Sputtering apparatus and method for manufacturing semiconductor device

Abstract

The present disclosure aims to provide a sputtering apparatus capable of preventing sputtered particles from adhering to unwanted areas and ensuring in-plane uniformity of the film thickness distribution across the entire substrate after sputtering, and a method for manufacturing a semiconductor device using the sputtering apparatus. [Solution] The sputtering apparatus according to the present disclosure comprises a vacuum chamber, a stage provided inside the vacuum chamber on which a substrate is placed, and a de-adhesion unit provided inside the vacuum chamber between a sputtering target and the edge of the substrate, spaced apart from the substrate. The de-adhesion unit has a de-adhesion unit electrode provided via an insulating unit, the stage has a stage electrode provided at its edge, and a power supply is provided between the de-adhesion unit electrode and the stage electrode.

Description

[Technical Field]

[0001] This disclosure relates to a sputtering apparatus and a method for manufacturing a semiconductor device using the sputtering apparatus. [Background technology]

[0002] In the field of power device semiconductors, metal films are formed on relatively thin substrates (also called "wafers") by sputtering using a target larger than the outer diameter of the substrate. During sputtering, there is a problem in that sputtered particles flying from the edge of the target are incident on the substrate at an angle and adhere to unwanted areas. Here, unwanted areas refer to areas where sputtered particles do not need to adhere, such as the edges of the substrate and the sides of the stage.

[0003] To address the above problem, a conventional technique has been disclosed in which an anti-adhesion section is placed at the edge of the substrate to prevent sputtered particles from adhering to the edges of the substrate (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-183810 [Overview of the project] [Problems that the invention aims to solve]

[0005] In Patent Document 1, after sputtering, there are areas on the substrate where no film is deposited or areas where the film is deposited but the thickness is thin. Therefore, it is not possible to ensure in-plane uniformity of the film thickness distribution across the entire substrate after sputtering. Consequently, there is a problem in that the effective area for manufacturing products is reduced, and production efficiency deteriorates.

[0006] This disclosure is made to solve such problems and aims to provide a sputtering apparatus that can prevent sputtered particles from adhering to unwanted areas and ensure in-plane uniformity of the film thickness distribution across the entire substrate after sputtering, and a method for manufacturing a semiconductor device using the sputtering apparatus. [Means for solving the problem]

[0007] To solve the above problems, the sputtering apparatus according to this disclosure comprises a vacuum chamber, a stage provided inside the vacuum chamber on which a substrate is placed, and a de-adhesion unit provided inside the vacuum chamber between a sputtering target and the edge of the substrate, spaced apart from the substrate. The de-adhesion unit has a de-adhesion unit electrode provided via an insulating unit, the stage has a stage electrode provided at its edge, and a power supply is provided between the de-adhesion unit electrode and the stage electrode. [Effects of the Invention]

[0008] According to this disclosure, it is possible to prevent sputtered particles from adhering to unwanted areas and to ensure in-plane uniformity of the film thickness distribution across the entire substrate after sputtering. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the configuration of a sputtering apparatus according to Embodiment 1. [Figure 2] Figure 2 shows the sputtering process according to Embodiment 1. [Figure 3] Figure 3 shows the sputtering process according to Embodiment 1. [Figure 4] Figure 4 is a diagram illustrating the kinetic energy of sputtered particles. [Figure 5] Figure 5 shows the configuration of a sputtering apparatus according to a modified example 1 of Embodiment 1. [Figure 6] Figure 6 shows the configuration of a sputtering apparatus according to a modified example 2 of Embodiment 1. [Figure 7] FIG. 7 is a flowchart illustrating a method for manufacturing a semiconductor device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] First Embodiment FIG. 1 is a diagram illustrating the configuration of a sputtering apparatus according to the first embodiment.

[0011] The sputtering apparatus comprises a vacuum chamber 1 and a vacuum pump 2. When performing sputtering, the vacuum pump 2 is used to evacuate the interior of the vacuum chamber 1 to a vacuum state.

