KR20220040386A - Plasma processing apparatus and plasma generation method - Google Patents

Abstract

An objective of the present invention is to achieve cleaning in a processing container and suppressing of consumption of a part. Provided is a plasma processing device having: a processing container; a metal window wherein an interior of the processing container is divided into an upper part antenna chamber and a lower part processing chamber, and having a plurality of partial windows; an inductive coupling antenna disposed on an upper part of the metal window in the antenna chamber, and generating an inductive coupling plasma in the processing chamber; a lower part electrode in which a substrate is disposed in the processing chamber, and to which a high-frequency power for a bias voltage is applied; a capacitance element connected to one or a plurality of the partial windows at one end part, and connected to the ground at the other end part; and a resistance element connected to one or the plurality of the partial windows at the one end part in parallel with the capacitance element, and connected to the ground at the other end part.

Description

Plasma processing apparatus and plasma generation method

The present disclosure relates to a plasma processing apparatus and a plasma generating method.

For example, Patent Document 1 proposes a plasma processing apparatus in which the inside of a processing container is partitioned into an upper antenna chamber and a lower processing chamber, and provided with a plurality of divided metal windows. A filter is connected to a plurality of divided metal windows.

[Patent Document 1] Japanese Patent Laid-Open No. 2011-29584

When plasma is generated in the exhaust space in the plasma processing apparatus, by-products are deposited on the wall surface of the exhaust space, and when the by-products are separated from the wall surface and exhausted, they affect the substrate as anti-reflection particles from the vacuum pump. . In addition, the consumption of the material constituting the wall surface in the processing vessel is accelerated, so that the particles increase and affect the copper substrate. Due to these, a defect (defect) is generated on the substrate.

The present disclosure provides a technique capable of cleaning the inside of a processing container and suppressing consumption of parts.

According to an aspect of the present disclosure, a processing container and a metal window partitioning the interior of the processing container into an upper antenna chamber and a lower processing chamber, the metal window having a plurality of partial windows, is disposed on the upper portion of the metal window in the antenna chamber, An inductively coupled antenna for generating inductively coupled plasma in the processing chamber, a substrate disposed in the processing chamber, a lower electrode to which a high frequency power for a bias voltage is applied, one end connected to one or a plurality of the partial windows, and the other end portion There is provided a plasma processing apparatus having a capacitive element connected to the ground in , and a resistive element connected to one or a plurality of the partial windows at one end in parallel with the capacitive element and connected to the ground at the other end.

According to one aspect, cleaning in the processing container and consumption of parts can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of the plasma processing apparatus which concerns on embodiment.
Fig. 2 is a diagram showing an example of an impedance adjustment circuit according to an embodiment;
3 is a view showing an example of a pattern of a plurality of partial windows formed on the metal window according to the embodiment.
Fig. 4 is a diagram showing an example of capacitance and anode impedance of an impedance adjusting circuit according to an embodiment;
Fig. 5 is a view showing an example of the presence or absence of an impedance adjustment circuit according to the embodiment and a result of consumption of parts;
Fig. 6 is a view showing another example of the presence or absence of an impedance adjustment circuit according to the embodiment and a result of consumption of parts;
Fig. 7 is a view showing another example of the presence or absence of an impedance adjustment circuit according to the embodiment and a result of consumption of parts;
Fig. 8 is a view showing another example of the presence or absence of an impedance adjustment circuit according to the embodiment and a result of consumption of parts;
Fig. 9 is a diagram showing the presence or absence of an impedance adjustment circuit according to the embodiment and an example of discharge results in an exhaust space;
Fig. 10 is a view showing an example of the presence or absence of an impedance adjustment circuit and the number of defects on a target substrate according to the embodiment;
11 is a time chart showing an example of a plasma generation method according to the embodiment;
Fig. 12 is a diagram showing an example of the result of plasma ignition by VUV light according to the embodiment;

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, the form for implementing this indication is demonstrated. In each figure, the same code|symbol is attached|subjected to the same structural part, and the overlapping description may be abbreviate|omitted.

[Plasma processing unit]

A plasma processing apparatus according to an embodiment will be described with reference to FIGS. 1 to 3 . BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of the plasma processing apparatus which concerns on embodiment. 2 is a diagram showing an example of an impedance adjustment circuit according to an embodiment. 3 is a view showing an example of a pattern of a plurality of partial windows formed on the metal window according to the embodiment.

The plasma processing apparatus according to the embodiment is used, for example, for etching a metal film, an ITO film, an oxide film, or the like when forming a thin film transistor on a glass substrate for a flat panel display (FPD), or for an ashing process for a resist film. Here, as the FPD, a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display panel (PDP), and the like are exemplified.

