Substrate management method

Abstract

This invention provides a substrate management method that controls the substrate temperature after film deposition and manages the substrate condition after film deposition. [Solution] The system has a substrate stage 3 that holds a substrate Sw, and the position of the substrate stage 3 separated from the target 21 is defined as the retracted position, the position of the substrate stage 3 facing the target 21 with a distance between them is defined as the film deposition position, and the position of the substrate Sw separated from the holding surface 3a of the substrate stage 3 at the retracted position is defined as the transport position. After depositing a predetermined thin film on the film deposition surface of the substrate Sw held by the substrate stage 3 at the film deposition position by sputtering of the target 21, the substrate stage 3 is moved to the retracted position and the substrate Sw is moved to the transport position, at which point the substrate state is managed. The system includes the steps of placing a radiation thermometer 4 in the vacuum chamber 1 corresponding to the transport position of the substrate Sw, measuring the temperature of the outer edge of the back surface of the substrate Sw with the radiation thermometer 4 at the transport position of the substrate Sw after film deposition, and managing the substrate state based on the measurement value of the radiation thermometer 4.

Description

Technical Field

[0001] The present invention relates to a substrate management method, and more particularly to a method for managing the state of a substrate after film formation when a predetermined thin film is formed on a substrate as a film formation object by sputtering a target.

Background Art

[0002] A sputtering apparatus is generally known as an apparatus for forming a predetermined thin film on a film formation surface (one surface) of a substrate as a film formation object such as a large-area glass substrate. In this type of sputtering apparatus, during film formation by sputtering of a target, an increase in the substrate temperature due to radiant heat from the plasma generated between the target and the substrate is inevitable. When the temperature of the substrate rises above a predetermined temperature during film formation, depending on the film type of the thin film to be formed and the type of the substrate (for example, the presence or absence of an underlayer such as an organic film previously formed), problems such as a change in the film quality (crystal structure, etc.) or thermal degradation of the underlayer may occur.

[0003] Normally, an electrostatic chuck is provided on the holding surface of the substrate stage on which the substrate is installed, and a cooling mechanism is assembled to the substrate stage. During film formation, the substrate held (adsorbed) on the holding surface of the substrate stage is mainly cooled below a predetermined temperature by contact heat conduction with the substrate stage. However, there are cases where the substrate temperature rises above the predetermined temperature due to some reason. Therefore, it is required to manage the state of the substrate after film formation, such as whether a thin film having a normal film quality has been formed or whether the underlayer previously formed on the substrate has been adversely affected. For this, there is no choice but to measure the substrate temperature by some method.

[0004] A device capable of measuring the substrate temperature during film deposition is known, for example, in Patent Document 1. In this device, a through-hole is provided in the substrate stage, facing the back surface (the other side) of the substrate, and the substrate temperature is measured by a radiation thermometer placed below the substrate stage through this through-hole. However, when an opening for a through-hole is provided in the holding surface of the substrate stage, the substrate is not adsorbed in the area with the opening, so the cooling performance due to contact heat conduction is locally reduced on the back surface of the substrate facing the opening, and the temperature of that back surface at this time changes depending on the state of substrate adsorption, etc. Therefore, there is a problem that the correct surface temperature at a specific location on the back surface of the substrate cannot always be captured.