[0012] An electrostatic chuck stage 5 is provided inside the vacuum chamber 1, and when performing sputtering, a substrate 6 is placed on the electrostatic chuck stage 5. The electrostatic chuck stage 5 has a stage electrode 13 at its end portion. The stage electrode 13 is circular in plan view.

[0013] A sputtering target 4 is provided at a position facing the substrate 6 when sputtering is performed. A discharge power supply 3 is connected to the sputtering target 4. When the discharge power supply 3 is turned on, discharge occurs inside the vacuum chamber 1, and sputtering can be started.

[0014] During sputtering, an adhesion prevention member 7 is disposed between the sputtering target 4 and the end portion of the substrate 6. The adhesion prevention member 7 is circular along the end portion of the substrate 6, and is disposed spaced apart from the substrate 6. The adhesion prevention member 7 has an adhesion prevention electrode 9 with a surface exposed to the substrate 6 side. The adhesion prevention electrode 9 is covered by an insulating portion 8 inside the adhesion prevention member 7.

[0015] The holding section 10 holds the adhesion-preventing section 7. The adhesion-preventing section lifting mechanism 11 can move the holding section 10 in the vertical direction, and by moving the holding section 10 up and down, the adhesion-preventing section 7 can also be moved in the vertical direction. When placing the substrate 6 on the electrostatic chuck stage 5 or removing the substrate 6 from the electrostatic chuck stage 5, the holding section 10 is moved using the adhesion-preventing section lifting mechanism 11 to increase the space between the electrostatic chuck stage 5 and the adhesion-preventing section 7. Note that although the example in FIG. 1 shows a case where the holding section 10 (the adhesion-preventing section 7) moves up and down, the electrostatic chuck stage 5 may alternatively be moved up and down. In this case, a mechanism for moving the electrostatic chuck stage 5 up and down is required.

[0016] A power supply 12 for the adhesion-preventing section is disposed between the adhesion-preventing section electrode 9 and the stage electrode 13. During sputtering, when the power supply 12 for the adhesion-preventing section is turned on, an electric field is generated between the adhesion-preventing section electrode 9 and the stage electrode 13. The insulating section 14 is provided to insulate the wiring between the adhesion-preventing section electrode 9 and the stage electrode 13 from the vacuum chamber 1.

[0017] FIG. 2 is a diagram showing a state of sputtering according to the first embodiment, and shows a part of FIG. 1.

[0018] The sputtering target 4 is composed of a backing plate 21 and a target material 22. The backing plate 21 is a base for the target material 22.

[0019] After the inside of the vacuum chamber 1 is evacuated to a vacuum state using the vacuum pump 2, argon gas is introduced into the vacuum chamber 1 and the discharge power supply 3 is turned on, whereby discharge occurs in the vacuum chamber 1. Then, when ionized argon ions collide with an erosion portion 23 of the target material 22, sputtered particles (particles of the material constituting the target material 22) are scattered from the target material 22 and adhere to the substrate 6.

[0020] Ero-Jon 23 corresponds to a region in the target material 22 where the magnetic field strength during discharge is higher than in other regions. A higher magnetic field strength in Ero-Jon 23 leads to a higher density of argon ions, resulting in more argon ions colliding with Ero-Jon 23 than in other regions. Consequently, more sputtered particles are scattered from Ero-Jon 23 than from other regions (arrows in Figure 2). As shown in Figure 2, Ero-Jon 23 gradually indents with each argon ion collision. Ero-Jon 23 is circular in plan view.

[0021] The anti-adhesion section 7 can prevent sputtered particles flying from the erosion 23 near the anti-adhesion section 7 from adhering to unwanted areas. However, sputtered particles flying from the erosion 23 far from the anti-adhesion section 7 may be incident on the substrate at a shallow angle, pass between the anti-adhesion section 7 and the substrate 6, and wrap around to and adhere to unwanted areas. The sputtering apparatus according to this embodiment 1 prevents sputtered particles from being incident on the substrate at a shallow angle, passing between the anti-adhesion section 7 and the substrate 6, and adhering to unwanted areas.

