TW202231132A - Plasma processing apparatus and plasma generating method - Google Patents

Abstract

The invention provides a plasma processing apparatus and a plasma generating method capable of realizing cleaning in a processing container and suppressing part loss. The plasma processing apparatus includes: a processing container; a metal window which divides the inside of the processing container into an upper antenna chamber and a lower processing chamber, and which has a plurality of partial windows; an inductively coupled antenna disposed in the antenna chamber at an upper portion of the metal window and capable of generating inductively coupled plasma in the processing chamber; a lower electrode to which a substrate can be placed in the processing chamber and to which high-frequency electric power for a bias voltage is applied; a capacitor element, one end of which is connected to one or more of the partial windows, and the other end of which is grounded; and a resistive element connected in parallel with the capacitive element at one end to one or more of the partial windows and grounded at the other end.

Description

Plasma processing device and plasma generation method

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

For example, Patent Document 1 proposes a plasma processing apparatus in which the inside of a processing container is divided into an upper antenna chamber and a lower processing chamber, and a plurality of divided metal windows are provided. Filters are connected to the plurality of divided metal windows. [Prior Art Literature] [Patent Literature]

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

[Problems to be Solved by the Invention]

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 detached from the wall surface and discharged, they will be discharged from the vacuum pump as a by-product. The bouncing particles have an impact on the substrate. Furthermore, the increase in particles due to the accelerated consumption of the material constituting the wall surface in the processing container also affects the substrate. Due to these, defects are generated on the substrate.

The present disclosure provides a technique that can achieve "cleaning in the processing container and suppression of the consumption of parts". [means to solve the problem]

According to an aspect of the present disclosure, a plasma processing apparatus is provided, which is characterized by comprising: a processing container; a metal window, which divides the interior of the processing container into an upper antenna chamber and a lower processing chamber, and has a plurality of parts window; an inductively coupled antenna, which is arranged on the upper part of the aforementioned metal window in the aforementioned antenna chamber, and generates inductively coupled plasma in the aforementioned processing chamber; A capacitive element, one end is connected to one or more of the aforementioned partial windows, and the other end is grounded; and a resistive element is connected in parallel with the aforementioned capacitive element, one end is connected to one or more of the aforementioned partial windows, and the other end is grounded. [Effect of invention]

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

Hereinafter, referring to the drawings, a description will be given of a form for implementing the present disclosure. In each of the drawings, the same components are sometimes given the same reference numerals and overlapping descriptions are omitted.

[Plasma processing device] A plasma processing apparatus according to an embodiment will be described with reference to FIGS. 1 to 3 . FIG. 1 is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment. FIG. 2 is a diagram showing an example of an impedance adjustment circuit according to the embodiment. FIG. 3 is a diagram showing an example of a pattern of a plurality of partial windows formed in the metal window of the embodiment.

The plasma processing apparatus of the embodiment is used for etching of metal films, ITO films, oxide films, etc., or ashing of photoresist films when forming thin film transistors on glass substrates for FPD (Flat Panel Display), for example. . Here, as an FPD, a liquid crystal display (LCD), an electroluminescence (Electro Luminescence: EL) display, a plasma display panel (PDP), etc. are illustrated, for example.

The plasma processing apparatus has an airtight processing container 1 in the shape of a square cylinder, and is formed of a conductive material such as aluminum whose inner wall surface is anodized (anodized aluminum). The processing container 1 is grounded by the ground wire 1a. The processing container 1 is divided into an upper antenna chamber 3 and a lower processing chamber 4 by a metal window 2 formed to be insulated from the processing container 1 . In this example, the metal window 2 constitutes the top wall of the processing chamber 4 . The metal window 2 is made of, for example, a non-magnetic and conductive metal. An example of a non-magnetic and conductive metal is aluminum or an alloy containing aluminum. The metal window 2 is supported on the 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 of pieces by the insulator 6, and gas is supplied to each partial window . Each partial window has a gas space (not shown) inside, and has a plurality of gas discharge ports on the surface facing the processing chamber 4 , and supplies gas into the processing chamber 4 from the plurality of gas discharge holes. The gas supply pipe 20a penetrates from the ceiling of the processing container 1 to the outside thereof, and is connected to the processing gas supply part 20 including a processing gas supply source, a valve system, and the like. Therefore, in the 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.