The plasma processing apparatus has an airtight processing container 1 in the shape of a square cylinder made of a conductive material, for example, aluminum whose inner wall surface is anodized (anodized). The processing container 1 is grounded by a grounding wire 1a. The processing chamber 1 is divided into an upper antenna chamber 3 and a lower processing chamber 4 by a metal window 2 formed insulated from the processing chamber 1 . The metal window 2 constitutes the ceiling wall of the processing chamber 4 in this example. The metal window 2 is made of, for example, a non-magnetic material and a conductive metal. Examples of the nonmagnetic and conductive metal are aluminum or an alloy containing aluminum. The metal window 2 is supported on a side wall of the processing container 1 .

A gas supply pipe 20a is provided so as to communicate with the gas flow path 12 . The gas flow path 12 is branched into a plurality of branch pipes (not shown), and is connected to a partial window (see FIG. 3 ) of the metal window 2 divided into a plurality by an insulating material 6 , and each partial window supply gas to Each of the partial windows has a gas space therein (not shown), has a plurality of gas outlets on a surface adjacent to the process chamber 4 , and supplies gas into the process chamber 4 from the plurality of gas outlets. The gas supply pipe 20a penetrates from the ceiling of the processing vessel 1 to the outside thereof, and is connected to a processing gas supply unit 20 including a processing gas supply source, a valve system, and the like. Accordingly, in plasma processing, the processing gas supplied from the processing gas supply unit 20 is discharged into the processing chamber 4 through the gas supply pipe 20a.

In the antenna chamber 3 , a high frequency (RF) antenna 13 is disposed on the metal window 2 so as to be adjacent to the metal window 2 . The high-frequency antenna 13 is spaced apart from the metal window 2 by a spacer 17 made of an insulating member. The high frequency antenna 13 constitutes a spiral antenna, and the metal window 2 is divided into, for example, 24 partial windows under the spiral antenna. The high-frequency antenna 13 is disposed on the metal window 2 through the spacer 17 of the insulating member in the antenna chamber 3 , and generates an inductively-coupled plasma in the processing chamber 4 of the inductively-coupled antenna. This is an example.

During plasma processing, from the first high-frequency power supply 15, high-frequency power for forming an induced electric field, for example, having a frequency of 1 MHz to 27 MHz, is transmitted to the high-frequency antenna 13 through the matching unit 14 and the power supply member 16 . ) is supplied to Although not shown, the high-frequency antenna 13 of this example is concentrically configured with an outer annular antenna, an intermediate annular antenna, and an inner annular antenna, and power feeding units 41 , 42 , 43 connected to the power feeding member 16 , respectively. has An antenna wire extends in the circumferential direction from each of these power feeding units 41 , 42 , 43 to constitute a tricyclic high-frequency antenna 13 . A capacitor (not shown) is connected to the terminal of each antenna wire, and each antenna wire is connected to the sidewall 3a of the high frequency antenna 13 via the capacitor and grounded. An induced electric field is formed in the processing chamber 4 by the high-frequency antenna 13 supplied with the high-frequency power in this way, and the processing gas supplied into the processing chamber 4 is converted into plasma by the induced electric field.

A stage ST for arranging the processing target substrate G, for example, a glass substrate, is provided below the processing chamber 4 to face the high-frequency antenna 13 with the metal window 2 interposed therebetween. The stage ST has a lower electrode 23 and an insulator frame 24 . The lower electrode 23 is made of a conductive material, for example, aluminum whose surface is anodized. The target substrate G disposed on the lower electrode 23 is adsorbed and held by an electrostatic chuck (not shown).

The lower electrode 23 is accommodated in the insulator frame 24 , and is supported on the bottom surface of the processing chamber 4 . In addition, on the side wall 4a of the processing chamber 4, a loading/unloading port 27a for loading and unloading the processing target substrate G and a gate valve 27 for opening and closing the processing chamber 4 are provided.

A second high frequency power supply 29 is connected to the lower electrode 23 via a matching device 28 by a power supply line 25a provided in a hollow post 25 . The second high frequency power supply 29 applies high frequency power for bias voltage, for example, high frequency power having a frequency of 1 MHz to 6 MHz to the lower electrode 23 during plasma processing. The lower electrode 23 arranges the processing target substrate G on the arrangement surface, generates a bias voltage on the processing target substrate G by the high frequency power for the bias voltage, and generates a bias voltage in the plasma generated in the processing chamber 4 . Ions are effectively drawn into the target substrate G.

