Substrate holding mechanism, film forming apparatus, and film forming method

Abstract

The invention provides a substrate holding mechanism, a film forming apparatus and a film forming method. The substrate holding mechanism is capable of electrostatically adsorbing a substrate to be processed when a conductive film is formed by plasma CVD or plasma ALD, and the film forming apparatus uses the substrate holding mechanism. The substrate holding mechanism includes: a stage configured from a dielectric and supporting a substrate to be processed; the adsorption electrode is arranged in the objective table; and a heater that heats the stage and electrostatically adsorbs the substrate to be processed to the surface of the stage by Johnson Rahbek force, the stage having: a ring-shaped adhesion region that is positioned on the surface of the stage at a position corresponding to the outer periphery of the substrate to be processed and that adheres to the substrate to be processed; a function of preventing a raw material gas for forming a conductive film from bypassing to the back surface side of the substrate to be processed; and a groove part which is provided in an annular shape in a portion of the surface of the stage outside of the adhesion region, and which is capable of accumulating a conductive deposition film generated by the raw material gas.

Description

[0001] This application is a divisional application of an application with an application date of November 26, 2019, application number 201911173253.8, and invention name “Substrate holding mechanism and film forming device”. Technical Field

[0002] The present disclosure relates to a substrate holding mechanism and a film forming apparatus. Background Art

[0003] In the manufacturing process of semiconductor devices, plasma processing such as dry etching, sputtering, and plasma CVD is often used for semiconductor wafers as substrates to be processed.

[0004] In such plasma processing, an electrostatic chuck using electrostatic attraction is often used to hold a substrate to be processed (for example, Patent Documents 1 to 5).

[0005] On the other hand, when a conductive film is formed by an isotropic film forming method such as plasma CVD or plasma ALD, the electrostatic chuck function may not be able to be utilized because the source gas bypasses the holding surface of the substrate to be processed and a conductive deposited film is accumulated. Therefore, when a conductive film is formed by plasma CVD or plasma ALD, the plasma treatment is performed without using an electrostatic chuck and the substrate is placed on a substrate mounting table.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 5-67673

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 7-130830

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 9-260472

[0009] Patent Document 4: Japanese Patent Application Publication No. 2003-297912

[0010] Patent Document 5: Japanese Patent Application Publication No. 2009-21592 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] The present disclosure provides a substrate holding mechanism capable of electrostatically adsorbing a substrate to be processed when forming a conductive film by plasma CVD or plasma ALD, and a film forming apparatus using the substrate holding mechanism.

[0013] Solutions for solving problems

[0014] A technical solution disclosed in the present invention relates to a substrate holding mechanism, which holds a processed substrate when a conductive film is formed by plasma CVD or plasma ALD, wherein the substrate holding mechanism includes: a stage, which is composed of a dielectric and is used to support the processed substrate; an adsorption electrode, which is arranged in the stage and is used to electrostatically adsorb the processed substrate; and a heater, which heats the stage and applies a DC voltage to the adsorption electrode, thereby electrostatically adsorbing the processed substrate to the surface of the stage by using the Johnson-Rahbek force, wherein the stage has: a close contact area, which is annular and located at a position on the surface of the stage corresponding to the outer periphery of the processed substrate, and is in close contact with the processed substrate, and has the function of preventing a raw material gas used to form the conductive film from bypassing the back side of the processed substrate; and a groove portion, which is annular and is arranged on the surface of the stage at a portion outside the close contact area, and can accumulate a conductive deposited film generated by the raw material gas.

[0015] Effects of the Invention

[0016] According to the present disclosure, there are provided a substrate holding mechanism capable of electrostatically adsorbing a substrate to be processed when forming a conductive film by plasma CVD or plasma ALD, and a film forming apparatus using the substrate holding mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a perspective view showing a substrate holding mechanism according to one embodiment.

[0018] Figure 2 It is a plan view showing a substrate holding mechanism according to one embodiment.

[0019] Figure 3 It is a cross-sectional view showing a substrate holding mechanism according to one embodiment.

[0020] Figure 4 This is a cross-sectional view showing an enlarged view of a main part of a substrate holding mechanism according to an embodiment.

