TW462081B - Plasma CVD system and plasma CVD film deposition method - Google Patents

Abstract

The plasma CVD device and plasma CVD film formation method of the present invention are provided to extend the maintenance cycle and also reduce the fluorination of a cathode electrode in a plasma CVD device. On a cathode electrode 17, there is provided with a plurality of gas introduction ports 5 for introducing the gas between the cathode electrode 17 and an anode electrode 3. There is provided with a plurality of recesses 14 for increasing the area of the cathode electrode 17, at the face opposed to the anode electrode 3 of this cathode electrode 17 provided with the gas introduction ports 5. The recess 14 has a width more than 3 mm and smaller than the pitch of the gas introduction port 5, and has opening area larger than the opening area of the gas introduction port 5.

Description

^ 62081 V. Description of the invention (1) [Detailed description of the invention] [Technical field to which the invention belongs] The present invention relates to a plasma CVD plasma CVD thin film forming method used in semiconductor manufacturing operations. Team [Previous Technology] One of the semiconductor manufacturing operations is a plasma CVD (chemical vapor deposition) film forming operation that forms a predetermined thin layer on a substrate. In this manufacturing operation, a substrate is placed in a closed processing chamber, and a film-forming gas is supplied to a pair of electrodes provided in the processing chamber. At the same time, high-frequency power is applied to cause plasma generation, and the gas molecules of the film-forming gas are decomposed. A chemical reaction occurs and a thin film is formed on the substrate surface. The film forming chamber of the conventional plasma CVD apparatus shown in FIG. 8 is provided with a pair of electrodes 2 and 3 in a processing chamber, a substrate 4 is disposed on the anode electrode 3, and a film forming gas is introduced from another cathode electrode electrode 2. The purpose of installing the upper heater 11 and the lower heater 11 is to uniformly heat the substrate 4 to a predetermined temperature. The film-forming gas is supplied through the supply pipe I connected to the cathode electrode 2 and is introduced between the cathode electrode 2 and the anode electrode 3 through the dispersion plate 2 and the gas introduction hole 5 provided on the cathode electrode 2. . For the film-forming gas introduced between the electrodes 2 and 3, the high-frequency electric power of the RF high-frequency power source 9 is applied through the film-forming gas introduction tube 15 and the anode bracket 13 to generate a plasma, which is formed on the substrate 4. Prescribed film. The residual gas' of the plasma-forming film-forming gas is discharged to the exhaust system through the exhaust pipe 7 and processed. One such device is the ability to form a thin film collectively known as an amorphous silicon film

89120210.ptd Page 4 4 620 8 1 V. Description of the invention (2) (SiN, si02, argonized α-Si, hydrogenated a-Si (N +), etc.) plasma CVD device. For the film-forming gas, a mixture of SiIj4, nh3, and N2 is used in the formation of SiN; a mixture of 4 gases of Sil and H2 is used in the formation of α-Si; mixed composition. The film-forming gas includes a gas (non-film-forming gas) that simply participates in the reaction without forming a film. In the above examples, 〇3, ~, I, n20, and h belong to the Han film-forming gas. On the contrary, a gas that can form a film by reacting alone, for example, the above-mentioned s i 1 'TEOS is called a main film-forming gas. However, a thin film produced by such a plasma CVD method has a feature that a plasma region formed adjacent to the substrate 4 is formed. The adjacent plasma area referred to here refers to the area connected to the plasma area and its peripheral parts. The peripheral parts include the insulation rings 16 and 20, the inside of the exhaust pipe 7, and the like. Therefore, with the increase in the number of substrates during the film formation process, the surface of the cathode electrode 2 or the surface of the insulator is formed into a thin film, and such a film is referred to as a cumulatively formed film. In the area adjacent to the plasma, the film formed in the area with a lower surface temperature (about 16 (rc)) tends to become powdery. This powdery film is easy to peel off under the influence of factors such as vibration and pressure changes. On the other hand, as the thickness of the accumulated film increases with increasing thickness, the stress of the film will increase, and it will not be peeled off soon. [Problems to be Solved by the Invention] As mentioned above, the conventional method The technology has the following problems due to the formation of a powdery film and a cumulative film formation: (1) Frequent maintenance cycles