In addition, in the lower electrode 23 , a temperature control mechanism including heating means such as a ceramic heater or a refrigerant passage, and a temperature sensor are provided in order to control the temperature of the substrate G to be processed (both shown). not). All piping and wiring for these mechanisms and members are led out of the processing container 1 through the hollow post 25 .

Between the stage ST and the sidewall 4a of the processing chamber 4 , a baffle plate 32 is continuously or intermittently provided to surround the stage ST in an annular shape, and gas passes from the processing chamber 4 into the exhaust space. make it An exhaust device 30 including a vacuum pump or the like is connected to the bottom of the processing chamber 4 through an exhaust pipe 31 . The exhaust space under the baffle plate 32 is exhausted by the exhaust device 30 , and the inside of the processing chamber 4 is set and maintained at a predetermined vacuum atmosphere (eg, 1.33 Pa) during plasma processing.

A fine cooling space (not shown) is formed on the back side of the substrate G disposed on the lower electrode 23 , and a He gas flow path 45 for supplying He gas as a heat transfer gas at a constant pressure is provided. installed. A He gas line 46 is connected to the He gas flow path 45 , and is connected to a He source through a pressure control valve 47 .

An observation window 33 is provided on the side wall 4a of the processing chamber 4 , and a VUV light source unit 34 is attached to the observation window 33 . The VUV light source unit 34 injects VUV (Vacuum Ultra Violet) light with a wavelength of 100 to 200 nm into the processing chamber 4 . When the incident VUV light is irradiated to gas molecules in the processing chamber 4 , the gas molecules absorb light energy and emit electrons. By emission of this electron, plasma ignition can be accelerated|stimulated.

Each component of the plasma processing apparatus is connected to and controlled by a control unit 50 including a computer. In addition, the control unit 50 includes a user interface 51 including a keyboard for the process manager to input commands to manage the plasma processing apparatus, and a display for visualizing and displaying the operating status of the plasma processing apparatus. connected. Further, a storage unit 52 is connected to the control unit 50 . In the storage unit 52, there are a control program for realizing various processes executed in the plasma processing apparatus under control of the control unit 50, and a program, that is, a recipe, for executing a process in each component unit of the plasma processing apparatus according to processing conditions. It is stored. The recipe may be stored in a hard disk or a semiconductor memory, or may be set at a predetermined position in the storage unit 52 while being accommodated in a portable storage medium such as a CD-ROM or DVD. Alternatively, the recipe may be appropriately transmitted from the other device, for example, through a dedicated line. Then, if necessary, an arbitrary recipe is called from the storage unit 52 according to an instruction from the user interface 51 or the like and the control unit 50 executes the desired recipe in the plasma processing apparatus under the control of the control unit 50 . processing is performed.

[Impedance adjustment circuit]

An impedance adjustment circuit 18 is connected to the metal window 2 . The impedance adjustment circuit 18 will be described with reference to FIG. 2 . FIG. 2 mainly shows the cross section of one partial window 22a among the 24 partial windows of the metal window 2 and the impedance adjustment circuit 18 to which the partial window 22a is connected, the plasma processing of FIG. Other configurations of the device are simplified.

Fig. 3 is a plan view of the impedance adjustment circuit 18, with only the metal window 2 being omitted. In the example of FIG. 3 , the metal window 2 is divided into 24 partial windows including one partial window 22a. The 24 partial windows 22a, 22b, 22c ... are collectively referred to as the partial window 22 . These 24 partial windows 22 are a part of dividing the metal window 2 , are disposed through the insulating material 6 , and constitute the metal window 2 . In this example, if the shape of the wall surface of the processing chamber 4 facing the lower electrode 23 is rectangular, the inner peripheral region 5a at the center of the rectangle, and the annular middle region surrounding the outer side of the inner peripheral region 5a ( 5b), divided into an annular outer peripheral region 5c surrounding the outside of the intermediate region 5b. The inner peripheral region 5a has four partial windows 22 in which the rectangular inner peripheral region 5a is substantially diagonally divided. In addition, the intermediate region 5b has a total of eight partial windows 22 divided in the radial direction so that each side of the annular intermediate region 5b is divided into two halves. In addition, the outer peripheral region 5c has a total of 12 partial windows 22 divided in the radial direction so that each side of the annular outer peripheral region 5c is divided into three equal parts. In this embodiment, although not shown, the inner annular antenna corresponds to the inner peripheral region 5a, the middle annular antenna corresponds to the middle region 5b, and the outer annular antenna corresponds to the outer peripheral region 5c. are placed

With this configuration, the 24 partial windows 22 included in the metal window 2 are insulated from the processing container 1 by being disposed through the insulating material 6 , and the partial windows 22 are also insulated from each other. . Examples of the material of the insulator 6 are, for example, ceramic or polytetrafluoroethylene (PTFE).