[0021] Figure 5 It is a cross-sectional view showing a part of a substrate holding mechanism according to another embodiment.

[0022] Figure 6 Yes means Figure 5 2 is a cross-sectional view of a modified example of a substrate holding mechanism according to another embodiment shown.

[0023] Figure 7 Yes means Figure 5 A cross-sectional view of another modified example of a substrate holding mechanism according to another embodiment is shown.

[0024] Figure 8 It is a cross-sectional view showing a film forming apparatus to which a substrate holding mechanism according to an embodiment is applied. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments will be described with reference to the drawings.

[0026] <Substrate holding mechanism>

[0027] First, a substrate holding mechanism according to an embodiment will be described. Figure 1 is a perspective view showing a substrate holding mechanism according to one embodiment. Figure 2 is a top view showing a substrate holding mechanism according to one embodiment, Figure 3 is a cross-sectional view showing a substrate holding mechanism according to one embodiment, Figure 4 This is a cross-sectional view showing an enlarged view of a main part of a substrate holding mechanism according to an embodiment.

[0028] The substrate holding mechanism 1 holds the semiconductor wafer (hereinafter simply referred to as the wafer) as a substrate to be processed in a film forming device that forms a conductive film on the semiconductor wafer (hereinafter simply referred to as the wafer) as a substrate to be processed by plasma CVD or plasma ALD in a chamber maintained in a vacuum. Examples of the conductive film to be formed include Ti film, TiN film, W film, Ni film, etc.

[0029] The substrate holding mechanism 1 includes a stage 2 for placing (supporting) a wafer W as a substrate to be processed, and a support member 3 attached to the center of the back side of the stage 2 so as to extend downward.

[0030] The stage 2 is formed of a dielectric, such as a ceramic such as aluminum nitride (AlN). An adsorption electrode 11 for adsorbing the wafer W is buried in the interior of the stage 2 near its surface, thereby forming an electrostatic chuck. The adsorption electrode 11 is formed of, for example, Mo, and is formed in, for example, a mesh shape. A DC power supply 14 is connected to the adsorption electrode 11 via a power supply line 13, and a DC voltage is applied to the adsorption electrode 11 to electrostatically adsorb the wafer W. The DC power supply 14 can be turned on and off by a switch (not shown). In addition, the adsorption electrode 11 also functions as a ground electrode relative to the plasma.

[0031] A heater 12 is buried below the adsorption electrode 11 inside the stage 2. A heater power supply 16 is connected to the heater 12 via a power supply line 15, and the temperature of the stage 2 is controlled by controlling the output of the heater 12 based on the detection value of a temperature sensor (not shown) such as a thermocouple.

[0032] On the surface of the stage 2, a sealing area 21 is formed in a circular ring shape and in close contact with the wafer W at a position corresponding to the outer periphery of the wafer W. The sealing area 21 has the function of preventing the raw material gas used to form the conductive film from bypassing the back side of the wafer W. Thus, the formation of a conductive deposited film on the back side of the wafer can be suppressed. From the perspective of exerting such a function, the width X1 of the sealing area 21 is preferably 10 mm to 40 mm. The sealing area 21 is formed in such a way that its outer diameter is smaller than the diameter of the wafer W. This is because, when the outer diameter of the sealing area 21 is larger than the diameter of the wafer W, it will cause the deposit to climb onto the wafer W.

[0033] An adsorption surface 22 for adsorbing the wafer W is formed on the inner side of the close-fitting area 21, and the adsorption surface 22 is formed to be about 20 μm to 70 μm lower than the close-fitting area 21 to form a concave portion. The adsorption surface 22 is, for example, an embossed surface formed by applying embossing processing. A space 23 is formed between the adsorption surface 22 and the back side of the wafer. A gas inlet 24 is formed on the adsorption surface 22, so that the back side gas supplied from the gas supply source 18 via the gas supply path 17 is supplied from the gas inlet 24 to the space 23. The gas supply source 18, the gas supply path 17, and the gas inlet 24 constitute a back side gas supply mechanism. As the back side gas, a gas with high thermal conductivity such as helium (He) gas is used, and the heat of the stage 2 is transferred to the wafer W by means of the back side gas.

