JP4613092B2 - Deposition equipment - Google Patents

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, after raising the temperature of a processing substrate installed in a vacuum chamber to a predetermined temperature, a source gas and a reaction are performed. By repeating either the step of introducing one of the gases and adsorbing it on the processing substrate, and the step of once evacuating the introduced gas and then introducing the other and reacting on the processing substrate, the atomic layer is reduced to about A barrier layer having a predetermined thickness is obtained by laminating metal layers (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.

  In addition, when the film is formed by the ALD method, if the volume of the vacuum chamber is large, the adsorption rate of the source gas and reaction gas to the processing substrate is slowed down, and the source gas and reaction gas cannot be rapidly evacuated. As a result, there arises a problem that the film forming speed cannot be kept high.

  Therefore, in view of the above points, the object of the present invention is to prevent the target from being contaminated in the same vacuum chamber and to perform the film formation by the chemical film formation method and the film formation by the sputtering method. In addition, an object of the present invention is to provide a film forming apparatus capable of maintaining a high film forming rate by a chemical film forming method.

  In order to solve the above problems, a film forming apparatus of the present invention includes a vacuum chamber provided with a vacuum evacuation unit, the vacuum chamber having a target that is a film forming material, and sputtering the target by a sputtering method. A sputtering chamber capable of forming a film and a gas introducing means, and a chemical film forming chamber in which a predetermined gas is introduced from the gas introducing means and a film can be formed by a chemical film forming method is divided into right and left. A film forming apparatus provided with a substrate transfer means for allowing the processing substrate to move between the film forming positions in the sputtering chamber and the chemical film forming chamber, wherein the processing substrate faces the processing substrate in the sputtering chamber. The distance between the processing substrate in the chemical film forming chamber and the inner wall of the chemical film forming chamber facing the processing substrate in the chemical film forming chamber is in the range of 0.07 to 0.3. With the feature set to That.

  According to the present invention, after the processing substrate is moved to the sputtering chamber by the substrate transfer means, the predetermined thin film is formed by the sputtering method. Next, the substrate is transferred from the sputtering chamber to the chemical film formation chamber by the substrate transfer means, and a predetermined thin film is formed by the chemical film formation method. In this case, during the film formation by the chemical film formation method on the processing substrate on the substrate stage, the side wall of the sputtering chamber that forms a boundary with the chemical film formation chamber itself becomes a partition, and the chemical film formation method is performed. The flow of the raw material gas and the reaction gas introduced when performing the process to the vicinity of the target is suppressed, and thereby the contamination of the target due to the gas adsorption is prevented.

  In addition, since the distance between the processing substrate and the inner wall of the chemical film formation chamber facing the processing substrate is smaller than that of the sputtering chamber, the volume in the chemical film formation chamber is reduced, and the source gas and reaction are reduced. The adsorption rate of the gas to the processing substrate can be increased, and the source gas and the reaction gas can be rapidly evacuated. As a result, the deposition rate can be kept high.

  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.

  In addition, if a gas introducing means is provided that enables introduction of a predetermined gas along the side wall of the sputtering chamber that forms a boundary with the chemical film forming chamber, the film is formed on the processing substrate by the chemical film forming method. In the meantime, by introducing a gas through this gas introduction means and forming a gas curtain between the sputtering chamber and the chemical film formation chamber, the source gas introduced when performing the chemical film formation method or The reaction gas may be prevented from flowing into the sputtering chamber.

  Further, the chemical film forming gas introducing means has a ring-shaped head portion provided so as to surround the processing substrate, and a predetermined gas is jetted to the bed portion toward the processing substrate. If a plurality of gas introduction holes are formed at intervals, a predetermined gas may be evenly supplied to the processing substrate.

  It is preferable to connect the exhaust pipe of the vacuum exhaust means to the sputtering chamber and the chemical film formation chamber, respectively, so that each chamber can be evacuated independently.

  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. In addition, there is an effect that the film forming rate by the chemical film forming method can be kept high.

