JP2013149513A - Plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing device capable of reliably preventing sneak of a plasma to a shower plate rear face side during processing at low running costs.SOLUTION: A plasma processing device M1 comprises: a processing chamber 10; gas introduction means 3 for introducing gas in the processing chamber; and plasma generation means for generating the plasma in the processing chamber by exciting the gas introduced in the processing chamber. The gas introduction means is provided with a plate unit 30 opposed to a processing surface of a substrate S1 in the processing chamber. The plate unit is constituted by at least two shower plates 33, 33, 33laminated at equal intervals of 1 mm or less in an upward and downward direction. Plural injection ports H are bored on each shower plate, and each injection port of the shower plate positioned on an upper side is opposed to a portion of the shower plate immediately below it that has no injection port. The plasma processing device further comprises conduction means 4 for making electric potentials of each shower plate coincident with each other.

Description

  The present invention relates to a processing chamber that performs a predetermined process on a substrate, a gas introduction unit that introduces a gas into the processing chamber, and a plasma generation unit that generates a plasma in the processing chamber by exciting the gas introduced into the processing chamber. And a plasma processing apparatus.

  For example, in a semiconductor device manufacturing process, film formation or etching is performed on a substrate such as a semiconductor wafer, a glass substrate, or a resin film in a processing chamber capable of forming a vacuum atmosphere. In some cases, as a film forming process using plasma, for example, a plasma CVD method is known. A plasma CVD apparatus for forming a film by this plasma CVD method usually introduces a gas introduction means for introducing various gases selected in accordance with a thin film to be formed on a film formation surface of a substrate, and introduces it into a processing chamber. Plasma generating means for exciting the generated gas and generating plasma in the processing chamber. Then, ions and active species in the plasma are deposited on the surface of the base material to form an insulating film, a semiconductor film, and the like.

  By the way, if the gas is introduced non-uniformly into the processing chamber, the film thickness and film quality of the thin film formed on the substrate surface become non-uniform, resulting in problems such as deterioration of the characteristics of the semiconductor device. For this reason, in a conventional plasma CVD apparatus, usually, a single shower plate in which a plurality of gas jets having the same hole diameter are arranged in a predetermined pattern and disposed opposite to a processing surface of a substrate in a processing chamber (Gas introduction means) is provided (for example, refer to Patent Document 1). However, in the above-described conventional example, depending on the film forming conditions such as the pressure in the processing chamber during film formation, the back side of the shower plate (on the side opposite to the surface facing the base material) is provided through one of the outlets of the shower plate. ) Plasma may wrap around.

  When the plasma circulates to the back side of the shower plate in this way, a film is formed up to the inner surface of the jet port, and the hole diameter of the jet port becomes smaller than before the film forming process is performed. As a result, there arises a problem that the flow rate of the gas ejected from each ejection port becomes non-uniform, which makes it impossible to form a good film. Also, once the film is formed on the inner surface of the shower plate ejection port, it cannot be easily removed by the known dry cleaning performed at a constant cycle in the processing chamber, and the shower plate needs to be replaced at a relatively short cycle. This causes an increase in running cost.

JP 2006-152416 A

  In view of the above points, it is an object of the present invention to provide a low-running-cost plasma processing apparatus that can reliably prevent plasma from wrapping around the back side of the shower plate during processing.

  In order to solve the above problems, a processing chamber for performing a predetermined process on the substrate, a gas introduction means for introducing a gas into the processing chamber, and a plasma introduced into the processing chamber by exciting the gas introduced into the processing chamber In the plasma processing apparatus of the present invention comprising the plasma generating means to be operated, the gas introducing means includes a plate unit arranged to face the processing surface of the base material in the processing chamber, and the plate is moved upward in the direction from the base material to the plate unit. The plate unit is composed of at least two shower plates laminated at equal intervals in the vertical direction, and a plurality of shower plates that allow the gas to be ejected to each shower plate. In addition to the opening of the spout, each spout of the shower plate located on the upper side of the shower plate located directly below it Formed by direction, and further comprising a conducting means for matching the potential of each shower plate.

  According to the present invention, the plate unit disposed to face the processing surface of the base material in the processing chamber is configured by at least two shower plates stacked at equal intervals in the vertical direction. Then, a gas is introduced into the processing chamber through a plurality of jets provided in each shower plate, and the introduced gas is excited to generate a plasma in the processing chamber. A film forming process and an etching process are performed.

