JP2017137544A - Film deposition apparatus and substrate discrimination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film deposition apparatus and a substrate discrimination method capable of specifying an abnormal substrate quickly as much as possible.SOLUTION: In a substrate discrimination method, a film deposition apparatus SM including holding means 5 for holding a substrate W to be processed in a vacuum chamber 1, a film deposition source 2, E, 13 for applying a deposition process to the substrate, and temperature measuring means 6 for measuring a substrate temperature at the deposition processing time, is provided with discrimination means C for detecting a temperature change amount of the substrate per unit time based on a measured value by the temperature measuring means, and discriminating abnormality of the substrate from the detected temperature change amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film forming apparatus including a holding unit that holds a substrate to be processed in a vacuum chamber, a film forming source that performs a film forming process on the substrate, and a film forming process on the substrate in the film forming apparatus. In some cases, the present invention relates to a substrate discrimination method for discriminating an abnormal state of a substrate.

  A sputtering apparatus is known as this type of film forming apparatus (see, for example, Patent Document 1). This includes a target disposed opposite to holding means for holding a substrate to be processed in the vacuum chamber, gas introducing means for introducing a rare gas into the vacuum chamber, and a power source for supplying power to the target. Then, after evacuating the vacuum chamber to a predetermined pressure, a rare gas is introduced, and direct current or high frequency power having a negative potential is applied to the target to form plasma in the vacuum chamber. Sputtered particles scattered from the target are deposited on one surface of the substrate by depositing and depositing the rare gas ions on the target, and a predetermined thin film is formed according to the target species. In addition, during film formation using such a sputtering apparatus, the substrate may be heated to a predetermined temperature. In such a case, a temperature sensor for measuring the substrate temperature is incorporated, and based on the measurement result of the temperature sensor. In general, the substrate temperature is controlled.

  Here, for example, when a film formation process is performed using the above sputtering apparatus in a semiconductor device manufacturing process, the sputtering apparatus includes a substrate such as a silicon wafer (hereinafter referred to as “normal substrate”) that has been appropriately subjected to various processes in the previous process. ”) Are transferred sequentially, and the substrate on which the film has been formed is transferred to the subsequent process after the film formation is completed. However, the substrate that has not been properly treated for some reason (hereinafter referred to as“ abnormal ” Substrate ”) may be transferred to the sputtering apparatus.

  Conventionally, regardless of whether the substrate is a normal substrate or an abnormal substrate, a film forming process is performed, and the abnormal substrate is excluded by an inspection in an inspection process in a subsequent process. For example, in order to reduce product yield and productivity, it is preferable to specify as soon as possible and exclude it from the manufacturing process. Also, in the sputtering apparatus, the film formation process is performed according to the film formation conditions set in advance. However, a film formation failure such as a film thickness shortage may occur for some reason. It is preferable to identify as soon as possible without waiting for the inspection process and to exclude it from the manufacturing process.

JP-A-11-222673

  In view of the above points, an object of the present invention is to provide a film forming apparatus and a substrate discriminating method capable of specifying an abnormal substrate as quickly as possible.

  In order to solve the above problems, a holding unit for holding a substrate to be processed in a vacuum chamber, a film forming source for performing a film forming process on the substrate, and a temperature measuring unit for measuring the substrate temperature during the film forming process The film forming apparatus according to the present invention includes a determination unit that detects a temperature change amount of the substrate per unit time based on a measurement value of the temperature measurement unit, and determines a substrate abnormal state from the detected temperature change amount. It is characterized by providing.

  Here, the present inventors have conducted extensive research and, when the substrate material and the thickness of the thin film formed on the substrate surface are different, the substrate per unit time even when the film is formed under the same film formation conditions. It came to know that the temperature change amount of was different. According to the present invention, in order to determine the abnormal state of the substrate based on the temperature change amount of the substrate during the film forming process, the abnormal substrate is identified as quickly as possible without waiting for the inspection process in the subsequent process, The substrate can be excluded from the manufacturing process.

  In the present invention, a film forming source includes a target, a gas introducing means for introducing a rare gas into a vacuum chamber, and a power source for supplying power to the target, and performs film forming processing by a sputtering method. In addition, when a thin film having a transmittance of radiation having a wavelength in a predetermined range generated during the film forming process is formed to be smaller than the substrate, a radiation thermometer disposed on the other surface side of the substrate is used as the temperature measuring means. If used, the radiated light emitted from the thin film by the incidence of sputtered particles passes through the substrate and enters the radiation thermometer, so that the film thickness of the thin film formed on one surface of the substrate can be measured. An abnormal substrate with no thickness formed can be identified as quickly as possible, and the abnormal substrate can be excluded from the manufacturing process.