[0005] Incidentally, in the above-mentioned sputtering apparatus, an earth-grounded protective plate that functions as an anode is usually installed around the target. As a result, the outer edge of the substrate, where the density of the plasma generated between the target and the substrate is highest, is the most prone to heating and reaching high temperatures. Therefore, the inventors have diligently conducted research and have found that by measuring the substrate temperature at a specific location on the outer edge of the substrate after film deposition, the substrate condition after film deposition can be appropriately controlled. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2004-281618 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention is based on the above findings and aims to provide a substrate management method that controls the substrate temperature after film formation and manages the substrate condition after film formation. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a substrate management method comprising: a substrate stage that holds a substrate to be deposited in a vacuum chamber in which a target is placed; a retracted position where the substrate stage is spaced away from the target; a deposition position where the substrate stage is spaced away from the target and facing it; and a transport position where the substrate is spaced away from the holding surface of the substrate stage at the retracted position of the substrate stage; moving the substrate stage to the deposition position while the substrate is held by the substrate stage at the retracted position; depositing a predetermined thin film on one side of the substrate by sputtering of the target; and managing the state of the substrate when the substrate stage is moved to the retracted position and the substrate is moved to the transport position after deposition, characterized in that the substrate state is managed by: placing at least one radiation thermometer in the vacuum chamber corresponding to the transport position of the substrate; measuring the temperature of the outer edge of the other side of the substrate with the radiation thermometer at the transport position of the substrate after deposition; and managing the state of the substrate based on the measurement value of the radiation thermometer.

[0009] According to the present invention, when the substrate is moved to the transport position after film deposition, a radiation thermometer is used to measure the temperature of the outer edge of the other side of the substrate (i.e., the area that reached the highest temperature during sputtering). This configuration allows the temperature at a specific location on the back surface of the substrate to be constantly captured, regardless of the substrate area (i.e., even when the substrate area is large). By managing this measurement to remain below a preset temperature (hereinafter referred to as the "first preset temperature"), it is possible to manage the state of the substrate after film deposition, such as whether a thin film with the correct film quality has been deposited or whether the underlying layer pre-deposited on the substrate has been adversely affected. The first preset temperature can be set by experimentally determining in advance the highest temperature reached during film deposition at the outer edge of the substrate to be measured by the radiation thermometer (for example, by attaching a thermolabel (registered trademark) to the substrate and measuring it), or the amount of temperature drop of the substrate after the substrate stage is moved to the retraction position and the substrate is moved to the transport position after film deposition.

[0010] Furthermore, it is preferable that the present invention further includes a step of measuring the temperature of the outer edge of the other side of the substrate before processing using a radiation thermometer at the transport position. With this, if the temperature of the outer edge of the substrate before processing is controlled to be below a predetermined set temperature (hereinafter referred to as the "second set temperature") (i.e., if processing is started after cooling to the second set temperature), the substrate state can be controlled more reliably. The second set temperature can be set by experimentally determining in advance the substrate temperature before processing, such as the temperature at which the substrate state would change if processing were started as is.

[0011] Furthermore, it is preferable that the present invention further includes a step of providing a swivel mechanism to the light-receiving part of the radiation thermometer to change the temperature measurement area at the outer edge of the other surface of the substrate. This increases the area that can be measured by the radiation thermometer, and allows for accurate measurement of the temperature at the outer edge of the substrate. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic cross-sectional view of a sputtering apparatus according to an embodiment of the present invention. [Figure 2] A schematic cross-sectional view of a sputtering apparatus according to an embodiment of the present invention. [Figure 3] A schematic cross-sectional view of a sputtering apparatus according to an embodiment of the present invention. [Figure 4] A cross-sectional view along the line IV-IV in Figure 1. [Modes for carrying out the invention]

[0013] The following describes an embodiment of the substrate management method of the present invention, using the example of a rectangular glass substrate with an organic film formed as an underlayer on its surface (hereinafter referred to as "substrate Sw"), and depositing an aluminum film on one side (the film-depositing surface) of substrate Sw by sputtering, with reference to the drawings.

[0014] Referring to Figures 1 to 3, Sm is a sputtering apparatus capable of implementing the substrate management method of this embodiment. The sputtering apparatus Sm includes a vacuum chamber 1. The vacuum chamber 1 consists of a first chamber 1a and a second chamber 1b connected to each other via a partition plate 11. The partition plate 11 has an opening 11a through which a substrate Sw, held on a substrate stage 3 in the film deposition position described later, faces into the first chamber 1a. Although not specifically illustrated and described, exhaust pipes from a vacuum pump are connected to the first and second chambers 1a and 1b, so that a vacuum atmosphere of a predetermined pressure can be formed inside them. In the following, the direction in which the first and second chambers 1a and 1b are connected is the X-axis direction (left-right direction in Figure 1), the plane perpendicular to the X-axis direction is the YZ plane, the direction in which each of the targets 21 described later is arranged side-by-side in the YZ plane is the Y-axis direction (direction perpendicular to the plane of the paper in Figure 1), and the longitudinal direction of each target 21 is the Z-axis direction (up-down direction in Figure 1). Directions such as "up" and "down" are based on the installation position of the sputtering apparatus Sm shown in Figure 1.