Inside the antenna chamber 3 , a high frequency (RF) antenna 13 is arranged so as to be fastened to the metal window 2 so as to face the metal window 2 . The high-frequency antenna 13 is separated from the metal window 2 by a spacer 17 formed of an insulating member. The high-frequency antenna 13 is formed as a helical antenna, and the metal window 2 is divided into 24 partial windows, for example, at the lower part of the helical antenna. The high-frequency antenna 13 is an example of an inductively coupled antenna that is disposed on the upper portion of the metal window 2 in the antenna chamber 3 via an insulating member spacer 17 and generates inductively coupled plasma in the processing chamber 4 .

In the plasma treatment, high-frequency power having a frequency of, for example, 1 MHz to 27 MHz for forming an induced electric field is supplied from the first high-frequency power source 15 to the high-frequency antenna 13 via the matching device 14 and the power feeding member 16 . Although not shown, the high-frequency antenna 13 of this example is formed of an outer loop antenna, a middle loop antenna, and an inner loop antenna concentrically, and has a power feeding portion 41, a power feeding portion 41 connected to the power feeding member 16, 42, 43. The antenna wires extend in the circumferential direction from the respective feeding parts 41 , 42 , and 43 , and constitute the high-frequency antenna 13 having three loops. A capacitor (not shown) is connected to the terminal of each antenna line, and each antenna line is connected to the side wall 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 for supplying high-frequency power as described above, and the processing gas supplied into the processing chamber 4 is made into a plasma by the induced electric field.

Below the inside of the processing chamber 4, there is provided a stage ST on which the substrate G to be processed, such as a glass substrate, is placed so as to face the high-frequency antenna 13 with the metal window 2 interposed therebetween. The stage ST has the lower electrode 23 and the insulator frame 24 . The lower electrode 23 is made of a conductive material such as aluminum whose surface is anodized. The to-be-processed substrate G mounted on the lower electrode 23 is adsorbed and held by an electrostatic jig (not shown).

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

The lower electrode 23 is connected to a second high-frequency power supply 29 via a matching device 28 by a power supply line 25a provided in the hollow support 25 . The second high-frequency power supply 29 applies high-frequency power for a bias voltage, for example, a high-frequency power having a frequency of 1 MHz to 6 MHz, to the lower electrode 23 during plasma processing. The lower electrode 23 mounts the substrate G to be processed on the mounting surface, generates a bias voltage on the substrate G to be processed by the high-frequency power for the bias voltage, and causes the electricity generated in the processing chamber 4 to generate a bias voltage. The ions in the slurry are efficiently introduced into the substrate G to be processed.

Furthermore, in order to control the temperature of the substrate G to be processed, the lower electrode 23 is provided with a temperature control mechanism and a temperature sensor (both not shown) constituted by heating means such as a ceramic heater or a refrigerant flow path, etc. . The piping or wiring for these mechanisms or components is all led out of the processing container 1 through the hollow support 25 .

Between the stage ST and the side wall 4 a of the processing chamber 4 , a baffle 32 is provided so as to surround the stage ST continuously or intermittently and annularly, so that the gas passes through the exhaust space from the processing chamber 4 . An exhaust device 30 including a vacuum pump or the like is connected to the bottom of the processing chamber 4 via an exhaust pipe 31 . The exhaust space under the baffle 32 is evacuated by the exhaust device 30, and the inside of the processing chamber 4 is set and maintained in a predetermined vacuum atmosphere (for example, 1.33 Pa) during the plasma processing.

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

An observation window 33 is provided on the side wall 4 a of the processing chamber 4 , and a VUV light source unit 34 is mounted on the observation window 33 . The VUV light source unit 34 injects VUV (Vacuum Ultra Violet: vacuum ultraviolet) light with a wavelength of 100 to 200 nm into the processing chamber 4 . When the incident VUV light is irradiated to the gas molecules in the processing chamber 4, the gas molecules absorb light energy and release electrons. Plasma ignition is facilitated by the release of the electrons.

Each component of the plasma processing apparatus is connected to and controlled by a control unit 50 formed of a computer. In addition, the control unit 50 is connected to a user interface 51 composed of a keyboard, a display, and the like. The keyboard is used by the process manager to input commands for managing the plasma processing apparatus, and the display is used to display the electricity. Visual display of the operating status of the pulp processing plant. Furthermore, the memory unit 52 is connected to the control unit 50 . The memory unit 52 stores therein control programs for realizing various processes executed in the plasma processing apparatus under the control of the control unit 50 , and for causing the respective components of the plasma processing apparatus to execute processing according to processing conditions. A program is a recipe. The recipe may be stored in a hard disk or a semiconductor memory, or may be set in a predetermined position of the memory portion 52 while being accommodated in a portable storage medium such as CD-ROM and DVD. Also, the recipe may be appropriately transferred from other devices, eg, via a dedicated line. Furthermore, as necessary, according to an instruction from the user interface 51 or the like, an arbitrary recipe is read from the memory unit 52, and the control unit 50 executes the recipe, thereby, under the control of the control unit 50, plasma processing is performed. The device performs the desired processing.