  Referring to FIGS. 1 to 3, reference numeral 1 denotes a film forming apparatus of the present invention capable of performing film formation by an ALD method, which is a chemical film formation method, and film formation by a sputtering method, in the same vacuum chamber. . The film forming apparatus 1 has a vacuum chamber 11 having a vacuum exhaust means 2 such as a turbo molecular pump (see FIG. 2). In this case, the vacuum chamber 11 is divided into a left and right at a central portion thereof into a sputtering chamber 11a and an ALD chamber (chemical film formation chamber) 11b that communicate with each other.

In the vacuum chamber 11, the processing substrate S is placed in the same plane between a film formation position in a sputtering chamber 11 a facing a target described later and a film formation position in an ALD chamber 11 b concentric with a gas ring described later. A substrate transfer means 3 is provided for movement. The substrate transport unit 3 includes a driving unit 31 such as a motor, and a rotary base 33 is connected to a rotating shaft 32 of the driving unit 31 (see FIG. 2). Two substrate mounting portions 33a and 33b having circular openings are formed on the turntable 33 disposed in the vacuum chamber 11 so as to face each other, and processing substrates S ₁ and S ₂ such as silicon wafers are formed. Can be held respectively.

  In the ALD chamber 11b, a first gas and a second gas which are located immediately above the film formation position in the ALD chamber 11b and into which a predetermined gas is introduced when the process substrate S is formed by a chemical film formation method. Each gas introducing means 41, 42 is provided. A substrate stage 43 having a driving means 43a such as an air cylinder is provided on the bottom surface of the ALD chamber 11b, and the processing substrate S placed on the substrate placement portions 33a and 33b by the substrate transport means 3 is transferred to the ALD chamber 11b. When the substrate stage 43 is moved from the lowered position below the turntable 33 to the raised position by the driving means 43a, the substrate stage 43 passes through the openings of the substrate placement portions 33a and 33b. The processing substrate S is supported at a predetermined height position. The substrate stage 43 incorporates, for example, a resistance heating type heating means (not shown), and the heating means 43 and the gas introduction means 41 and 42 constitute the chemical film forming means 4.

  The first and second gas introduction means 41 and 42 have ring-shaped head portions 41a and 42a that are concentrically provided and shifted in the vertical direction, and each bed portion 41a and 42a has a processing substrate. Four gas introduction holes 41b and 42b are formed by shifting the angle by 90 degrees so that a predetermined gas is ejected toward S (see FIG. 3). Each of the head portions 41a and 42a communicates with a predetermined gas source (for example, a source gas source and a reactive gas source) (not shown) via gas pipes 41c and 42c 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), and tungsten (W). The reaction gas is an ammonia gas that reacts with the raw material gas and deposits a metal thin film containing a metal constituent element in the chemical structure.

Then, after the processing substrates S ₁ and S ₂ supported by the substrate stage 43 are heated to a predetermined temperature by the built-in heating means 43, either the source gas or the reaction gas is introduced to process the processing substrate S. ₁ and the process of adsorbing to S ₂ and the process of once evacuating one of the gases and then introducing the other to react on the treated substrates S ₁ and S ₂ , thereby repeating the metal nitridation at about the atomic layer. A physical layer is laminated | stacked and the thin film of a predetermined film thickness is obtained.

A sputtering cathode 51 is provided on the ceiling of the sputtering chamber 11b so that a predetermined adhesion layer can be formed by sputtering prior to thin film formation by ALD. The sputtering cathode 51 has a known structure and includes a target 51a provided to face the processing substrates S ₁ and S ₂ . The target 51a 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 51a is connected to a sputtering power source 52 that applies a DC voltage or a high-frequency voltage to the target 51a in order to generate plasma in front of the target 51a. In this case, the substrate S1, S2, may be connected to a bias power source not shown so that a bias voltage can be applied. A third gas introduction means 53 is also provided in the sputtering chamber 11a. The gas introduction means 53 communicates with a gas source (not shown) via a gas pipe 53a provided with a mass flow controller, and can introduce a sputtering gas such as argon at a constant flow rate. The gas introduction means 53 constitutes the sputtering means 5.