4 620 8 1 V. Description of the invention (3), not only pollution caused by particles such as powder, etc. on the board, but also due to the pollution to the gas system, the exhaust capacity is reduced. In order to prevent this failure, at present, after continuous film formation processing is performed on a predetermined number of substrates, ^ cleansing with a corrosive silver gas (fluorine-based gas such as Cf4, NF3, etc.), and transforms the accumulated film and powder film. Remove into gas. After the cleaning process, the decaying gas and its by-products (HF, etc.) remain in the processing chamber. Therefore, a residue treatment must be performed in order to eliminate these effects. The residue treatment t is usually the same as the treatment performed under film formation conditions. In this way, the so-called cyclic processing, which frequently and repeatedly uses a plurality of substrates for film formation processing, cleaning processing, and residual production processing, in the processing room, limits the number of substrates that can be continuously formed in a cycle, so it is strongly It is hoped that the number of film-forming substrates will increase (2) The film-forming speed accompanied by electrode fluorination will decrease and frequent electrode regeneration will occur through frequent and repeated periodic processing, which slowly forms on the surface of the cathode electrode. Fluoride) ^ Using this phenomenon, the film-forming speed gradually decreased in the first dozens of cycles, and abnormal discharge (arc discharge) failure occurred hundreds of k 'months later. Therefore, in a relatively short period of time, the deterioration of the cathode electrode surface can be removed by grinding or the cathode electrode must be replaced (called cathode electrode regeneration). This is the current problem. The subject of the present invention is: by using # 描 4 + ki, you can help increase the electrode area on the 1st day to solve the problems of conventional techniques, and provide a fluorination that can be changed while extending the maintenance period. Phenomena of plasma CVD device and plasma CVD thin film formation method: ° [Solution to Problem] ''

^ 62081 V. Description of the invention (4) The invention is equipped with a processing chamber capable of decompression, and the processing chamber is equipped with a plate electrode having a substrate for grounding and a ground electrode and a 罝 introduction hole capable of applying high frequency waves. 2 electrodes, through the 2nd electrode: body two into the hole at the first! A film is formed by supplying gas between the second electrode and the second electrode. The exhaust pipe of the above-mentioned processing chamber is exhausted, and a plasma CVD recess is provided on the surface of the second electrode with the first electrode Γ-». Unlike the gas introduction hole formed through the second electrode, it is. : Is formed in the form and therefore includes non-through holes and trenches. '' Once the second electrode is provided with a recessed portion, the non-entrained gas is retained in the recessed portion. Since 1 dagger does not easily form a build-up film in the recessed portion, the maintenance period can be long. The non-film-forming gas is effectively ionized from the remaining recessed portion with a high-density energy-releasing body introduction hole. Therefore, the electric coupling can reduce the required high-frequency power, and the voltage Vdc can be greatly reduced Lower, the skin of the second electrode: the slope of the bit can be made smoother. Therefore, the second invention can be suppressed, and the formation of the second gaseous substance can be suppressed. The towel s to less than the pitch of the gas introduction holes = the recess has more than 3 positions, which is the pitch of the introduction holes, which refers to the gas-electric red VD device. The so-called distance between the gas and the recess === the distance or the eight holes of the gas guide: 3rd WV—especially when the recess has a width range of more than 3—or even less than the gap between the gas introduction holes, λ- 廿 can be greatly reduced, The slope of the J electrode of the second electrode can be made smoother. Therefore, generation of fluoride at the second electrode can be suppressed.

