Sputtering apparatus and support program used therefor

Abstract

In order to perform sputter film formation at an optimal tilt angle according to film formation conditions, a vacuum chamber (12) capable of forming a film on a substrate (2), and an electrode unit (13) provided inside the chamber and including a sputter electrode (131) are provided. The electrode unit is supported by a shaft (14) via a tilt unit (15). The shaft is movable in a first axial direction (X) parallel to the surface of the substrate at the film formation position with respect to the chamber, and is movable in a second axial direction (Z) perpendicular to the surface of the substrate at the film formation position. The tilt unit enables adjustment of the tilt angle (θ) formed by the surface of a target (132) attached to the sputter electrode with respect to the surface of the substrate at the film formation position.

Description

Technical Field

[0001] The present invention relates to a sputtering apparatus and a support program used therefor.

Background Art

[0002] There is known a sputtering apparatus in which the surface of a substrate mounting table for holding a substrate and the surface of a target mounting table for holding a target are arranged to be non-parallel (Patent Document 1). By arranging the surface of the substrate holder and the surface of the target to be non-parallel, it is said that the film formation rate can be reduced and an extremely thin MgO film can be accurately formed with good reproducibility (see

[0013] of the same document).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above prior art, since the inclination angle between the surface of the substrate holder and the surface of the target is fixed, sputter film formation cannot be performed at an optimal inclination angle according to the material and other film formation conditions.

[0005] The problem to be solved by the present invention is to provide a sputtering apparatus capable of performing sputter film formation at an optimal inclination angle according to film formation conditions and a support program used therefor.

Means for Solving the Problems

[0006] The present invention includes a housing, a chamber provided inside the housing and capable of reducing pressure to form a film on a substrate, and an electrode unit provided inside the chamber and including a sputtering electrode. The electrode unit is supported via a tilt unit by a shaft that is movable in a first axial direction parallel to the surface of the substrate at the film formation position with respect to the housing and is movable in a second axial direction perpendicular to the surface of the substrate at the film formation position. The tilt unit solves the above problems by a sputtering apparatus capable of adjusting the inclination angle formed by the surface of the target attached to the sputtering electrode with respect to the surface of the substrate at the film formation position.

Advantages of the Invention

[0007] According to the present invention, sputter film formation can be performed at an optimal inclination angle according to film formation conditions.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of the main part showing a sputtering apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. 1. As shown in FIG. 1, the sputtering apparatus 1 of the present embodiment has a housing 11 composed of a frame (a skeletal member of the housing, not shown), a panel, etc., and the inside of the housing 11 is a chamber 12 that can be set to a predetermined degree of vacuum. The chamber 12 has airtightness and can be set to a predetermined degree of vacuum by an exhaust device 112 provided at the exhaust port 111 of the housing 11.

[0010] The chamber 12 according to the present embodiment includes a film formation chamber 121 facing the target 132 mounted on the sputtering electrode 131 and the substrate 2 mounted on the susceptor 16. The film formation chamber 121 of the present embodiment is partitioned by four side wall panels 113 constituting the side surface of the chamber 12, a bottom panel 114 attached to the frame of the housing 11, and a ceiling panel 115 also attached to the frame of the housing 11. And as will be described later, the electrode unit 13 of the present embodiment is movable in the X-axis direction and the Z-axis direction via the shaft 14 and is tiltable by the tilt unit 15. Therefore, a movable panel 133 whose opening follows according to the movable range of the electrode unit 13 is rotatably provided on the electrode unit 13. By providing the movable panel 133, scattering of sputtering particles to the outside of the film formation chamber 121 is suppressed.

[0011] In the chamber 12 of this embodiment, a porous quartz plate 122 and a porous metal plate 123 are provided. As shown in FIG. 1, the porous quartz plate 122 and the porous metal plate 123 of this embodiment are provided in front of the target 132 on the inner wall of the film formation chamber 121, and the porous quartz plate 122 is disposed on the front surface of the porous metal plate 123. The porous metal plate 123 is electrically coupled to the plasma and supplies electrons to the plasma. At this time, the potential of the porous metal plate 123 may be ground, or a controlled negative potential may be supplied to more actively supply electrons. Further, in order to increase the power efficiency consumed in the actual sputtering phenomenon among the high-frequency power input to the target 132, the porous metal plate 123 may increase the surface area by stacking a plurality of sheets. The porous quartz plate 122 has a function of preventing the deposition of sputtered particles on the porous metal plate 123 and maintaining a constant supply of electrons. Further, the porous quartz plate 122 also has a function of preventing the reverse deposition of the material of the porous metal plate 123 sputtered when a negative potential is supplied onto the substrate 2.

[0012] The sputtering apparatus 1 of this embodiment further includes a gas supply device 124, and supplies argon gas, oxygen gas, etc. as a process gas during film formation to the film formation chamber 121.

[0013] The sputtering electrode 131 of this embodiment supplies high-frequency power to the target 132 mounted at the tip. The diameter of the sputtering electrode 131 of this embodiment is not particularly limited, but it is preferably applied to a heavy object having a diameter of 190 mm or more. Further, the frequency of the high-frequency power of this embodiment is not particularly limited, but may include a frequency of 13.56 MHz. Further, the material of the target 132 is not particularly limited, and targets made of various materials can be used.

