for limiting a range in which a film is formed, a support unit 7 for supporting the deposition plate 4, which will be described later. Coaxial feeders 12a and 12b that supply high-frequency power from a high-frequency power source to the discharge electrode 3, a matching unit 13, a high vacuum exhaust unit 20 that exhausts gas in the film forming chamber 6, a low vacuum exhaust unit 21, and a film forming chamber 6 Is provided. In addition, in this figure, the structure regarding gas supply is abbreviate | omitted.

The film forming chamber 6 is a vacuum container, and a microcrystalline silicon film or the like is formed on the substrate 8 therein. The film forming chamber 6 is held on the table 22 while being inclined by α = 7 ° to 12 ° with respect to the vertical direction. For this reason, the normal line of the film-forming treatment surface of the substrate 8 of the counter electrode 2 faces 7 ° to 12 ° above the horizontal direction. By slightly tilting the substrate 8 from the vertical direction, the substrate 8 can be held with less effort using the weight of the substrate 8 while suppressing an increase in the installation space of the apparatus, and the adhesion between the substrate 8 and the counter electrode 2 is further improved. Thus, the temperature distribution and potential distribution of the substrate 8 can be made uniform, which is preferable.
Further, the film forming chamber 6 may be held at α = 90 ° with respect to the vertical direction, that is, in the horizontal direction. In this case, the installation space of the apparatus is required according to the size of the substrate, but the substrate 8 is adhered to the counter electrode 2 by using the entire weight of the substrate 8, so that the temperature distribution and the potential distribution of the substrate 8 are made more uniform. It is preferable in the case of making it.

  The counter electrode 2 is a conductive plate made of a non-magnetic material having holding means (not shown) that can hold the substrate 8. When performing self-cleaning, it is preferable to have fluorine radical resistance, and it is desirable to use a plate of nickel alloy, aluminum or aluminum alloy. The counter electrode 2 is an electrode (for example, a ground side electrode) facing the discharge electrode 3. One surface of the counter electrode 2 is in close contact with the surface of the soaking plate 5, and the other surface is in close contact with the surface of the substrate 8 during film formation.

  The heat equalizing plate 5 circulates a temperature-controlled heat medium inside or incorporates a temperature-controlled heater to control its own temperature so that the entire temperature is substantially uniform and is in contact with it. It has a function of making the temperature of the counter electrode 2 uniform at a predetermined temperature. Here, the heat medium is a non-conductive medium, and high heat conductive gas such as hydrogen and helium, fluorine-based inert liquid, inert oil, pure water, and the like can be used. The use of a fluorine-based inert liquid (for example, trade name: Galden, F05, etc.) is preferable because the pressure does not increase even within the range and control is easy.

  The soaking plate holding mechanism 11 holds the soaking plate 5 and the counter electrode 2 so as to be substantially parallel to the side surface (the right side in FIG. 1) of the film forming chamber 6, and the soaking plate 5 and the counter electrode 2. And the substrate 8 is held so as to be close to and away from the discharge electrode 3. The soaking plate holding mechanism 11 can bring the soaking plate 5 and the like closer to the discharge electrode 3 during film formation and position the substrate 8 from the discharge electrode 3 within a range of 3 mm to 10 mm, for example.

  The deposition preventing plate 4 is grounded to limit the range in which the film is formed by suppressing the range in which the plasma spreads. The support plate 7 covers the space on the discharge electrode 3 opposite to the counter electrode 2. Is held by. In the case of the present embodiment, as shown in FIG. 1, no film is formed on the wall on the back side (the side opposite to the substrate 8) of the deposition preventing plate 4 inside the film forming chamber 6.

  The support portion 7 is a member extending vertically inward from the side surface (the left side surface in FIG. 1) of the film forming chamber 6. The support portion 7 is coupled to the deposition preventing plate 4 and is opposite to the counter electrode 2 in the discharge electrode 3. The deposition preventing plate 4 is held so as to cover the side space. Further, the support portion 7 is insulatively coupled to the discharge electrode 3 and holds the discharge electrode 3 substantially parallel to the side surface of the film forming chamber 6 (the left side surface in FIG. 1).