[Impedance adjustment circuit] An impedance adjustment circuit 18 is connected to the metal window 2 . Referring to FIG. 2 , the impedance adjustment circuit 18 will be described. FIG. 2 mainly shows a section of one of the 24 partial windows 22a of the metal window 2 and the impedance adjustment circuit 18 to which the partial window 22a is connected, and simplifies other structures of the plasma processing apparatus of FIG. 1 .

FIG. 3 is a diagram showing only the metal window 2 in a plan view, omitting the illustration of the impedance adjusting circuit 18 . 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 also collectively referred to as the partial windows 22. The 24 partial windows 22 are parts obtained by dividing the metal window 2 , and are placed through the insulator 6 to constitute the metal window 2 . In this example, when the shape of the wall surface of the processing chamber 4 facing the lower electrode 23 is made into a rectangle, it is divided into an inner peripheral region 5a at the center of the rectangle, and an annular middle surrounding the outer side of the inner peripheral region 5a. The region 5b and the annular outer peripheral region 5c surrounding the outer side of the intermediate region 5b. The inner peripheral region 5a has four partial windows 22, and is formed by dividing the rectangular inner peripheral region 5a approximately diagonally. In addition, the intermediate region 5b has a total of eight partial windows 22, which are divided in the radial direction so as to halve each side of the annular intermediate region 5b. In addition, the outer peripheral region 5c has a total of 12 partial windows 22, which are 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 loop antenna is arranged to correspond to the inner peripheral region 5a, the middle loop antenna to the intermediate region 5b, and the outer loop antenna to correspond to the outer peripheral region 5c.

With this configuration, the 24 partial windows 22 included in the metal window 2 are placed via the insulator 6, thereby insulating from the processing container 1 and insulating the partial windows 22 from each other. An example of a material of the insulator 6 is ceramic or polytetrafluoroethylene (PTFE).

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

Returning to FIG. 2 , the impedance adjustment circuits 18 are provided on a one-to-one basis for each partial window 22 . However, it is not limited to this, and one impedance adjustment circuit 18 may be provided for a plurality of partial windows 22 . That is, the plurality of partial windows 22 are divided into one or a plurality of regions, and each of the one or a plurality of regions can be connected to the impedance adjustment circuit. For example, in the example of FIG. 3 , the 24 partial windows 22 can also be divided into three areas: the inner peripheral area 5a, the intermediate area 5b and the outer peripheral area 5c, and the inner peripheral area 5a, the intermediate area 5b and the outer peripheral area. Each of the regions 5c is connected to one impedance adjustment circuit. For example, the entire surface of the metal window 2 can be cleaned uniformly by adjusting the impedance on an area-by-area basis for the inner peripheral region 5a where by-products are easily deposited, and the intermediate and outer peripheral regions 5b and 5c where it is difficult to deposit. In addition, in the case where the impedance adjustment circuit 18 is provided for one partial window 22, the impedance can be adjusted individually for each partial window 22 when, for example, the deposition state is different at the corners and sides of the metal window 2. The circuit 18 is adjusted to perform cleaning equally.

In the example of FIG. 2 and FIG. 3 , one impedance adjustment circuit 18 is provided for each of the partial windows 22a, 22b, 22c･･･. That is, in this example, the 24 impedance adjustment circuits 18 are connected one-to-one with respect to the 24 partial windows 22 . The impedance adjustment circuit is an R+C parallel circuit having a capacitance element 60 and a resistance element 61 . In this example, one capacitive element 60 and one resistive element 61 connected in parallel to the capacitive element 60 are connected to each partial window 22 . One end of the capacitive element 60 is connected to the partial window 22, and the other end is grounded. The resistive element 61 is connected in parallel with the capacitive element 60, one end is connected to the partial window 22, and the other end is grounded.

The capacitance element 60 is a variable capacitance element. However, the capacitive element 60 may also be a fixed capacitive element. By making the capacitance element 60 a variable capacitance element, it is possible to variably adjust the impedance (hereinafter, also referred to as anode impedance) of the metal window 2 which is the anode electrode when the high-frequency power for the bias voltage is supplied. , and more accurate impedance adjustment can be performed. In addition, when the impedance adjustment circuit 18 is provided for each of a plurality of regions, the capacitive element 60 may be connected to a plurality of partial windows 22 for each of the regions. In the same way, the resistive element 61 can also be connected in parallel with the capacitive element 60 and connected with a plurality of partial windows 22 .

