TW202124755A - Film forming apparatus and film forming method for DLC film - Google Patents

Abstract

This film forming apparatus (10) has: a reaction vessel (20); a support portion (60) for supporting a film (1) to be formed in the reaction vessel; a rotating portion (70) for rotating the support portion; a first supply pipe (100) for supplying a hydrocarbon-containing raw material gas to the reaction vessel through a first valve (130); a second supply pipe (200) for supplying, through a second valve (230), a reaction gas including hydrogen radicals activated by an inductively coupled plasma, into the reaction vessel filled with the raw material gas, under a pressure higher than the internal pressure of the reaction vessel; and a DC power source (80) for applying, through the support portion, a negative bias to the film to be formed, wherein carbon ions generated by the reaction between the raw material gas and the reaction gas are attracted, by the negative bias, to the film to be formed, and the DLC film is deposited on the film to be formed.

Description

Film forming device and method of DLC film

The present invention relates to a film forming device and a film forming method for DLC (Diamond Like Carbon) film.

The DLC film is an amorphous film in which the crystalline structure is hexagonal, that is, graphite bonds, and the crystal structure is cubic, that is, diamond bonds.

As a manufacturing method of the DLC film, a PVD (Physical Vapor Deposition) method and a CVD (Chemical Vapor Deposition) method are known. Among PVD methods such as sputtering method and ion vapor deposition method, compared with CVD method, the surface of the DLC film is coarser and the wear resistance is also low.

Patent Document 1 uses a compound of C and F such as C ₄ F ₈ gas, and hydrocarbon gas such as C ₂ H ₄ gas and CO gas as the film forming gas in the RF plasma CVD method. Patent Document 1 discloses a method of plasma-forming the film-forming gas to generate active species, and forming a CF film on a semiconductor wafer using the active species at a process temperature of 400°C. Patent Document 1 points out that graphite bonding and diamond bonding are mixed in the CF film. In addition, Patent Document 1 discloses that due to the addition of CO gas, there are more diamond bonds than graphite bonds. [Prior Technical Documents] [Patent Documents]

[Patent Document 1] JP 11-265885 A

[The problem to be solved by the invention]

However, in the RF plasma CVD method, the film-forming object must be heated to 250°C or higher. In the case of a substrate such as a semiconductor wafer, the mounting table can be heated. However, when the film formation object is not a substrate but a three-dimensional structure, especially a structure having unevenness on the film formation surface, it is difficult to uniformly heat, and it is preferable to form a film at a room temperature level that does not require forced heating.

The purpose of the present invention is to provide a film forming apparatus and a film forming method capable of performing a low-temperature process and suppressing the generation of particles or by-products to form a DLC film. [Means to solve the problem]

One aspect of the present invention relates to a film forming device having: Reaction vessel A support part, which supports the film-forming object in the above-mentioned reaction container; A rotating part, which rotates the above-mentioned support part; A first supply pipe for supplying a hydrocarbon-containing raw material gas to the reaction vessel via a first valve body; The second supply pipe is located in the reaction vessel filled with the raw material gas, and passes the reaction gas of hydrogen radicals activated by the inductively coupled plasma through the second supply pipe at a pressure higher than the pressure in the reaction vessel. The valve body is supplied to the above-mentioned reaction vessel; A DC power supply that applies a negative bias to the film-forming object via the support part, The carbon ions generated by the reaction of the raw material gas and the reaction gas are attracted to the film formation target by the negative bias voltage, and the DLC film is deposited on the film formation target.