In addition, FIG. 3 is an example of the pattern of the some partial window 22 formed in the metal window 2, The pattern of the partial window is not limited to this. The metal window 2 does not need to be divided|segmented. That is, the metal window 2 may have one or two or more partial windows 22 .

Returning to FIG. 2 , the impedance adjustment circuit 18 is provided 1:1 for each of the partial windows 22 . However, the present invention is not limited thereto, and one impedance adjustment circuit 18 may be provided for the plurality of partial windows 22 . That is, the plurality of partial windows 22 may be divided into one or a plurality of regions, and may be connected to the impedance adjustment circuit for each one or a plurality of regions. For example, in the example of FIG. 3 , the twenty-four partial windows 22 are divided into three regions: the inner peripheral region 5a, the middle region 5b, and the outer peripheral region 5c, and the inner peripheral region 5a, the middle region One impedance adjustment circuit may be connected to each of (5b) and the outer peripheral region 5c. For example, by separately adjusting the impedance of the inner peripheral region 5a in which by-products are liable to be deposited, the intermediate region 5b and the outer peripheral region 5c in which the by-products are difficult to be deposited, the entire surface of the metal window 2 is uniformly adjusted for each region. can be cleaned In addition, when the impedance adjustment circuit 18 is provided for each of the partial windows 22 , for example, when the state of deposition is different at the corner and the edge of the metal window 2 , the impedance for each of the partial windows 22 . Adjustment circuits 18 can be individually adjusted for uniform cleaning.

2 and 3, the impedance adjustment circuit 18 is provided one by one with respect to one partial window 22a, 22b, 22c.... That is, in this example, the 24 impedance adjustment circuits 18 are connected 1:1 with respect to the 24 partial windows 22 . The impedance adjustment circuit is an R+C parallel circuit having a capacitor 60 and a resistance element 61 . In this example, one capacitive element 60 and one resistive element 61 are connected in parallel with the capacitive element 60 for each partial window 22 . The capacitive element 60 is connected to the partial window 22 at one end and to the ground at the other end. The resistive element 61 is connected to the partial window 22 at one end in parallel with the capacitive element 60, and is connected to the ground at the other end.

The capacitor 60 is a variable capacitor. However, the capacitor 60 may be a fixed capacitance element. By using the capacitive element 60 as a variable capacitive element, the impedance (hereinafter also referred to as anode impedance) of the metal window 2 serving as the anode electrode in the supply of the high frequency power for the bias voltage can be variably adjusted and more precisely adjusted. Impedance adjustment can be performed. In addition, when the impedance adjustment circuit 18 is provided for each of a plurality of regions, the capacitor 60 may be connected to a plurality of partial windows 22 for each region. Similarly, the resistive element 61 may be connected to the plurality of partial windows 22 in parallel with the capacitor 60 .

With this configuration, in the supply of high frequency power for bias voltage, the lower electrode 23 is used as a cathode electrode, and the metal window 2 is used as an anode electrode which is a counter electrode opposite to the lower electrode 23, and an impedance adjustment circuit ( 18) adjusts the anode impedance. Thereby, in the metal window 2, a desired potential difference with the plasma is generated by the capacitance of the capacitor 60, and deposits of by-products adhering to the metal window 2 are removed by sputtering of the plasma. cleaning is possible. Further, when the high frequency power for the bias voltage is supplied to the lower electrode 23, each part in the processing container 1 can also function as an anode, but the metal window 2 is more actively used as an anode to function as a cathode electrode, i.e. By strengthening the coupling with the lower electrode 23 , it is possible to suppress the consumption of the parts in the processing container 1 by plasma sputtering.

If the potential difference in the metal window 2 is too large, not only the removal of by-products adhering to the metal window 2 but also the metal window 2 is consumed. Removal of the product becomes insufficient. Accordingly, the capacitance of the capacitor 60 is within a range capable of suppressing excessive consumption of the metal window 2 and other parts in the processing container 1 during cleaning while removing by-products adhering to the metal window 2 . It is important to adjust In this way, while suppressing particles, the lifespan of each part can be increased, and the maintenance cycle can be lengthened.

[Impedance adjustment circuit: capacitive element]

From the above, the inventors have found that, in order to both reduce particles by cleaning the metal window 2 and suppress consumption of parts in the processing container 1 such as the metal window 2 during cleaning, an appropriate capacitive element A range of doses of (60) was derived by experiment.

