JP6596602B2 - Plasma processing method and plasma processing apparatus - Google Patents

Description

  The present invention relates to a plasma processing method and a plasma processing apparatus.

  In recent years, with the increase in area and integration of semiconductor devices, low vapor pressure liquid materials having a relatively low vapor pressure are used as reaction materials in plasma processing apparatuses such as film forming apparatuses. For example, a thermal CVD (Chemical Vapor Deposition) in which a heater is provided in the shower plate, the shower plate is heated by the heater, and a low vapor pressure liquid material is vaporized and supplied from the shower plate to the reaction chamber to form a film on the substrate. An apparatus is provided (see, for example, Patent Document 1).

Japanese Patent No. 3883918

  However, in a plasma processing apparatus that applies high frequency power to the shower plate, if the shower plate is provided with a heater, the high frequency power may be superimposed on the heater, making it difficult to control the heating of the heater. Further, when cleaning the shower plate, it is necessary to remove the heater from the shower plate. Thereby, the productivity in plasma processing may decrease.

  In view of the circumstances as described above, an object of the present invention is to provide a plasma processing method and a plasma processing apparatus with improved productivity.

In order to achieve the above object, a plasma processing method according to an aspect of the present invention includes heating a substrate support placed in a vacuum vessel to a first temperature. A first plasma is generated under a first discharge condition between the substrate support and the shower plate facing the substrate support, and the shower plate is heated by the heat of the substrate support and the first plasma. The The temperature of the shower plate is monitored without contact. After the temperature of the shower plate reaches a second temperature higher than the temperature heated by the heat of the substrate support table, a process gas is jetted from the shower plate toward the substrate support table, and the substrate support table The second plasma is generated between the first and second shower plates under the second discharge condition, and the substrate supported by the substrate support is processed by the second plasma.
According to such a plasma processing method, the temperature of the shower plate can be accurately heated without providing a heater in the shower plate. Further, when cleaning the shower plate, it is not necessary to remove the heater from the shower plate. Thereby, productivity in plasma processing is improved.

In the plasma processing method, in the step of processing the substrate, the second temperature may be a temperature at which the temperature of the shower plate is maximized in the step of processing the substrate.
According to such a plasma processing method, since the temperature of the shower plate has already reached the maximum temperature before the substrate is subjected to the plasma processing with the process gas, the temperature change of the shower plate is suppressed during the plasma processing with the process gas. . Thereby, for example, the thickness of the film formed on the substrate is less likely to vary.

In the plasma processing method, in the plasma processing step, the second discharge condition includes a discharge power, a reaction gas flow rate, and a processing time. When the plurality of substrates are processed and the second temperature changes each time the substrate is processed, the discharge power, the reaction gas flow rate, and the processing time are changed according to the value of the second temperature. The substrate may be processed by changing at least one of them.
According to such a plasma processing method, when a plurality of substrates are processed, even if the second temperature changes each time the substrate is processed, the discharge power and the reaction gas flow rate are changed according to the value of the second temperature. In addition, plasma processing is performed while changing at least one of the processing times. Thereby, for example, the film quality of the film formed on the substrate is less likely to vary.

In the plasma processing method, further, in the plasma processing step, the substrate is processed for each of a plurality of substrates, the substrate is processed for each of a plurality of substrates, and then a cleaning gas is jetted into the vacuum vessel, so that the vacuum The inside of the container may be washed.
According to such a plasma processing method, after processing a plurality of substrates, cleaning gas is ejected and the inside of the vacuum vessel is cleaned.

In the plasma processing method, the temperature of the shower plate may be monitored by a radiation thermometer disposed outside the vacuum vessel on the back side of the shower plate.
According to such a plasma processing method, the temperature of the shower plate is measured by a radiation thermometer arranged outside the vacuum vessel on the back side of the shower plate. As a result, the temperature of the shower plate is measured in a non-contact manner, and the radiation thermometer is less likely to affect the temperature of the shower plate.

  In the plasma processing method, the second discharge condition may be different from the first discharge condition. Thereby, the substrate is subjected to plasma treatment under the second discharge condition different from the first discharge condition.

In order to achieve the above object, a plasma processing apparatus according to an embodiment of the present invention includes a vacuum vessel, a substrate support, a shower plate, a power supply source, a temperature measurement device, and a control device. The vacuum container is maintained in a reduced pressure state. The substrate support is disposed in the vacuum vessel and has a substrate mounting surface and a heating mechanism. The substrate support can set the substrate mounting surface to the first temperature by the heating mechanism, and can support the substrate. The shower plate faces the substrate support. The power supply source generates plasma between the substrate support and the shower plate. The temperature of the shower plate is measured without contact. The control device monitors the temperature of the shower plate by the temperature measuring device and generates a first plasma according to a first discharge condition between the substrate support and the shower plate. The control device heats the shower plate with the heat of the substrate support and the first plasma, and the temperature of the shower plate is higher than the temperature heated by the heat of the substrate support. Then, the process gas is sprayed from the shower plate toward the substrate support. The controller may process the substrate by the second plasma by generating a second plasma according to a second discharge condition between the substrate support and the shower plate.
According to such a plasma processing apparatus, the temperature of the shower plate is accurately heated without providing a heater in the shower plate. Further, when cleaning the shower plate, it is not necessary to remove the heater from the shower plate. Thereby, productivity in plasma processing is improved.

  As described above, according to the present invention, productivity in plasma processing is improved.

It is a schematic sectional drawing which shows the plasma processing apparatus which concerns on this embodiment. It is a schematic graph which shows the relationship between the process time which concerns on this embodiment, and the temperature of a shower plate. It is a schematic graph which shows the relationship between the process time which concerns on a comparative example, and the temperature of a shower plate. FIG. 1A is a schematic graph showing the relationship between the process time and the film formation speed according to the present embodiment. FIG. 5B is a schematic graph showing the relationship between the process time and the film formation rate according to the comparative example. It is a schematic graph which shows the relationship between shower plate temperature and the film-forming speed | rate. FIG. 1A is a schematic graph showing the relationship between the process time and the film formation speed according to the present embodiment. FIG. 4B is a schematic graph showing the relationship between the process time and the film thickness according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, XYZ axis coordinates may be introduced.

