JP2006176823A - Film deposition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the contamination of a target caused by a gaseous starting material or reaction gas to be introduced at the time of performing an ALD (Atomic Layer Deposition) process in the case a film deposition system is composed so that film deposition by an ALD process and film deposition by a sputtering process can be performed to a treatment substrate on a substrate stage in the same chamber. <P>SOLUTION: A substrate stage 12 is arranged inside a vacuum chamber 11, and a sputtering film deposition means 4 having a target is provided in such a manner that the target 41a and a treatment substrate are confronted each other. A partition plate 5 of partitioning a first space 51 in which the target is present and a second space 52 in which the substrate stage is present is provided, an opening part 5a to which the treatment substrate faces is formed at the partition plate, and a shielding means 6 freely movable between a close position at which the opening part is covered to enable the separation between the first space and the second space, and an open position at which the opening part is released is arranged. The second space is provided with a chemical film deposition means capable of performing film deposition according to a chemical film deposition process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a film forming apparatus for forming a predetermined thin film on a processing substrate, and in particular, at least one of film formation by a sputtering method and film formation by a chemical film formation method is performed in the same vacuum chamber. The present invention relates to a film forming apparatus.

In recent years, along with higher integration and higher speed of LSIs, semiconductor elements have been miniaturized and multilayered, and accordingly, embedded wiring structures have been used. As a wiring material embedded in an interlayer connection hole such as a via hole or a trench formed in an insulating film, it is a mainstream to use copper having a small specific resistance value. Here, it is known that copper in the embedded wiring has a property of being easily diffused into an insulating film such as SiO ₂ unlike other wiring materials such as aluminum.

  In this case, in order to prevent insulation failure caused by diffusion into the insulating film, for example, between the insulating film and the copper thin film for wiring formation (inner surface of the interlayer connection hole), by CVD method or sputtering method, By interposing a conductive thin film (barrier film), it is considered that the copper thin film and the insulating film are prevented from coming into direct contact to suppress or prevent diffusion into the insulating film.

Examples of the film formation method for the barrier film include a chemical film formation method, for example, an ALD method. In this ALD method, the temperature of a processing substrate installed in a vacuum chamber is raised to a predetermined temperature, and then a source gas and reaction are performed. By repeating either the step of introducing one of the gases and adsorbing the gas onto the processing substrate, or the step of once evacuating the introduced gas and then introducing the other gas to react on the processing substrate, the atomic layer is reduced to about A metal nitride layer is laminated to obtain a barrier film having a predetermined thickness (Patent Document 1).
Japanese Patent Laid-Open No. 11-54459 (for example, see the description of claim 1)

  When a barrier film is formed by this ALD method, there is a problem that sufficient adhesion strength to an interlayer insulating film or the like cannot be obtained. From this, it is conceivable to form an adhesion layer of the barrier film by sputtering, for example, prior to formation of the barrier film by ALD. In this case, if the formation of the barrier film by the ALD method and the formation of the adhesion layer by the sputtering method are performed in separate vacuum chambers, problems such as a reduction in the working efficiency of the barrier film formation occur. Therefore, it is required to form a barrier film by an ALD method and an adhesion layer by a sputtering method.

  When thin film formation by ALD method and thin film formation by sputtering method can be performed in the same vacuum chamber, the gas introduced during film formation by ALD method is adsorbed on the surface of sputtering target. There is a risk of contamination. If the target is contaminated, a problem such as inducing abnormal discharge occurs at the time of film formation by sputtering, and good film formation cannot be performed.

  Therefore, in view of the above points, an object of the present invention is to perform film formation by chemical film formation and film formation by sputtering in a single vacuum chamber while preventing target contamination. To provide an apparatus.

  In order to solve the above problems, a film forming apparatus of the present invention includes a vacuum chamber to which a vacuum evacuation unit is connected, and a substrate stage in which a processing substrate can be installed is disposed in the vacuum chamber. A film forming apparatus having a target which is a film forming material arranged to face a substrate stage and provided with a sputtering film forming means capable of forming a film on a processing substrate on the substrate stage by sputtering. A partition plate is provided for partitioning the chamber into a first space in which the target exists and a second space in which the substrate stage exists, and an opening is formed on the partition plate so that the processing substrate on the substrate stage faces, and the opening is covered. Shielding means that is movable between a closed position that allows the first space and the second space to be isolated from each other and an open position that opens the opening is disposed in the second space. Has a gas introducing means for introducing the gas, characterized in that the chemical film forming means capable of performing film formation by a chemical deposition method to process the substrate on the substrate stage provided in the second space.