The high vacuum evacuation unit 20 is a vacuum pump for high vacuum evacuation that exhausts the gas in the film forming chamber 6 that has been evacuated roughly to make the inside of the film forming chamber 6 a high vacuum. The valve 23 is a valve that opens and closes the path between the high vacuum exhaust unit 20 and the film forming chamber 6.
The low vacuum evacuation unit 21 is a vacuum pump for roughing evacuation that first exhausts the gas in the film forming chamber 6 to make the inside of the film forming chamber 6 a low vacuum. The valve 24 opens and closes the path between the low vacuum exhaust unit 21 and the film forming chamber 6.

  The table 22 holds the film forming chamber 6 via a holding unit 25 arranged on the upper surface. A region in which the low vacuum evacuation unit 21 is disposed is formed inside the table 22.

FIG. 2 is a schematic diagram for explaining the supply of electric power to the discharge electrode 3.
The discharge electrode 3 is constituted by a plurality of divided electrodes 30 arranged in a direction perpendicular to the longitudinal direction of long divided electrodes 30 each having a feeding point. Both ends of the discharge electrode 3 according to the first embodiment are feeding points, and as an example, the discharge electrode 3 includes six elongated divided electrodes 30 (divided electrodes 30_1 to 30_6). In the following description, the side electrodes indicate the divided electrodes 30_1 and 30_6, and the center electrode indicates the divided electrodes 30_2 to 30_5.

In the first embodiment, one film forming chamber 6 is described as being applied to the thin film manufacturing apparatus 1 including six divided electrodes 30, but the number of divided electrodes 30 is greater than six. There may be one, few, or one, and there is no particular limitation.
Further, the number of the divided electrodes 30 is preferably determined so that the width of each divided electrode 30 is eliminated so as to eliminate the influence of standing waves due to high-frequency wavelengths in vacuum and plasma generation. It is preferable to make the arrangement a little larger than the width of the substrate 8 in order to make the plasma uniform.
The method of dividing the side electrode and the central electrode is also an example, and the divided electrodes 30_1, 30_2, 30_5, and 30_6 may be used as the side electrodes, and only the divided electrodes 30_3 and 30_4 may be used as the central electrodes.

  A feeding point (both ends) of each divided electrode 30 is provided with a high-frequency power source 31 that outputs high-frequency power and a matching unit 13 that matches the impedance between the high-frequency power source 31 and the divided electrode 30.

  Further, an RF monitor 34 is provided for each divided electrode 30 between each divided electrode 30 and the matching unit 13. The RF monitors 34 are provided at both ends of the divided electrode 30, and measurement points for measuring a stay time distribution (hereinafter referred to as “phase stay time distribution”) and a voltage distribution at each phase difference of the high-frequency power in the divided electrode 30. Become. The RF monitor 34 measures the voltage of the high-frequency power, and a time interval analyzer (hereinafter referred to as “TIA”) is connected to the RF monitor 34 to measure the phase residence time distribution. The TIA measures the phase difference between signals under measurement (high-frequency power supplied to both ends of the divided electrode 30), and measures the distribution of the frequency at which each phase difference occurs. This frequency distribution is a phase residence time distribution (see FIGS. 4 and 5 described later).

  Then, the phase of the voltage waveform of the high-frequency power output from the high-frequency power supply 31 is supplied to the feeding point of each divided electrode 30 with a temporal change. Thereby, as shown in FIG. 1, the counter electrode 2 placed and placed on the substrate 8 is disposed at a position parallel to the discharge electrode 3. In the meantime, high-frequency power is supplied, and a film forming raw material gas (not shown) is blown out and supplied from the discharge electrode 3, whereby plasma is generated and a film forming process is performed on the substrate 8.

  The high frequency power supply 31 is a signal of a predetermined frequency (for example, between approximately 10 MHz and approximately 100 MHz, preferably 60 MHz) output from the transmitter 32, and the phase is modulated by the phase modulator 33. High frequency power is output based on the signal.