[0022] Figure 3 shows the sputtering process according to Embodiment 1, and is a partial view of Figure 2.

[0023] The sputtering apparatus according to this first embodiment is characterized by applying a voltage between the anti-deposition electrode 9 and the stage electrode 13. In the figure, "V" corresponds to the power supply 12 for the anti-deposition unit shown in Figure 1.

[0024] When the power supply 12 for the anti-adhesion unit is turned ON and a voltage is applied between the anti-adhesion unit electrode 9 and the stage electrode 13, an electric field is generated between the anti-adhesion unit electrode 9 and the stage electrode 13. Sputtered particles incident on the substrate 6 at a shallow angle are affected by the electric field between the anti-adhesion unit electrode 9 and the stage electrode 13, causing their trajectory to change and causing them to adhere to the substrate 6. This prevents sputtered particles from adhering to unwanted areas.

[0025] Figure 4 is a diagram illustrating the kinetic energy of sputtered particles.

[0026] The kinetic energy of sputtered particles flying between the anti-deposition electrode 9 and the stage electrode 13 is modeled after a parallel plate capacitor as shown in Figure 4.

[0027] Of the two electrodes constituting the parallel plate capacitor shown in Figure 4, one corresponds to the anti-deposition electrode 9, and the other corresponds to the stage electrode 13. "V," "D," and "L" in Figure 4 correspond to "V," "D," and "L" in Figure 3, respectively. That is, "V" indicates the voltage applied by the anti-deposition power supply 12 between the anti-deposition electrode 9 and the stage electrode 13, "D" indicates the distance between the anti-deposition part 7 and the end of the electrostatic chuck stage 5, and "L" indicates the width of the anti-deposition electrode 9.

[0028] In Figure 4, velocity V x Assume that sputtered particles are incident horizontally to the electrodes at the center of a parallel plate capacitor to which a voltage V [V] is applied. In this case, the equation of motion of the sputtered particles in the y-direction within the capacitor is given by equation (1) below. In equation (1), "e" represents the elementary charge and "m" represents the mass of the sputtered particle.

[0029]

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[0030] Let t=0 be the time when the sputtered particle enters the edge of the capacitor, and let y=0 be its position in the y-direction at that time. Then, using the distance L the sputtered particle travels within the capacitor, the applied voltage V and the velocity V of the sputtered particle are... x The relationship can be expressed by the following equation (2).

[0031]

number

[0032] When equation (2) is summarized in terms of the kinetic energy of sputtered particles and expressed in terms of the range of kinetic energy for typical sputtered particles, we obtain the following equation (3). The unit in equation (3) is electron volts. The range of kinetic energy for typical sputtered particles is disclosed, for example, in "the journal of the Minerals, 2011, Vol.63, No.6, P.48".

[0033]

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[0034] Rearranging equation (3), we get 0 <VL 2 / D 2 The value becomes ≤60. In order to change the trajectory of a sputtered particle having kinetic energy within the above range, 0 <VL 2 / D 2 A voltage V that satisfies ≤60 must be applied.

[0035] Based on the above, the sputtering apparatus according to this embodiment 1 applies a voltage between the anti-adhesion electrode 9 and the stage electrode 13 during sputtering. Therefore, sputtered particles that enter between the anti-adhesion part 7 and the substrate 6 at a shallow angle to the substrate 6 are bent in a direction perpendicular to the substrate 6 by the action of electrostatic force and adhere to the edges of the substrate 6. This prevents sputtered particles from wrapping around and adhering to unwanted areas. In other words, it is possible to prevent sputtered particles from adhering to unwanted areas and to ensure in-plane uniformity of the film thickness distribution across the entire substrate 6 after sputtering.

[0036] Furthermore, the sputtering apparatus according to this embodiment 1 does not allow the anti-adhesion part 7 and the substrate 6 to come into contact during sputtering. Therefore, damage to the substrate 6 can be prevented.