  (First embodiment)

  FIG. 1 is a schematic sectional view showing a plasma processing apparatus according to this embodiment.

  The plasma processing apparatus 1 according to this embodiment is, for example, a single-wafer type plasma processing apparatus that performs plasma processing on the substrates 80 one by one. For example, when one substrate 80 is carried into the vacuum container 10 from outside the vacuum container 10, the substrate 80 is subjected to plasma processing on the substrate support 30, and is carried out of the vacuum container 10 after the plasma processing. This series of operations may be repeated for a plurality of substrates 80.

  The plasma processing apparatus 1 includes a film forming unit that forms a film on the substrate 80 by a plasma CVD method and an etching unit that removes the film formed on the substrate 80 by dry etching. The plasma processing apparatus 1 includes a vacuum vessel 10, a support unit 11, a lid unit 12, a shower head 20, a substrate support base 30, a gas supply source 40, a power supply source 50, a temperature measurement device 60, And a control device 70.

  The plasma is formed by a capacitive coupling method, for example, between the shower head 20 and the substrate support 30 (plasma formation space 10p). The plasma is formed by glow discharge, for example. When the plasma processing apparatus 1 functions as a plasma CVD apparatus, for example, the shower head 20 functions as a cathode, and the substrate support 30 functions as an anode. Further, when the plasma processing apparatus 1 functions as an etching apparatus such as RIE (Reactive Ion Etching), for example, the shower head 20 functions as an anode, and the substrate support 30 functions as a cathode.

  The vacuum container 10 surrounds the substrate support 30. The lid 12 faces the vacuum container 10. The support portion 11 is attached to the lid portion 12. For example, a vacuum pump (not shown) such as a turbo molecular pump is connected to the vacuum vessel 10 through a gas exhaust port 10h. Thereby, the inside of the vacuum vessel 10 is maintained in a reduced pressure state. For example, in the example of FIG. 1, the space surrounded by the shower head 20, the vacuum vessel 10, and the support portion 11 is maintained in a reduced pressure state by a vacuum pump.

  In the plasma processing apparatus 1, the space 15 surrounded by the lid portion 12, the shower head 20, and the support portion 11 may be an air atmosphere or a reduced pressure atmosphere. The potential of the lid 12 is, for example, a ground potential. The lid 12 functions as a shield box that shields the high frequency input to the shower head 20. When the space 15 maintains a reduced pressure state, the vacuum vessel 10 and the lid portion 12 can be combined into a vacuum vessel. In this case, at least a part of the space in the vacuum container can be maintained in a reduced pressure state. The vacuum vessel 10 is provided with a pressure gauge 13 for measuring the pressure in the vacuum vessel 10. The pressure gauge 13 is an ionization vacuum gauge, for example.

  The shower head 20 includes a head body 21, a shower plate 22, and an insulating member 27. The shower head 20 is supported by the support portion 11 of the vacuum vessel 10 via the insulating member 27. Thereby, the shower head 20 is insulated from the vacuum vessel 10. The shower head 20 is configured to be detachable from the plasma processing apparatus 1.

  The head body 21 and the shower plate 22 form an internal space 28 of the shower head 20. Process gas is introduced into the internal space 28 via a gas introduction pipe 42 provided inside the head body 21. The final end (gas introduction port) of the gas introduction pipe 42 is located, for example, near the center of the internal space 28. As a result, the process gas is evenly supplied to the internal space 28. The number of gas inlets is not limited to one, and a plurality of gas inlets may be provided in the head main body 21. Further, the head body 21 may be provided with a flow path through which the heat medium flows. Thereby, the conductance of the gas introduction pipe 42 is improved. The heat medium can be adjusted to, for example, 25 ° C. or more and 150 ° C. or less (for example, 80 ° C.) by a temperature control mechanism (not shown) provided outside the vacuum container 10.

  The shower plate 22 is joined so as to be in close contact with the head body 21. The shower plate 22 faces the substrate support base 30. The shower plate 22 has a gas ejection surface 22s on the side opposite to the internal space 28, a plurality of gas ejection holes 23, and a back surface 22r on the internal space 28 side. Each of the plurality of gas ejection holes 23 penetrates the shower plate 22. That is, each of the plurality of gas ejection holes 23 is connected between the internal space 28 and the plasma forming space 10p. The process gas is ejected from the gas ejection surface 22 s through the plurality of gas ejection holes 23 from the internal space 28.

  A heater heating mechanism is not provided in the shower plate 22. This is based on the fact that when the shower plate 22 is provided with a heater, when the high frequency power is supplied to the shower plate 22, the high frequency power is superimposed on the heater, making it difficult to control the heating of the heater. Further, since the shower plate 22 is provided with a plurality of gas ejection holes 23, it is difficult to provide a heater and a heating medium flow path so as to avoid the individual gas ejection holes 23. based on. Therefore, the shower plate 22 is heated from the substrate support table 30 side by the heat of the substrate support table 30 or is heated by plasma or the like formed in the plasma formation space 10p.

  The head main body 21 and the shower plate 22 include, for example, a conductor such as aluminum (Al), an aluminum alloy, and stainless steel. The head body 21 and the shower plate 22 may be subjected to an oxide film treatment as necessary in order to improve the corrosion resistance. The thickness of the shower plate 22 is 5 mm or more and 50 mm or less. The inner diameter of the gas ejection hole 23 is not less than 0.3 mm and not more than 1 mm. Each of the plurality of gas ejection holes 23 has the same inner diameter. The pitch in the X-axis direction and the Y-axis direction of the plurality of gas ejection holes 23 is 3 mm or more and 20 mm or less.

  The substrate support 30 includes a substrate placement surface 30s and a heating mechanism 30h that heats the substrate placement surface 30s. The heating mechanism 30h is, for example, a heater. The substrate 80 is supported by the substrate placement surface 30s. The substrate placement surface 30 s is substantially parallel to the gas ejection surface 22 s of the shower plate 22. The substrate support 30 includes, for example, a conductor. The substrate placement surface 30s may be a conductor or an insulator. For example, an electrostatic chuck may be installed on the substrate placement surface 30s. When the substrate support 30 includes an insulator or an electrostatic chuck, a parasitic capacitance 31 is generated between the substrate 80 and the ground when the substrate support 30 is grounded.