[0034] The pressure of the back side gas is preferably set high, at 20 Torr to 100 Torr, so that the amount of leaked gas can be increased and the intrusion of the source gas to the back side of the wafer W can be suppressed.

[0035] A groove 25 is formed on the surface of the stage 2 outside the close contact area 21. The groove 25 is provided in an annular shape and can accumulate a conductive deposited film generated by a raw material gas for forming a conductive film. The conductive deposited film is accumulated on the surface of the stage 2 outside the close contact area 21. Figure 4 As shown, by providing the groove 25, the conductive deposited film 28 is accumulated in the groove 25. Therefore, even if the conductive deposited film 28 increases with time, it is possible to suppress the formation of the conductive deposited film in the close contact area 21 when the wafer W is shifted during loading, and the escape of the charge of the electrostatic chuck can be suppressed. From this point of view, it is preferred that the depth (distance d (refer to Figure 4 )) is in the range of 20 μm to 100 μm, for example, 50 μm. Furthermore, the width of the groove 25 is preferably in the range of 0.5 mm to 2 mm.

[0036] The portion of the surface of the stage 2 outside the groove 25 is formed higher than the close contact area 21 and serves as a guide 26 for guiding the wafer W. The side wall portion connecting the groove 25 to the guide 26 is, for example, tapered.

[0037] A lift pin through hole 27 is formed on the outer side of the close contact area 21 of the stage 2 so as to penetrate in the vertical direction. A lift pin (not shown) is inserted through the lift pin through hole 27 so as to be able to be raised and lowered, and the lift pin protrudes from the wafer placement surface (the surface of the close contact area 21) when the wafer is transferred to the stage 2.

[0038] From the viewpoint of effectively correcting the warpage of the wafer W as the substrate to be processed, the wafer W is adsorbed by the Johnson-Rabbeck force by supplying power to the adsorption electrode 11. The adsorption of the wafer W by the Johnson-Rabbeck force is performed by making the dielectric material constituting the stage 2 have some conductivity, that is, the volume resistivity at the film forming temperature is 1×10 9 Ω·cm~1×10 12 Ω·cm, which enables the charge to move. By using the Johnson-Rabbek force, the accumulated amount of charge can be increased, and an adsorption force higher than the Coulomb force can be obtained. By using AlN as a dielectric, a volume resistivity in the above range can be obtained, and the Johnson-Rabbek force can be effectively exerted. By adding appropriate additives to AlN according to the operating temperature, the volume resistivity can be adjusted to effectively exert the Johnson-Rabbek force. In order to effectively adsorb the wafer using the Johnson-Rabbek force, it is preferred to set the distance a from the adsorption electrode 11 to the adsorption surface of the wafer W to 0.5mm to 1.5mm.

[0039] The temperature of the surface of the stage 2 heated by the heater 12, that is, the film forming temperature of the wafer W, is preferably 200° C. or higher. When the heating temperature is 200° C. or higher, the warping of the wafer W as a substrate to be processed tends to increase, and the necessity of the function as an electrostatic chuck increases. The film forming temperature of the wafer W is more preferably 400° C. or higher, and further preferably 400° C. to 700° C.

[0040] like Figure 4 As shown, the adsorption electrode 11 is preferably arranged in such a manner that the distance b between the adsorption electrode 11 and the conductive deposited film 28 formed on the outside of the close contact area 21 is greater than the distance a between the adsorption electrode 11 and the wafer W, that is, b>a. As a preferred example, a is 1 mm and b is 2 mm or more. In this way, the leakage current to the conductive deposited film 28 can be effectively suppressed.

[0041] Furthermore, as described above, the adsorption electrode 11 also functions as a ground electrode for plasma. However, since the diameter of the adsorption electrode 11 is limited so as to satisfy b>a, the plasma region also corresponds to the diameter of the adsorption electrode 11. Therefore, if it is desired to further expand the plasma region, Figure 5 As shown, the auxiliary electrode 19 may be provided outside the adsorption electrode 11 so as to be electrically connected to the adsorption electrode 11 .