In one aspect of the present invention, the hydrogen radicals generated by activating the reaction gas by inductively coupled plasma can extract the hydrogen in the hydrocarbon as the raw material gas in the reaction vessel at room temperature. Generate carbon ions. In addition, in one aspect of the present invention, in the reaction vessel filled with the raw material gas introduced through the first valve body and the first supply pipe, the hydrogen-containing gas activated by the inductively coupled plasma The reaction gas of free radicals is supplied to the reaction vessel through the second valve body and the second supply pipe at a pressure higher than the pressure in the reaction vessel. According to this, it is possible to prevent the raw material gas and the reaction gas from flowing back to the second supply pipe. As a result, there is no situation in which the raw material gas and the reaction gas react in the second supply pipe, and accordingly, there is no situation in which the second supply pipe is contaminated with particles or reaction by-products. The film-forming object rotating in the reaction vessel can cause the DLC film to be deposited on the film-forming object by attracting carbon ions generated by the reaction of the raw material gas and the reaction gas by the negative bias voltage. According to this, even if the film formation target is not forcedly heated, the DLC film can be deposited at room temperature.

In one aspect of the present invention, the raw material gas supplied to the first supply pipe may contain H ₂ O, HF, or HCl as an additive gas. _{With H 2} O as an added gas, hydrophilicity can be imparted to the film-forming object. ^{The negative ions F-} or Cl ^- generated from HF or HCl as the added gas can impart water repellency to the film-forming object.

In one aspect of the present invention, the reaction gas before activation supplied to the second supply pipe may contain CF ₄ , C ₂ F ₆ , C ₃ F ₈ , O ₂ or O ₃ as an additive gas. The negative ions F ^- generated from CF ₄ , C ₂ F ₆ , and C ₃ F ₈ that are added gases can impart water repellency to the film-forming object. _{The active oxygen generated from O 2} and O ₃ as the added gas can impart hydrophilicity to the film-forming target.

In one aspect of the present invention, by increasing the absolute value of the negative bias applied by the DC power source, the diamond bond contained in the DLC film can be increased, and by reducing the absolute value, The graphite bonds contained in the above-mentioned DLC film increase. In this way, the ratio of diamond bonding and graphite bonding can be changed according to the purpose of the film-forming object.

In one aspect of the present invention, there is further provided an induction coil provided in the second supply pipe, and a high-frequency power supply connected to the induction coil, It is possible to increase the power of the high-frequency power supply to increase the diamond bonds contained in the DLC film, and reduce the power to increase the graphite bonds contained in the DLC film. In this way, the ratio of diamond bonding to graphite bonding can be changed by the power of the high-frequency power supply.

Another aspect of the present invention relates to a film forming method, It rotates the support part that supports the film-forming object in the reaction vessel, Applying a negative bias to the film-forming object via the supporting part, After the raw material gas is introduced into the reaction vessel from the first supply pipe via the first valve body, the first valve body is closed to set the inside of the reaction vessel to the first pressure, After the reaction gas is introduced into the reaction vessel from the second supply pipe via the second valve body at a second pressure higher than the first pressure, the second valve body is closed, The carbon ions generated by the reaction of the raw material gas and the reaction gas are attracted to the film formation target by the negative bias voltage, and the DLC film is deposited on the film formation target.

Other methods of the present invention can be preferably implemented in the film forming apparatus as one aspect of the present invention, and can achieve the same effects as the one aspect of the present invention. In addition, when the rotation of the support portion starts, the timing of the start of the application of the negative bias voltage may be before or after the introduction of the raw material gas.

Hereinafter, this embodiment will be described. In addition, the present embodiment described below does not unreasonably limit the content of the patent application. In addition, not all the configurations described in this embodiment are necessary constituent elements.

1. Film forming device Fig. 1 shows a film forming apparatus according to an embodiment. In FIG. 1, the film forming apparatus 10 has, for example, a reaction vessel 20 made of quartz. The reaction container 20 has a raw material gas inlet 30, a reaction gas inlet 40, and an exhaust port 50. In the reaction container 20, a support 60 for mounting and supporting the film formation object 1 is provided covering the inside and outside of the reaction container 20, for example. A rotating part that rotates the support part 60, such as a motor 70, is provided outside the reaction container 20. In addition, a DC power source 80 that applies a negative bias to the film formation target 1 via the support 60 is provided outside the reaction vessel 20.