  A power supply source 55 may be connected to the substrate support 30 so that bias power can be supplied to the substrate 80. The power supply source 55 may be, for example, a DC power supply or an AC power supply. For example, when the plasma processing apparatus 1 is used as an etching apparatus such as RIE, power is supplied to the substrate 80 by the power supply source 55 and a bias potential is applied to the substrate 80. The distance between the substrate support 30 and the shower plate 22 is 15 mm or more and 60 mm or less. As an example, the distance between the electrodes is 20 mm. The distance between the substrate support 30 and the shower plate 22 can be automatically adjusted appropriately by the control device 70.

  The substrate placement surface 30s is heated to a temperature in the range of 60 ° C. or more and 500 ° C. or less, for example, by the heating mechanism 30h. The substrate support 30 may be provided with a cooling mechanism for cooling the substrate placement surface 30s.

  In the plasma processing procedure 1, the planar shapes of the substrate placement surface 30 s and the shower plate 22 correspond to the planar shape of the substrate 80. For example, if the substrate 80 is a rectangular substrate applied to a panel or the like, the planar shape of the substrate mounting surface 30s and the shower plate 22 is rectangular. If the substrate 80 is a wafer substrate applied to a semiconductor device or the like, the planar shape of the substrate placement surface 30s and the shower plate 22 is circular. The area of the substrate placement surface 30 s and the shower plate 22 is larger than the area of the substrate 80. The substrate 80 is, for example, a glass substrate having a thickness of 0.5 mm. The size of the substrate 80 is 400 mm × 300 mm or more, for example, 1850 mm × 1500 mm.

  The gas supply source 40 includes a flow meter 41 and a gas introduction pipe 42. The gas supply source 40 supplies process gas (film forming gas, etching gas, inert gas, etc.) to the internal space 28 of the shower head 20. The flow rate of the process gas in the gas introduction pipe 42 is controlled by the flow meter 41.

  The power supply source 50 includes a power source 51, a matching circuit unit 52, and a wiring 53. The wiring 53 is connected near the center of the shower head 20. The matching circuit unit 52 is installed between the shower head 20 and the power source 51. The power source 51 is, for example, an RF power source. The power source 51 may be a VHF power source or a DC power source. When the power source 51 is a DC power source, the matching circuit unit 52 is excluded from the power supply source 50.

  The power supply source 50 generates plasma between the substrate support 30 and the shower plate 22. For example, when process gas is introduced from the shower head 20 into the plasma forming space 10 p and power is supplied from the power source 51 to the shower head 20 via the wiring 53, plasma is generated in the plasma forming space 10 p.

  For example, when the plasma processing apparatus 1 is a film forming apparatus, a film forming gas is introduced into the plasma forming space 10p, and film forming plasma is generated in the plasma forming space 10p to form a film on the substrate 80. On the other hand, when the plasma processing apparatus 1 is an etching apparatus, an etching gas is introduced into the plasma forming space 10p, etching plasma is generated in the plasma forming space 10p, and the film is removed from the substrate 80.

  In the plasma processing apparatus 1, a temperature measuring device 60 that monitors the temperature of the shower plate 22 in a non-contact manner is provided. The temperature measuring device 60 includes a first radiation thermometer 61 and a second radiation thermometer 62. Each of the first radiation thermometer 61 and the second radiation thermometer 62 is an optical fiber type radiation thermometer.

  The 1st radiation thermometer 61 has the optical fiber condensing part 61a and the main-body part 61b. The 2nd radiation thermometer 62 has the optical fiber condensing part 62a and the main-body part 62b. Each of the first radiation thermometer 61 and the second radiation thermometer 62 is disposed outside the vacuum vessel 10 on the back surface 22r side of the shower plate 22.

  Each of the optical fiber condensing units 61 a and 62 a is installed on the lid 12 by a fixing jig 65. For example, the optical fiber condensing unit 61 a is installed at the center of the shower plate 22, and the optical fiber condensing unit 62 a is installed at the end of the shower plate 22. Each of the optical fiber condensing units 61 a and 62 a is installed vertically toward the shower plate 22. Thereby, the in-plane distribution of the temperature of the shower plate 22 can be measured.

  Here, a transparent window member 25 is provided on the head main body 21 facing the optical fiber condensing unit 61a. Further, the head main body 21 is provided with a hole 21 h extending between the transparent window member 25 and the shower plate 22 in the vertical direction. Thereby, the 1st radiation thermometer 61 can receive the radiated light from the back surface 22r of the shower plate 22 which the optical fiber condensing part 61a opposes via the transparent window material 25 and the hole 21h. Thereby, the first radiation thermometer 61 can detect the temperature of the back surface 22r of the shower plate 22. The transparent window material 25 includes sapphire that has high corrosion resistance due to the reactive gas.

  Further, a transparent window member 26 is provided on the head main body 21 facing the optical fiber condensing unit 62a. The transparent window material 26 includes sapphire. The head body 21 is provided with a hole 21 h between the transparent window member 26 and the shower plate 22. Thereby, the 2nd radiation thermometer 62 can detect the temperature of the back surface 22r of the shower plate 22 which the optical fiber condensing part 62a opposes via the transparent window material 26 and the hole 21h.

  The relationship (temperature calibration curve) between the temperature of the gas ejection surface 22s and the temperature of the back surface 22r during the plasma processing is obtained in advance by simulation, experiment, or the like. Thereby, each of the 1st radiation thermometer 61 and the 2nd radiation thermometer 62 detects the temperature of the back surface 22r of the shower plate 22, and can measure the temperature of the gas ejection surface 22s accurately. The temperature calibration curve is stored in the control device 70.

  The optical fiber condensing parts 61 a and 62 a are attached to the cover part 12 having the ground potential and are insulated from the shower head 20. Thereby, even if high frequency power is input to the shower head 20, it is difficult for high frequency power to be applied to the optical fiber condensing units 61a and 62a. Even if the head main body 21 reaches a high temperature of 80 ° C. or higher, the optical fiber condensing portions 61 a and 62 a are separated from the head main body 21 and are thermally insulated from the head main body 21. As a result, the optical fiber condensing units 61 a and 62 a are less susceptible to thermal influence from the head body 21.