  In order to solve the above-described problem, the substrate discrimination method of the present invention is a method for performing a film forming process on a substrate held by a holding unit by operating a film forming source after the vacuum chamber is in a vacuum atmosphere. A film process, a detection process for measuring the substrate temperature in the film formation process, and detecting the temperature change amount of the substrate per unit time based on the measured value of the temperature measuring means, and the abnormal state of the substrate from the detected temperature change amount And a discrimination step for discriminating between.

  In the present invention, the abnormal state of the substrate is set not only in a state where various processes are not properly performed in the previous process, but also in a state where the material of the substrate itself is different from the original substrate. It is assumed that the predetermined thin film is not formed with a certain thickness.

  The present invention further includes a film thickness acquisition step of measuring the substrate temperature based on the radiated light transmitted through the substrate in the detection step and acquiring the thickness of the thin film formed based on the temperature change amount of the substrate. It is preferable. In this case, it is preferable that a silicon substrate is used as the substrate, and the wavelength of the radiated light detected in the detection step is set in a range of 1.2 μm to 15 μm. According to this, the emitted light of the wavelength of the said range is radiated | emitted from a thin film, permeate | transmitted a board | substrate, is detected, and substrate temperature is measured from this detected emitted light. Since the temperature change amount of the substrate has a correlation with the film thickness of the thin film, the film thickness of the thin film can be acquired.

1 is a schematic cross-sectional view showing a film forming apparatus according to an embodiment of the present invention. The graph which shows the experimental result which confirms the effect of this invention. The graph which shows the experimental result which confirms the effect of this invention. The graph which shows the experimental result which confirms the effect of this invention.

  Hereinafter, with reference to the drawings, a film forming apparatus according to an embodiment of the present invention will be described by taking as an example a sputtering apparatus for forming an aluminum oxide film on a substrate W to be processed by a sputtering method.

  Referring to FIG. 1, SM is a magnetron type sputtering apparatus, and this sputtering apparatus SM includes a vacuum chamber 1 that defines a processing chamber 10. Connected to the bottom wall of the vacuum chamber 1 is an exhaust pipe 11 leading to a vacuum exhaust means P composed of a turbo molecular pump, a rotary pump or the like. A gas pipe 12 leading to a gas source (not shown) of a sputtering gas which is a rare gas such as argon is connected to the side wall of the vacuum chamber 1, and a mass flow controller 13 is interposed in the gas pipe 12. Thereby, the sputter gas whose flow rate is controlled can be introduced into the processing chamber 10 which is evacuated by the vacuum exhaust means P at a constant exhaust speed, and the pressure in the processing chamber 10 is kept substantially constant during film formation by sputtering. To be. A cathode unit CU is attached to the ceiling of the vacuum chamber 1. In the following description, in FIG. 1, the direction facing the ceiling portion side of the vacuum chamber 1 is referred to as “up” and the direction facing the bottom portion side is described as “down”.

  The cathode unit CU includes a target 2, a backing plate 3 joined to the upper surface of the target 2 through a bonding material (not shown) such as indium, and a magnet unit 4 disposed above the backing plate 3. The target 2 is made of aluminum oxide formed into a circular plate shape in plan view by a known method according to the contour of the substrate W. The backing plate 3 has a refrigerant passage 30 therein, and the target 2 can be cooled by heat exchange with a refrigerant (for example, cooling water) flowing through the refrigerant passage 30. With the target 2 mounted, the peripheral edge 31 of the backing plate 3 is attached to the upper wall of the vacuum chamber 1 via the insulator I. An output from the high frequency power source E is connected to the target 2, and high frequency power is input to the target 2 during the film forming process.

  The magnet unit 4 generates a magnetic field in the space below the sputter surface (lower surface) 21 of the target 2, captures electrons etc. ionized below the sputter surface 21 during sputtering, and efficiently ionizes the sputtered particles scattered from the target 2. Therefore, the detailed description is omitted here.

  At the bottom of the vacuum chamber 1, for example, a metal stage 5 is disposed as a holding means so as to face the target 2, and the substrate W is positioned and held in a state where the upper surface as the film forming surface is opened. . In this case, an interval (TS distance) between the target 2 and the substrate W is set in a range of 25 to 80 mm in consideration of productivity, the number of scattering times, and the like.

  A radiation thermometer 6 as a temperature measuring means is arranged on the lower surface side of the substrate W of the stage 5. The radiation thermometer 6 measures the temperature of the substrate W by detecting the radiation light from the substrate W through the through-hole 51 provided in the stage 5. Although not shown, the radiation thermometer 6 includes a detection element that detects the intensity of the emitted light, an optical system such as a lens that guides the emitted light to the detection element, and a conversion processing unit that converts the detection value of the detection element into a temperature. Since what has the well-known structure which has can be used, detailed description beyond this is abbreviate | omitted here. A flange 61 is provided on the upper portion of the radiation thermometer 6, and an O-ring 62 is fitted into a concave groove formed on the upper surface of the flange 61, and in this state, attached to the lower surface of the stage 5 and vacuum-sealed. The radiation thermometer 6 is connected to the control means C described later.