With this configuration, when the high-frequency power for the bias voltage is supplied, the lower electrode 23 is set as the cathode electrode, and the metal window 2 is set as the anode electrode which is the opposite electrode facing the lower electrode 23, and the impedance adjustment circuit 18. The system adjusts the anode impedance. Thereby, in the metal window 2, a desired potential difference can be generated with the plasma by the capacitance of the capacitor element 60, and by-products adhering to the metal window 2 can be removed by the sputtering of the plasma of sediments”. In addition, when the high-frequency power for the bias voltage is supplied to the lower electrode 23, each component in the processing chamber 1 can also function as an anode, but by making the metal window 2 more actively function as an anode function, and strengthening the coupling of the cathode electrode, that is, with the lower electrode 23, it is possible to suppress the consumption of the parts in the processing container 1 caused by the sputtering of plasma.

When the potential difference between the metal windows 2 is too large, not only the by-products adhering to the metal windows 2 are removed but also the metal windows 2 are consumed. When the potential difference is too small, the removal of the by-products adhering to the metal windows 2 becomes insufficient. Therefore, it is important to adjust the capacitance of the capacitive element 60 to a range that "can remove by-products adhering to the metal window 2 while suppressing excessive consumption of the metal window 2 and other components in the processing container 1 during cleaning". Thereby, while suppressing particles, it is possible to prolong the life of each component and prolong the maintenance cycle.

[Impedance Adjustment Circuit: Capacitive Element] Based on the above, the inventors have derived, through experiments, an appropriate range of capacitance of the capacitor element 60 to take into account the reduction of particles by cleaning the metal window 2 and the suppression of the parts in the processing container 1 such as the metal window 2 during cleaning. consumption.

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

When the anode impedance Z of the metal window 2 is equal to or greater than 0, there is a possibility that it will become L-inductive (inductive) and cause resonance, and abnormal discharge may occur due to the resonance. Therefore, the anode impedance Z of the metal window 2 determines the range of the capacitance of the capacitive element 60 so as to ensure C (capacitance) below zero. Specifically, the capacitive element 60 has a capacitance value such that the anode impedance Z by the capacitive element 60 and the resistive element 61 becomes a negative value.

The region I in FIG. 4 is a region where the capacitance C of the capacitive element 60 is 0 to 500 pF and the anode impedance Z is -60Ω or less. In the region I where the anode impedance Z is -60Ω or less, there is a fear that discharge may occur in the exhaust space on the lower side of the baffle 32 . That is, the parts of the processing container 1 constituting the exhaust space may be sputtered by plasma to generate particles. On the other hand, in the metal window 2, since an appropriate potential difference is not generated, the removal of the deposit cannot be performed.

In addition, when the anode impedance Z is close to 0Ω, the consumption of the parts of the processing container 1 constituting the exhaust space is suppressed, but the consumption of the metal window 2 functioning as the upper electrode is accelerated. That is, when the capacitance C is 6000 pF or more, this area and the area I are not used because the consumption of all the components in the processing container 1 such as the metal window 2 cannot be suppressed at the same time.

Based on the above, the capacitance C of the capacitive element 60 is preferably controlled in the range of 500-2000 pF in the region II or the range of 2000-6000 pF in the region III. The range of the capacitance of the capacitive element 60 is controlled within the range of the region II or the region III and the anode impedance Z is adjusted, whereby the cleaning of the metal window 2 can be efficiently performed by plasma sputtering. At the same time, the consumption of the metal window 2 , the inner wall or baffle plate of the processing container 1 , and other components in the processing container 1 can be suppressed during cleaning.

In region III, the anode impedance Z is closer to zero than in region II. The closer the anode impedance Z is to 0, the stronger the coupling (electrical coupling) between the metal window 2 and the lower electrode 23 is and the higher the sputtering force of the metal window 2 is.

Therefore, the capacitance of the capacitive element 60 is independently adjusted for each region including the partial window 22 or a plurality of partial windows 22 by the state of the by-product of the metal window 2 . For example, in a certain part of the window 22, the capacitance range of the capacitance element 60 in the region III can also be used to enhance the sputtering force of the metal window 2 and improve the self-cleaning force. In the part of the window 22 or the area where attention is paid to both the self-cleaning force and the consumption of the parts, it is better to use the capacitance range of the capacitive element 60 in the area II.