  The control device 70 controls the heating mechanism 30h, the power source 51, the matching circuit unit 52, the flow meter 41, the distance between the substrate support 30 and the shower plate 22, and the like. Further, the temperature of the substrate mounting surface 30 s, the temperature of the shower plate 22 measured by the temperature measuring device 60, and the pressure in the vacuum vessel 10 measured by the pressure gauge 13 are sent to the control device 70. The temperature of the substrate placement surface 30s is sampled at a period of 0.1 second.

  The control device 70 generates plasma between the substrate support 30 and the shower plate 22. For example, the control device 70 controls the flow meter 41 to inject process gas from the shower plate 22 toward the substrate support 30. The control device 70 controls the power source 51 and the matching circuit unit 52 to generate plasma between the substrate support 30 and the shower plate 22.

  The plasma includes pre-discharge plasma (first plasma) under pre-discharge conditions (first discharge conditions) and process plasma (second plasma) under plasma processing conditions (second discharge conditions). The preliminary discharge plasma may be different from the plasma processing conditions or the same. In the present embodiment, a case where the preliminary discharge plasma and the plasma processing conditions are different is illustrated. The shower plate 22 having no heating mechanism is heated by the preliminary discharge plasma or the processing plasma. Further, the shower plate 22 is indirectly heated by the radiant heat generated by the substrate support 30 or a gas existing between the shower plate 22 and the substrate support 30 is heated as a heat medium.

  In the plasma processing method using the plasma processing apparatus 1, the substrate placement surface 30s of the substrate support 30 is set to the first temperature in advance. Next, the temperature of the shower plate 22 is set to a temperature (second temperature) higher than the temperature at which the shower plate 22 is heated by the heat of the substrate support 30 by the heat of the substrate support 30 and the preliminary discharge plasma. The Thereafter, the substrate 80 is plasma processed while the shower plate 22 is heated by the heat and processing plasma of the substrate support 30. The control device 70 may issue a warning when the temperature of the shower plate 22 exceeds a desired processing temperature, and interrupt or stop the plasma processing.

  Hereinafter, a plasma processing method using the plasma processing apparatus 1 will be described by taking plasma CVD as an example. As the source gas for film formation, for example, TEOS (tetraethylene orthosilicate) is used. The film formed on the substrate 80 is, for example, a silicon oxide film. As the source gas, organic silicon gas other than TEOS, silane, disilane, or the like may be used. The film formed on the substrate 80 may be a silicon nitride film, an amorphous silicon film, or the like.

  The plasma CVD uses a chemical reaction on the substrate 80 to form a film on the substrate 80. For this reason, the substrate temperature during film formation greatly affects the film formation speed.

  During film formation, reaction on the substrate surface proceeds while the precursor molecules are adsorbed on the substrate 80. For this reason, when the temperature of the substrate 80 changes during film formation, the film formation speed may vary. In the plasma processing apparatus 1, the substrate temperature is heated with high accuracy by the heating mechanism 30 h in order to suppress fluctuations in the deposition rate due to the substrate temperature.

  However, in plasma CVD, in addition to the substrate temperature, the temperature of the shower plate 22 also affects the deposition rate.

  For example, when TEOS gas is used as the process gas, since TEOS is liquid at room temperature, it is vaporized in advance by a vaporizer (not shown) before reaching the flow meter 41 and then introduced into the vacuum vessel 10. The The TEOS gas is used as a raw material gas for forming a gate insulating film of a thin film transistor, for example.

When a raw material gas having a molecular weight larger than that of an inorganic silicon-based gas (for example, SiH ₄ ) and vaporizing a liquid, such as a TEOS gas, is used, the film forming speed is not limited to the substrate temperature but also to the temperature of the shower plate 22. to be influenced. For example, as the temperature of the shower plate 22 decreases, TEOS is more likely to be adsorbed in the inner wall of the shower head 20 or in the gas ejection holes 23, and the amount of TEOS from the shower head 20 toward the substrate 80 decreases.

  That is, even if the temperature of the substrate 80 is kept constant, the amount of TEOS ejected from the shower plate 22 changes when the temperature of the shower plate 22 changes during film formation. For example, when the temperature of the shower plate 22 decreases and the amount of TEOS ejected from the shower plate 22 decreases, the concentration of TEOS reaching the substrate 80 decreases. This slows down the film formation rate. For this reason, in order to maintain a stable film formation rate, it is important how to control not only the substrate temperature but also the temperature of the shower plate 22 to be constant.

  In this embodiment, the temperature of the shower plate 22 is monitored by the temperature measuring device 60, and the shower plate 22 is heated by the heat of the substrate support 30 and the plasma generated in the vacuum vessel 10.

  In plasma CVD, before the substrate 80 is carried into the vacuum vessel 10, a so-called “pre-film formation” may be performed. In the pre-film formation, a film to be formed on the substrate 80 is formed on the inner wall of the vacuum vessel 10, the surface of the member in the vacuum vessel 10, the surface of the shower plate 22, and the like using plasma that is the same as or different from the processing plasma at the time of film formation. To do. By performing the pre-film formation, the inner wall of the vacuum vessel 10, the surface of the member in the vacuum vessel 10, the surface of the shower plate 22, etc. immediately after the start of film formation are in the inner wall of the vacuum vessel 10 during the film formation, The surface of the member, the surface of the shower plate 22 and the like are the same, and the processing plasma is stabilized immediately after the start of film formation.

  By the pre-film formation, the temperature of the shower plate 22 is heated to a predetermined temperature from the start of film formation by the heat of the substrate support 30 and the plasma at the time of pre-film formation. However, since the pre-film formation is a preliminary process before starting the film formation, the processing time is limited. For example, as the pre-film formation takes a longer time, silicon oxide having an excessive thickness accumulates on the inner wall of the vacuum vessel 10, the surface of the member in the vacuum vessel 10, the surface of the shower plate 22, and the like, which causes dust generation. Furthermore, if the pre-film formation is performed until the temperature of the shower plate 22 is saturated, the time required for the pre-film formation becomes long and productivity is lowered. Accordingly, the pre-deposition time is limited, and the shower plate 22 may not be heated sufficiently only by the heat of the substrate support 30 and the plasma during pre-deposition.