  According to the present invention, a predetermined thin film is formed by the sputtering method on the processing substrate on the substrate stage by operating the sputtering film forming unit while the shielding unit is held at the closed position. Next, the shielding means is moved from the closed position to the open position, the chemical film forming means is operated, and a predetermined thin film is formed on the processing substrate on the substrate stage by a chemical film forming method. In this case, the first space and the second space are isolated from each other by covering the opening with the shielding means while the thin film is formed by the chemical film formation method on the processing substrate on the substrate stage. The flow of the raw material gas and the reaction gas introduced into the first space where the target film formation method is carried out is prevented, thereby preventing contamination of the target due to gas adsorption.

  In the chemical film-forming method, for example, a step of introducing a source gas to adsorb the source gas on the surface of the processing substrate and a step of introducing a reaction gas and reacting with the adsorbed source gas are periodically repeated. This is an ALD method.

  If the substrate stage can be reciprocated toward the partition plate and the outer peripheral edge of the substrate stage can be brought into contact with the edge of the opening, the first film can be formed on the processing substrate by sputtering. The space and the second space can be sealed together. Thereby, for example, contamination of the side wall of the vacuum chamber that partitions the second space may be prevented during film formation by sputtering.

  The gas introducing means has a ring-shaped head portion provided on the partition plate side of the substrate stage so as to surround the substrate stage, and a predetermined gas is jetted toward the processing substrate on the bed portion. If a plurality of gas introduction holes are formed at predetermined intervals as described above, a predetermined predetermined gas may be evenly supplied to the processing substrate.

  If the exhaust pipe of the vacuum exhaust means is connected to the first space and the second space of the vacuum chamber, respectively, and the first space and the second space can be independently evacuated, for example, a substrate stage Even when the film formation is performed in a state where the first space and the second space are sealed with each other, the first space and the second space may be evacuated.

  Other gas introduction means for introducing a predetermined purge gas in the vicinity of the target existing in the first space in order to prevent gas from flowing into the vicinity of the target during film formation by the chemical film formation method. May be provided.

  As described above, the film forming apparatus of the present invention can perform the film formation by the chemical film formation method and the film formation by the sputtering method in the same vacuum chamber while preventing contamination of the target. There is an effect.

  Referring to FIGS. 1 to 4, 1 prevents the target from being contaminated in the same vacuum chamber, and improves the film formation by the ALD method, which is a chemical film formation method, and the film formation by the sputtering method. This is a film forming apparatus of the present invention that can be performed. The film forming apparatus 1 includes a vacuum chamber 11 having a vacuum exhaust unit 2 such as a turbo molecular pump, and a substrate stage 12 that enables a processing substrate S such as a silicon wafer to be placed on the bottom of the vacuum chamber 11. Is provided. In order to heat the processing substrate S to a predetermined temperature, the substrate stage 12 incorporates, for example, a known heating means (not shown) of a resistance heating method.

  Also, first and second gases that are introduced into the vacuum chamber 11 located immediately above the substrate stage 12 when a film is formed on the processing substrate S by a chemical film forming method are introduced. Introducing means 31 and 32 are provided, and the heating means and the gas introducing means 31 and 32 constitute the chemical film forming means 3. As shown in FIG. 3, the first and second gas introducing means 31 and 32 are respectively provided with ring-shaped head portions 31 a and 32 a that are concentrically provided so as to surround the substrate stage 12 and are shifted in the vertical direction. Each of the bed portions 31a and 32a has four gas introduction holes 31b and 32b that are shifted by 90 degrees so that a predetermined gas is ejected toward the processing substrate S. The head portions 31a and 32a communicate with predetermined gas sources (for example, a source gas source and a reactive gas source) (not shown) via gas pipes 31c and 32c provided with a mass flow controller.

  For example, when a barrier film is formed by an ALD method in an interlayer connection hole formed by patterning an insulating film formed on the processing substrate S, source gases include tantalum (Ta), titanium (Ti), tungsten (W), etc. The reaction gas is an ammonia gas that reacts with the raw material gas and deposits a metal thin film containing the constituent elements of the metal in the chemical structure.