4 620 8 1 V. Description of the invention (5) The third invention is the plasma CVD apparatus in which the opening area of the recess has a larger opening area than that of the gas introduction hole in the second or third invention. Since the opening area of the recessed portion is larger than the opening area of the gas introduction hole, the formation of a plasma in the recessed portion does not cause a defective state of plasma generation in the gas introduction hole ^ A fourth to sixth invention is a plasma CVD method Forming a predetermined thin film ^ Plasma CVD thin film formation method 'Using the electric paddle cvd perforation of the first to third inventions, first introduce a non-film-forming gas into the processing chamber, and then introduce a film-forming gas to form a plasma CVD characterized by a predetermined thin film Thin film formation method. As the non-film-forming gas, there are gases such as N2 and H2. As the film-forming gas, there are si and SiH. The non-film-forming gas is first introduced into the processing chamber, and then the film-forming body is introduced. First, the non-film-forming gas has entered the recess, so the film-forming gas introduced later will not be easily accessible to the person. Membrane gas for plasma separation '[Embodiment of the invention] According to the present invention, a plasma CVD device capable of suppressing the accumulation of cathode electrode electrodes to form tritium is used to improve the maintenance cycle; using a method that reduces the cathode electrode potential slope (hereinafter referred to as Vc) Plasma CVI) device to improve the fluorination of the cathode electrode. In the following, the effect of the improvement will be described while pointing out the configuration of the device and the mode of use of the device. FIG. 1 shows a plasma CVD apparatus according to this embodiment. The logic 1 of the plasma CVD apparatus is a pressure-reducing double-slot grate structure composed of an inner shell 18 and an outer shell 31.

A pair of parallel flat electrodes are provided in the processing chamber 1 and are composed of an anode electrode & 3 and a ° electrode 17. B

89120210.ptd Page 8 4 620 8 1 V. Description of the invention (6) The anode bracket 1 3 supporting the anode electrode 3 is grounded. The cathode electrode 17 has a plurality of gas introduction holes that can apply high-frequency power and can introduce gas into the film-forming gas supply processing chamber 1. The RF high-frequency power source 9 is connected to the cathode electrode 17 from the film-forming gas introduction pipe 15 through a coupling capacitor 19. The anode bracket 1 3 supporting the anode electrode 3 is grounded through the inner case 18 and the outer case 31. The high-frequency application circuit having such a structure can apply high-frequency power between the cathode electrode 17 and the anode electrode 3. The film-forming gas is supplied into the processing chamber 1 through the supply pipe 15, and the film-forming gas is introduced between the anode electrode 3 and the cathode electrode 17 through the dispersion plate 12 provided on the cathode electrode 17 and the gas introduction hole 5. The upper heater 10 provided at the cathode electrode 17 and the lower heater n provided at the anode electrode 3 are provided for heating the substrate I to maintain a constant temperature. The entire upper part of the cathode electrode 17 is covered with an insulating ring 8, and the outer periphery of the lower part is supported by the insulating ring 20, and the processing chamber is grounded! The inner case 8 and the outer case 31 are insulated from each other. The anode bracket 13 on which the substrate 4 is placed can be moved up and down. When the anode bracket 13 is raised, it closes the lower opening of the inner case 18 to form an inner shaft. The substrate 4 is enclosed within the ::. When the anode bracket 13 is lowered, the inner tank is opened, and the substrate 4 is pulled out of the outer casing as the outer tank. The anode bracket 13 is raised 'to form an inner groove. The high-frequency electricity of the Rp high-frequency power source is applied to the film-forming gas introduced between the cathode electrode 2 and the pole electrode, so that "electricity" occurs to form a thin film on the substrate 4. The residual gas of plasma = gas T treated by plasma , Through the exhaust pipe 7 connected to the processing chamber) to perform treatment 1