  When the film formation is started without the temperature of the shower plate 22 being sufficiently heated, the heat of the substrate support 30 and the processing plasma at the time of film formation cause the vacuum vessel 10 to be formed each time the substrate 80 is subjected to the film formation process. The surface temperature of the inner wall, the members in the vacuum vessel 10 and the shower plate 22 increases. Therefore, even if the film forming conditions other than the shower plate temperature are the same, the film forming speed changes each time the film forming process is repeated. In such a case, the thickness of the film formed on the substrate 80 varies for each film forming process.

In plasma CVD, after the film forming process, fluorine ions, fluorine radicals, or the like obtained by decomposing fluorine-based gas (NF ₃ or the like) may be introduced into the vacuum vessel 10 to clean the inside of the vacuum vessel 10.

  In the cleaning process, the plasma is not generated in the vacuum vessel 10, so that the shower plate 22 is exposed to the cleaning gas. Thereby, the temperature of the shower plate 22 is rapidly cooled. Thereafter, even if the shower plate 22 is heated again by the pre-film formation, the shower plate 22 rapidly cooled with the cleaning gas is not sufficiently heated, and the film formation process is started as it is. As a result, the thickness of the film formed on the substrate 80 varies for each film forming process.

  On the other hand, in the present embodiment, in order to compensate for insufficient heating at the time of pre-film formation, heating plasma in which an inert gas, nitrogen gas, or the like is discharged is used before the film formation is started. Furthermore, in this embodiment, the temperature of the shower plate 22 is monitored without contact. For example, the temperature measuring device 60 monitors the temperature of the shower plate 22 during pre-film formation, when heating plasma is generated, during film formation, and during cleaning.

  A specific example of the plasma processing method according to the present embodiment will be described below.

  2A and 2B are schematic graphs showing the relationship between the process time and the temperature of the shower plate according to this embodiment. FIG. 2B is a graph obtained by enlarging the P1 section of FIG.

  For example, in the section A, the plasma processing apparatus 1 is in a state before starting film formation. Section A is an idle state of the plasma processing apparatus 1. For example, in a state where the substrate 80 is not supported on the substrate support 30, the substrate support 30 is set to a temperature (first temperature) in the range of 60 ° C. to 500 ° C. by the heating mechanism 30 h. The first temperature is 380 ° C. as an example. The shower plate 22 is heated by the heat which the board | substrate support stand 30 has, and is set to 330 degreeC, for example. Even after section A, the temperature of the substrate support 30 is maintained at the first temperature.

  Next, in the section B <b> 1, preliminary discharge plasma is generated between the substrate support base 30 and the shower plate 22 under the preliminary discharge condition in a state where the substrate 80 is not supported on the substrate support base 30. Here, the preliminary discharge plasma includes plasma during pre-deposition and heating plasma. In section A-section B, the substrate may be supported on the substrate support 30. The substrate in this case is, for example, a dummy substrate.

  For example, in the section B1, pre-film formation is performed for 200 seconds in advance. As an example, the pre-film formation conditions are the same as the film formation conditions except for the film formation time and the temperature of the shower plate 22. In the pre-film formation, a silicon oxide film adheres to the inner wall of the vacuum vessel 10, the gas ejection surface 22 s of the shower plate 22, the surface of the substrate support 30, and the like. For example, a silicon oxide film having a thickness of 300 nm is attached to the substrate placement surface 30s. By the pre-film formation, for example, the temperature of the shower plate 22 increases by 5 ° C., and the temperature of the shower plate 22 is set to 335 ° C.

Next, heating plasma by nitrogen plasma is generated, and the shower plate 22 is heated by the heating plasma. An example of the nitrogen plasma conditions is N ₂ flow rate: 5 slm, pressure: 300 Pa, distance between the substrate support 30 and the shower plate 22: 20 mm, and discharge power: 10 kW.

  Thereby, in the section B1, the shower plate 22 is heated by the heat of the substrate support 30, the plasma during pre-deposition, and the heating plasma, and the temperature of the shower plate 22 is higher than 335 ° C. Set to Here, the second temperature (T2) in the first embodiment refers to the heat that the substrate support 30 has in the shower plate 22 and the processing plasma at the time of film formation when film formation is performed on one substrate 80. Is a temperature at which the temperature of the shower plate 22 is saturated. In other words, it is a temperature at which the temperature of the shower plate 22 is maximized during the period in which the single substrate 80 is subjected to film formation. In the example of FIGS. 2A and 2B, the second temperature (T2) is 358 ° C. In the embodiment, this temperature is called a saturation temperature.

  Furthermore, in the section B1, the temperature of the shower plate 22 is monitored by the temperature measuring device 60. When the temperature of the shower plate 22 reaches the second temperature (T2), the heated plasma is automatically extinguished. That is, the process in the section B1 is a process of setting the temperature of the shower plate 22 to the second temperature (T2), and the preliminary discharge condition is adjusted based on the shower plate temperature. After extinguishing the heated plasma, the temperature of the shower plate 22 naturally cools and falls to a third temperature (T3) lower than the second temperature (T2).

  Next, in the section C, the substrate 80 on the substrate support 30 is installed, and a process gas (for example, TEOS) is injected from the shower plate 22 toward the substrate support 30. Further, processing plasma during film formation is generated between the substrate support 30 and the shower plate 22 to perform film formation on the substrate 80 on the substrate support 30.

  In the section C, the film forming process is performed for each of the plurality of substrates 80 one by one. In the present embodiment, this is a “film formation cycle”. For example, in the example of FIGS. 2A and 2B, film formation processing is performed on a total of seven substrates 80 as one film formation cycle. In one film formation cycle, film formation is performed on the seven substrates 80 one by one under the same film formation conditions.

  In section C, each time a film formation process is performed on one substrate 80, the temperature of the shower plate 22 is changed from the third temperature (T3) to the second temperature by the heat of the substrate support 30 and the processing plasma during film formation. It rises to (T2). Here, the temperature of the shower plate 22 during film formation does not exceed the second temperature (T2). This is because the second temperature (T2) is the temperature at which the temperature of the shower plate 22 is maximized during film formation.