[0037] <Example 1> Figure 5 shows the configuration of a sputtering apparatus according to Modification 1 of Embodiment 1. In the figure, "V" corresponds to the power supply 12 for the anti-deposition section shown in Figure 1.

[0038] In the sputtering apparatus according to Modification 1, the anti-deposition electrode 9 is positioned outside the stage electrode 13.

[0039] According to Modification 1, the direction of the electric field between the anti-adhesion electrode 9 and the stage electrode 13 is from the outside to the inside of the substrate 6, so that sputtered particles can be slowed down and their leakage into unwanted areas can be efficiently prevented.

[0040] <Modification 2> Figure 6 shows the configuration of a sputtering apparatus according to a modified example 2 of Embodiment 1. In the figure, "V" corresponds to the power supply 12 for the anti-deposition section shown in Figure 1.

[0041] The sputtering apparatus according to Modification 2 includes a switch 31 that switches the polarity of the voltage V applied between the protective electrode 9 and the stage electrode 13 by the protective power supply 12. By switching the polarity of the voltage V using the switch 31, the direction of the electric field between the protective electrode 9 and the stage electrode 13 can be switched. Note that the protective power supply 12 may also include the switch 31.

[0042] According to Modification 2, if the direction of the electric field between the anti-adhesion electrode 9 and the stage electrode 13 is downward (from the anti-adhesion electrode 9 towards the stage electrode 13), sputtered particles can be attached to the edge of the substrate 6, similar to Embodiment 1. Also, if the direction of the electric field between the anti-adhesion electrode 9 and the stage electrode 13 is upward (from the stage electrode 13 towards the anti-adhesion electrode 9), sputtered particles can be attached to the anti-adhesion part 7. This prevents sputtered particles from adhering to unwanted areas.

[0043] <Embodiment 2> This second embodiment describes a method for manufacturing a semiconductor device using the sputtering apparatus according to the first embodiment.

[0044] Figure 7 is a flowchart showing a method for manufacturing a semiconductor device according to Embodiment 2. The following description will focus primarily on the manufacturing process using the sputtering apparatus according to Embodiment 1.

[0045] In the device formation process of step S1, ions are implanted into the substrate 6 to form the device.

[0046] In step S2, the substrate mounting process, the substrate 6 is placed on the electrostatic chuck stage 5.

[0047] In the movement process of step S3, the anti-attachment part 7 and the electrostatic chuck stage 5 are brought closer together.

[0048] In step S4, the voltage application step, a voltage is applied between the anti-deposition electrode 9 and the stage electrode 13 using the anti-deposition power supply 12.

[0049] In step S5, the electrode formation process, discharge is initiated to form electrodes on the substrate 6.

[0050] Furthermore, the element formation process in step S1 is performed using a device other than the sputtering apparatus according to Embodiment 1. In other words, the element formation process in step S1 is a process that is performed in advance before the manufacturing process using the sputtering apparatus according to Embodiment 1.

[0051] After the electrode formation process in step S5, the semiconductor device is completed as a product through processes such as dicing the substrate 6, wire bonding, and resin encapsulation.

[0052] According to Embodiment 2, by using the sputtering apparatus according to Embodiment 1, in-plane uniformity of the film thickness distribution across the entire substrate 6 after sputtering is ensured, making it possible to manufacture more semiconductor devices from a single substrate 6. Furthermore, since the anti-deposition part 7 and the substrate 6 are not brought into contact during sputtering, damage to the substrate 6 can be prevented, contributing to an improvement in the yield of semiconductor devices.

[0053] Within the scope of this disclosure, it is possible to freely combine the embodiments, or to modify or omit the embodiments as appropriate.

[0054] <Note> The various aspects of this disclosure are summarized below as an appendix.

[0055] (Note 1) Vacuum chamber and A stage is provided inside the vacuum chamber on which the substrate is placed, Between the sputtering target provided in the vacuum chamber and the edge of the substrate, an anti-adhesion portion is provided, which is spaced apart from the substrate. Equipped with, The anti-adhesion portion has an anti-adhesion electrode arranged via an insulating portion. The stage has stage electrodes positioned at its ends, A sputtering apparatus in which a power supply is located between the anti-deposition electrode and the stage electrode.