[0042] At this time, the auxiliary electrode 19 is provided below the adsorption electrode 11 and at a position sufficiently away from the conductive deposited film 28 (that is, a position where the distance between the auxiliary electrode 19 and the conductive deposited film 28 is greater than the distance a (see Figure 4 )). Moreover, if Figure 6 As shown in FIG. 1 , an adsorption electrode 11a formed by integrating an auxiliary electrode may also be provided. Figure 7 As shown, the auxiliary electrode 19 can also be switched on and off by using a switch 19a.

[0043] Next, the operation and effects of the substrate holding mechanism 1 configured as described above will be described.

[0044] When a substrate to be processed, such as a wafer, is subjected to plasma treatment, an electrostatic chuck has been used to adsorb the substrate to be processed. On the other hand, when a conductive film is formed by an isotropic film forming method such as plasma CVD or plasma ALD, the raw material gas bypasses the holding surface of the substrate to be processed to cause the conductive deposited film to accumulate, and the electrostatic chuck function cannot be exerted. Therefore, the electrostatic chuck function may not be exerted. Therefore, when a conductive film is formed by plasma CVD or plasma ALD, an electrostatic chuck is not used.

[0045] However, recently, with the development of device generations, wafers are prone to warping due to device changes and the use of new device materials. Due to the warping of the wafer, uniformity degradation and sparks between the wafer and the stage occur.

[0046] Therefore, in the present embodiment, the wafer W as the substrate to be processed can be electrostatically attracted in the substrate holding mechanism used when forming a conductive film by plasma CVD or plasma ALD.

[0047] That is, the substrate adsorption mechanism 1 includes: a stage 2, which is made of a dielectric and is used to place the wafer W; and an adsorption electrode 11, which is provided in the stage and is used to electrostatically adsorb the wafer W, and the substrate adsorption mechanism 1 uses the Johnson-Rabbeck force to adsorb the wafer W. In addition, the stage 2 has a circular ring-shaped close contact area 21 at a position corresponding to the outer periphery of the wafer W on its surface, and the wafer W is closely attached to the close contact area 21, and the close contact area 21 has a function of preventing the raw material gas for forming the conductive film from bypassing the back side of the wafer W. In addition, the stage 2 has a groove portion 25, which is provided in a circular ring shape on the surface of the stage 2 at the outer side of the close contact area 21, and can accumulate the conductive deposited film generated by the raw material gas for forming the conductive film.

[0048] In this way, since the adsorption force on the wafer W is increased by utilizing the Johnson-Rabbeck force, and since the close contact region 21 having the function of preventing the source gas from bypassing the back side of the wafer W and the groove portion 25 outside thereof capable of accumulating the conductive deposited film are provided, the formation of the conductive deposited film on the back side of the wafer W can be suppressed. Therefore, when the conductive film is formed by plasma CVD or plasma ALD, leakage current is not likely to be generated, and the wafer W can be reliably electrostatically adsorbed. Furthermore, since the wafer W can be electrostatically adsorbed by utilizing the high adsorption force generated by the Johnson-Rabbeck force, even if the wafer W is warped, the wafer W can be adsorbed and held in a state where the warping is corrected.

[0049] The warpage of the wafer W tends to increase when the heating temperature of the stage 2 heated by the heater 12, that is, the film forming temperature of the wafer W, is 200°C or higher, so the heating temperature is preferably 200°C or higher, more preferably 400°C or higher, and further preferably 400°C to 700°C.

[0050] The width X1 of the close contact area 21 is preferably 10 mm to 40 mm. This can improve the effect of suppressing the raw material gas from bypassing the back of the wafer W, and can effectively suppress the formation of the conductive deposited film on the back of the wafer W. In addition, by setting the depth of the groove 25 to a range of 20 μm to 100 μm and the width of the groove 25 to a range of 0.5 mm to 2 mm, the effect of suppressing the formation of the conductive deposited film in the close contact area 21 can be further improved.

[0051] Furthermore, when the wafer W is electrostatically adsorbed, the gas pressure of the back gas for heat conduction introduced into the space 23 on the back side of the wafer W is set higher to 30 Torr to 70 Torr, thereby increasing the amount of leaked gas and further effectively suppressing the intrusion of the raw material gas to the back side of the wafer W.