[0015] A gas inlet is provided in the upper wall of the first chamber 1a, and one end of a gas inlet pipe Gp (not shown) is connected to it. The other end of the gas inlet pipe Gp is ​​connected to a gas source via a flow control valve, which is composed of a mass flow controller or the like, so that a flow-controlled sputtering gas (e.g., argon gas) can be introduced into the first chamber 1a, specifically into the space between the substrate Sw held on the substrate stage 3 at the film deposition position described later and the target 21. A cathode unit 2 is also provided on the side wall of the first chamber 1a facing the partition plate 11.

[0016] The cathode unit 2 comprises six targets 21 arranged parallel to each other at equal intervals in the Y-axis direction within the YZ plane. Each target 21 is made of aluminum and has the same shape, and is sized to have a Z-axis length equal to or greater than the length of the substrate Sw. The number of targets 21 arranged in parallel is set appropriately according to the distance in the Y-axis direction between each target 21, taking into account the Z-axis length of each target 21, the film thickness distribution, etc., and the area of ​​the region in which each target 21 is arranged. Each target 21 is bonded to a backing plate 22 via a bonding material (not shown) such as indium or tin, and each backing plate 22 is supported by a single support plate 23, electrically insulated from each other. Although not specifically illustrated and explained, each target 21 is connected to an output cable from a sputtering power supply for supplying a predetermined power. As a sputtering power supply, a known pulsed DC power supply or a high-frequency power supply can be used, so further explanation is omitted.

[0017] A substrate stage 3 for holding a substrate Sw is positioned in the second chamber 1b. The substrate stage 3 is supported by a pivot shaft 31 pivotally supported within the second chamber 1b. By rotating the pivot shaft 31 around its axis, the substrate stage 3 is oscillated between a retracted position spaced apart from each target 21 in the first chamber 1a (the position of the substrate stage 3 shown in Figure 1) and a film deposition position facing each target 21 with a distance between them (the position of the substrate stage 3 shown in Figure 2). The substrate stage 3 is also provided with a plurality of through holes 32 that penetrate in the thickness direction, and a plurality of lift pins Lp are assembled to extend and retract from each through hole 32 to lift the substrate Sw, which is placed on the holding surface 3a (i.e., the upper surface of the substrate stage 3 in the retracted position) of the substrate stage 3, to a transport position spaced above the holding surface 3a (the position of the substrate Sw shown in Figure 3). Furthermore, each lift pin Lp is connected to a rod of an air cylinder Ac located outside the second chamber 1b, and is configured to be able to move up and down in the Z-axis direction. Alternatively, instead of the air cylinder Ac, a drive mechanism such as an electric motor may be used to enable each lift pin Lp to move up and down in the Z-axis direction. Although not specifically illustrated and described, a heating and cooling mechanism is assembled to the substrate stage 3, and an electrostatic chuck is provided on the holding surface 3a of the substrate stage 3. Since known components can be used, further explanation is omitted.