  Then, after raising the temperature of the processing substrate S placed on the substrate stage 12 to a predetermined temperature, a step of introducing one of the source gas and the reaction gas and adsorbing the processing substrate S to the processing substrate S, and this one gas Once the vacuum is evacuated, the process of introducing the other and reacting on the processing substrate S is repeated, whereby the metal nitride layer is stacked in the atomic layer to obtain a thin film having a predetermined thickness. When depositing a pure metal such as tantalum (Ta), titanium (Ti), or tungsten (W), the process of adsorbing the source gas and the process of depositing and modifying with H2 radicals or PVD are repeated. What should I do?

  Here, when a film is formed by the ALD method, there is a problem that the adhesion strength is weak. Therefore, in this embodiment, a sputtering cathode, which is a sputtering means, is formed on the upper surface of the vacuum chamber 12 so that a predetermined adhesion layer can be formed by the sputtering method prior to the thin film formation by the ALD method in the same vacuum chamber 11. 41 is provided.

  The sputtering cathode 41 has a known structure and has a target 41 a provided to face the processing substrate S. The target 41a is manufactured by a known method according to the composition of the thin film to be formed on the processing substrate S. For example, as a target for forming an adhesion layer of a barrier film by sputtering, the main component is a constituent element of a metal contained in a source gas such as tantalum (Ta), titanium (Ti), tungsten (W), etc. It is. The target 41a is connected to a sputtering power source 42 that applies a DC voltage or a high-frequency voltage to the target 41a in order to generate plasma in front of the target 41a. In this case, the processing substrate S is also connected to the sputtering power source 42 in order to apply a bias voltage.

  A third gas introduction unit 43 is provided in the upper part of the vacuum chamber 11. The gas introduction means 3 communicates with a gas source (not shown) via a gas pipe 43a provided with a mass flow controller, and can introduce a sputtering gas such as argon at a constant flow rate. 42 and the third gas introduction means 43 constitute the sputtering means 4.

  By the way, when the film-forming apparatus 1 is configured so that film formation by the ALD method and film formation by the sputtering method can be performed in the same vacuum chamber 11 as described above, the surface (sputter surface) of the target 41a is There is a possibility that the raw material gas and the adsorbed gas introduced during the film formation by the ALD method are adsorbed and contaminated. If the target 41a is contaminated, a problem such as inducing abnormal discharge occurs during film formation by sputtering, which may hinder good film formation.

  In the present embodiment, the partition plate 5 that partitions the vacuum chamber 11 into a first space 51 where the target 42a exists and a second space 52 where the substrate stage 12 exists is provided. An opening 5a is formed in the partition plate 5 so that the processing substrate S on the substrate stage 12 faces the target 41a, and the first space 51 and the second space 52 can be isolated from each other by covering the opening 5a. Shielding means 6 that is movable between a closed position and an open position that opens the opening 5a is disposed. As shown in FIG. 4, the shielding means 6 has a shutter portion 61 having an area larger than the area of the opening 5a. One end of an arm portion 62 is connected to the shutter 61, and the other end is the arm. It is connected to a rotating shaft 63 of a driving means such as a motor for turning the portion 62 in the horizontal direction.

  Accordingly, the first space 51 and the second space 52 can be isolated from each other by covering the opening 5a with the shutter portion 61 while the film is formed on the processing substrate S on the substrate stage 12 by the ALD method. Inflow of the target 41a due to the raw material gas or reaction gas into the first space 51 can be prevented, and contamination of the target 41a due to gas adsorption can be prevented. In this case, a fourth gas introduction means 44 that enables introduction of a predetermined purge gas such as a rare gas is provided in the vicinity of the target 41a, and the shutter portion is caused by a pressure difference between the first space 51 and the second space. It is preferable to prevent the source gas and the reaction gas from flowing into the first space through the gap between the opening 61 and the opening 5a.

  Further, in order to prevent contamination of the deposition preventing plate 11a provided in the vacuum chamber 11 that partitions the second space 52 during film formation by sputtering, the substrate stage 12 includes a driving means 12a such as an air cylinder. Can be moved up and down (reciprocating) toward the partition plate 5, and can be brought into contact with the partition plate 5. In this case, a seal (not shown) such as a heat-resistant O-ring or a metal labyrinth seal is provided on the outer peripheral edge of the substrate stage 12, and the substrate stage 12 is raised to partition the outer peripheral edge. It is also possible to form a film on the processing substrate s by a sputtering method in contact with the edge of the opening 5a formed in the plate 5 and with the first space and the second space 52 sealed. In this case, the thickness of the partition plate 5 is set so that the upper surface of the processing substrate S protrudes into the first space 51 (see FIG. 2).