[Impedance Adjustment Circuit: Resistive Element] The temperature of the metal window 2 is adjusted by circulating an insulating temperature-regulating medium in the flow path formed in the metal window 2 . When the insulating temperature-adjusting medium flows, triboelectric charging is generated, and the electric charges are stored in the metal window 2 and the metal window 2 is charged. There is also a case where a part of the electrons in the plasma is stored in the metal window 2 and the metal window 2 is charged. The point is that uncontrollable charges are not stored in the metal window 2 . When the metal window 2 is charged, the plasma becomes unstable and affects the processing of the substrate G to be processed. Therefore, in the impedance adjustment circuit 18, the resistance element 61 and the capacitance element 60 are connected to the metal window 2 in parallel. Thereby, the charging caused by the uncontrollable electric charge of the metal window 2 can be eliminated, and the stability of the plasma can be ensured.

[Parts consumption] Next, a description will be given of the results of experiments conducted regarding the presence or absence of the impedance adjustment circuit 18 and the consumption of components. FIG. 5 is a diagram showing an example of the presence or absence of the impedance adjustment circuit 18 and the consumption result of the components according to the embodiment. FIG. 5( a ) is an example of the consumption result of components when the metal window 2 is not provided with the impedance adjustment circuit 18 in the comparative example. FIG. 5( b ) is an example of the consumption result of components when the impedance adjustment circuit 18 is provided.

As an example of the components in the processing container 1, in FIGS. 5(a) and 5(b), the measurement on the substrate G to be processed, on the baffle plate 32, the inner wall plate (the side wall 4a), and the metal window 2 (under the ) consumption. As a result, in the comparative example and the present embodiment, the consumption amount on the substrate G to be processed does not change. On the other hand, regarding the baffle 32 and the inner wall plate (the side wall 4a), when the impedance adjusting circuit 18 of the present embodiment is provided, the consumption is more reduced than when the impedance adjusting circuit 18 of the comparative example is not provided. On the other hand, the consumption of the lower surface of the metal window 2 (the cleaning amount of by-products) increases. Based on the above results, when the impedance adjustment circuit 18 is provided in the metal window 2 , the metal window 2 can be cleaned while suppressing the consumption of the components in the processing container 1 . Thereby, the generation of fine particles can be suppressed. In addition, the consumption of the lower surface of the metal window 2 is adjusted to the extent that the capacitance C of the capacitive element 60 is not consumed by the metal window 2 itself.

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 consumption results of components. Samples of small pieces were placed at each location and consumption was determined. FIGS. 6(b) and (c) show the substrate G to be processed and the baffle 32 in positions 1 to 12 of the process space (on the baffle 32) in the processing chamber 4 shown in FIG. 6(a). consumption on. N represents the consumption of each component without the impedance adjustment circuit 18, M, L represent the case with the impedance adjustment circuit 18 (M is the capacitance C of the capacitive element 60 is 800 pF, L is the capacitive element The capacitance C of 60 is the consumption of each part of 1900pF).

According to this experiment, regardless of the presence or absence of the impedance adjustment circuit 18, the consumption amount on the substrate G to be processed is substantially the same. That is, it is known that the presence or absence of the impedance adjustment circuit 18 does not affect the state on the substrate G to be processed. On the other hand, the consumption amount on the baffle 32 is suppressed more in the case (M, L) with the impedance adjustment circuit 18 than in the case without the impedance adjustment circuit 18 (N).

Figures 7(b) and (c) show the side wall 4a (inside the exhaust space) of the processing chamber 4 at positions 13 to 33 of the exhaust space (under the baffle 32) in the processing chamber 4 shown in Figure 7(a). wall) and the consumption under the baffle 32. In addition, in the position where the data is not shown, the data can be obtained by the breakage of the sample or the like.

According to this experiment, the consumption amount in the inner wall (side wall 4a) of the processing chamber 4 and under the baffle plate 32 is in the case (M, L) with the impedance adjustment circuit 18, than in the case without the impedance adjustment circuit 18 (N) more suppressed.

FIGS. 8(b) and (c) show the consumption in the positions 49 to 66 of the lower surface of the metal window 2 shown in FIG. 8(a). According to this experiment, the consumption amount under the metal window 2 is larger in the case (M, L) with the impedance adjusting circuit 18 than in the case (N) without the impedance adjusting circuit 18 .

Based on the above results, the capacitance of the capacitive element 60 is adjusted by the impedance adjustment circuit 18 of the present embodiment, whereby the cleaning of the lower surface of the metal window 2 can be promoted, and the consumption of the components in the processing container 1 can be suppressed.