System, substrate transfer system, and exhaust treatment system. In this embodiment, as the cathode electrode 17 forming the gas introduction hole 5, a cathode electrode (hereinafter referred to as a porous structure) having a plurality of recesses 14 is mounted on a surface facing the anode electrode 3 in order to increase the electrode area. Cathode electrode). The recessed portion 14 of the porous cathode electrode 17 is different from the through hole of the gas introduction hole 5 ', which is a non-through hole. As shown in Fig. 2 (a), the recessed portions 14 are uniformly arranged so as to avoid the gas introduction holes 5. The shape of the recess 14 is shown in Fig. 2 (b). It is a non-through cylindrical hole. The shape of the concave portion 14 is not limited to a cylindrical shape, and any other shape may be used. Polygonal cones such as conical or triangular cones are acceptable. Moreover, instead of a hole shape, a groove shape with a fixed width may be used. When the groove shape is adopted, its shape may be any shape such as a straight line, a curved line, a ring, or a parallel line in which a plurality of linear grooves are arranged in parallel, and a lattice shape in which horizontal grooves and vertical grooves are arranged alternately. In this case, the grooves should be arranged to avoid the gas introduction holes 5. Recess! 4 If considering machining holes, it is better to use a tapered hole with a lower machining f. As shown in FIG. 3, the radius Γ of the recessed portion 14 is 5 to 30 times the thickness t of the cathode skin 24 formed on the surface of the cathode electrode during the film formation process. Specifically, the pitch of the gas introduction holes having a diameter of 0.3 mm or more (the distance between the gas introduction hole 5 and the distance between the "texture introduction hole and the recess" in Fig. 2 &), whichever is shorter) is as follows The size requirement is better. The depth of the recess 4 is determined by the relationship with the cathode skin 24. The cathode skin 24 is formed on the entire surface of the porous cathode electrode Π: the thickness of the skin is limited ', so the diameter of the recess 14 and the cathode cover Thickness of leather 24

89120210.ptd The 10th stomach 462081 V. Description of the invention (8) (about 1 mm) When the former is smaller, it can be considered that the recesses 14 are buried in the cathode skin 24. Once the recessed portion 14 is buried in the cathode skin 24, the area of the porous cathode electrode 17 cannot be enlarged. In order to increase the area of the cathode electrode 17, the depth of the recess 14 is as deep as possible. However, a depth of 5 minutes to a few bands can achieve sufficient results. Furthermore, the larger the number of the recesses 14 is, the higher the effect of increasing the electrode area is. 'Actually', the number of the recesses 4 and the strength of the porous cathode electrode itself should be taken into consideration. FIG. 4 shows an example of a surface view of the porous cathode electrode 17 shown in the gas introduction hole 5 and the recessed portion 14. As shown in FIG. In this example, the gas introduction holes 5 have a diameter of $ 0.8 minutes and are arranged in an equal rhombic shape at a pitch of 11 mm. The diameter of the recesses 14 must be 3 mm, and they are arranged in a regular hexagon at a pitch of 4 mm. By using the porous cathode electrode 17 described above, a recessed portion of the cathode skin 24 is formed in the recess 4 1 4 during the film formation process. The cathode skin potential slope Vc can be made slower. In theory, Vc and the formula-{(anode Skin area) * _ (cathode = skin area) 4 丨-(1) proportional relationship. This is because the skin voltage V !, V2 (refer to Fig. 6) related to the cathode = f potential slope Vc can be used under W2 = (a2 / a) 4---(2) A1, A2 in j: electrode area hole The area of the porous cathode electrode 17 in the form of ί i is larger than the area of the cathode electrode with only gas introduction. Therefore, substituting the area value into the formula, 丄 J, can be used with caution.