  On the other hand, a seal (not shown) such as a heat-resistant O-ring or a metallic labyrinth seal is provided on the outer peripheral edge of the lower surface of the shutter portion 61, and driving means is provided so that the shutter portion 61 can be moved up and down. If 63 is constituted, film formation by the ALD method can be performed on the processing substrate S in a state where the shutter 61 is lowered and the outer peripheral edge thereof is brought into contact with the partition plate 5 and the first space 51 is sealed. You may do it. The exhaust pipes 21 and 22 of the vacuum exhaust means 2 are respectively connected to the first space 51 and the second space 52 of the vacuum chamber. For example, a switching valve (not shown) is arranged upstream of the vacuum pump, This switching valve is switched so that the first space 51 and the second space 52 can be evacuated independently.

  By the way, when performing the film formation by the ALD method, in order to increase the film formation rate, the material gas or the reaction gas introduced into the second space 52 is rapidly increased while the adsorption rate of the material gas or the reaction gas to the processing substrate is increased. It is necessary to be able to evacuate. On the other hand, when the film is formed on the processing substrate S by the sputtering method, it is necessary to set the distance between the target 41a and the processing substrate S in order to improve the uniformity of the thin film thickness within the processing substrate surface. is there.

  In the present embodiment, at the position where the substrate stage 12 is in contact with the partition plate 5, the distance between the target 41a and the processing substrate S is longer than 120 mm and the position where the substrate stage 12 is lowered (according to the ALD method). The position between the target 41a and the processing substrate S is shorter than 300 mm, and the volume of the second space 52 is as small as possible from the bottom surface of the vacuum chamber of the partition plate 5 The height position is set. The distance between the head portions 31a and 32a and the processing substrate S is set in a range of 15 to 30 mm. As a result, when the film is formed by the ALD method, the source gas and the reactive gas can be switched quickly, and the film formation rate can be increased.

  Next, the operation when a barrier film is formed prior to the formation of the wiring buried layer in the interlayer connection hole formed in the insulating film using the film forming apparatus 1 of the present invention will be described. After the pretreatment process such as degassing of the surface of the processing substrate S is completed, the processing substrate S is placed on the substrate stage 12. In this state, the shielding means 6 is in the open position, and the first space 51 and the second space 52 are in communication (see FIG. 1). Next, the substrate stage 12 is raised to isolate the first space 51, and when the pressure in the first space 51 reaches a predetermined value, the sputtering gas is introduced into the first space 51 via the third gas introduction means 4. At the same time, a high frequency voltage is applied to the target 16 via the sputtering power source 42 to generate plasma in front of the target 41a, the target 41a is sputtered, and an insulating film side adhesion layer is formed on the insulating film with a predetermined film thickness. Form (see FIG. 2).

  Next, the substrate stage 12 is lowered, and the processing substrate S is heated by operating the heating means built in the substrate stage 12 (see FIG. 1). In this case, the shielding means 6 is moved from the open position to the closed position by the driving means 63 to isolate the first space 51 and the second space 52 from each other. In this case, the first space 51 and the second space 52 are independently evacuated by the evacuation means 2. Next, when the pressure in the second space 52 reaches a predetermined value and the processing substrate S reaches a predetermined temperature, the raw material gas is introduced through the first gas introduction means 31 and the raw material gas is introduced onto the surface of the processing substrate. To adsorb. Next, the supply of the raw material gas is stopped by controlling the mass flow controller provided in the first gas introduction means 31, and vacuum discharge is performed until the pressure in the second space 52 reaches a predetermined value again.

  Next, a reactive gas is introduced into the second space 52 via the second gas introducing means 32 and reacted with the source gas adsorbed on the surface of the processing substrate substrate S. In this case, the reaction gas may be radicalized and introduced. Then, the mass flow controller provided in the second gas introduction means 32 is controlled to stop the supply of the reaction gas, and the vacuum is discharged again until the pressure in the second space 52 reaches a predetermined value again. Then, by repeating the above procedure a desired number of times, a barrier film having a predetermined thickness is formed on the adhesion layer.