[0018] When depositing an aluminum film using the above-described sputtering apparatus Sm, the first chamber 1a and the second chamber 1b are evacuated by a vacuum pump at the retracted position of the substrate stage 3. When the first chamber 1a and the second chamber 1b reach a vacuum atmosphere of a predetermined pressure, the substrate Sw is transported into the second chamber 1b by a vacuum transport robot in a transport chamber connected to the second chamber 1b (not specifically illustrated and explained). At this time, the air cylinder Ac is driven to make the lift pin Lp protrude from the holding surface 3a of the substrate stage 3 in the retracted position, and the substrate Sw before processing is transferred to the lift pin Lp at the transport position. Once the substrate Sw is transferred to the lift pin Lp, the air cylinder Ac is driven to lower the lift pin Lp, and the substrate Sw is placed on the holding surface 3a of the substrate stage 3. Once the substrate Sw is placed on the holding surface 3a, the substrate Sw is held by the substrate stage 3 in the retracted position by an electrostatic chuck. Then, the rotation axis 31 of the substrate stage 3 is rotated to swing the substrate stage 3 from the retracted position to the film deposition position. This separates the atmosphere between the first chamber 1a and the second chamber 1b, with the substrate Sw facing the first chamber 1a. Simultaneously, argon gas is introduced at a predetermined flow rate from the gas introduction tube Gp, and pulsed DC power or high-frequency power is supplied to each target 21 by the sputtering power supply. As a result, each target 21 is sputtered by argon ions in the plasma, and the sputtered particles scattered from each target 21 adhere to and accumulate on the film deposition surface of the substrate Sw held on the substrate stage 3 in the film deposition position, thereby forming an aluminum film. At this time, an anti-adhesion plate (not shown) is appropriately provided inside the first chamber 1a to prevent leakage of sputtered particles into the second chamber 1b.

[0019] When the film formation on the substrate Sw is completed, the introduction of argon gas and the power supply to each target 21 are stopped. The rotary shaft 31 is rotationally driven to swing the substrate stage 3 from the film formation position to the retracted position, and then the adsorption of the substrate Sw by the electrostatic chuck is released. Along with this, the air cylinder Ac is driven to project the lift pin Lp upward from the holding surface 3a of the substrate stage 3, move the substrate Sw after film formation to the transfer position, and recover the substrate Sw by a vacuum transfer robot. When forming a film on the substrate Sw using the sputtering apparatus Sm, the substrate temperature may rise above the predetermined temperature due to some reason. Therefore, it is necessary to manage the state of the substrate after film formation, such as whether a thin film with a normal film quality has been formed or whether it has adversely affected the underlying layer previously formed on the substrate Sw.

[0020] Referring also to FIG. 4, in the present embodiment, radiation thermometers 4 are respectively arranged at the four corners of the bottom in the second chamber 1b so as to measure the temperature of the outer edge portion of the back surface (the other surface) of the substrate Sw at the transfer position. Then, each radiation thermometer 4 measures the temperature of the outer edge portion of the back surface of the substrate Sw at the transfer position after film formation, and the state of the substrate is managed based on the temperature of the outer edge portion of the back surface of the substrate Sw measured by each radiation thermometer 4. In this case, if the temperature of the back surface of the substrate Sw is measured within a range of 130 mm or less inward from the outer edge (each side) of the substrate Sw as the outer edge portion of the back surface of the substrate Sw, the influence of the heat of the outer edge portion of the substrate Sw can be sufficiently grasped. Further, if the distance between the back surface of the substrate Sw and the upper surface of the substrate stage 3 at the transfer position is set to be greater than 100 mm, the influence of heat radiation from the substrate stage 3 can be suppressed (even when the temperature of the substrate stage 3 is set to the second set temperature described later), and the temperature of the back surface of the substrate Sw can be measured more accurately.

[0021] Further, each radiation thermometer 4 is provided with a pivoting mechanism 41 including a stepping motor Sp and a gear mechanism, and the light receiving part 42 of each radiation thermometer 4 is configured to be rotatable at a predetermined angle within the X-Y plane about the rotation axis of the stepping motor Sp. By rotating the light receiving part 42 with this pivoting mechanism 41, the temperature measurement area at the outer edge of the back surface of the substrate Sw at the above-described conveyance position can be changed.