Vc μμ ,, A smaller value of the morphology. For example, Vdc and the smaller force l tC *, because V H l 0 is also smaller. + Ion acceleration generated by electric field E of Vdc

462081

According to the formula F = qE --- (3), the lower Vcd is, the smaller the value of cd is, and the smaller the ionic collision of the porous cathode electrode is suppressed. The collision of 1 ^ ions on the sputtering surface of the surface structure (atoms) inhibits the release of the secondary electrons of the electrode and the dirt on the surface of the porous cathode electrode 2 ^ 4, 7 ^^ \ Therefore it effectively suppresses gold foreign matter The base rate has been improved. In addition, the generation efficiency of the electropolymerization, which suppresses the overflow of the ions, is improved, so unlike the conventional technology, electrical destruction can be generated. In this way, the film-forming treatment is performed. (# The state of the surface of the porous cathode electrode can stabilize the film formation speed to 14 and avoid the gas introduction hole 5 ′ as shown in FIG. 2 or FIG. 4. Through the arrangement of the recess Φ Sj can suppress the formation of a thin film in the recess 14. This It is because the gas # 1 film S1 H4 in the film formation process does not easily enter (replace) the inside of the recessed portion 14 and the gases nh3, N2, and h2 stay in the recessed portion 14. This is the analysis of the original Qiu Er A as follows. When there is only the introduction hole 5, the partial pressure of the new SiH4 in the gas introduction hole 5 = before the film-forming reaction is high. When according to this embodiment, when the recessed portion 14 is provided, it will not pass from the non-through hole. The internal supply of milk in the recessed part 4 ”gas is trapped in the recessed part 14. Therefore, the unreacted = I knife pressure in the recessed part 14 is low, and the non-film-forming gas 3, h, & It is occupied by pressure. It will be described with reference to FIG. 5. This diagram shows that the gas is not straight from the gas introduction hole 5.

^ 62081 V. Description of the invention (10) 'The energy is transmitted indirectly, but the energy is transmitted indirectly from the recess 14. First, the RF high-frequency power supply provides energy (electricity) to the porous cathode electrode 17 and transfers the energy to the electrons on the cathode skin 24 formed along the surface of the porous cathode electrode 17. The high-energy electrons obtained at the cathode skin 24 transfer the energy to the molecules in the film-forming gas in the negative glow 22. The molecules in the film-forming gas that receive energy are decomposed into activated particles (ions, atomic groups) with higher energy under the action of ionization. In the figure, 25 is an anode electrode column 26 is an anode skin, 27 is a stacking surface, and 28 is a substrate surface. The non-film-forming gases N and rhenium have a small molecular weight and a fast moving speed (good diffusivity). Therefore, it is considered that N and rhenium are mainly present in the recess 14. In the concave portion 14, the above-mentioned ionization effect is very strong due to the hollow cathode electrode phenomenon, and the energy density is high. Since energy has a characteristic of transmitting from high density to low density, it is considered that the high-density energy generated in the concave portion i 4 is diffused to the outside in the form of a spherical surface like a conductive wave with the concave portion 14 as the center. The arrows in Figure 5 indicate this form of diffusion. It can be speculated that this diffusion of energy is caused by the collision of particles (mainly the collision of particles of the same mass). The energy from RF power is transmitted to the main film-forming gas supplied from the gas introduction hole 5 through the negative glow generated through the recess Η, and the main gas is decomposed. In this way, compared with the conventional method, the RF power required for quality can be greatly reduced. Hu Lianmin Probability of indirectly introducing the main film-forming gas into the recessed portion 14 ′ N2, M3 and the existence opportunity of dissociated molecules and atoms thereof 2: :: The probability of the existence of the film-forming gas S i Η * is reduced. Therefore, even if the dissociation effect of the gas increases at °, the film formation is not caused to be concave.卩 14, users can extend the maintenance