FIG. 3 is a schematic diagram showing a voltage distribution on the discharge electrode 3 when the phase difference is fixed. The length of the discharge electrode 3 is ½ wavelength of the high frequency power. In FIG. 3, the left-right direction is the longitudinal direction of the discharge electrode 3, and high-frequency power is fed to both end portions in the longitudinal direction (left-right direction) of the discharge electrode 3, and the phase difference is 0 ° and ± 180 °. Shows the case.
As shown in FIG. 3, the high-frequency voltage distribution is a symmetrical voltage standing wave distribution with the center of the discharge electrode 3 as a boundary. When the phase difference is 0 °, the center in the longitudinal direction of the discharge electrode 3 becomes the antinode of the voltage standing wave, and is the position where the voltage is the highest. At this time, the longitudinal end (feeding point) of the discharge electrode 3 becomes a node of the voltage standing wave, and the voltage becomes zero. On the other hand, when the phase difference is 180 °, the central portion in the longitudinal direction of the discharge electrode 3 becomes a node of the voltage standing wave, and the longitudinal end portion (feeding point) of the discharge electrode 3 becomes the antinode of the voltage standing wave. Become.

  FIG. 4 is a schematic diagram illustrating an example of a phase difference distribution when a triangular wave is used as the phase modulation waveform of the high-frequency power supplied to the discharge electrode 3.

  When the phase modulation waveform is a triangular wave, the time a required for the change from the phase difference 0 ° to the phase difference 90 ° is the same as the time a required for the change from the phase difference 90 ° to the phase difference 180 °. As described above, when the phase modulation waveform is a triangular wave, the time (phase change speed) required for the change of the phase difference in each phase difference is constant. Therefore, when the phase modulation waveform is a triangular wave, the phase residence time distribution, which is the frequency (time) at which the antinode portion of the high-frequency voltage stays at each position in the longitudinal direction of the discharge electrode 3 corresponding to each phase difference angle, is constant. .

  FIG. 5 is a schematic diagram showing an example of the phase difference distribution when a sine wave (hereinafter referred to as “sin wave”) is used as the phase modulation waveform of the high-frequency power supplied to the discharge electrode 3.

  When the phase modulation waveform is a sine wave, the time c required for the change from the phase difference 90 ° to the phase difference 180 ° seems to be longer than the time b required for the change from the phase difference 0 ° to the phase difference 90 °. In addition, as the phase difference increases, the time required to change the phase difference increases. For this reason, when the phase modulation waveform is a sine wave, the phase residence time distribution becomes long at the longitudinal end portion of the discharge electrode 3, which is the position corresponding to the antinode of the high frequency voltage at the phase difference of 180 °.

FIG. 6 is a graph showing an example of the film thickness distribution when a triangular wave is used as the phase modulation waveform of the high-frequency power supplied to the discharge electrode 3. On the other hand, FIG. 7 is a graph showing the film thickness distribution when a sine wave is used as the phase modulation waveform of the high-frequency power supplied to the discharge electrode 3. The vertical axis in FIGS. 6 and 7 represents the film thickness, but is a value normalized with an average value of 1.0.
When the phase modulation waveform is a sine wave, the phase residence time is longer in the region where the phase difference is larger than in the case where the phase modulation waveform is a triangular wave, and therefore the phase residence time at the longitudinal end of the discharge electrode 3 is longer. . For this reason, the influence of the voltage distribution when the phase difference of FIG. 3 is ± 180 ° becomes large. As can be seen from FIG. 7, when the phase modulation waveform is a sine wave, The film thickness increases.

From this, it was found that when the voltage distribution of the high frequency power supplied to the discharge electrode 3 is uniform, the phase residence time of the high frequency power and the film thickness distribution in the longitudinal direction of the discharge electrode 3 have a proportional relationship. .
When the phase modulation waveform is a triangular wave, the phase residence time distribution is uniform, but in the example of FIG. 6, the film thickness distribution is not constant. This is because the high-frequency power supplied at each phase difference is not uniform.

FIG. 8 shows an example of the film thickness distribution when the film is formed with the phase difference fixed at 0 ° and ± 180 °. The vertical axis in FIG. 8 indicates the film thickness, but is a value normalized with the maximum value of the film thickness at a phase difference of 0 ° being 1.0.
FIG. 9 shows an example of the voltage value at each phase difference of the high-frequency power supplied to the discharge electrode 3. Here, in order to perform phase modulation on the supplied high frequency, the impedance matching of the matching unit 13 is fixed in a matching state with a phase difference of 0 °. The vertical axis in FIG. 9 indicates the voltage value, but is a value normalized with the voltage value at a phase difference of 0 ° being 1.0. The voltage value is measured by the RF monitor 34.
As shown in FIG. 9, the voltage value of the high-frequency power supplied to the discharge electrode 3 is maximum when the phase difference is 0 °, and is minimum about 0.5 when the phase difference is ± 180 °. . This is because the impedance matching is adjusted by the matching unit 13 so that the reflected power is reduced under the condition that the phase difference is fixed at 0 °. Therefore, the phase difference is large from the phase difference 0 ° after the matching adjustment. This is because the reflected power increases with time.
As shown in FIGS. 8 and 9, the voltage value is 1.0 when the phase difference is 0 °, and the film thickness is 1.0 at the maximum at the measurement position of 0 mm. On the other hand, when the phase difference is ± 180 °, the voltage value is about 0.5, and the film thickness is about 0.5 at the measurement position ± about 550 mm.