  Here, each jet port formed in the upper shower plate is opposed to a portion of the shower plate positioned directly below the jet port, and the electric potentials of the shower plates are made to coincide with each other. It is possible to reliably prevent the plasma from entering the back side of the shower plate through one of the outlets of the shower plate. Therefore, when the film forming process is performed on the base material by the plasma CVD method using the plasma processing apparatus of the present invention, the film is not formed on the inner surface of the shower plate outlet, compared with before the film forming process. As a result, the hole diameter of the jet nozzle does not become small. For this reason, since the exchange period of a shower plate can be lengthened compared with the conventional example provided with one shower plate, a running cost can be reduced.

  In this invention, what is necessary is just to set the space | interval of a shower plate to 1 mm or less, when the pressure of a predetermined process is in the range of 10-200 Pa. In this case, if the interval is set to be larger than 1 mm, there is a possibility that the plasma may wrap around to the back side of the shower plate.

  In the present invention, the conduction means is preferably a conductive spacer provided between the shower plates. According to this, the electric potential of each shower plate can be easily matched by the simple structure of providing the spacer.

The figure which shows the structure of the plasma processing apparatus of 1st Embodiment of this invention. FIG. 2A is an enlarged plan view showing a main part of the shower plate shown in FIG. FIG. 2B is a cross-sectional view taken along line IIb-IIb in FIG. The figure which shows the structure of the plasma processing apparatus of 2nd Embodiment of this invention.

  1 and 2, in the plasma processing apparatus of the first embodiment of the present invention, a base material to be processed is a silicon substrate S having a diameter of 300 mm, and a silicon nitride film is formed on the surface of the silicon substrate S. A parallel plate type plasma CVD apparatus M1 that forms a film will be described as an example. The plasma CVD apparatus M1 includes a vacuum chamber 1 that defines a processing chamber 10. The vacuum chamber 1 has an exhaust port 1a connected to the vacuum pump P so that the processing chamber 10 can be evacuated. As the vacuum pump P, a turbo molecular pump, a rotary pump, or the like can be used alone or in combination.

  A columnar stage 2 that also serves as an electrode is provided on the bottom of the vacuum chamber 1 via an insulator I, and an electrostatic chuck (not shown) is provided on the surface of the stage 2. Thus, the silicon substrate S transported by a transport means (not shown) (for example, a well-known transport robot having a hand at the end of the arm) can be positioned and held with the deposition surface of the silicon substrate S facing upward. . The stage 2 is connected to the high frequency power source E1 via a blocking capacitor and a matching box (not shown) so that a negative or alternating bias potential can be applied to the silicon substrate S during processing.

  A gas introducing means 3 is provided on the upper portion of the vacuum chamber 1 so that a film forming gas can be introduced into the processing chamber 10. The gas introduction unit 3 includes a plate unit 30 that is disposed in the processing chamber 10 so as to face the processing surface (film formation surface) of the silicon substrate S. Hereinafter, the direction from the silicon substrate S toward the plate unit 30 will be described as “up”, and the direction from the plate unit 30 toward the silicon substrate S will be described as “down”.

The plate unit 30 includes a disk-shaped base 31 that also serves as an electrode, having a diameter larger than the diameter of the silicon substrate S, and an annular protrusion 32 that protrudes from the base 31 toward the lower stage 2. It is composed of at least two (three in the present embodiment) disk-shaped shower plates 33 ₁ , 33 ₂ , and 33 ₃ that are mounted near the tip of the protrusion 32 and are stacked at equal intervals in the vertical direction. The The distance d1 between the shower plates 33 is set to 1 mm or less. If the distance d1 is larger than 1 mm, there is a possibility that plasma may circulate on the back side of the shower plate when the processing pressure is set within a range of 10 to 200 Pa.