[0052] Furthermore, it is preferable to arrange the adsorption electrode 11 in such a manner that the relationship between the distance b between the adsorption electrode 11 and the conductive deposited film 28 formed outside the close contact area 21 and the distance a between the adsorption electrode 11 and the wafer W is b>a. Thus, the leakage current to the conductive deposited film 28 can be effectively suppressed, and the reduction in the function of the electrostatic chuck can be suppressed.

[0053] Furthermore, since the adsorption electrode 11 also functions as a ground electrode for plasma, it is not necessary to separately provide a ground electrode, thereby reducing the space for electrodes and wiring.

[0054] In this case, the plasma region is limited by the diameter of the adsorption electrode 11 formed so as to satisfy b>a. However, the plasma region can be expanded by providing an auxiliary electrode outside the adsorption electrode 11 at a position sufficiently away from the conductive deposited film 28 .

[0055] <Film forming equipment>

[0056] Next, a film forming apparatus to which a substrate holding mechanism according to an embodiment is applied will be described.

[0057] Figure 8 It is a cross-sectional view showing a film forming apparatus to which a substrate holding mechanism according to an embodiment is applied.

[0058] The film forming apparatus 100 forms a Ti film by plasma CVD or plasma ALD by forming a high frequency electric field on parallel plate electrodes.

[0059] The film forming apparatus 100 has a substantially cylindrical metal chamber 101. The chamber 101 has an exhaust chamber 151 that protrudes downward in a manner covering a circular hole 150 formed in the center of a bottom wall 101b of the main body. An exhaust pipe 152 is connected to the side of the exhaust chamber 151, and an exhaust device 153 having a pressure control valve and a vacuum pump is provided on the exhaust pipe 152. The exhaust device 153 can be used to exhaust the chamber 101 and control the pressure in the chamber 101 to a reduced pressure state of a predetermined pressure.

[0060] The side wall of the chamber 101 is provided with an input / output port 157 for inputting and outputting wafers W between the chamber 101 and a wafer transfer chamber (not shown) provided adjacent to the chamber 101 , and a gate valve 158 for opening and closing the input / output port 157 .

[0061] A substrate mounting mechanism 1 according to one embodiment is provided inside the chamber 101 for adsorbing and holding a wafer W as a substrate to be processed. The substrate mounting mechanism 1 has the above-mentioned structure, so the description thereof is omitted. The support member 3 of the substrate holding mechanism 1 is attached to the bottom wall of the exhaust chamber 151 via the insulating member 4.

[0062] A shower head 110 which also functions as an upper electrode of a parallel plate electrode is provided on the ceiling 101a of the chamber 101 by means of an insulating member 109 in a manner opposite to the stage 2 of the substrate holding mechanism 1. The shower head 110 functions as a gas introduction portion. The shower head 110 has a base member 111 and a shower plate 112, and the outer peripheral portion of the shower plate 112 is screwed to the base member 111 via an intermediate member 113 in the shape of a circular ring. The shower plate 112 is in the shape of a circular plate, and a flange is formed on its outer periphery. In addition, a gas diffusion space 114 is formed between the base member 111 and the shower plate 112. The base member 111 has a flange portion 111a formed on its outer periphery, and the flange portion 111a is supported by the insulating member 109. The shower plate 112 has a gas ejection surface 118 opposite to the stage 2, and a plurality of gas ejection holes 115 are formed in the shower plate 112. A gas introduction hole 116 is formed near the center of the base member 111. A gas pipe of a gas supply mechanism 120 described later is connected to the gas introduction hole 116, and a processing gas supplied from the gas supply mechanism 120 is introduced into the chamber 101 through the shower head 110 in a shower shape.

[0063] The base member 111 of the shower head 110 is provided with a heater 147 for heating the shower head 110. The heater 147 is powered by a heater power source (not shown) to heat the shower head 110 to a desired temperature. A heat insulating member 149 is provided in a recess formed in the upper portion of the base member 111.