4 is a diagram showing an example of the capacitance C and the impedance of the capacitor 60 of the impedance adjustment circuit 18 according to the embodiment. 4 , the horizontal axis indicates the capacitance C [pF] of the capacitor 60 , and the vertical axis indicates the anode impedance Z [Ω] of the metal window 2 .

When the anode impedance Z of the metal window 2 becomes 0 or more, it becomes L-characterized (inductive) and there is a fear that resonance may occur, and abnormal discharge may occur due to the resonance. Therefore, the anode impedance Z of the metal window 2 determines the capacitance range of the capacitive element 60 so as to ensure a C-characteristic (capacitance) of 0 or less. Specifically, the capacitor 60 has a capacitance value at which the anode impedance Z of the capacitor 60 and the resistance element 61 becomes a negative value.

In the region I in Fig. 4, the capacitance C of the capacitor 60 is 0 to 500 pF, and the anode impedance Z is -60 Ω or less. In the region I where the anode impedance Z is −60 Ω or less, there is a risk that a discharge may occur in the exhaust space below the baffle plate 32 . That is, there is a possibility that the parts of the processing container 1 constituting the exhaust space are sputtered by the plasma to generate particles. On the other hand, in the metal window 2, since an appropriate potential difference does not occur, it is impossible to remove the deposit.

Further, when the anode impedance Z approaches 0 ?, consumption of the parts of the processing vessel 1 constituting the exhaust space is suppressed, but consumption of the metal window 2 functioning as the upper electrode is promoted. That is, when the capacity C is 6000 pF or more, suppressing the consumption of parts in the processing container 1 such as the metal window 2 is not compatible in all cases, so this region and the region I are not used. .

From the above, it is preferable to control the capacitance C of the capacitor 60 to be in the range of 500 to 2000 pF in the region II or in the range of 2000 to 6000 pF in the region III. By adjusting the anode impedance Z by controlling the capacitance range of the capacitive element 60 to the range of the region II or region III, it is possible to efficiently clean the metal window 2 by plasma sputtering. At the same time, during cleaning, it is possible to suppress the consumption of parts in the processing container 1 , such as the metal window 2 , the inner wall of the processing container 1 , and the baffle plate.

In region III, the anode impedance (Z) is closer to zero than in region II. As the anode impedance Z approaches zero, the coupling (electrical coupling) between the metal window 2 and the lower electrode 23 becomes stronger, and the sputtering force of the metal window 2 increases.

Therefore, according to the state of the by-product of the metal window 2 , the capacitance of the capacitor 60 is independently adjusted for each of the partial windows 22 or each region including the plurality of partial windows 22 . For example, in some partial windows 22 , the range of capacitance of the capacitor 60 in region III may be used in order to strengthen the sputtering force of the metal window 2 and increase the self-cleaning power. It is more preferable to use the range of capacitance of the capacitor 60 in the region II for the partial window 22 or region where both self-cleaning power and parts consumption are important.

[Impedance adjustment circuit: resistance element]

An insulating temperature regulating medium is passed through the flow path formed in the metal window 2 , thereby adjusting the temperature of the metal window 2 . When the insulating temperature control medium flows, triboelectric charging occurs, electric charges are accumulated in the metal window 2, and the metal window 2 is charged up. A part of electrons in the plasma accumulates in the metal window 2 , and the metal window 2 is charged up in some cases. It is important not to accumulate uncontrollable charges on the metal window 2 . When the metal window 2 is charged, the plasma becomes unstable, which affects the processing of the target substrate G. For this reason, the impedance adjustment circuit 18 connects the resistance element 61 to the metal window 2 in parallel with the capacitor element 60 . Thereby, the charge-up of the metal window 2 by an uncontrollable electric charge can be eliminated, and the stability of plasma can be ensured.

[Parts consumption]

Next, the results of experiments with respect to the presence or absence of the impedance adjustment circuit 18 and consumption of parts will be described. 5 is a diagram showing an example of the presence or absence of the impedance adjustment circuit 18 according to the embodiment and the result of consumption of parts. Fig. 5 (a) is an example of the result of consumption of parts in the case of the comparative example in which the impedance adjustment circuit 18 is not provided in the metal window 2 . Fig. 5 (b) is an example of the result of consumption of parts when the impedance adjustment circuit 18 is provided.