462081 V. Description of Invention (11) Cycle. The non-film-forming gas stays inside the recessed portion 14, so it is not easy to accumulate film formation inside the region, and the number of substrates to be formed can be increased in one processing cycle. Even when the main film-forming gas and the non-film-forming gas are introduced into the gas introduction hole 5 at the same time, the effects of the aforementioned reduction in RF power, the increase in the maintenance cycle, and the increase in the number of substrates that can be formed in one processing cycle can be obtained. However, the above-mentioned effect is better when "the non-film-forming gas is first introduced from the gas introduction hole 5, and RF power is applied, and then the film-forming gas is introduced." It is presumed that this is because the presence of the main film-forming gas in the recessed portion is reduced. [Example 1] However, in plasma CVD film formation, it is required to reduce the discharge resistance. The specified parameters of the discharge impedance are Vdc and Vpp. As shown in FIG. 6 (a), vdc represents a DC bias voltage applied between the cathode electrode 7 and the anode electrode 3 due to the asymmetry of the electrode. As shown in FIG. 6 (b), Vpp is a high-frequency voltage (peak-to-peak) applied between the anode electrode 3 and the cathode electrode 17. FIG. 7 shows the results of the test only by lowering Vpp by providing the recess 14 in the cathode electrode 17. In the embodiment, the plasma CVD apparatus shown in FIG. 1 is used as the plasma CVD apparatus shown in FIG. 8 in the conventional example. During the experiment, only the porous cathode electrode with a concave portion with a diameter of 0.3 nm (Example 丨), the porous cathode electrode with a concave portion with a diameter of 0.2 mm (Example 2), and the flat cathode electrode without a concave portion (a conventional example) were replaced. Three types of cathode electrodes were used without changing the other hard bodies. The discharge characteristics and the film quality of S i N were compared. 8. The size of the glass substrate is 37 X 47cm2, and the temperature of the substrate is 29 (rc, according to the following _

89120210.ptd V. Description of the invention (12) Conditions are compared. • Film forming conditions

Flow rate: SiH4 / NH3 / N2 Flow rate = 80sccm / 240sccm / l00〇sccm Pressure: 239_ 4Pa / 212.8Pa / 266Pa RF Power: 700W / 850W / 1000W • Regarding the gas clean conditions, Examples 1 and 2 and Comparative Examples are all It is the same as the film formation conditions. ”,” • Residual conditions are the same as film formation conditions. Removal of the electrode • Gas introduction holes: 0.8 mm, 956 are equally arranged (the diameter of the gas introduction holes is determined to be 0.8 minutes without the occurrence of cathode skin). • Cathode skin area / anode skin area ratio ψomm / φ2mm means approximately the same meaning, the same applies hereinafter. Know the cathode of the cathode. Except that there is no recess, it is the same as the porous cathode electrode. • Cathode skin area / anode skin area =: 0.5 The area of the cathode electrode and the area of the anode electrode can be easily calculated and calculated. Therefore, the limit of the plasma generation area cannot be considered simply as the t-correspondence of the electrode area. It is difficult to determine the plasma generation area. Therefore, the ratio can only be used as a reference value. The area of I means that each evaluation project in Figure 7 has the following meanings for plasma CVD films:

89120210.ptd Page 15 4 620 8 1 V. Description of the invention (13) — *-(1) Vdc, Vpp (refer to Figure 6)

The lower the Vpp, the easier it is to form a low impedance plasma. . ^ ”When comparing the Ray / j of the image, according to Ohm's law (I X V), the smaller Vpp is: the larger the flow. The lower the Vdc, the larger the cathode skin area / the anode skin area, the less easily the cathode electrode surface will be damaged. (2) WER ratio—As an approximate expression of the wet corrosion ratio, it can be compared with thermal oxidation, which indicates how many times the corrosion is faster or slower. This value is clearer. * Teng Zhenyue

(3) RI The higher the value, the higher the refractive index. This value is 1. 8 ~ 2. 0 for the plasma SiN, and the better the film quality. (4) The value of stress (negative direction), the better the N-H / Si-Η film quality. The higher the productivity. This value indicates the stress of the film, the smaller the value. (5) IR-peak ratio The number indicating the ratio of the electromagnetic wave absorptivity.

The larger the Si-N / Si_H, the better the film quality.