  Although not particularly shown, the sputtering apparatus SM has a control means C including a known microcomputer, sequencer, and the like. The control means C not only manages the operation of the vacuum evacuation means P, the operation of the high frequency power supply E, the operation of the mass flow controller 13, etc., but also the temperature of the substrate W per unit time based on the measured value of the radiation thermometer 6. The change amount is detected, and the abnormal state of the substrate W can be determined from the detected temperature change amount. For this reason, the control means C corresponds to the “discriminating means” in the claims. In addition, the abnormal state of the substrate W is a state in which various processes are not appropriately performed on the substrate W in the previous process (for example, the substrate W is not formed on the back surface of the substrate W, so that it is originally formed on the back surface of the substrate W. Not only in a state where a film that should not be formed, etc.) and in a state where the material of the substrate W itself is different from the original substrate (for example, different lots), but also in a predetermined thin film with a predetermined thickness on the surface of the substrate W In which the film thickness is not formed (though the thin film is formed on the surface of the substrate W but the film thickness is outside the preset allowable range). Hereinafter, an embodiment of the substrate discriminating method of the present invention will be described by taking as an example a case where an abnormal state of the substrate W is discriminated when an aluminum oxide film is formed on the surface of the substrate W using the sputtering apparatus SM.

After the substrate W is set on the stage 5 in the vacuum chamber 1, the inside of the processing chamber 10 is evacuated by operating the vacuum pump P. When the inside of the processing chamber 10 reaches a predetermined pressure (for example, 1 × 10 ⁻⁵ Pa), the mass flow controller 13 is controlled to introduce argon gas at a predetermined flow rate (for example, 5 to 2000 sccm) (at this time, the processing chamber The pressure in 10 becomes 0.06-26 Pa). At the same time, high frequency power (2 to 40 MHz (for example, 13.56 MHz), 0.1 to 40 kW) is supplied from the sputtering power source E to the target 2 to form plasma in the vacuum chamber 1. As a result, the sputtering surface 21 of the target 2 is sputtered, and the sputtered particles scattered are adhered and deposited on the surface of the substrate W, whereby an aluminum oxide film is formed (film formation step).

  In the present invention, the temperature of the substrate W is measured by the radiation thermometer 6 in the film forming process (detection process). Here, when the material of the substrate W is different, the emissivity of the back surface of the substrate W is different, the intensity of the radiated light from the back surface is different, and the temperature change amount of the substrate per unit time is different. For example, when the normal substrate is a silicon substrate, the temperature change amount of the substrate per unit time when an aluminum oxide film is formed on the silicon substrate is obtained in advance, and the temperature change amount obtained in advance and the detection step When the difference from the obtained temperature change amount exceeds the allowable range, it can be specified that the substrate is a different substrate (for example, an aluminum oxide substrate) whose material is different from that of the normal substrate.

  In this way, not only the material of the substrate itself is different, but also a film that is not formed on the normal substrate may be formed on the back surface of the substrate. For example, a normal substrate is a silicon substrate, and a silicon substrate in which an aluminum oxide film that is not formed on the normal substrate is formed on the back surface. Also in this case, since the emissivity of the back surface of the substrate W is different, the intensity of the emitted light from the back surface is different. And when the difference of the temperature change amount calculated | required in advance and the temperature change amount calculated | required at the detection process exceeds an allowable range, it can identify as an abnormal board | substrate.

  Moreover, if the wavelength of the radiated light detected by the radiation thermometer 6 is set in the range of 1.2 μm to 15 μm that transmits silicon, the radiated light emitted from the aluminum oxide film formed on the silicon substrate W is silicon. The light is transmitted through the substrate W and detected by the radiation thermometer 6. At this time, since there is a correlation between the film thickness of the aluminum oxide film and the temperature change obtained in the detection step, the film thickness of the aluminum oxide film is obtained if such a correlation is obtained in advance as a calibration curve. (Film thickness acquisition step). When the film thickness of the aluminum oxide film is out of the allowable range, it can be determined as an abnormal substrate.

  According to the present embodiment, since the abnormal state of the substrate W is determined based on the temperature change amount of the substrate W during the film forming process, the abnormal substrate is identified as quickly as possible without waiting for the inspection process in the subsequent process. In addition, the abnormal substrate can be excluded from the manufacturing process.