[0022] According to the above embodiment, when the substrate Sw after film formation moves to the above-described conveyance position, by measuring the temperature at the outer edge of the back surface of the substrate Sw with the radiation thermometer 4, even when the substrate area is large, the temperature at a specific position on the back surface of the substrate can always be captured. And if this measured value is managed so as to be equal to or lower than a first set temperature set in advance, it is possible to manage the state of the substrate after film formation, such as whether a thin film with a normal film quality has been formed or whether the underlying layer previously formed on the substrate has been adversely affected. The first set temperature can be set in advance experimentally, such as the maximum temperature reached during film formation at the outer edge of the substrate Sw to be measured by the radiation thermometer 4 (for example, measured by attaching a thermo label (registered trademark) to the substrate Sw), or the amount of temperature drop of the substrate after moving the substrate stage 3 to the above-described retracted position and then moving the substrate Sw to the above-described conveyance position.

[0023] Also, by measuring the temperature at the outer edge of the back surface of the substrate Sw before processing with the radiation thermometer 4 at the above-described conveyance position and managing the temperature at the outer edge of this substrate Sw so as to be equal to or lower than a second set temperature set in advance, the above-described substrate state can be managed more reliably. The second set temperature can be set in advance experimentally, such as the temperature of the substrate before processing that will cause the above-described substrate state to change if the processing is started as it is. Further, by providing a pivoting mechanism 41 to the light receiving part 42 of the radiation thermometer 4 and changing the temperature measurement area at the outer edge of the back surface of the substrate Sw, the measurable area by the radiation thermometer 4 increases, and the temperature at the outer edge of the substrate Sw can be measured accurately.

[0024] While embodiments of the present invention have been described above, various modifications are possible as long as they do not deviate from the technical concept of the present invention. In the above embodiments, an example was described in which four radiation thermometers 4 are arranged, but the number of radiation thermometers 4 is not limited to this, and it is sufficient to have at least one or more. Also, in the above embodiments, an example was described in which a stepping motor Sp and a gear mechanism are used as the oscillating mechanism 41, but the oscillating mechanism is not limited to this, and other mechanisms can be used as long as they can change the temperature measurement area on the outer edge of the back surface of the substrate Sw.

[0025] Furthermore, although the above embodiment described an example using an aluminum target 21, the present invention is not limited to this and can be applied to targets made of other materials. Also, although the above embodiment described an example of a cathode unit 2 in which a plurality of targets 21 are arranged side by side in the same plane, the present invention can also be applied to a rotary cathode unit in which the target is formed in a cylindrical shape and the outer surface of the target is sputtered while the target is rotated. [Explanation of symbols]

[0026] Sw...Substrate (object to be deposited on), 1...Vacuum chamber, 1a...First chamber (vacuum chamber), 1b...Second chamber (vacuum chamber), 21...Target, 3...Substrate stage, 3a...Holding surface, 4...Infrared thermometer, 41...Swivel mechanism, 42...Light receiving unit.

Claims

1. A substrate management method comprising a substrate stage that holds a substrate to be deposited in a vacuum chamber in which a target is placed, wherein the position of the substrate stage separated from the target is defined as the retracted position, the position of the substrate stage opposite the target with a distance between them is defined as the deposition position, and the position of the substrate separated from the holding surface of the substrate stage at the retracted position is defined as the transport position, wherein after a predetermined thin film is deposited on one side of the substrate held on the substrate stage at the deposition position by sputtering of the target, the substrate stage is moved to the retracted position and the substrate is moved to the transport position, and the state of the substrate is managed, A substrate management method characterized by including the steps of: placing at least one radiation thermometer in a vacuum chamber corresponding to the transport position of the substrate, measuring the temperature of the outer edge of the other side of the substrate using the radiation thermometer at the transport position of the substrate after film deposition; and managing the substrate condition based on the measurement value of the radiation thermometer.

2. The substrate management method according to claim 1, further comprising the step of measuring the temperature of the outer edge of the other side of the substrate before processing using the radiation thermometer at the transport position.

3. The substrate management method according to claim 1 or 2, further comprising the step of providing a swivel mechanism to the light-receiving part of the radiation thermometer to change the temperature measurement area at the outer edge of the other surface of the substrate.

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