In each shower plate 33 ₁ , 33 ₂ , 33 ₃ , a plurality of outlets H 1, H 2, H 3 having the same hole diameter d 2 are formed in a staggered manner. The hole diameter d2 of each of the outlets H1, H2, and H3 is appropriately set within a range of, for example, 0.1 to 2 mm in consideration of the flow rate of the film forming gas to be supplied. And each spout H of the shower plate located in the upper side is formed facing the part which does not have each spout H of the shower plate located immediately below it. As shown in FIG. 2 (a), the most the spout H3 of the shower plate 33 ₃ positioned on the upper side is formed to face the respective spout H2 is not part of the shower plate 33 ₂ positioned immediately below the Yes. When the center-to-center distance in a plan view between the jets H2 shower plate 33 ₃ jets H3 and the shower plate 33 _2, d3, between the four jets H2, adjacent thereto and any spout H3 Are equal to each other. Therefore, gas which has passed through the ejection port H3 of the shower plate 33 _3, flows evenly jets H2 shower plate 33 ₂ immediately below. If the opening position of each ejection port H1 of the shower plate 33 ₁ the same as the opening position of the spout H3 of the shower plate 33 _3, the shower plate 33 of the spout H2 shower plate 33 ₂ is located immediately below ₁ of are opposed to each ejection port H1 is not part becomes to be formed, moreover, in a plan view between the four spout H1 of the shower plate 33 ₁ jets H2 shower plate 33 ₂ and adjacent thereto The center distances d3 are equal to each other. Therefore, gas which has passed through the jets H2 shower plate 33 _2, flows evenly spout H1 of the shower plate 33 ₁ immediately below. Thus, by opening the outlets H1, H2, and H3 of the shower plates 33 ₁ , 33 ₂ , and 33 ₃ , it becomes possible to introduce gas more evenly into the processing chamber 10.

Most compartmented space between the shower plate 33 ₃ and the base 31 and the protrusion 32 located on the upper side serves as a gas diffusion chamber 34. A gas pipe 35 penetrating the upper wall of the vacuum chamber 1 is connected to the base portion 31, and the other end of the gas pipe 35 communicates with a gas source of film forming gas via a mass flow controller (not shown). In the present embodiment, for example, a mixed gas of silane gas (SiH ₄ ), ammonia gas, and nitrogen gas can be used as the film forming gas.

The shower plate _{33 1,} 33 2, 33 ₃ between the conductive (e.g., metal) spacers 4 are provided, it is possible to match the potential of each shower plate _{33 1,} 33 2, 33 _3. In addition, a high frequency power source E2 is connected to the base 31. By applying high frequency power from the high frequency power source E2, the film forming gas introduced into the processing chamber 10 can be excited to generate plasma. It has become. The high frequency power source E2 constitutes the plasma generating means described in the claims. Hereinafter, a film forming method using the plasma CVD apparatus M1 will be described by taking a case where a silicon nitride film is formed on the surface of the silicon substrate S as an example. As the silicon nitride film forming conditions, since well-known conditions can be used, detailed description is omitted here.

First, the silicon substrate S is transferred into the processing chamber 10 by transfer means (not shown), and the transferred silicon substrate S is positioned and held on the stage 2. After the processing chamber 10 is evacuated to a predetermined pressure by the vacuum pump P, a mixed gas of silane gas, ammonia gas, and nitrogen gas is supplied from the gas pipe 35 to the plate unit 30 as a film forming gas. The mixed gas is diffused in the gas diffusion chamber 34 and then introduced into the processing chamber 10 through a plurality of jets H opened in the shower plates 33 ₃ , 33 ₂ , and 33 ₁ . At the same time, by applying high frequency power from the high frequency power source E2 to the base 31 of the plate unit 30, the film forming gas introduced into the processing chamber 10 is excited to generate plasma. When high frequency power is applied from the high frequency power supply E1 to the stage 2 and a negative or alternating bias potential is applied to the silicon substrate S, ions and active species (radicals) in the plasma are deposited on the surface of the silicon substrate S. Thus, a silicon nitride film is formed.

Here, the plate unit 30 disposed opposite to the processing surface of the silicon substrate S in the processing chamber 10 is configured by shower plates 33 ₁ , 33 ₂ , 33 ₃ stacked at equal intervals in the vertical direction, and further on the upper side. Each jet port formed in the shower plate positioned is opposed to a portion of the shower plate positioned immediately below it without each jet port, and the potentials of the shower plates 33 ₁ , 33 ₂ , and 33 ₃ are matched by the spacer 4. It was set as the structure made to do. By adopting such a configuration, it is possible to reliably prevent the plasma from flowing to the back surface side of the shower plate through the outlet H of any of the shower plates 33 ₁ , 33 ₂ , and 33 ₃ during the film forming process. . Accordingly, no silicon nitride film is formed on the inner surface of the outlet H of the shower plates 33 ₁ , 33 ₂ , and 33 ₃ , and the hole diameter d 2 of the outlet H is smaller than before the film forming process is performed. Don't be. For this reason, since the exchange period of a shower plate can be lengthened compared with the conventional example provided with one shower plate, a running cost can be reduced.