  Next, in order to confirm the effect, the following experiment was performed using the sputtering apparatus SM. In this experiment, a bare silicon substrate W1 having a diameter of 300 mm was used as the substrate W, and this bare silicon substrate W1 was set on the stage 5 in the vacuum chamber 1, and then argon gas was introduced into the processing chamber 10 at a flow rate of 100 sccm (at this time) The pressure in the processing chamber 10 was about 1.3 Pa), and a high frequency power of 13.56 MHz was supplied to the target 2 at 2 kW. Thereby, plasma was formed in the processing chamber 10, and the target 2 was sputtered to form an aluminum oxide film on the surface of the bare silicon substrate W1. The result of measuring the temperature of the substrate W1 during the film formation is shown by a broken line L1 in FIG. At this time, the wavelength of the radiated light detected by the radiation thermometer 6 was set to 0.8 μm which does not transmit silicon. FIG. 2 shows a temperature measurement result when an aluminum oxide film is formed on the surface of the aluminum oxide substrate W2 by a solid line L2, and the aluminum oxide film is formed on the surface of the silicon substrate on which 5400 mm of the aluminum oxide film has been formed in advance. A temperature measurement result when the film is formed is indicated by a solid line L3. And the result of having calculated | required the amount of substrate temperature changes per unit time at the time of forming an aluminum oxide film | membrane on the bare silicon substrate W1 surface is shown with the broken line L1 in FIG. In FIG. 2, the solid line L2 indicates the amount of change in substrate temperature per unit time when an aluminum oxide film is formed on the surface of the aluminum oxide substrate W2. According to this, it was confirmed that the substrate temperature change amount per unit time is different when the type of the substrate is different. Accordingly, it has been found that if the amount of temperature change is obtained, an abnormal substrate having a different substrate type from a normal substrate can be detected.

  Further, the wavelength of the radiated light detected by the radiation thermometer 6 is set to 10 μm that transmits silicon, and the substrate temperature is measured while the aluminum oxide film is formed on the surface of the bare silicon substrate W1. The amount of change in substrate temperature per hit was determined. FIG. 4 shows the relationship between the thickness of the aluminum oxide film and the amount of change in temperature. According to this, it was found that the film thickness of the aluminum oxide film can be measured by previously obtaining the amount of change in substrate temperature per unit time and creating a calibration curve or a mathematical expression.

  As mentioned above, although embodiment of this invention was described, this invention is not limited above. In the above embodiment, the case where an insulator film is formed using an insulator target 2 such as aluminum oxide has been described as an example. However, a metal film using a metal target such as aluminum or copper is used. Of course, the present invention can also be applied to the film formation.

  Moreover, although the said embodiment demonstrated the sputtering apparatus to the example, this invention is applicable also to other film-forming apparatuses like a CVD apparatus and a vacuum evaporation system.

  C: Control means (discriminating means), E: Sputtering power source (film forming source, power source), SM ... Sputtering apparatus (film forming apparatus), W ... Substrate, 1 ... Vacuum chamber, 2 ... Target (film forming source), 5 ... substrate stage (holding means), 6 ... radiation thermometer (measuring means), 13 ... mass flow controller (film forming source, gas introducing means).

Claims (5)

In a film forming apparatus comprising: a holding unit that holds a substrate to be processed in a vacuum chamber; a film forming source that performs a film forming process on the substrate; and a measuring unit that measures a substrate temperature during the film forming process.
A film forming apparatus, comprising: a determination unit that detects a temperature change amount of a substrate per unit time based on a measurement value of a temperature measurement unit, and determines an abnormal state of the substrate from the detected temperature change amount. 2. The film forming apparatus according to claim 1, wherein the film forming source has a target, a gas introducing means for introducing a rare gas into the vacuum chamber, and a power source for supplying power to the target, and performs a film forming process by a sputtering method. In the case where a thin film having a transmittance of radiated light having a wavelength in a predetermined range generated during the film forming process is smaller than the substrate is formed on one surface of the substrate,
A film forming apparatus using a radiation thermometer arranged on the other surface side of the substrate as the temperature measuring means. A film forming step of performing a film forming process on the substrate held by the holding unit by operating the film forming source after the vacuum chamber is in a vacuum atmosphere;
A detection step of measuring the substrate temperature in the film forming step, and detecting a temperature change amount of the substrate per unit time based on the measured value of the substrate temperature;
And a discrimination step of discriminating an abnormal state of the substrate from the detected temperature change amount.   It further includes a film thickness acquisition step of measuring the substrate temperature based on the radiation having a wavelength transmitted through the substrate in the detection step and acquiring the film thickness of the thin film formed based on the temperature change amount of the substrate. The substrate discrimination method according to claim 3, wherein:   4. The substrate discriminating method according to claim 3, wherein a silicon substrate is used as the substrate, and the wavelength of the radiated light detected in the detecting step is set in a range of 1.2 [mu] m to 15 [mu] m. How to determine.

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