As an example of the parts in the processing container 1, in FIGS. 5A and 5B, on the target substrate G, on the baffle plate 32, on the inner wall plate (side wall 4a), the metal The consumption of the window (2) (lower side) was measured. As a result, in the comparative example and this embodiment, the consumption amount on the to-be-processed substrate G did not change. On the other hand, when the impedance adjustment circuit 18 of this embodiment is provided on the baffle plate 32 and on the inner wall plate (side wall 4a), when the impedance adjustment circuit 18 of the comparative example is not provided Consumption was further reduced. On the other hand, the consumption of the lower surface of the metal window 2 (the amount of cleaning of by-products) increased. From the above results, when the impedance adjustment circuit 18 is provided in the metal window 2 , it is possible to clean the metal window 2 while suppressing consumption of the parts in the processing container 1 . Thereby, generation|occurrence|production of a particle can be suppressed. In addition, the consumption amount of the lower surface of the metal window 2 adjusts the capacitance C of the capacitor 60 to such an extent that the metal window 2 itself is not consumed.

6 to 8 are diagrams showing other examples of the presence or absence of the impedance adjustment circuit 18 according to the embodiment and the result of consumption of parts. A small piece of sample was placed at each location, and the consumption was measured. 6(b) and 6(c) are views of the processing target substrate G at positions 1 to 12 in the process space (above the baffle plate 32) in the processing chamber 4 shown in FIG. 6(a). ) represents the consumption on the stomach and on the baffle plate 32 . N is when the impedance adjustment circuit 18 is not present, M and L are when the impedance adjustment circuit 18 is present, M is when the capacitance C of the capacitive element 60 is 800 pF, L is the capacitive element ( 60) shows the consumption of each part when the capacity (C) is 1900 pF.

According to this experiment, the consumption on the target substrate G was substantially the same regardless of the presence or absence of the impedance adjustment circuit 18 . That is, it turned out that the presence or absence of the impedance adjustment circuit 18 does not affect the state on the target board|substrate G. As shown in FIG. On the other hand, the consumption on the baffle plate 32 could be suppressed when the impedance adjustment circuit 18 was present (M, L) compared to the case where the impedance adjustment circuit 18 was not (N).

7(b) and 7(c) are sidewalls of the processing chamber 4 at positions 13 to 33 in the exhaust space (under the baffle plate 32) in the processing chamber 4 shown in FIG. 7(a). (4a) (inner wall) and consumption under the baffle plate 32 are shown. In addition, in a position where data is not shown, data could not be acquired due to damage to the sample or the like.

According to this experiment, the consumption amount under the inner wall (side wall 4a) and the baffle plate 32 of the processing chamber 4 is, when the impedance adjustment circuit 18 is present (M, L), the impedance adjustment circuit 18 is It was able to suppress rather than the case where there is no (N).

Figs. 8(b) and (c) show the consumption at positions 49 to 66 of the lower surface of the metal window 2 shown in Fig. 8(a). According to the present experiment, the consumption of the lower surface of the metal window 2 was greater when the impedance adjustment circuit 18 was present (M, L) than when the impedance adjustment circuit 18 was not (N).

From the above results, by adjusting the capacitance of the capacitor 60 by the impedance adjustment circuit 18 according to the present embodiment, the cleaning of the lower surface of the metal window 2 is facilitated while the parts in the processing container 1 are reduced. consumption could be reduced.

When the capacitance C of the capacitive element 60 is made small, the anode impedance becomes high, the coupling between the metal window 2 and the lower electrode 23 becomes difficult, and the by-product of the metal window 2 is difficult to remove. lose On the other hand, if the capacitance C of the capacitor 60 is reduced, coupling between the inner wall of the processing chamber 4 and parts in the processing container 1 such as the baffle plate 32 and the lower electrode 23 is easy to occur. , the consumption of the inner wall or the baffle plate 32 increases.

If the capacitance C of the capacitive element 60 is increased, the anode impedance is lowered, the coupling between the metal window 2 and the lower electrode 23 becomes easy, so that by-products of the metal window 2 are removed. it gets easier On the other hand, if the capacitance C of the capacitor 60 is increased, coupling between the inner wall of the processing chamber 4 or parts in the processing container 1 such as the baffle plate 32 and the lower electrode 23 becomes difficult. , the consumption of the inner wall or the baffle plate 32 is reduced.

Accordingly, the metal window ( It is possible to achieve both the cleaning of 2) and suppression of consumption of parts in the processing container 1 . As a result, generation of particles can be reduced.

9 is a diagram showing an example of the presence or absence of the impedance adjustment circuit 18 according to the embodiment and the discharge result of the exhaust space. The exhaust space is a space under the baffle plate 32 .