  From this, it was found that there is a proportional relationship between the voltage distribution of the high frequency power supplied to the discharge electrode 3 and the film thickness distribution corresponding to the longitudinal direction of the discharge electrode 3.

As described above, when the phase difference in FIG. 9 is ± 180 °, the voltage value is about 0.5. Therefore, the influence of the phase difference of ± 180 ° is greatly increased by referring to FIG. It becomes the both ends of the electrode 3. For this reason, if the phase modulation waveform is controlled so as to lengthen the phase residence time at both ends of the discharge electrode 3, the film thickness distribution at both ends of the discharge electrode can be improved.
Further, since the film thickness at the measurement position ± about 550 mm near the both end portions of the discharge electrode 3 in FIG. 8 is about 0.5, the film thickness approaches 1.0 which is the film thickness at the measurement position 0 mm. Is determined to require twice the phase residence time. On the other hand, in order to change the voltage value of about 0.5 when the phase difference is ± 180 ° in FIG. 9 to 1.0 which is the voltage value when the phase difference is 0 °, it is necessary to double it. .

  As described above, from the results shown in FIGS. 6 to 9, the inventors have analyzed the film forming conditions from various directions, and as a result, the film thickness distribution formed on the substrate 8 is supplied to the discharge electrode 3. We discovered a new high-frequency power supply condition that is proportional to the product of the residence time distribution at each phase difference of the high frequency and the voltage distribution.

Therefore, when the thin film manufacturing apparatus 1 according to this embodiment forms a film on the substrate 8, the film formed on the substrate 8 is formed by setting the product of the phase residence time distribution and the voltage distribution within a predetermined range. A film thickness distribution adjustment process is performed to make the thickness uniform.
FIG. 10 is a flowchart showing the flow of film thickness distribution adjustment processing according to the first embodiment. In addition, the film thickness distribution adjustment process according to the first embodiment is performed when a single film is formed on the substrate 8 in order to obtain a condition for making the film thickness distribution uniform.

  First, in step 100, film forming conditions are selected. The film forming conditions are, for example, SiH 4 gas flow rate, H 2 gas flow rate, film forming pressure, input high frequency power, substrate electrode distance, phase modulation angle, phase modulation waveform, phase modulation frequency, and the like.

  In the next step 102, the RF monitor 34 measures the voltage distribution in the discharge electrode 3 when the phase difference is set at each value. FIG. 11 shows an example of the measured voltage distribution at the discharge electrode 3. In the example of FIG. 11, the voltage value is maximized when the phase difference is 0 °, and the voltage value is minimized when the phase difference is ± 180 °.

ｘは位相差である。Ａは所定の範囲にある定数であり、特定の製膜条件で形成される膜の膜厚に相当する値である。（１）式で算出される積は、定数Ａは選定した値を中心値とした許容膜厚分布を考慮した所定範囲内（例えば±１０％）となればよい。
（１）式のＶ（ｘ）に計測した電圧分布が入力されることによって、位相滞在時間分布が算出され、算出された位相滞在時間分布となる位相変調波形が選定される。 In the next step 104, a phase modulation waveform is obtained such that the product of the phase residence time distribution P (x) and the voltage distribution V (x) becomes a constant within a predetermined range as shown in the equation (1). Select.

x is a phase difference. A is a constant within a predetermined range, and is a value corresponding to the film thickness of a film formed under specific film forming conditions. The product calculated by the equation (1) may be a constant A within a predetermined range (for example, ± 10%) in consideration of the allowable film thickness distribution with the selected value as the center value.
By inputting the measured voltage distribution to V (x) in equation (1), the phase residence time distribution is calculated, and the phase modulation waveform that becomes the calculated phase residence time distribution is selected.