Here, to enhance the uniformity of the film thickness of the processing substrate _S 1, _{S 2} plane in formation with respect to substrate _S 1, _{S 2} by a sputtering method, a target 51a and the substrate mounting portion 33a, 33b The distance L1 between the upper processing substrate S is set in a range of 120 mm to 300 mm. On the other hand, when film formation is performed by the ALD method, the source gas and the reaction gas are uniformly supplied to the processing substrates S ₁ and S ₂ , the adsorption rate to the processing substrate S is high, and the source gas and the reaction gas are rapidly evacuated. It is necessary to make it possible to maintain a high film formation rate.

In the present embodiment, the distance L2 between the processing substrates S ₁ and S ₂ supported by the substrate stage 43 and the upper wall of the ALD chamber 11b facing the processing substrates S ₁ and S ₂ is in the range of 20 mm to 35 mm. As set (the ratio of the distance L2 to the distance L1 is in the range of about 0.07 to 0.3 (D1: D2 = 1: 0.07 to 0.3)) up to the upper surface of the ALD chamber 11b. The height was set and the vacuum chamber 11 was formed in an L-shaped cross section (see FIG. 1). In this case, the distance between the head portions 41a and 42a and the processing substrates S ₁ and S ₂ is preferably set in a range of 15 to 30 mm. If it is shorter than 15 mm, the gas introduced into the ALD chamber 11b is not sufficiently diffused, and the raw material gas and the reactive gas cannot be evenly supplied to the processing substrates S ₁ and S ₂ . On the other hand, if it is longer than 30 mm, the distance D2 is increased, the volume of the ALD chamber 11b is increased, and the film formation rate cannot be kept high. For this reason, the distance D2 is set in the range of 20 mm to 35 mm in consideration of the attachment of the head portion to the ALD chamber 11b and the like.

  Further, in order to prevent the source gas and reaction gas introduced when performing the ALD method from flowing into the sputtering chamber 11a, an inert gas is formed along the side wall 111 of the sputtering chamber 11a that forms a boundary with the ALD chamber 11b. A third gas introduction means 6 for introducing a predetermined gas such as is provided.

  By forming the film forming apparatus 1 as described above, the side wall 111 of the sputtering chamber 11a that forms a boundary with the ALD chamber 11b becomes a partition during film formation by the ALD method, and the third along the side wall 111 is the third. Introducing an inert gas through the gas introducing means 5 and forming a gas curtain in the space 11c at the boundary between the sputtering chamber 11a and the ALD chamber 11b, are introduced when the ALD method is performed. As a result, contamination of the target 51a due to gas adsorption can be prevented.

Further, by setting the height dimension of the ALD chamber 11b to be small, the volume of the ALD chamber 11b is reduced, and the source gas and the reaction gas are uniformly supplied to the processing substrates S ₁ and S ₂ on the substrate stage 43. The adsorption speed is increased and the source gas and reaction gas can be quickly evacuated. As a result, the film formation rate by the ALD method can be kept high. In this case, the exhaust pipes 21 and 22 of the evacuation unit 2 are connected to the sputtering chamber 11a and the ALD chamber 11b, respectively. For example, a switching valve (not shown) is disposed upstream of the evacuation unit 2. By switching this switching valve, each chamber 11a, 11b can be evacuated independently.

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 surfaces of the _two processing substrates S ₁ and S ₂ is finished, the rotating means 33 is rotated by the driving means 31 and placed on the substrate placement parts 33a and 33b, respectively. the processing substrate _{S 1,} moves to the film formation position in the sputtering chamber 11a (in this case, the other substrate _{S 2,} is in the deposition position of the ALD chamber 11b).

Next, when the evacuation unit 2 is operated and the pressure in the sputtering chamber 11a reaches a predetermined value, the sputtering gas is introduced through the third gas introduction unit 53 and the high frequency is supplied to the target 51a through the sputtering power source 52. By applying a voltage, plasma is generated in front of the target 51a, the target 51a is sputtered, and an insulating film side adhesion layer is formed with a predetermined thickness on the insulating film. In this case, not performed film formation by ALD method to other substrate S _2.