  Next, referring to FIG. 3, in the plasma processing apparatus according to the second embodiment of the present invention, the base material to be processed is a long sheet-like base material S1, and a silica film is formed on the sheet-like base material S1. A winding type plasma CVD apparatus M2 that forms a film will be described as an example. In addition, as sheet-like base material S1, what consists of polyethylene terephthalate (PET), polyethylene (PEN), polypropylene (PP), glass etc., and the thickness is 1-10 micrometers can be used, for example. The same members or elements as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The plasma CVD apparatus M2 includes a vacuum chamber 1. A partition plate 11 is provided inside the vacuum chamber 1, and the partition plate 11 partitions the processing chamber 10a and the preparation chamber 10b. The partition plate 11 has an opening 12 for conveying the sheet-like substrate S1. The vacuum chamber 1 is provided with an exhaust port 1a connected to the vacuum pump P so that the processing chamber 10a and the preparation chamber 10b can be evacuated.

  The preparation chamber 10b is disposed between the feeding roller 4, the winding roller 5 having the same structure as the feeding roller 4, and between the feeding roller 4 and the winding roller 5. An intermediate roller 6 for guiding the material S1 is accommodated. The processing chamber 10a accommodates a rotating drum 7 that also serves as a grounded electrode. The sheet-like substrate S1 is conveyed from the feeding roller 4 to the winding roller 5 in a state where the sheet-like substrate S1 is wound around the peripheral surface of the rotating drum 7 at a predetermined holding angle. The rotating drum 7 has a peripheral surface cooled by a cooling medium flowing inside.

  The vacuum chamber 1 is provided with gas introducing means 3a so that a film forming gas can be introduced into the processing chamber 10a. The gas introduction means 3 a includes a plate unit 30 a that is disposed to face the processing surface (film formation surface) of the sheet-like substrate S1 wound around the peripheral surface of the rotary drum 7. Hereinafter, the direction from the sheet-like base material S1 wound around the rotary drum 7 toward the plate unit 30a will be described as “up”, and the direction from the plate unit 30a toward the sheet base material S1 will be described as “down”.

The plate unit 30a includes a plate-like base 31 that also serves as an electrode connected to the high-frequency power source E2, an annular protrusion 32 that protrudes from the base 31 toward the rotary drum 7, and a vicinity of the tip of the protrusion 32. It is composed of at least two (three in the present embodiment) shower plates 36 ₁ , 36 ₂ , and 36 ₃ stacked at equal intervals in the vertical direction. Each shower plate 36 ₁ , 36 ₂ , 36 ₃ has a concavely curved shape corresponding to the peripheral surface of the rotating drum 7, and the distance between the electrode 31 and the sheet-like substrate S 1 is uniform. I am doing so. When the pressure of the film forming process is within the range of 10 to 200 Pa, the interval between the shower plates 36 may be set to 1 mm or less.

Each shower plate _{36 1,} 36 2, 36 _3, a plurality of ejection ports H1, H2, H3 with the same pore size have been opened in a staggered, diameter of each ejection port H1, H2, H3 is Considering the flow rate of the film forming gas to be supplied, it is appropriately set within a range of 0.1 to 2 mm, for example. Then, as in the first embodiment, each ejection port H3 of the shower plate ₃₆₃ which is positioned on the upper side, are formed to face the respective spout H2 is not part of the shower plate 36 ₂ positioned immediately below the Yes. Similarly, each ejection port H2 of the shower plate 36 ₂ is formed to face the respective spout H1 is not part of the shower plate 36 ₁ positioned immediately below. Most compartmented space between the shower plate ₃₆₃ and the base 31 and the protrusion 32 located on the upper side serves as a gas diffusion chamber 34. A gas pipe 35 penetrating the wall surface of the vacuum chamber 1 is connected to the base 31, and the other end of the gas pipe 35 communicates with a film source gas source via a mass flow controller (not shown). In the present embodiment, a mixed gas of silane gas (SiH ₄ ), N ₂ O gas, and argon gas or the like can be used as the film forming gas.

Between the shower plate _{36 1,} 36 2, 36 ₃ spacer 4 is provided, it is possible to match the potential of each shower plate _{36 1,} 36 2, 36 _3. Further, a high frequency power source E2 is connected to the base 31 so that plasma can be generated by exciting the film forming gas introduced into the processing chamber 10a. Hereinafter, the film forming method using the plasma CVD apparatus M2 will be described taking a case where a silica film is formed on the surface of the sheet-like substrate S1 as an example. Since the known conditions for forming the silica film can be used, detailed description thereof is omitted here.