FIG. 12 is a diagram illustrating an example of the phase residence time distribution corresponding to the voltage distribution for each phase difference illustrated in FIG. 11. In the example of FIG. 12, the phase residence time is minimum when the phase difference is 0 °, and the phase residence time is maximum when the phase difference is ± 180 °.
The phase modulation waveform selected so as to satisfy the phase residence time distribution as shown in FIG. 12 may be other waveforms such as a square wave as well as a sin wave or a triangular wave.
The phase modulation waveform is selected by, for example, inputting the measurement result of the RF monitor 34 to the phase modulator 33 and the phase modulator 33. Thereby, in film thickness distribution adjustment processing, phase residence time distribution can be adjusted easily.

  In the next step 106, a single film is formed on the substrate 8.

  In the next step 108, it is determined whether or not the film thickness distribution of the formed single film is within a predetermined range (for example, ± 10%). In the case of determination, the process proceeds to step 110. After the film thickness distribution adjustment process is completed, a silicon thin film used for, for example, a solar cell panel is formed using the selected phase modulation waveform.

Disturbance of the film thickness distribution may occur due to the peripheral structure of the discharge electrode 3 of the thin film manufacturing apparatus 1 or the film forming gas flow distribution.
Therefore, in step 110, the voltage distribution is adjusted by the phase modulator 33 so that the change range of the phase angle becomes a more appropriate change range between 0 ° and ± 180 ° so that the film thickness distribution is within a predetermined range. Is finely adjusted. Alternatively, the phase modulation waveform is finely adjusted in order to finely adjust the phase residence time distribution. Thereafter, the process returns to step 106, and a single film is formed. Note that both the voltage distribution and the phase stay time distribution may be finely adjusted so that the film thickness distribution falls within a predetermined range.

As described above, the thin film manufacturing apparatus 1 according to the first embodiment includes the RF monitor 34 that measures the phase residence time distribution of the high-frequency power in the discharge electrode 3 and the voltage distribution in the discharge electrode 3, and the phase residence time. At least one of the phase residence time distribution and the voltage distribution is adjusted so that the product of the distribution and the voltage distribution falls within a predetermined range.
Therefore, the thin film manufacturing apparatus 1 according to the first embodiment can make the film thickness distribution formed on the substrate 8 constant by adjusting the two parameters of the phase residence time distribution and the voltage distribution. When the film forming process is performed, the selection of the high-frequency power supply conditions is made appropriate, and the film thickness distribution can be made uniform easily and in a short time.

In the film thickness distribution adjustment process according to the first embodiment, the case where the product of the phase stay time distribution and the voltage distribution is within a predetermined range by adjusting the phase stay time distribution has been described. Not limited to this, the product may be within a predetermined range by adjusting the voltage distribution based on the phase residence time distribution measured by the RF monitor 34.
In this case, the voltage distribution is adjusted by adjusting the impedance of the high-frequency power supply 31. Specifically, the voltage value is adjusted by adjusting the values of resistors, capacitors, and coils constituting the matching unit 13. In addition, the distribution shape of the voltage distribution is adjusted by changing the change range of the phase angle of the phase modulator 33. Thus, the voltage distribution can be easily adjusted in the film thickness distribution adjustment process.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.

The configuration of the thin film manufacturing apparatus 1 according to the second embodiment is the same as the configuration of the thin film manufacturing apparatus 1 according to the first embodiment shown in FIGS.
The RF monitor 34 according to the second embodiment measures only the phase residence time distribution without measuring the voltage distribution in the discharge electrode 3.

  FIG. 13 is a flowchart showing a flow of film thickness distribution adjustment processing according to the second embodiment. In FIG. 13, the same steps as those in FIG. 10 are denoted by the same reference numerals as those in FIG.

  The film thickness distribution adjustment process according to the second embodiment proceeds to step 200 when the film forming conditions are selected in step 100.

  In step 200, the phase residence time distribution in the discharge electrode 3 is measured by the RF monitor 34.

  In step 202, a single film is formed on the substrate 8.

  In the next step 204, the voltage distribution in the discharge electrode 3 is estimated from the measured phase residence time distribution and the film thickness of the formed single film, and the process proceeds to step 104 '. That is, the value obtained by dividing the phase residence time distribution from the single film thickness distribution in the longitudinal direction of the discharge electrode 3 is a value proportional to the voltage distribution.