When the capacitance C of the capacitive element 60 is reduced, the anode impedance becomes high, the coupling between the metal window 2 and the lower electrode 23 becomes difficult, and the by-products of the metal window 2 become difficult to remove. On the other hand, when the capacitance C of the capacitive element 60 is reduced, the inner wall of the processing chamber 4 or the parts in the processing chamber 1 such as the baffle 32 and the lower electrode 23 become easily coupled, and the inner wall or the lower electrode 23 is easily coupled. The consumption of the baffle 32 increases.

When the capacitance C of the capacitive element 60 is increased, the anode impedance becomes lower, the coupling between the metal window 2 and the lower electrode 23 becomes easier, and the by-products of the metal window 2 become easier to remove. On the other hand, when the capacitance C of the capacitive element 60 is increased, it becomes difficult to couple between the inner wall of the processing chamber 4 or the parts in the processing chamber 1 such as the baffle 32 and the lower electrode 23, and the inner wall or the lower electrode 23 becomes difficult to couple. The consumption of the baffle 32 is reduced.

Thereby, the capacitance C of the capacitive element 60 is adjusted within the range of the area II where the capacitance C of the capacitive element 60 shown in FIG. 4 is small and the area III where the capacitance C is large. Consumption of parts in the processing container 1 is suppressed. As a result, the generation of fine particles can be reduced.

FIG. 9 is a diagram showing an example of discharge results in the presence or absence of the impedance adjustment circuit 18 and the exhaust space in the embodiment. The exhaust space is the space below the baffle 32 .

FIG. 9( a ) shows the stability of discharge in the exhaust space under the baffle 32 without the impedance adjustment circuit 18 , and FIG. 9( b ) shows the stability of the discharge with the impedance adjustment circuit 18 . Stability of discharge in exhaust space. 9(a) and 9(b) show the process conditions of the pressure of the processing chamber 4, the gas flow rates of the Cl ₂ gas and the BCl ₃ gas, and the power density of the high-frequency power of the bias voltage. The pressure of the processing chamber 4 is controlled at 10mT (1.33Pa) ~ 70mT (9.31Pa). In this process condition, the case where the discharge instability does not occur is indicated by the diagonal line of "OK", and the case where the discharge instability occurs is represented by the diagonal line of "NG". Thereby, the usable ranges of pressure and power density are shown. However, the type of gas is an example, and is not limited to this. For example, in the case of etching a metal film such as aluminum, Cl ₂ gas and BCl ₃ may be used, and in the case of etching a SiO ₂ film, CF ₄ gas and O ₂ gas may be used.

As a result of the experiment, in the case of the impedance adjustment circuit 18 shown in FIG. 9(b), compared with the case without the impedance adjustment circuit 18 shown in FIG. 9(a), no discharge is generated in the exhaust space. The range of stable process conditions is wider, and discharge instability in the exhaust space is suppressed. Thereby, the generation of fine particles can be suppressed.

FIG. 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 substrate G that has been processed. The number of defects indicates the number of defects such as disconnection generated on the processed substrate G that has been processed.

FIG. 10( a ) shows the number of defects on the processed substrate G without the impedance adjustment circuit 18 , and FIG. 10( b ) shows the processed defects with the impedance adjustment circuit 18 . The number of defects on the substrate G. Thereby, in the case of having the impedance adjusting circuit 18 of FIG. 10( b ), the number of defects can be greatly reduced compared with the case that the impedance adjusting circuit 18 of FIG. 10( a ) is not provided.

[Plasma Generation Method: Plasma Ignition] When the capacitance of the capacitive element 60 of the impedance adjustment circuit 18 is increased and the impedance of the metal window 2 is adjusted to be low, the ignition of the plasma may deteriorate. Therefore, in order to promote the ignition of the plasma, the capacitance element 60 which is a variable capacitance element is used. When the plasma is ignited, the capacitance of the capacitance element 60 is set to a value in the range of the region II, for example, and the metal window 2 is adjusted to a high impedance. , so as to control the potential of the metal window 2 to increase. After the plasma is ignited, the capacitance of the capacitive element 60 can also be increased to a value in the range of region III, for example, and the metal window 2 can be adjusted to a low impedance.