The first supply pipe 100 is connected to the source gas inlet 30. In the first supply pipe 100, when the first valve body 120 is in an open state, the raw material gas at a flow rate controlled by the flow controller 130 is supplied from the raw gas container 110 to the raw gas inlet 30. The second supply pipe 200 is connected to the reaction gas inlet 40. The second supply pipe 200 is provided with a reaction gas activation device 210 and a second valve body 230. The reaction gas container 220 supplies the reaction gas to the reaction gas activation device 210. The reaction gas system activated by the reaction gas activation device 210 is supplied to the reaction gas inlet 40 through the second valve body 230 through the second supply pipe 200. The raw material gas is hydrocarbon, such as CH ₄ , C ₂ H ₂ or C ₂ H ₄ . The activated reaction gas is H radical (H ^* ). Hydrocarbon is reacted with H radicals (H ^* ), and the hydrogen in the hydrocarbon is extracted at room temperature to generate carbon ions. The carbon ions are attracted to the film-forming object 1 to which the negative bias is applied to form a DLC film. The exhaust pipe 300 is connected to the exhaust port 50. The exhaust pipe 300 is provided with an exhaust pump 310 and an exhaust valve 320. In addition, the control unit 400 controls the film forming operation of the DLC film, and can control the valve bodies 120, 230, 320, the motor 70, the DC power supply 80, the high frequency power supply 212, and the exhaust pump 310.

FIG. 2 shows an example of the reaction gas container 220 and the reaction gas activation device 210. In FIG. 2, the reaction gas is, for example, water vapor H ₂ O, and the water vapor is activated to generate H radicals (H ^* ). Therefore, the reaction gas container 220 includes a humidifier 240 that stores the water 2 and an inert gas container 250. In the humidifier 240, an inert gas such as argon Ar is introduced from the inert gas container 250 through the tube 260. The water 2 bubbled by the argon Ar becomes water vapor and is supplied to the second supply pipe 200. For example, an induction coil 270 is provided around the second supply pipe 200 made of quartz. The high-frequency power supply 212 shown in FIG. 1 is connected to the induction coil 270. For example, the electromagnetic energy applied by the induction coil 270 is 20 W and the frequency is 13.56 MHz. The induction coil 270 generates an inductively coupled plasma 3 of reaction gas in the second supply pipe 200. According to this, it becomes Ar + H ₂ O→Ar ^* +OH ^* +H ^* , and H radical (H ^* ) can be generated.

Even if it is different from FIG. 2, the reaction gas container 220 of FIG. 1 may contain, for example, HF as the reaction gas. HF 210 By the reaction gas in the reaction gas is activated activating means, be ^{HF → H * + H + +} F * + F -, free radicals may be generated H (H ^*). Further, as the polarization state by anion F ^- is attached to the DLC film, the DLC film as described later, may have a generally water-repellent.

As shown in FIG. 3 or FIG. 4, the raw material gas and/or the reaction gas may be additionally added with gas. Therefore, as shown in FIG. 3, even if the added gas container 140 and the flow controller 150 are connected to the first supply pipe 100. In addition, as shown in FIG. 4, even if the additive gas container 280 is connected to the reactive gas activation device 210 instead of this.

Here, the DLC film to be formed can be made water-repellent (hydrophobic) by the addition gas added to the source gas and/or the reaction gas. When the negative ions F ^- or Cl ^- are present in the reaction vessel 20, the negative ions are formed on the surface of the DLC film, and the DLC film becomes water-repellent. As the additive gas for water repellency contained in the additive gas container 140, HF or HCl can be cited. As the additive gas for water repellency contained in the additive gas container 280, fluorocarbon CxFy, for example, CF ₄ , C ₂ F ₆ or C ₃ F ₈ can be cited.