[0064] The gas supply mechanism 120 includes a TiCl4 gas supply source 121, an Ar gas supply source 122, an H2 gas supply source 123, an NH3 gas supply source 124, and an N2 gas supply source 125. TiCl4 is used as a Ti raw material gas. Ar gas is used as a plasma generation gas, a carrier gas, and a purge gas. H2 gas is used as a reducing gas, NH3 gas is used as a nitriding gas, and N2 gas is used as a purge gas.

[0065] The TiCl4 gas supply source 121 is connected to a TiCl4 gas supply line 131, the Ar gas supply source 122 is connected to an Ar gas supply line 132, the H2 gas supply source 123 is connected to an H2 gas supply line 133, the NH3 gas supply source 124 is connected to an NH3 gas supply line 134, and the N2 gas supply source 125 is connected to an N2 gas supply line 135. In addition, each gas line is provided with a mass flow controller 137 and two switch valves 136 located before and after the mass flow controller 137.

[0066] The Ar gas supply line 132 is connected to the TiCl4 gas supply line 131, and the NH3 gas supply line 134 and the N2 gas supply line 135 are connected to the H2 gas supply line 133. The TiCl4 gas supply line 131 and the H2 gas supply line 133 are connected to the gas mixing unit 138, and the mixed gas mixed in the gas mixing unit 138 is connected to the gas introduction hole 116 via the gas pipe 139. Then, the mixed gas reaches the gas diffusion space 114 through the gas introduction hole 116, and is sprayed toward the wafer W in the chamber 101 through the gas ejection hole 115 of the shower plate 112.

[0067] A high-frequency power supply 141 is connected to the shower head 110 via a matching device 140, so that high-frequency power is supplied from the high-frequency power supply 141 to the shower head 110. The shower head 110 functions as an upper electrode of a parallel plate electrode. On the other hand, the adsorption electrode 11 provided in the stage 2 of the substrate holding mechanism 1 functions as a lower electrode (ground electrode) of the parallel plate electrode. Therefore, by supplying high-frequency power to the shower head 110, a high-frequency electric field is formed between the shower head 110 and the adsorption electrode 11, and the processing gas ejected from the shower head 110 is plasmatized by the high-frequency electric field. That is, the high-frequency power supply 141 functions as a plasma generating mechanism. The frequency of the high-frequency power supply 141 is preferably set to 200kHz to 13.56MHz, and typically 450kHz is used.

[0068] The film forming apparatus 100 has a control unit 160 that controls the substrate holding mechanism 1, the valve 136, the mass flow controller 137, the matching device 140, the high-frequency power supply 141, etc., which are its components. The control unit 160 has a CPU (computer), and has a main control unit that controls the above-mentioned components, an input device, an output device, a display device, and a storage device. A storage medium is installed in the storage device, and the storage medium stores a program for controlling the processing performed by the film forming apparatus 100, that is, a processing recipe. The main control unit reads the prescribed processing recipe stored in the storage medium, and controls the film forming apparatus 100 in a manner such that the prescribed processing is performed based on the processing recipe.

[0069] Next, a description will be given of a Ti film forming process performed using the above-described film forming apparatus 100 .

[0070] First, after adjusting the pressure in the chamber 101, the gate valve 158 is opened, and a wafer W is introduced into the chamber 101 from the transfer chamber (not shown) via the input / output port 157, and the wafer W is placed on the surface of the stage 2 maintained at a predetermined temperature of the substrate holding mechanism 1. Then, Ar gas as a plasma generating gas, H2 gas as a reducing gas, and TiCl4 gas as a Ti raw material gas are flowed into a pre-flow supply line (not shown) for pre-flow supply. Next, while keeping the gas flow rate and pressure the same, the pipeline for film formation is switched, and these gases are introduced into the chamber 101 simultaneously or sequentially through the showerhead 110.

[0071] After the introduction of these gases begins, high frequency power is applied to the shower head 110 from the high frequency power supply 41, and plasma is generated at a predetermined time in the chamber 101. At the same time, a DC voltage is applied to the adsorption electrode 11 from the DC power supply 14, so that the wafer W is electrostatically adsorbed to the stage 2 by the Johnson-Rabbeck force.