Fig. 9(a) shows the discharge stability of the exhaust space under the baffle plate 32 in the absence of the impedance adjustment circuit 18, and Fig. 9(b) shows the exhaust in the case where the impedance adjustment circuit 18 is present. It represents the discharge stability of space. Process conditions of the pressure of the process chamber ₄ , the gas flow rates of Cl2 gas and BCl3, and the power density of the high frequency power of a bias voltage are _shown to (a) and (b) of FIG. The pressure in the treatment chamber 4 was controlled to be 10 mT (1.33 Pa) to 70 mT (9.31 Pa). A case in which discharge instability did not occur under these process conditions is indicated by a diagonal line of "OK", and a case in which discharge instability occurs is indicated by an oblique line of "NG". This shows the usable range of pressure and power density. However, the gas type is an example and is not limited to this. For example, when etching a metal film such as aluminum, Cl ₂ gas and BCl ₃ may be used, and when etching the SiO ₂ film, CF ₄ gas and O ₂ gas may be used.

As a result of the experiment, when there is the impedance adjusting circuit 18 shown in FIG. 9B, compared to the case without the impedance adjusting circuit 18 shown in FIG. 9A, discharge is unstable in the exhaust space. The range of process conditions in which this does not occur is widened, and discharge instability in the exhaust space is suppressed. Thereby, generation|occurrence|production of a particle can be suppressed.

10 is a diagram showing an example of the presence or absence of the impedance adjustment circuit 18 according to the embodiment and the number of defects on the processed target substrate G. The number of defects represents the number of defects, such as disconnection, which have occurred on the processed target substrate G.

Fig. 10 (a) shows the number of defects on the processed target substrate G when there is no impedance adjustment circuit 18, and Fig. 10 (b) shows the impedance adjustment circuit 18 The number of defects on the target substrate G in this case is shown. According to this, when the impedance adjusting circuit 18 of FIG. 10B was present, the number of defects could be significantly reduced compared with the case without the impedance adjusting circuit 18 of FIG. 10A.

[Plasma Generation Method: Plasma Ignition]

When the capacitance of the capacitive element 60 of the impedance adjustment circuit 18 is increased and the metal window 2 is adjusted to a low impedance, ignition of plasma may deteriorate. Therefore, in order to promote plasma ignition, when plasma is ignited using the capacitor 60 of the variable capacitance element, the capacitance of the capacitor 60 is set to, for example, a value in the region II, and the metal window 2 is is controlled to increase the potential of the metal window 2 by adjusting it to a high impedance. After plasma ignition, the capacitance of the capacitor 60 may be increased, for example, to a value in the region III, and the metal window 2 may be adjusted to have a low impedance.

Specifically, for the capacitor 60 , a first capacitance value and a second capacitance value smaller than the first capacitance value are previously stored in the storage unit 52 . When processing the substrate, the control unit 50 refers to the storage unit 52 and adjusts the capacitor 60 to a second capacitance value when the high frequency power for forming an induction electric field is supplied to the high frequency antenna 13 in advance. After the set time has elapsed, that is, after plasma ignition, the capacitor 60 may be adjusted to the first capacitance value.

Instead of using all of the capacitive elements 60 as variable capacitive elements, the variable capacitive element is used only for the specific partial window 22 of the 24 partial windows 22 or the partial window 22 of the specific area, and a portion of the other area A fixed-capacitance element may be used for the window 22 . Thereby, cost can be reduced. The circuit of the variable-capacitance element and the circuit of the fixed-capacitance element may be switched by a switch.

You may promote plasma ignition by creating an ignition recipe in advance, making it memorize|stored in the memory|storage part 52, and controlling the pressure in the process chamber 4 using the ignition recipe. It is a time chart which showed an example of the plasma generation method which concerns on embodiment performed based on an ignition recipe. The horizontal axis of FIG. 11 shows time, and shows a time chart of a source (high frequency power for induced electric field formation), bias (high frequency power for bias voltage), and pressure. Stage 1 is before plasma ignition, Stage 2 is after plasma ignition (in process).

The control unit 50 controls the pressure in the processing chamber 4 to 20 mT (2.66 Pa) in step 1 set in the ignition recipe. The control unit 50 starts supplying the source at the start time t ₀ of step 2. The source is stabilized at time t ₁ . The bias supply is started at time t ₁ . The bias is stabilized at time t ₂ . The pressure in the processing chamber 4 is lowered to 10 mT (1.33 Pa) at a time t ₂ at which the bias is stabilized after a predetermined time has elapsed from the time t ₁ .

According to this, after setting the high pressure in the processing chamber 4 in Step 1, when the bias is stabilized in Step 2, the pressure in the processing chamber 4 is lowered, thereby making plasma ignition easier. In addition, when the bias is not applied, the pressure in the processing chamber may be adjusted to the second pressure value when the source is applied after a predetermined time has elapsed and the source is stabilized. In addition, even when the source and the bias are applied, if the timing at which the source is stable is later than the timing at which the bias is stable, the pressure in the processing chamber 4 may be lowered at the timing at which the source is stable.