  In the film forming cycle, after the film forming process for one substrate 80 is completed, the processing plasma is stopped and the film forming process is ended. Thereby, the temperature of the shower plate 22 falls to the third temperature (T3). Subsequently, the next substrate 80 is supported on the substrate placement surface 30 s, and the film formation process is performed also on the next substrate 80. As a result, the temperature of the shower plate 22 changes from the third temperature (T3) to the second temperature (T2) again. This is repeated for a total of seven substrates 80. In other words, in the film forming cycle, the temperature fluctuation in which the temperature of the shower plate 22 rises and falls between the third temperature (T3) and the second temperature (T2) is repeated seven times. Thereafter, the processing plasma is extinguished.

  Next, in the section D, cleaning gas such as fluorine ions and fluorine radicals is introduced into the vacuum vessel 10. Thereby, cleaning of the inner wall of the vacuum vessel 10, the gas ejection surface 22s of the shower plate 22, the surface of the substrate support 30 and the like is performed. For example, the silicon oxide film deposited on the inner wall of the vacuum vessel 10, the gas ejection surface 22 s of the shower plate 22, the surface of the substrate support 30, etc. is removed. At this time, the shower plate 22 exposed to the cleaning gas is rapidly cooled to a temperature lower than the third temperature.

  Next, in the section B2, the temperature of the shower plate 22 is changed to the second temperature (T2) by the heat of the substrate support 30 and the preliminary discharge plasma in a state where the substrate 80 is not supported on the substrate support 30. The shower plate 22 is heated again. Thereafter, the film forming cycle of the section C is performed again.

  Even if one film formation cycle is repeated a plurality of times by the above plasma processing method, the film formation conditions for each substrate 80 in each film formation cycle are the same, and the film formation speed when forming a film on each substrate 80 is the same. In addition, the thickness of the film formed on each substrate 80 is less likely to vary.

  Next, plasma processing according to a comparative example will be described.

  FIGS. 3A and 3B are schematic graphs showing the relationship between the process time and the temperature of the shower plate according to the comparative example. FIG.3 (b) is the graph which expanded the P1 area of Fig.3 (a).

  Also in the comparative example, in the section A, the substrate support base 30 is set to the first temperature (T1). After the section A, the temperature of the substrate support 30 is maintained at the first temperature.

  Next, in the section B1, preliminary discharge plasma is generated. The preliminary discharge plasma of the comparative example is a plasma only for pre-deposition, or plasma during pre-deposition and heating plasma. However, it is assumed that the generation time of the heating plasma in the comparative example is shorter than that in the present embodiment. Therefore, in the comparative example, film formation is started in a state where the temperature of the shower plate 22 does not reach the second temperature (T2).

  Thereby, in the comparative example, even if the shower plate 22 is heated by the heat of the substrate support 30 and the processing plasma at the time of film formation in the section C, the temperature of the shower plate 22 is the second temperature in the film formation cycle. It becomes difficult to reach (T2). For example, in the example of FIGS. 3A and 3B, the temperature of the shower plate 22 increases stepwise for each film forming process in the film forming cycle, and each time the film forming cycle is repeated, The temperature rises relatively. In the comparative example, the temperature of the shower plate 22 becomes the second temperature (T2) when the film formation process is performed on the last substrate 80 in the fourth film formation cycle.

  Therefore, in the comparative example, the film forming conditions for each substrate 80 in each film forming cycle are different, and the film forming speed and the thickness of the film formed on each substrate 80 vary.

  FIG. 4A is a schematic graph showing the relationship between the process time and the film formation speed according to the present embodiment. FIG. 4B is a schematic graph showing the relationship between the process time and the film formation rate according to the comparative example.

  As shown in FIG. 4A, in this embodiment, the film formation speed when forming a film on each substrate 80 is stable in each film formation cycle. On the other hand, in the comparative example shown in FIG. 4B, the film formation rate when forming a film on each substrate 80 gradually increases in each film formation cycle. Furthermore, in the comparative example, every time the film formation cycle is repeated, the film formation speed when forming a film on each substrate 80 is relatively increased.

  As described above, in this embodiment, in order to suppress variation in the film formation rate when the film formation process is performed on each substrate 80, the temperature of the shower plate 22 is increased by the preliminary discharge plasma before the film formation cycle is started. Is raised to the second temperature (T2).

  Accordingly, since the temperature of the shower plate 22 is the second temperature (T2), which is the maximum temperature, immediately after the film formation cycle, the temperature of the shower plate 22 is unlikely to vary in each film formation cycle. As a result, the film formation speed when forming a film on each substrate 80 and the thickness of the film formed on each substrate 80 are less likely to vary.

  Further, in the present embodiment, the shower plate 22 is not provided with a heater mechanism. Thereby, when the shower plate 22 is washed, the operation of removing the heater from the shower plate 22 is not required. If a heater is provided in the shower plate 22, there may be temperature spots in the shower plate 22 depending on the vicinity of the heater and the distance from the heater, but such a possibility does not occur.

  In the present embodiment, the temperature of the shower plate 22 is measured without contact. For example, the temperature of the shower plate 22 is measured by a temperature measuring device 60 disposed outside the vacuum vessel 10 on the back side of the shower plate 22. Thereby, the temperature measuring device 60 is configured not to come into contact with the shower plate 22, and the installation of the temperature measuring device 60 does not cause a temperature spot on the shower plate 22.

  Further, since the temperature of the shower plate 22 is directly measured by the temperature measuring device 60, it is not necessary to investigate the relationship between the temperature of the shower plate 22 and the discharge conditions by trial and error, and no prior experiment, simulation, or the like is required. .

  When the temperature of the shower plate 22 reaches the second temperature (T2) only by the pre-deposition, it is not necessary to generate the heating plasma, and the film formation cycle may be started after the pre-deposition.