[0072] Then, while Ar gas, H2 gas, and TiCl4 gas are introduced simultaneously or sequentially at a predetermined time, plasma is continuously generated or at a predetermined time, and a Ti film is formed on the surface of the wafer W by plasma CVD or plasma ALD. That is, in the case of plasma CVD, while Ar gas, H2 gas, and TiCl4 gas are introduced into the chamber 101, plasma is continuously generated in the chamber 101 by the high-frequency power supply 41. In addition, in the case of plasma ALD, while Ar gas and N2 gas are continuously supplied, TiCl4 gas and H2 gas are alternately supplied, and plasma is generated at the time of supplying H2 gas, for example.

[0073] At this time, the temperature of the stage 2 surface (film formation temperature of the wafer W) can be set to a range of 300° C. to 700° C. The temperature is preferably 400° C. to 700° C., and more preferably 500° C. to 600° C.

[0074] The pressure in the chamber 101 is determined based on plasma damage, the in-plane uniformity of the Ti film, and the like, and is preferably in the range of 13.3 Pa to 1333 Pa (0.1 Torr to 10 Torr).

[0075] At the film forming temperature of 300° C. to 700° C. as described above, when an electrostatic chuck is not used as in the conventional method, warping occurs in the wafer W. Due to the warping of the wafer W, degradation of uniformity or sparking between the wafer W and the stage may occur.

[0076] In contrast, in the substrate holding mechanism 1 having the above structure, when a Ti film as a conductive film is formed, the formation of a conductive deposited film on the back surface of the wafer W can be suppressed, and the electrostatic chuck function can be maintained. Furthermore, since the Johnson-Rabbeck force with a high adsorption force is used as the electrostatic adsorption force, the warpage of the wafer W can be reliably corrected.

[0077] <Other applications>

[0078] The embodiments have been described above, but the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The above embodiments may be omitted, replaced, and modified in various ways without departing from the appended claims and their gist.

[0079] For example, in the above embodiment, an example is shown in which the support member 3 for supporting the stage 2 is provided as the substrate holding mechanism 1, but the stage 2 may be directly provided on the bottom of the chamber without providing the support member 3.

[0080] Moreover, in the above-mentioned embodiment, an example of placing a semiconductor wafer as a processed substrate on a stage is shown, but it is not limited to this. For example, the surface of the stage may be facing downward, and the processed substrate may be supported on the surface and adsorbed and held by electrostatic adsorption.

[0081] In addition, the example using a semiconductor wafer as the processed substrate is shown, but the processed substrate is not limited to a wafer, and may be another processed substrate such as an FPD substrate. When the processed substrate is a rectangular shape such as an FPD substrate, the close contact area and the groove portion may be set to a frame shape.

[0082] Furthermore, the above-mentioned film forming apparatus is merely an example, and any film forming apparatus is not particularly limited as long as it uses plasma. The plasma generation method is also arbitrary.

Claims

1. A substrate holding mechanism for holding a substrate to be processed when a conductive film is formed, wherein: The substrate holding mechanism comprises: A stage, which is made of a dielectric and is used to support a substrate to be processed; an adsorption electrode, which is disposed in the stage and is used for electrostatically adsorbing the processed substrate; and a heater provided in the stage and arranged below the adsorption electrode, By applying a DC voltage to the adsorption electrode, the substrate to be processed is electrostatically adsorbed to the surface of the stage by utilizing the Johnson-Rabbeck force. The stage has: a close contact area, which is annular and is provided at a position on the surface of the stage corresponding to the outer periphery of the substrate to be processed, close contacting the substrate to be processed, and having a function of preventing the raw material gas used for forming the conductive film from bypassing to the back side of the substrate to be processed; an adsorption surface which is a concave portion and is provided on a portion of the stage which is inside the close contact area in a manner connected to the close contact area; a groove portion which is annular and provided on a portion of the surface of the stage outside the close contact area so as to be connected to the close contact area, and capable of accumulating a conductive deposited film generated by the raw material gas; and a guide portion, which is annularly disposed on the surface of the stage at a portion outside the groove portion, the guide portion having a height higher than the close fitting area and a tapered side wall portion connected to the bottom of the groove portion, for guiding the substrate to be processed, The adsorption surface, the close fitting area, the groove portion and the guide portion are an integrated structure. The distance from the adsorption electrode to the adsorption surface of the substrate to be processed adsorbed on the stage is 0.5 mm to 1.5 mm, The distance between the adsorption electrode and the conductive deposited film formed on the surface of the stage at an outer side than the close contact area is larger than the distance from the adsorption electrode to the adsorption surface of the substrate to be processed adsorbed on the stage.