  After the barrier film having a predetermined thickness is formed, the shielding unit 6 is moved again from the closed position to the open position, and the substrate stage 12 is raised to isolate the first space 51 and the second space 52 from each other (FIG. 2). When the pressure in the first space 51 reaches a predetermined value, the sputtering gas is introduced into the first space 51 via the third gas introduction means 4 and the high frequency voltage is applied to the target 41a via the sputtering power source 42. Is applied to generate plasma in front of the target 41a, and the target 41a is sputtered to form a metal thin film, that is, a barrier film side adhesion layer on the surface of the barrier film.

  In the present embodiment, the substrate stage 12 is raised and the first space 51 and the second space 52 are separated from each other. However, the present invention is not limited to this. Instead, for example, during the film formation by the ALD method, the shielding unit 6 may be held at the open position, and a sputtering gas may be introduced to generate a plasma by applying a high frequency voltage to the target 41a. In this case, while the source gas and the reaction gas are reacted to form a barrier film on the surface of the processing substrate S, a metal whose main component is a constituent element of the same metal as the source gas is incident on the processing substrate S by sputtering. As a result, the content of the constituent elements of the metal in the barrier film can be increased and modified, and a dense barrier film can be obtained.

  When the source gas is an organometallic compound, this constituent element is incident on the surface of the processing substrate S by sputtering, so that decomposition is accelerated and impurities such as carbon are ejected from the barrier film. A membrane can be obtained. For example, when metal tantalum is used as the target 41a, organic tantalum gas is used as the source gas, and ammonia gas is used as the reaction gas, the metal tantalum is incident while the organic tantalum and ammonia gas react on the surface of the processing substrate S. Then, a tantalum nitride thin film is deposited on the surface of the processing substrate S.

  In this embodiment, an example in which a barrier layer is formed between an insulating film and a copper wiring film is described as an example, and the ALD method is used as a chemical film formation method, but the present invention is not limited to this. Instead, the chemical film-forming method may be a CVD method, and can be applied as long as a thin film is formed by performing a sputtering method and a chemical film-forming method.

Sectional drawing which shows schematically the film-forming apparatus of this invention in the position which implements a chemical film-forming method. Sectional drawing which shows schematically the film-forming apparatus of this invention in the position which implements sputtering method. The figure explaining the gas ring used when performing a chemical film-forming method. The figure explaining the shielding means which isolates 1st space and 2nd space mutually

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposition apparatus 11 Vacuum chamber 12 Substrate stage 2 Vacuum exhaust means 3 Chemical film formation means 3a, 3b, 43 Gas introduction means 4 Sputtering film formation means 41a Target 5 Partition plate 5a Opening 6 Shielding means

Claims (6)

A vacuum chamber to which an evacuation unit is connected is provided. In this vacuum chamber, a substrate stage capable of setting a processing substrate is disposed, and a target that is a film forming material disposed to face the substrate stage is provided. A film forming apparatus provided with a sputtering film forming means capable of forming a film on the processing substrate on the substrate stage by a sputtering method,
A partition plate is provided for partitioning the vacuum chamber into a first space where a target is present and a second space where a substrate stage is present, and an opening is formed on the partition plate so that the processing substrate on the substrate stage faces. Shielding means that is movable between a closed position that allows the first space and the second space to be isolated from each other and an open position that opens the opening is disposed, and a predetermined gas is introduced into the second space. A film forming apparatus comprising: a gas introducing unit configured to provide a chemical film forming unit capable of forming a film on a processing substrate on a substrate stage by a chemical film forming method. The chemical film-forming method is an ALD method in which a source gas is introduced to adsorb the source gas on the surface of the processing substrate, and a reaction gas is introduced to react with the adsorbed source gas periodically. The film forming apparatus according to claim 1, wherein: 3. The film forming apparatus according to claim 1, wherein the substrate stage is reciprocally movable toward the partition plate so that an outer peripheral edge portion of the substrate stage can contact an edge portion of the opening. The gas introducing means has a ring-shaped head portion provided on the partition plate side of the substrate stage so as to surround the substrate stage, and a predetermined gas is jetted toward the processing substrate on the bed portion. The film forming apparatus according to claim 1, wherein a plurality of gas introduction holes are formed at predetermined intervals as described above. The exhaust pipe of the evacuation means is connected to the first space and the second space of the vacuum chamber, respectively, and the first space and the second space can be independently evacuated. Or the film-forming apparatus in any one of Claim 4. 6. The film forming apparatus according to claim 1, further comprising another gas introduction unit that allows introduction of a predetermined purge gas in the vicinity of the target in the first space.

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