  (Second Embodiment)

  In the second embodiment, the second temperature (T2) is not the saturation temperature of the shower plate 22, but is higher than the first temperature (T1) and equal to or lower than the saturation temperature. In the second embodiment, the film forming cycle is started from a state where the temperature of the shower plate 22 is lower than the saturation temperature. In this case, the temperature of the shower plate 22 varies for each film forming process, and the film forming speed may vary. However, by grasping the relationship between the temperature of the shower plate 22 and the film formation speed before the film formation process, variations in film thickness can be suppressed.

  FIG. 5 is a schematic graph showing the relationship between the shower plate temperature and the film formation rate.

  As shown in FIG. 5, the film formation rate increases as the temperature of the shower plate 22 increases. The reason is as described above. Here, the film formation conditions other than the shower plate temperature are the same. This result shows that the thickness of the film formed on the substrate 80 can be controlled by controlling the film formation time according to the temperature of the shower plate 22 even if the temperature of the shower plate 22 is different for each film formation process. means.

  FIG. 6A is a schematic graph showing the relationship between the process time and the film formation speed according to this embodiment. FIG. 6B is a schematic graph showing the relationship between the process time and the film thickness according to this embodiment.

  In the example of FIG. 6A, the deposition rate increases for each deposition process in the deposition cycle. This is because the temperature of the shower plate 22 increases with each film forming process.

  However, even in such a case, in each film forming cycle, the film forming speed for each film forming process is calculated from the calibration curve (FIG. 5), and the film forming time is calculated from the calculated film forming speed, whereby each substrate 80 is obtained. A film having the same thickness can be formed.

  For example, in each film forming cycle, when the temperature of the shower plate 22 increases and the film forming speed increases for each film forming process, the film forming time increases as the number of film forming processes increases in each film forming cycle. shorten. Thereby, the film thickness for each substrate 80 in each film formation cycle becomes uniform (FIG. 6B).

  Furthermore, in each film forming cycle, the temperature of the shower plate 22 may fluctuate due to an unexpected reason. For example, there is a possibility that the temperature of the shower plate 22 fluctuates due to a change in the processing time for each substrate 80, an increase in the interval at which the substrates are transferred to the transfer chamber, or an unstable output of the heating mechanism 30h. There is. Even in such a case, a film having the same thickness is formed on each substrate 80 by calculating the film forming speed for each film forming process from the calibration curve (FIG. 5) and calculating the film forming time from the calculated film forming speed. be able to.

  In addition to the film formation time, at least the film formation condition parameters such as the discharge power, the reaction gas flow rate, the distance between the shower plate 22 and the substrate support 30, the film formation pressure, etc., depending on the temperature of the shower plate 22. By changing one, a film having the same thickness can be formed on each substrate 80.

  An example of the film formation condition parameters is shown below. The following film formation conditions are also examples of the film formation conditions (section C) of the first embodiment.

Film: TEOS silicon oxide film Source gas (gas flow rate): TEOS (0.1 slm to ₂ slm), O ₂ ( ₂ slm to 60 slm)
Discharge power: 0.5 kW to 17 kW Distance between shower plate and substrate support: 15 mm to 35 mm Deposition pressure: 50 Pa to 400 Pa

Film: Silicon oxide film Source gas (gas flow rate): SiH ₄ (0.1 slm to 5 slm), N ₂ O ( ₂ slm to 60 slm), Ar (2 slm to 60 slm)
Discharge power: 0.5 kW to 17 kW Distance between shower plate and substrate support: 15 mm to 35 mm Deposition pressure: 50 Pa to 400 Pa

Film: Amorphous silicon film Source gas (gas flow rate): SiH ₄ (0.1 slm to 3 slm), Ar (2 slm to 60 slm)
Discharge power: 0.1 kW to 5 kW Distance between shower plate and substrate support: 15 mm to 35 mm Deposition pressure: 50 Pa to 400 Pa

Film: Silicon nitride film Source gas (gas flow rate): SiH ₄ (0.1 slm to 5 slm), NH ₃ ( ₂ slm to 60 slm), N ₂ ( ₂ slm to 60 slm),
Discharge power: 0.5 kW to 17 kW Distance between shower plate and substrate support: 15 mm to 35 mm Deposition pressure: 50 Pa to 400 Pa

  For example, when the temperature of the shower plate 22 is within a range of ± 10 ° C. with respect to a temperature (eg, 348 ° C.) lower than the saturation temperature (eg, 358 ° C.) during the film forming process, The film thickness can be controlled by adjustment. For example, when the temperature of the shower plate 22 is relatively low in the above range, the film formation rate can be increased by increasing the discharge power. Conversely, when the temperature of the shower plate 22 is relatively high in the above range, the film formation rate can be reduced by reducing the discharge power. Thereby, a film having the same thickness can be formed on each substrate 80.

  Further, when the temperature of the shower plate 22 is within a range of ± 10 ° C. with respect to a temperature (for example, 348 ° C.) lower than the saturation temperature during the film forming process, the film thickness is controlled by adjusting the gas flow rate. Is possible. For example, when the temperature of the shower plate 22 is relatively low in the above range, the deposition rate can be increased by increasing the gas flow rate. Conversely, when the temperature of the shower plate 22 is relatively high in the above range, the film formation rate can be reduced by reducing the gas flow rate. Thereby, a film having the same thickness can be formed on each substrate 80.

  Furthermore, in addition to controlling the film thickness, the film quality can also be controlled. For example, when the temperature of the shower plate 22 is within a range of ± 10 ° C. based on a temperature (for example, 348 ° C.) lower than the saturation temperature during the film formation process, the film quality can be adjusted by adjusting the discharge power. Is possible.

  For example, in the case where a silicon nitride film is formed on the substrate 80, if the temperature of the shower plate 22 is relatively low in the above range, if the film is formed in this state, the film density becomes low. In this case, the film density can be returned to a predetermined range by increasing the discharge power. On the contrary, if the film is formed in a state where the temperature of the shower plate 22 is relatively high within the above range, the film density becomes high. In that case, the film density can be returned to a predetermined range by reducing the discharge power.

  On the other hand, in the case where the silicon oxide film is formed on the substrate 80, if the temperature of the shower plate 22 is relatively low in the above range, the film density is increased if the film is formed in this state. In this case, the film density can be returned to a predetermined range by reducing the discharge power.