Similarly, the DLC film to be formed can be made hydrophilic by the addition gas added to the source gas and/or the reaction gas. By forming highly hydrophilic functional groups (OH, CHO, COOH, etc.) on the surface of the DLC film, the DLC film can be hydrophilic. As the hydrophilic additive gas contained in the additive gas container 140, H ₂ O can be cited. Examples of the hydrophilic additive gas contained in the additive gas container 280 include O ₂ or O _{3 that} generates active oxygen.

2. DLC film forming method Fig. 5 is a timing chart showing a method of forming a DLC film. In the initial state, the valve bodies 120, 230, and 320 are closed. At time t1 in FIG. 5, the first valve body 120 is opened, and the source gas from the source gas container 110 is supplied to the reaction container 20 through the first supply pipe 100 and the first valve body 120. At time t2, the first pressure in the reaction vessel 20 when the first valve body 120 is closed is set to P1. At time t3 after time t2, the second valve body 230 is opened, and the reactive gas containing hydrogen radicals activated by the reactive gas activation device 210 is supplied to the reaction through the second supply pipe 200 and the second valve body 230 Container 20.

Here, the reaction gas activated by the reaction gas activation device 210 needs a pressure capable of generating plasma. The second pressure P2 that can generate plasma in the reactive gas activation device 210 is, for example, 5 to 15 Pa. In this embodiment, the first pressure P1 in the reaction vessel 20 is set to P1<P2. For example, when the second pressure P2 is set to 10 Pa, the first pressure P1 is set to, for example, 1 Pa, which is preferably lower than More than one digit.

Since P1<P2, there is no case where the raw material gas flows back toward the second supply pipe 200 via the second valve body 230. Accordingly, in the second supply pipe 200 and the reactive gas activation device 210, there is no situation where the raw material gas reacts with the reactive gas. In this way, it is possible to prevent the contamination of the second supply pipe 200 and the reaction gas activation device 210 by particles or reaction by-products that may be generated by the reaction of the raw material gas and the reaction gas.

After time t3, since the source gas and hydrogen radicals react in the reaction vessel 20 to generate carbon ions, the formation of the DLC film toward the film formation target 1 is started. Therefore, at least at time t2 before time t3 at which the second valve body 230 is opened, the motor 70 is rotated, and the negative bias voltage is applied to the film forming object 1 by the DC power supply 80. In this way, by the negative bias voltage, carbon ions are attracted to the film-forming object 1 being rotated, and a DLC film is formed on the film-forming object 1. This film forming operation is continued until the time t5 when the exhaust valve 320 is opened and the inside of the reaction vessel 20 is exhausted by the exhaust pump 310. At time t6 after time t5, the motor 70 and the DC power supply 80 are turned off. At the time t7 when the exhaust is completed, the film forming operation of the DLC film ends.

Here, the hydrogen radicals generated by activating the reaction gas by the inductively coupled plasma can extract the hydrogen in the hydrocarbon as the raw material gas in the reaction vessel 20 at room temperature to generate carbon ions. According to this, even if the film formation target is not forcedly heated, the DLC film can be deposited at room temperature. This is better than the RF plasma CVD method, which must heat the film-forming object to 250°C or higher. In particular, if the film-forming object 1 is a three-dimensional structure other than a substrate, especially a structure having unevenness on the film-forming surface, it is difficult to uniformly heat, so this embodiment is also suitable for forming a three-dimensional structure having unevenness. membrane.

Furthermore, it is reported that a film-forming object with a DLC film is used in various applications. According to its use, the surface of the film-forming object 1 can be made hydrophilic or water-repellent by using the additive gas shown in FIG. 3 and/or FIG. 4. In addition, the ratio of diamond bonding and graphite bonding in the DLC film can be changed according to the purpose of the film-forming object 1. For example, by increasing the absolute value of the negative bias applied by the DC power supply 80, the diamond bond contained in the DLC film can be increased, and by reducing its absolute value, the graphite bond contained in the DLC film can be increased. Increase. Or, by increasing the power of the high-frequency power supply 212, the diamond bonds contained in the DLC film can be increased, and by reducing its power, the graphite bonds contained in the DLC film can be increased. This point is better than Patent Document 1 in which the ratio is controlled by the addition/non-addition of CO gas.