  In step 104 ', a phase modulation waveform is selected such that the product of the measured phase residence time distribution and the estimated voltage distribution is within a predetermined range.

  As described above, in the thin film manufacturing apparatus 1 according to the second embodiment, the RF monitor 34 measures only the phase residence time distribution of the high-frequency power in the discharge electrode 3, so that the apparatus configuration is simplified.

  As described above, the RF monitor 34 measures the voltage of the power feeding portion of the discharge electrode 3. For this reason, the disturbance of the film thickness distribution due to the peripheral structure of the discharge electrode 3 and the film-forming gas flow distribution or the like may cause fine adjustment of the phase modulation waveform. On the other hand, in the second embodiment, the voltage distribution of the discharge electrode 3 is estimated directly from the film thickness distribution. For this reason, the fine adjustment of the phase modulation waveform is reduced, the selection of the supply condition of the high frequency power is made more appropriate, and the film thickness distribution to be formed can be made uniform more easily.

  As mentioned above, although this invention was demonstrated using said each embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiments without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention. Moreover, you may combine said each embodiment suitably.

For example, the phase modulation waveform may be different depending on the film quality to be formed, such as an amorphous solar cell or a microcrystalline solar cell.
Furthermore, although the film | membrane kind to form into a film showed embodiment mainly having a thin film silicon system, it is not limited to this. Here, the silicon-based is a general term including silicon (Si), silicon carbide (SiC), silicon germanium (SiGe), silicon nitride (SiNx), silicon oxide (SiOx), and the like. It includes quality silicon.

  In addition, the flow of the film thickness distribution adjustment process described in each of the above embodiments is also an example, and unnecessary steps can be deleted, new steps can be added, and the processing order can be changed without departing from the gist of the present invention. It may be replaced.

DESCRIPTION OF SYMBOLS 1 Thin film manufacturing apparatus 2 Counter electrode 3 Discharge electrode 8 Substrate 30 Divided electrode 31 High frequency power supply (RF power supply)
33 Phase modulator 34 RF monitor

Claims (6)

A vacuum processing apparatus that forms plasma with high-frequency power,
A high frequency power supply that outputs high frequency power;
A phase modulator for modulating the phase of the high-frequency power;
A counter electrode;
A discharge electrode that is supplied with the high-frequency power and forms plasma with the counter electrode;
Measuring means for measuring at least one of a residence time distribution at each phase difference of the high-frequency power in the discharge electrode and a voltage distribution in the discharge electrode;
With
A vacuum processing apparatus that adjusts at least one of the stay time distribution and the voltage distribution so that a product of the stay time distribution and the voltage distribution falls within a predetermined range.   The vacuum processing apparatus according to claim 1, wherein the stay time distribution is adjusted by adjusting a phase modulation waveform of the phase modulator.   The vacuum processing apparatus according to claim 1, wherein the voltage distribution is adjusted by adjusting at least one of an impedance of the high-frequency power source and a range of change in phase angle of the phase modulator. Plasma-treating the substrate held on the counter electrode by plasma;
The at least one of the residence time distribution at each phase difference of the high-frequency power in the discharge electrode and the voltage distribution in the discharge electrode is finely adjusted based on the film thickness distribution formed on the substrate. Item 4. A vacuum processing apparatus according to item 3. Plasma-treating the substrate held on the counter electrode by plasma;
The measuring means measures the stay time distribution,
The vacuum processing apparatus according to claim 1, wherein the voltage distribution is estimated based on a film thickness distribution formed on the substrate. A high-frequency power source that outputs high-frequency power; a phase modulator that modulates the phase of the high-frequency power; a counter electrode; a discharge electrode that is supplied with the high-frequency power and forms plasma between the counter electrode; and the discharge A film thickness distribution formed on the substrate by plasma in a vacuum processing apparatus comprising: a measuring unit that measures at least one of a residence time distribution at each phase difference of the high-frequency power in the electrode and a voltage distribution in the discharge electrode An adjustment method,
A film thickness distribution adjusting method for adjusting at least one of the stay time distribution and the voltage distribution so that a product of the stay time distribution and the voltage distribution falls within a predetermined range.

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