  Thereby, a film having the same film quality can be formed on each substrate 80.

Further, when the temperature of the shower plate 22 overshoots the saturation temperature due to abnormal discharge or the like, the temperature of the shower plate 22 can be lowered by introducing cooling gas into the shower plate 22. For example, when the temperature of the shower plate 22 becomes 10 ° C. or more higher than the saturation temperature, a cooling gas is introduced into the shower plate 22 to cool the shower plate 22 to the saturation temperature. Here, the cooling gas is at least one gas such as N ₂ , Ar, H ₂ , and He.

  As mentioned above, although embodiment of this invention was described, this invention is not limited only to the above-mentioned embodiment, Of course, a various change can be added.

  For example, in the sections B1 and B2, the pre-deposition may be performed after the heating plasma is generated. Thus, after the silicon oxide film adheres to the inner wall of the vacuum vessel 10, the gas injection surface 22 s of the shower plate 22, the surface of the substrate support 30, and the like, these surfaces are not heated, but these surfaces are not heated. After being heated, a silicon oxide film adheres to these surfaces and the like. Thereby, peeling (dust generation) of the silicon oxide film from these surfaces and the like is suppressed.

  When the plasma processing apparatus 1 is applied to dry etching, the temperature of the shower plate 22 is adjusted to a temperature at which the temperature of the shower plate 22 is maximized during the etching process before the etching cycle is started. After this, if an etching cycle is started, it goes without saying that the same etching rate can be obtained for each etching process in each etching cycle.

DESCRIPTION OF SYMBOLS 1 ... Plasma processing apparatus 10 ... Vacuum container 10h ... Gas exhaust port 10p ... Plasma formation space 11 ... Support part 12 ... Cover part 13 ... Pressure gauge 15 ... Space 20 ... Shower head 21 ... Head main body 21h ... Hole 22 ... Shower plate 22s ... Gas ejection surface 22r ... Back surface 23 ... Gas ejection holes 25, 26 ... Transparent window material 27 ... Insulating member 28 ... Internal space 30 ... Substrate support 30s ... Substrate mounting surface 30h ... Heating mechanism 31 ... Capacity 40 ... Gas supply Source 41 ... Flow meter 42 ... Gas introduction pipe 50, 55 ... Power supply source 51 ... Power source 52 ... Matching circuit unit 53 ... Wiring 60 ... Temperature measuring device 61 ... First radiation thermometer 61a ... Optical fiber condensing unit 61b ... Main body Part 62 ... Second radiation thermometer 62a ... Optical fiber condensing part 62b ... Main body part 65 ... Fixing jig 70 ... Control device 80 ... Substrate

Claims (7)

Heating the substrate support placed in the vacuum vessel to a first temperature;
A first plasma according to a first discharge condition is generated between the substrate support and a shower plate made of a conductor facing the substrate support, and the shower plate is heated by the heat and the first plasma of the substrate support. Heat the
Non-contact monitoring of the temperature of the shower plate by directly receiving the radiation emitted from the back surface of the shower plate by a radiation thermometer disposed outside the vacuum vessel on the back side of the shower plate And
After the temperature of the shower plate has reached the second temperature higher than the temperature heated by the substrate support table of the heat formed toward a plurality of gas ejection holes provided in the shower plate to the substrate support table The film-forming gas is injected while suppressing the adsorption of the film gas into the inner wall of the shower plate and the plurality of gas injection holes, and a second discharge condition is generated between the substrate support and the shower plate. A plasma processing method of generating a plasma and forming a film on the substrate supported by the substrate support by the second plasma. The plasma processing method according to claim 1,
In the step of processing the substrate, the second temperature is a temperature at which the temperature of the shower plate is maximized in the step of processing the substrate. The plasma processing method according to claim 1,
In the plasma processing step, the second discharge condition includes a discharge power, a reaction gas flow rate, and a processing time, and the substrate is processed for each of a plurality of substrates, and the second temperature changes each time the substrate is processed. In some cases, the substrate is processed by changing at least one of the discharge power, the reaction gas flow rate, and the processing time according to the value of the second temperature. The plasma processing method according to any one of claims 1 to 3, further comprising:
In the plasma processing step, the substrate is processed for each of a plurality of substrates, the substrate is processed for each of a plurality of substrates, and then a cleaning gas is jetted into the vacuum vessel to clean the inside of the vacuum vessel. A plasma processing method according to any one of claims 1 to 4,
The first discharge condition is:
Heating the shower plate while forming the same film as the film formed on the substrate on the inner wall of the vacuum vessel and the shower plate;
And a step of heating the shower plate with a heating plasma in which an inert gas or a nitrogen gas is discharged . A plasma processing method according to any one of claims 1 to 5,
As the radiation thermometer,
The plasma processing method using the 1st radiation thermometer arrange | positioned at the back side of the center part of the said shower plate, and the 2nd radiation thermometer arrange | positioned at the back side of the edge part of the said shower plate . A vacuum vessel in which a reduced pressure state is maintained;
It is arrange | positioned in the said vacuum vessel, has a substrate mounting surface and a heating mechanism, can set the said substrate mounting surface to 1st temperature with the said heating mechanism, and can support a board | substrate. A substrate support,
A conductor shower plate facing the substrate support;
A power supply source for generating plasma between the substrate support and the shower plate;
The temperature of the shower plate is measured in a non-contact manner by directly receiving the radiation emitted from the back surface of the shower plate by a radiation thermometer disposed outside the vacuum vessel on the back surface side of the shower plate. A temperature measuring device,
The temperature of the shower plate is monitored by the temperature measuring device to generate a first plasma according to a first discharge condition between the substrate support and the shower plate, and the heat of the substrate support and the first A plurality of gas jets provided on the shower plate after the shower plate is heated by plasma and the temperature of the shower plate reaches a second temperature higher than the temperature heated by the heat of the substrate support. The film-forming gas is sprayed toward the substrate support while suppressing the adsorption of the film-forming gas from the holes into the inner wall of the shower plate and the plurality of gas ejection holes, and the substrate support and the shower plate by generating second plasma by the second discharge condition between, it can be deposited processing the substrate by the second plasma Plasma processing apparatus and a control device.

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