1: Filming object 2: water 3: Plasma 10: Film forming device 20: reaction vessel 30: Raw material gas inlet 40: Reactive gas inlet 50: exhaust port 60: Support Department 70: Motor 80: DC power supply 100: 1st supply pipe 110: Raw gas container 130: 1st valve body 140: add gas container 200: 2nd supply pipe 210: Reactive gas activation device 212: high frequency power supply 220: Reactive gas container 230: 2nd valve body 270: induction coil 280: Add gas container 300: Exhaust pipe 310: Exhaust pump 320: exhaust valve

[Fig. 1] is a schematic explanatory diagram of a film forming apparatus according to an embodiment of the present invention. [Fig. 2] A diagram showing an example of the reactive gas activation device shown in Fig. 1. [Fig. [Fig. 3] is a diagram showing a modified example of supplying source gas and additive gas to the first supply pipe. [Fig. 4] is a diagram showing a modified example of supplying reaction gas and additive gas to the second supply pipe. [Fig. 5] is a timing chart showing the film forming method.

10: Film forming device

20: reaction vessel

30: Raw material gas inlet

40: Reactive gas inlet

50: exhaust port

60: Support Department

70: Motor

80: DC power supply

100: 1st supply pipe

110: Raw gas container

120: 1st valve body

130: 1st valve body

200: 2nd supply pipe

210: Reactive gas activation device

212: high frequency power supply

220: Reactive gas container

230: 2nd valve body

300: Exhaust pipe

310: Exhaust pump

320: exhaust valve

400: Control Department

Claims (6)

A film forming device having: Reaction vessel A support part, which supports the film-forming object in the above-mentioned reaction container; A rotating part, which rotates the above-mentioned support part; A first supply pipe for supplying a hydrocarbon-containing raw material gas to the reaction vessel via a first valve body; The second supply pipe is located in the reaction vessel filled with the raw material gas, and passes the reaction gas of hydrogen radicals activated by the inductively coupled plasma through the second supply pipe at a pressure higher than the pressure in the reaction vessel. The valve body is supplied to the above-mentioned reaction vessel; A DC power supply that applies a negative bias to the film-forming object via the support part, The carbon ions generated by the reaction of the raw material gas and the reaction gas are attracted to the film formation target by the negative bias voltage, and the DLC film is deposited on the film formation target. The film forming apparatus of claim 1, wherein the raw material gas supplied to the first supply pipe may contain H ₂ O, HF, or HCl as an additive gas. The film forming apparatus of claim 1, wherein the reaction gas before activation supplied to the second supply pipe may contain CF ₄ , C ₂ F ₆ , C ₃ F ₈ , O ₂ or O ₃ as an additive gas. Such as the film forming device of any one of claims 1 to 3, wherein By increasing the absolute value of the negative bias voltage applied by the DC power supply, the diamond bond contained in the DLC film is increased, and by reducing the absolute value, the graphite bond contained in the DLC film is increased . Such as the film forming device of any one of claims 1 to 3, wherein Further having an induction coil provided in the second supply tube, and a high-frequency power supply connected to the induction coil, by increasing the power of the high-frequency power supply, the diamond bond contained in the DLC film can be increased, By reducing the above-mentioned power, the graphite bonds contained in the above-mentioned DLC film are increased. A film forming method that rotates a support part that supports a film forming object in a reaction vessel, Applying a negative bias to the film-forming object via the supporting part, After the raw material gas is introduced into the reaction vessel from the first supply pipe via the first valve body, the first valve body is closed to set the inside of the reaction vessel to the first pressure, After the reaction gas is introduced into the reaction vessel from the second supply pipe via the second valve body at a second pressure higher than the first pressure, the second valve body is closed, The carbon ions generated by the reaction of the raw material gas and the reaction gas are attracted to the film formation target by the negative bias voltage, and the DLC film is deposited on the film formation target.

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