(6) DR Two-to-two speed 'The faster the film-forming speed indicates the uniformity of film thickness, it can be seen from Fig. 7 that it is better at zero. Quality (stress, thirst-type decay: the order of the membrane under the conditions of σ and the conventional formation is Example 1, 2 and η membrane speed 4) 'in order from good to poor, and Therefore, through comparison,

4 62081 V. Description of the invention (14) The conditions for film formation are the same. The provision of a porous cathode electrode with a recess can reduce Vdc and Vpp, and the effect of reducing RF power can be seen. In particular, when the diameter of the small hole in the recess is 2 mm to 3 mm, vdc can be greatly reduced. [Example 2] In this experiment, it has been shown that by providing the recessed portion 14 on the cathode electrode 17, the maintenance cycle of frequency ', the reduction of the film-forming speed caused by electrode fluorination, and the frequent electrode regeneration cycle can be improved. The experimental content is the same as that of Example 1 except for the following content. There are two types of comparison objects: a porous cathode electrode with a small hole diameter of 0 3 min (example) and a flat cathode electrode without a concave portion (conventional example). Experimental film formation conditions: flow rate: SiH4 / NH3 / N2 flow rate = 100 sccm / 3 0 0 sccm / 1 0 0 0 sccin pressure: 239.4Pa RF power: 7 0 0W conventional film formation conditions: / melon amount '$ 1114 / 5 / Pad flow = 100sccm / 300sccm / 1000sccm Pressure: 66.5Pa

RF power: 1 300W The experimental results are shown in Tables 1 to 3. First, it shows the improvement effect of frequent periodic processing. [Table 1] Apparatus — _ _ --- ——- — '-Continuous film thickness in one cycle (Note 1) Conventional example 3 0 0 0 nm Example 9 0 0 0 ηιπ

^ 62081

5. Description of the invention (15) (Note 1), the film thickness (estimated value) of siN particles with a size of more than 1000 can be continuously formed on the substrate. In the embodiment, a thicker film can be continuously formed in one cycle because the porous cathode electrode reduces the sputtering phenomenon. As a result, the number of substrates that can be processed in one cycle can be increased by about three times. The effect of improving the decrease in film formation rate by the fluorination of the porous cathode electrode is shown below. [Table 2] Device Vdc (V) Vpp (V) ---------- Initial speed decrease rate (Note 2) Known example ~~ 1 5 2 ~ 704 ~ 768 --------- --------- ----1.2% / cycle 1 140 Example + 3 0 ~ 484 ~ 51 6 ~ 0.005% / cycle-3 0 (Note 2): 1 ~ 1 〇 cycle The rate of decrease in the initial film formation rate (average). From the above results, it can be seen that the decrease rate of the initial film formation speed is improved about 240 times. The following shows the improvement of the regeneration of porous cathode electrodes with multiple abnormal discharges: The regeneration described in! Refers to the removal of fluoride from porous cathode electrodes _ Device cathode electrode regeneration frequency (Note 3) Conventional example about 5 0 0 Cycle 1a Example about 50,000 cycles once J% open joint double-hiding time; 电极 electrode regeneration frequency (estimated value)

89120210.Ptd Page 18 462081 V. Description of the invention (16) According to the above results, the continuous service life of the porous cathode electrode can be extended by 100 times. That is, even if the porous cathode electrode is fluorinated, the plasma efficiency in the recess can still be improved. Since the generated plasma has nothing to do with the release of secondary electrons, it is less affected by the surface state of the electrode, so the maintenance cycle can be extended accordingly. [Effects of the embodiment and the examples] According to the above-mentioned embodiment and the embodiment, the provision of the recessed portion on the porous cathode electrode has the following advantages compared with a conventional cathode electrode having no recessed portion. 〇) The number of substrates that can be processed in one cycle increases. $ Can reduce the decrease of the initial film formation rate caused by the fluorination of the porous cathode electrode. 〉 2 丨 It can extend the continuous service life of the porous cathode electrode. In order to achieve the required film quality, the necessary RF power can be reduced. [Effect of the invention] A groove is formed in the second electrode for 1m of the electrode, so the second electrode can be prevented from being sold and the maintenance period can be greatly extended . The use of the recess can make the gasification: the slope of the elephant skin potential is gentle, which can improve the degree of the first degree, and the film formation gas root method is introduced separately into the non-film-forming gas with good quality of the V film, so as to make full use of this Function of the device 'formation [Description of component number]