Specifically, for the capacitive element 60 , the first capacitance value and the second capacitance value smaller than the first capacitance value are stored in the memory unit 52 in advance. During substrate processing, the control unit 50 may adjust the capacitance element 60 to the second capacitance value when referring to the memory unit 52 and supply the high-frequency power for forming the induced electric field to the high-frequency antenna 13 , and set the capacitance value through a preset value. After the time, that is, after the plasma is ignited, the capacitance element 60 is adjusted to the first capacitance value.

It is also possible not to make all the capacitive elements 60 variable capacitive elements, but to use variable capacitive elements only in a specific partial window 22 of the 24 partial windows 22 or a partial window 22 in a specific area, and use variable capacitive elements in parts of other areas. Window 22 uses fixed capacitive elements. Thereby, the cost can be reduced. The circuit of the variable capacitance element and the circuit of the fixed capacitance element can also be switched by a switch.

Plasma ignition can also be promoted by preparing an ignition recipe in advance and storing it in the memory unit 52 , and using the ignition recipe to control the pressure in the processing chamber 4 . FIG. 11 is a timing chart showing an example of the plasma generation method of the embodiment executed based on the ignition recipe. The horizontal axis of FIG. 11 represents time, and represents a timing chart of the source (high-frequency power for the formation of the induced electric field), the bias (the high-frequency power for the bias voltage), and the pressure. Step 1, represents before the plasma is ignited, and step 2, represents after the plasma is ignited (during the 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 the supply from the source at the start time t0 of step 2 . source, which is stabilized at time t1. At time t1, the supply of the bias voltage is started. The bias voltage is stabilized at time t2. At time t2 when the bias voltage has stabilized after a predetermined time has elapsed from time t1, the pressure in the processing chamber 4 is lowered to 10 mT (1.33 Pa).

Thereby, in step 1, after the pressure in the processing chamber 4 is set high, in step 2, when the bias voltage is stabilized, the pressure in the processing chamber 4 is lowered, whereby the electrical Slurry ignition becomes easier. In addition, the source may be applied without applying a bias voltage, and when the source has stabilized after a preset time has elapsed, the pressure in the processing chamber may be adjusted to the second pressure value. In addition, even when the source and the bias are applied, when the source is stabilized later than the bias is stabilized, the pressure within 4 can be reduced at the time when the source is stabilized.

[VUV light] When the plasma is ignited, the VUV light can also be irradiated into the processing chamber 4 from the VUV light source unit 34 through the observation window 33 shown in FIG. 1 . Thereby, the gas molecules absorb the light energy of the VUV light and release electrons. Plasma ignition is facilitated by the release of the electrons.

FIG. 12 is a diagram showing an example of the result of plasma ignition by irradiation of VUV light according to the embodiment. No. 0 of FIG. 12 shows the case where high-frequency power for forming an induced electric field of 1 kW is applied and the plasma is ignited. △ represents the case where the high-frequency power for the formation of the induced electric field of 2 kW was applied and the plasma was ignited. × represents the case where the plasma is not ignited. The pressure of the processing chamber 4 is set in the range of 5mT (0.665Pa)-90mT (11.9Pa). When the plasma space is irradiated with VUV light (with VUV), compared with the case where the VUV light is not irradiated, the plasma can be promoted more in the gas types including O ₂ gas, Ar gas, and He gas. ignite.

According to the plasma processing apparatus and the plasma generation method of the present embodiment, it is possible to achieve cleaning in the processing container and suppress consumption of parts.

It should be understood that the plasma processing apparatus and the plasma generation method of the embodiments disclosed this time are illustrative and non-restrictive in all respects. The embodiment can be deformed and improved in various forms without departing from the scope and gist of the appended claims. The matters described in the above-mentioned plural embodiments may be adopted in other configurations within the scope of non-contradiction, and may be combined within the scope of non-contradiction.

1: Handling the container 2: Metal Windows 3: Antenna Room 4: Processing room 6: Insulator 13: High frequency antenna 15: The first high frequency power supply 16: Power supply components 18: Impedance adjustment circuit 20: Process gas supply part 23: Lower electrode 29: Second high frequency power supply 30: Exhaust 32: Baffle 34: VUV light source unit 60: Capacitive element 61: Resistive element G: substrate to be processed ST: Platform