[0056] (Note 2) The power supply applies a voltage between the anti-adhesion electrode and the stage electrode. If the voltage is V, the distance between the protective part and the end of the stage is D, and the width of the protective part electrode is L, then 0 <VL 2 / D 2 A sputtering apparatus as described in Appendix 1 that satisfies ≤60.

[0057] (Note 3) The sputtering apparatus as described in Appendix 1, wherein the anti-adhesion electrode is positioned outside the stage electrode.

[0058] (Note 4) The sputtering apparatus according to Appendix 1, further comprising a switch that switches the polarity of the voltage applied between the anti-deposition electrode and the stage electrode of the power supply.

[0059] (Note 5) A method for manufacturing a semiconductor device using the sputtering apparatus according to Supplementary Note 1, wherein (a) a step of placing the substrate on the stage; (b) a step of bringing the adhesion prevention portion and the stage closer to each other; (c) a step of applying a voltage between the adhesion prevention portion electrode and the stage electrode; (d) a step of starting discharge to form an electrode on the substrate; comprising: in the step (c), when V is the voltage, D is the distance between the adhesion prevention portion and an end of the stage, and L is a width of the adhesion prevention portion electrode, 0 < V L 2 / D 2 A method for manufacturing a semiconductor device, wherein said voltage satisfying ≦ 60 is applied.

[0060] (Supplementary Note 6) The method for manufacturing a semiconductor device according to Supplementary Note 5, further comprising, before the step (a), (e) a step of forming an element by implanting ions into the substrate. Description of Reference Numerals

[0061] 1: vacuum chamber, 2: vacuum pump, 3: discharge power supply, 4: sputtering target, 5: electrostatic chuck stage, 6: substrate, 7: adhesion prevention portion, 8: insulating portion, 9: adhesion prevention portion electrode, 10: holding portion, 11: adhesion prevention portion lifting mechanism, 12: adhesion prevention portion power supply, 13: stage electrode, 14: insulating portion, 21: backing plate, 22: target material, 23: erosion, 31: switch.

Claims

1. Vacuum chamber and A stage is provided inside the vacuum chamber on which the substrate is placed, Between the sputtering target provided in the vacuum chamber and the edge of the substrate, an anti-adhesion portion is provided, which is spaced apart from the substrate. Equipped with, The anti-adhesion portion has an anti-adhesion electrode arranged via an insulating portion. The stage has stage electrodes positioned at its ends, A sputtering apparatus in which a power supply is located between the anti-deposition electrode and the stage electrode.

2. The power supply applies a voltage between the anti-adhesion electrode and the stage electrode. If the voltage is V, the distance between the anti-adhesion part and the end of the stage is D, and the width of the anti-adhesion part electrode is L, then 0 < VL ２ / D ２ A sputtering apparatus according to claim 1 that satisfies ≤ 60.

3. The sputtering apparatus according to claim 1, wherein the anti-adhesion electrode is positioned outside the stage electrode.

4. The sputtering apparatus according to claim 1, further comprising a switch that switches the polarity of the voltage applied between the anti-deposition electrode and the stage electrode of the power supply.

5. A method for manufacturing a semiconductor device using the sputtering apparatus described in claim 1, (a) A step of placing the substrate on the stage, (b) A step of bringing the anti-attachment part and the stage closer together, (c) A step of applying a voltage between the anti-adhesion electrode and the stage electrode, (d) A step of starting a discharge to form electrodes on the substrate, Equipped with, In step (c) above, if the voltage is V, the distance between the anti-adhesion part and the end of the stage is D, and the width of the anti-adhesion part electrode is L, then 0 < VL ２ / D ２ A method for manufacturing a semiconductor device, comprising applying the voltage that satisfies ≤ 60.

6. The method for manufacturing a semiconductor device according to claim 5, further comprising the step of (e) implanting ions into the substrate to form an element, prior to step (a).

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