2. The substrate holding mechanism according to claim 1, wherein: The width of the close-fitting area is 10 mm to 40 mm.

3. The substrate holding mechanism according to claim 1, wherein: The depth of the groove portion relative to the close contact region is 20 μm to 100 μm, and the width of the groove portion is 0.5 mm to 2 mm.

4. The substrate holding mechanism according to claim 1, wherein: The distance from the adsorption electrode to the adsorption surface of the substrate to be processed adsorbed on the stage is 1 mm. The distance between the adsorption electrode and the conductive deposited film formed on the surface of the stage at an outer side than the close contact region is 2 mm or more.

5. The substrate holding mechanism according to claim 1, wherein: The temperature of the surface of the stage heated by the heater is 200° C. or higher.

6. The substrate holding mechanism according to claim 5, wherein: The temperature of the surface of the stage heated by the heater is 400°C to 700°C.

7. The substrate holding mechanism according to claim 1, wherein: The suction surface serving as the recessed portion is an embossed surface obtained by embossing.

8. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The substrate holding mechanism further includes a back side gas supply mechanism for supplying a back side gas for heat conduction to a space between the substrate to be processed and the adsorption surface.

9. The substrate holding mechanism according to claim 8, wherein: The back side gas supply mechanism sets the pressure of the back side gas to 20 Torr to 100 Torr.

10. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The adsorption electrode functions as a ground electrode for plasma.

11. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The volume resistivity of the dielectric material constituting the stage at the film forming temperature is 1×10 9 Ω·cm~1×10 12 Ω·cm level.

12. The substrate holding mechanism according to claim 11, wherein: The dielectric is AlN.

13. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The substrate holding mechanism also has an auxiliary electrode, which is used to expand the plasma area. The auxiliary electrode is located outside the adsorption electrode. The distance between the auxiliary electrode and the conductive deposited film is greater than the distance from the adsorption electrode to the adsorption surface of the processed substrate adsorbed on the stage.

14. The substrate holding mechanism according to claim 13, wherein: The adsorption electrode and the auxiliary electrode are integrated into one structure.

15. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The substrate holding mechanism further includes a support member that is attached to the center of the back side of the bottom surface of the stage in a manner extending downward.

16. The substrate holding mechanism according to any one of claims 1 to 5, wherein: The substrate holding mechanism further includes a lift pin through hole, which is disposed at an outer side of the close fitting area of ​​the stage and passes through the stage in a vertical direction.

17. A film forming device for forming a conductive film, wherein: The film forming device comprises: A chamber for performing a film forming process; The substrate holding mechanism according to any one of claims 1 to 5, which is provided in a chamber; a gas introduction unit for introducing a gas for forming the conductive film into the chamber; a plasma generating mechanism for generating plasma in the chamber; and An exhaust mechanism is used to exhaust the interior of the chamber.

18. The film forming device according to claim 17, wherein: The gas introduction part has a shower head for introducing the gas into the chamber in a shower shape. The plasma generating mechanism includes a high-frequency power source for applying high-frequency power to the shower head.

19. The film forming device according to claim 17 or 18, wherein: A Ti film is formed as the conductive film using a Ti raw material gas and a reducing gas as gases for forming the conductive film.

20. A film forming method for forming a conductive film on a substrate, the film forming method comprising the following steps: placing the substrate on the substrate holding mechanism provided in the chamber according to any one of claims 1 to 5; introducing a gas for forming the conductive film into the chamber from a gas introduction portion; generating plasma of the gas by a plasma generating mechanism; and The conductive film is formed by exposing the substrate to the plasma.

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