89120210.ptd Page 19 4 6 20 8 1 V. Description of the invention (17) 2 Anode electrode 4 Substrate 5 Gas introduction hole 7 Exhaust pipe 9 R F South frequency power supply 14 Recess 15 Film-forming gas supply tube 17 Porous cathode electrode

89120210.ptd Page 20 462081 Brief description of the drawings Fig. 1 is a schematic sectional view of a processing chamber according to this embodiment. a FIG. 2 is an explanatory view of a porous cathode electrode according to this embodiment, and is a surface view, and (b) is a cross-sectional view. Fig. 3 is a diagram illustrating the dimensions of the recessed portion and the gas introduction hole according to the embodiment. FIG. 4 is a surface view of a porous cathode electrode according to this embodiment. Fig. 5 is a schematic diagram showing the direction of energy transmission in the recessed portion according to this embodiment. Figure 6 (a) and (b) are explanatory diagrams of Vdc and Vpp. Fig. 7 is a table showing the experimental results of the examples and examples of 鲂 鲂 鲂 孙孙 护 媸 羽 4 υ 乂 乂. FIG. 24 is a schematic cross-sectional view extending to a place according to a conventional example.

89120210.ptd Page 21

Claims (1)

4 6 20 81 1. A plasma CVD apparatus, comprising: a pressure-reducible processing chamber, a processing chamber having a substrate on which a substrate is placed and grounded, and a pair of flat electrodes ^ ~ Many glass can apply high-frequency waves to the second electrode, a film-forming gas supply point that passes through the gas introduction hole of the second electrode and supplies the gas between the 1 and the second electrode, and the exhaust pipe of the chamber exhaust; A concave portion is provided on the surface of the mu pole. ） Upper brother 2 electricity 2 _ If the electric range 申请 vd # 罟 of the scope of patent application, 甘 a 目 q < electricity 釆 L νϋ 泉 罝, where the above-mentioned recesses are more than 3mm and smaller than the above-mentioned gas introduction hole spacing Width. 3. If the scope of patent application is the first! Or the plasma device according to item 2, wherein the opening area of the recessed portion has an opening area larger than that of the gas introduction hole. 4_ Plasma CVD thin film formation method, which uses plasma CVD method to form a predetermined thin film, which is characterized by: using a processing chamber equipped with a reduced pressure 'a pair of flat electrodes arranged in the processing chamber has a mounting substrate And a grounded second electrode, a second electrode having a plurality of gas introduction holes, and a high-frequency wave can be applied, a film-forming gas supply pipe that supplies gas between the first and second electrodes through the gas introduction holes of the second electrode, and The exhaust pipe of the chamber exhaust is provided with a recessed plasma CVD device on the surface of the second electrode which is opposite to the first electrode. Film gas to form the above-mentioned prescribed thin film. 5. The plasma CVD thin film formation method according to item 4 of the application, wherein said plasma CVD apparatus having a width of 3 mm or more and a width smaller than the pitch of said gas introduction holes is used to form said predetermined thin film. 89120210.ptd Page 22 462081 6. Application patent scope 6. The plasma CVD thin film forming method as described in item 5 of the patent application scope, wherein the above plasma CVD device with an opening area of the recessed portion having an opening area larger than that of the gas introduction hole is used. To form the prescribed film 89120210.ptd Page 23