The sheet-like substrate S <b> 1 is conveyed from the feeding roller 4 to the take-up roller 5 via the rotating drum 7. After the processing chamber 10a is evacuated to a predetermined pressure by the vacuum pump P, a mixed gas of silane gas, N ₂ O gas, and argon gas is supplied from the gas pipe 35 to the plate unit 30a as a film forming gas. The supplied silane gas is diffused in the gas diffusion chamber 34 and then introduced into the processing chamber 10a through a plurality of jets H3, H2, H1 provided in the shower plates 36 ₃ , 36 ₂ , 36 _{1 respectively.} The At the same time, high-frequency power is supplied from the high-frequency power source E2 to the gas introduction means 30, whereby the mixed gas introduced into the processing chamber 10a is excited and plasma is generated. At this time, the pressure in the processing chamber 10a is preferably set in a range of 10 to 200 Pa. Since the rotating drum 7 is grounded, ions and active species (radicals) in the plasma are deposited on the surface of the sheet-like substrate S1 to form a silica film.

Here, the plate unit 30a disposed opposite to the processing surface of the sheet-like substrate S1 in the processing chamber 10a is configured by shower plates 36 ₁ , 36 ₂ , and 36 ₃ that are stacked at equal intervals of 1 mm or less in the vertical direction. Further, each outlet H formed in the shower plate positioned on the upper side is made to face a portion of the shower plate positioned directly below it without each outlet H, and each shower plate 36 ₁ , 36 ₂ , 36 ₃ The potentials of these are made to coincide with each other by the spacer 4. By adopting such a configuration, during the film forming process, can be reliably prevented that the plasma from flowing to the shower plate rear surface side via the shower plate 36 _1, 36 _2, 36 ₃ or jets H of . Therefore, the inner surface of the shower plate 36 _1, 36 _2, 36 ₃ jets H without silica film is formed, the hole diameter of the ejection port H as compared with before performing the film forming process is not reduced. For this reason, since the exchange period of a shower plate can be lengthened compared with the conventional example provided with one shower plate, a running cost can be reduced.

  The present invention is not limited to the above embodiment. For example, the plasma CVD apparatus has been described as an example in the above embodiment, but the present invention can be applied to a plasma processing apparatus having a shower plate such as an etching apparatus. For example, when applied to an etching apparatus, it is possible to prevent the plasma from wrapping around the back side of the shower plate, so that it is possible to prevent the hole diameter from being changed by etching the shower plate outlet, and to increase the replacement period of the shower plate. .

Moreover, although the case where three shower plates were laminated | stacked was demonstrated to the example in the said embodiment, you may laminate | stack two or four or more shower plates. When four or more shower plates are stacked, two types of shower plates (33 ₁ , 33 ₂ ) having different opening positions of the outlets may be stacked alternately as in the above embodiment.

  Moreover, in the said embodiment, a vacuum chamber wall surface can also be combined with the base part of a plate unit. In this case, it is only necessary to attach a shower plate to the protruding portion protruding from the vacuum chamber wall surface, and the number of parts can be reduced.

  Moreover, the method for generating plasma is arbitrary, and not only the capacitive coupling method as in the above embodiment but also a known inductive coupling method, ICP method, or the like can be used.

E2: High-frequency power source (plasma generating means), M1, M2 ... Plasma CVD apparatus (plasma processing apparatus), H (H1, H2, H3) ... Outlet, S ... Silicon substrate (base material), S1 ... Sheet-like base material , 3 ... gas introduction means, 4 ... spacer (conducting means), 10, 10a ... processing chamber, 30 ... plate _unit, 33 _{1, 33} 2, 33 _3, 36 1, ₃₆ 2, 36 3 _... shower plate.

Claims (3)

A plasma comprising: a processing chamber for performing a predetermined process on a substrate; a gas introducing means for introducing a gas into the processing chamber; and a plasma generating means for generating a plasma in the processing chamber by exciting the gas introduced into the processing chamber. In the processing device,
The gas introduction means includes a plate unit disposed to face the processing surface of the base material in the processing chamber, the direction from the base material toward the plate unit is up, the direction from the plate unit to the base material is down, and the plate unit is The shower plate is composed of at least two shower plates stacked at equal intervals in the vertical direction. Each shower plate is provided with a plurality of jet outlets that allow the gas to be jetted. A plasma processing apparatus, wherein each jet port is formed so as to be opposed to a portion of the shower plate located immediately below it without each jet port, and further includes conduction means for matching the potential of each shower plate.   2. The plasma processing apparatus according to claim 1, wherein when the pressure of the predetermined processing is within a range of 10 to 200 Pa, the interval between the shower plates is set to 1 mm or less. 3. The plasma processing apparatus according to claim 1, wherein the conducting means is a conductive spacer provided between the shower plates.

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