1 is a schematic cross-sectional view showing an example of a plasma processing apparatus according to an embodiment. [ Fig. 2] Fig. 2 is a diagram showing an example of an impedance adjustment circuit according to the embodiment. [ Fig. 3] Fig. 3 is a diagram showing an example of a pattern of a plurality of partial windows formed in the metal window of the embodiment. [ Fig. 4] Fig. 4 is a diagram showing an example of the capacitance and anode impedance of the impedance adjustment circuit according to the embodiment. [ Fig. 5] Fig. 5 is a diagram showing an example of the presence or absence of an impedance adjustment circuit according to the embodiment and a result of consumption of components. [ Fig. 6] Fig. 6 is a diagram showing another example of the presence or absence of the impedance adjustment circuit according to the embodiment and the consumption result of components. [ Fig. 7] Fig. 7 is a diagram showing another example of the presence or absence of the impedance adjustment circuit according to the embodiment and the consumption results of components. [ Fig. 8] Fig. 8 is a diagram showing another example of the presence or absence of the impedance adjustment circuit according to the embodiment and the consumption result of the components. [ Fig. 9] Fig. 9 is a diagram showing an example of the discharge results in the presence or absence of the impedance adjustment circuit according to the embodiment and the discharge space. [ Fig. 10] Fig. 10 is a diagram showing an example of the presence or absence of an impedance adjustment circuit and the number of defects on a substrate to be processed according to the embodiment. [ Fig. 11] Fig. 11 is a timing chart showing an example of the plasma generation method according to the embodiment. [ Fig. 12] Fig. 12 is a diagram showing an example of the results of plasma ignition by VUV light according to the embodiment.

18: Impedance adjustment circuit

22a: Partial windows

60: Capacitive element

61: Resistive element

Claims (10)

A plasma processing device, characterized by: processing containers; a metal window, which divides the interior of the aforementioned processing container into an upper antenna chamber and a lower processing chamber, and has a plurality of partial windows; The inductively coupled antenna is arranged on the upper part of the aforementioned metal window in the aforementioned antenna chamber, and generates inductively coupled plasma in the aforementioned processing chamber; The lower electrode, the substrate is placed in the processing chamber, and the high-frequency power for bias voltage is applied; A capacitive element, one end is connected to one or more of the aforementioned partial windows, and the other end is grounded; and The resistance element is connected in parallel with the capacitive element, one end is connected to one or more of the above-mentioned partial windows, and the other end is grounded. The plasma processing apparatus of claim 1, wherein, The plurality of partial windows are divided into one or a plurality of regions, and each of the divided regions is connected to the capacitance element and the resistance element. The plasma processing apparatus of claim 1 or 2, wherein, The aforementioned capacitive element is a variable capacitive element. The plasma processing apparatus of claim 1 or 2, wherein, The aforementioned capacitive element is a fixed capacitive element. The plasma processing device of any one of claims 1 to 4, wherein, The capacitance element has a capacitance value such that the impedance due to the capacitance element and the resistance element becomes a negative value. The plasma processing device of any one of claims 1 to 5, wherein, The capacitance element has a capacitance value such that the impedance of the metal window becomes -60Ω or more. The plasma processing device of claim 6, wherein, The capacitance element has a capacitance value such that the impedance of the metal window becomes -15Ω or less. A plasma generation method is performed by a plasma processing device, the plasma processing device is provided with: a processing container; a metal window divides the inside of the processing container into an upper antenna chamber and a lower processing chamber, and has A plurality of partial windows; an inductively coupled antenna, which is arranged on the upper part of the metal window in the antenna chamber, and generates inductively coupled plasma in the processing chamber; a lower electrode, which mounts a substrate in the processing chamber and applies a bias voltage high-frequency power used; a capacitive element, one end is connected to one or more of the aforementioned partial windows, and the other end is grounded; and a resistive element is connected in parallel with the aforementioned capacitive element, one end is connected to one or more of the aforementioned partial windows, and the other end is grounded, the A plasma generation method, characterized by: The process of adjusting the pressure in the processing chamber to the first pressure value with reference to a memory unit that stores a first pressure value and a second pressure value lower than the first pressure value for the pressure in the processing chamber in advance; and The process of applying the high-frequency power for the formation of the induced electric field to the inductive coupling antenna, and adjusting the pressure in the processing chamber to the second pressure value after a preset time has elapsed. The plasma generation method of claim 8, wherein: The high-frequency power for bias voltage is applied to the lower electrode, and a preset time elapses from the time when the application of the high-frequency power for the induced electric field formation and the high-frequency power for the bias voltage is relatively slow Then, the process of adjusting the pressure in the processing chamber to the second pressure value. The plasma generation method of claim 8, wherein, Referring to a memory portion in which a first capacitance value and a second capacitance value smaller than the first capacitance value are stored for the capacitance element in advance, when the high-frequency power for forming the induced electric field is applied, the capacitance element is adjusted to The second capacitance value is adjusted to the first capacitance value after a preset time has elapsed.

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