[VUV light]

At the time of plasma ignition, VUV light may be irradiated into the processing chamber 4 from the VUV light source unit 34 through the observation window 33 shown in FIG. 1 . Thereby, gas molecules absorb the light energy of VUV light and emit electrons. By emission of this electron, plasma ignition can be accelerated|stimulated.

It is a figure which shows an example of the result of plasma ignition by irradiation of VUV light which concerns on embodiment. 12 in FIG. 12 shows a case in which plasma is ignited by applying 1 kW of high-frequency power for forming an induced electric field. Δ indicates a case in which plasma is ignited by applying 2 kW of high-frequency power for forming an induced electric field. x shows the case where plasma did not ignite. The pressure in the processing chamber 4 was set in the range of 5 mT (0.665 Pa) to 90 mT (11.9 Pa). In the case where VUV light was irradiated to the plasma space (with VUV), plasma ignition was accelerated compared to the case where VUV light was not irradiated in all gases of the gas species O ₂ gas, Ar gas, and He gas.

According to the plasma processing apparatus and plasma generation method of the present embodiment, cleaning in the processing container and consumption of parts can be suppressed.

It should be considered that the plasma processing apparatus and the plasma generation method according to the disclosed embodiment are illustrative in all respects and not restrictive. Embodiments can be modified and improved in various forms without departing from the appended claims and the gist thereof. The matters described in the plurality of embodiments can be combined within the non-contradictory range, and other configurations can be taken within the non-contradictory range.

Claims (10)

In the plasma processing apparatus,
processing vessel;
a metal window partitioning the inside of the processing vessel into an upper antenna chamber and a lower processing chamber and having a plurality of partial windows;
an inductively coupled antenna disposed above the metal window in the antenna chamber and generating an inductively coupled plasma in the processing chamber;
a lower electrode to which a substrate is disposed in the processing chamber and to which a high frequency power for a bias voltage is applied;
a capacitive element connected to one or a plurality of the partial windows at one end and connected to the ground at the other end;
A resistive element connected to one or a plurality of the partial windows at one end in parallel with the capacitive element and connected to the ground at the other end
Plasma processing apparatus comprising a. According to claim 1,
The plurality of partial windows are divided into one or a plurality of regions, and are connected to the capacitive element and the resistance element for each of the divided regions. 3. The method of claim 1 or 2,
wherein the capacitor is a variable capacitance element. 3. The method of claim 1 or 2,
The capacitor is a fixed-capacitance element. 5. The method according to any one of claims 1 to 4,
The plasma processing apparatus according to claim 1, wherein the capacitance element has a capacitance value such that an impedance of the capacitor element and the resistance element becomes a negative value. 6. The method according to any one of claims 1 to 5,
wherein the capacitive element has a capacitive value such that an impedance of the metal window is -60 Ω or more. 7. The method of claim 6,
wherein the capacitive element has a capacitive value such that the impedance of the metal window is -15 Ω or less. a processing chamber, a metal window having a plurality of partial windows dividing the interior of the processing chamber into an upper antenna chamber and a lower processing chamber; an inductively coupled antenna, a substrate disposed in the processing chamber, a lower electrode to which a high frequency power for bias voltage is applied, a capacitive element connected to one or a plurality of the partial windows at one end and connected to ground at the other end; A method for generating plasma performed in a plasma processing apparatus having a resistive element connected to one or a plurality of the partial windows at one end in parallel with the capacitive element and connected to ground at the other end,
adjusting the pressure in the processing chamber to the first pressure value with reference to a storage unit storing in advance a first pressure value with respect to the pressure in the processing chamber and a second pressure value lower than the first pressure value;
A step of applying high-frequency power for forming an inductive electric field to the inductively coupled antenna, and adjusting the pressure in the processing chamber to a second pressure value after a predetermined time has elapsed
Plasma generation method comprising a. 9. The method of claim 8,
A high frequency power for a bias voltage is applied to the lower electrode, and the pressure in the processing chamber is adjusted to the second pressure value after a predetermined time has elapsed from a timing when the high frequency power for forming an induced electric field and the high frequency power for the bias voltage are late. Plasma generation method comprising the process of: 9. The method of claim 8,
When the high-frequency power for forming an induced electric field is applied by referring to a storage unit in which a first capacitance value and a second capacitance value smaller than the first capacitance value are previously stored in the capacitor, the capacitor is converted into the second capacitance. adjusting the capacitance value, and adjusting the capacitive element to the first capacitance value after a lapse of a predetermined time.

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