Then, by rotating the turntable 33 by the drive means 31, the one of the substrate S ₁ forming the insulating film side adhesive layer is moved to the film formation position in the ALD chamber 11b (in this case, the other substrate S ₂ is It moves to the film forming position in the sputtering chamber 11a). Then, by the driving means 43a, to support the substrate S and the substrate stage 43 is moved to the raised position, the heating means is embedded substrate stage is operated to heat the substrate S _1, the substrate S ₁ is given When the pressure in the ALD chamber 11b with reaching the temperature reaches a predetermined value, through the first gas introducing means 41 introduces a source gas is adsorbed raw material gas on the surface of the treated substrate S _1. Next, the supply of the raw material gas is stopped by controlling the mass flow controller provided in the first gas introduction means 41, and vacuum discharge is performed until the pressure in the ALD chamber 11b reaches a predetermined value again.

Then, through the second gas introducing means 42, introducing a reactive gas into the ALD chamber 11b, is reacted with the raw material gas adsorbed on the substrate the substrate S ₁ surface. In this case, the reaction gas may be radicalized and introduced. Then, the mass flow controller provided in the second gas introduction means 42 is controlled to stop the supply of the reaction gas, and the vacuum is discharged until the pressure in the ALD chamber 11b 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. While the barrier film is formed by ALD on the processing substrate S _1, on the substrate S ₂ in the sputtering chamber 11a is similar to the above, is formed by a sputtering method is performed.

After forming a predetermined film thickness of the barrier film, and moves the substrate stage 43 in the lowered position by the driving means 43a, placing the processed substrate S ₁ on the substrate platform 33a, and further rotate the rotary table 33, the barrier film is moved to the film formation position again sputtering chamber 11a of the substrate S ₁ which is formed, when the pressure reaches a predetermined value, as well as introducing a sputtering gas through the third gas introducing means 53, the sputtering power source A high frequency voltage is applied to the target 51a via 52 to generate plasma in front of the target 51a, and the target 51a 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 transport means 3 having the turntable 33 has been described. However, the processing substrates S ₁ and S ₂ are formed on the sputtering chamber 11a and the chemical deposition chamber 11b. If it can be made to move between, it will not be limited to this.

  Further, an example in which a barrier layer is formed between an insulating film and a copper wiring film will be described, and the ALD method is used as a chemical film forming method. However, the present invention is not limited to this. The film 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 formation method.

  In this embodiment, the gas introduction means 41 and 42 using the ring-shaped head portions 41a and 41b are described. However, the present invention is not limited to this, and a shower is provided on the upper surface of the chemical film formation chamber. A plate or the like may be provided, and the heating means may be an infrared heater provided on the ceiling of the ALD chamber 11b.

1 is a cross-sectional view schematically showing a film forming apparatus of the present invention. Sectional drawing along the II-II line of FIG. The figure explaining the gas ring used when performing a chemical film-forming method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Film-forming apparatus 11 Vacuum chamber 11a Sputtering chamber 11b Chemical film-forming chamber (ALD chamber)
3 Substrate transport means 41a, 41b, 53 Gas introduction means 51a Target

Claims (5)

A vacuum chamber provided with a vacuum evacuation unit, the vacuum chamber having a target that is a film forming material, a sputtering chamber capable of performing film formation by sputtering the target by a sputtering method, and a gas introduction unit And a chemical film forming chamber in which a predetermined gas is introduced from this gas introducing means and a film can be formed by a chemical film forming method. A film forming apparatus provided with a substrate transfer means for allowing the processing substrate to move freely between them, wherein a chemical growth is performed with respect to a distance between the processing substrate and a target disposed opposite to the processing substrate in the sputtering chamber. A film forming apparatus characterized in that a distance between a processing substrate and an inner wall of a chemical film forming chamber facing the processing substrate in the film chamber is set in a range of 0.07 to 0.3. 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 composition according to claim 1, further comprising another gas introduction means for introducing a predetermined gas along a side wall of the sputtering chamber that forms a boundary with the chemical film formation chamber. Membrane device. The gas introduction means for chemical film formation has a ring-shaped head portion provided so as to surround the processing substrate, and a predetermined interval is emitted to the bed portion so as to eject a predetermined gas toward the processing substrate. The film forming apparatus according to claim 1, wherein a plurality of gas introduction holes are formed by placing a plurality of gas introduction holes. The exhaust pipe of the vacuum exhaust means is connected to a sputtering chamber and a chemical film formation chamber, respectively, and each chamber can be independently vacuum exhausted. 2. The film forming apparatus according to 1.

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