[0014] The susceptor 16 of this embodiment is composed of a conductive material, holds the substrate 2, and can rotate at a predetermined rotational speed by a driving device 162 connected to the rotation axis 161. The susceptor 16 may be configured to perform a deposition process on a plurality of substrates 2 in a single process. The material constituting the susceptor 16 is not particularly limited, and examples thereof include Inconel, silicon carbide, graphite, and silicon. The conductivity of the susceptor 16 does not necessarily have to be exhibited at room temperature, and may be exhibited when the substrate 2 is heated at less than 450°C.

[0015] Also, a heater 163 for heating the substrate 2 to a predetermined temperature is provided below the susceptor 16. The heating method of the heater 163 is not limited, and examples thereof include a resistance heating method using graphite or silicon carbide as a resistor, and a light heating method using a halogen lamp. Note that the heater 163 is not an essential component in the present invention and may be provided as needed.

[0016] The electrode unit 13 of this embodiment is attached to the shaft 14 via the tilt unit 15. The shaft 14 penetrates the ceiling panel 115 of the housing 11 (chamber 12) and extends upward, and is movable in the X-axis direction as will be described later. Therefore, a long hole (not shown) through which the shaft 14 penetrates is formed in the ceiling panel 115. A slide plate 116 that closes and seals this long hole and through which the shaft 14 penetrates airtightly is provided on the upper surface of the ceiling panel 115.

[0017] The slide plate 116 is slidably supported by a linear rail (not shown) provided to extend in the X-axis direction on the frame of the housing 11. An X-axis drive mechanism including a feed screw mechanism for moving in the X-axis direction is provided between the slide plate 116 and the linear rail. For example, by turning a handle, the position of the slide plate 116 in the X-axis direction (and as a result, the positions of the shaft 14 and the electrode unit 13) can be adjusted.

[0018] Further, as shown in FIG. 2, the shaft 14 is fixed to the lifting plate 141, and a Z-axis drive mechanism including a feed screw mechanism 142 for vertically moving the lifting plate in the Z-axis direction is provided between the slide plate 116 and the lifting plate 141. Then, for example, by turning the handle to rotate the feed screw mechanism 142, the position of the lifting plate 141 in the Z-axis direction with respect to the slide plate 116 (and as a result, the positions of the shaft 14 and the electrode unit 13) can be adjusted.

[0019] As shown in FIG. 1, in the sputtering apparatus 1 of the present embodiment, when the rotation center point of the susceptor 16 is C1 and the center point of the target 132 mounted on the sputter electrode 131 is C2, the distance in the Z-axis direction from the rotation center point C1 of the susceptor 16 to the center point C2 of the target 132 is defined as the height Z, and the distance in the X-axis direction from the rotation center point C1 of the susceptor 16 to the center point C2 of the target 132 is defined as the offset length X. Although the movable range of the shaft 14 in the present embodiment is not particularly limited, for example, it is preferably movable in the range where the height Z is 0 to 350 mm and the offset length X is 0 to 590 mm.

[0020] FIG. 3 is a perspective view showing an example of the tilt unit 15 in FIG. 1, and is a perspective view looking obliquely upward from below the tilt unit 15. FIG. 4 is a side view of the tilt unit 15. FIGS. 3 and 4 show a state in which the electrode unit 3 is tilted at an inclination angle θ = 45°. FIG. 5 is a diagram showing the cam slide mechanism of the tilt unit 15 in FIG. 1. In the present embodiment, as shown in FIG. 5, a bellows tube 17 is provided between the first plate 151 of the tilt unit 15 and the sputter electrode 131, and a cable 18 for supplying high-frequency power to the sputter electrode 131 is inserted through the inside of the shaft 14 and the bellows tube 17 from the outside of the housing 11 and connected to the sputter electrode 131. The upper end of the bellows tube 17 is fixed to the first plate 151 of the tilt unit 15, and the lower end of the bellows tube 17 is fixed to the sputter electrode 131.

[0021] The tilt unit 15 of this embodiment is a mechanical structural member that can adjust the inclination angle θ formed by the surface of the target 132 mounted on the sputtering electrode 131 with respect to the surface of the substrate 2 at the film formation position. Here, as shown in FIG. 1, in the sputtering apparatus 1 of this embodiment, when the plane parallel to the surface of the substrate 2 is PL1, the plane parallel to the surface of the target 132 is PL2, the rotation center point of the susceptor 16 is C1, and the center point of the target 132 mounted on the sputtering electrode 131 is C2, the angle θ formed by the plane PL1 parallel to the surface of the substrate 2 and the plane PL2 parallel to the surface of the target 132 is defined as the inclination angle of the electrode unit 3. The range of the inclination angle θ of the tilt unit 15 of this embodiment is not particularly limited, but for example, it is more preferable that the inclination angle θ can be adjusted in the range of 0° to 90° (including both ends).

[0022] As shown in FIGS. 3 and 4, the tilt unit 15 of this embodiment includes a first plate 151 fixed to the lower end of the shaft 14, a pair of second plates 152, 152 fixed to both ends of the first plate 151 so as to be spaced apart from each other, and a third plate 153 fixed across between the pair of second plates 152, 152. In FIG. 4, one of the pair of second plates 152, 152 on the front side is shown. A first cam hole 154 and a second cam hole 155 are formed at corresponding positions on each of the pair of second plates 152. As shown in FIGS. 3 and 4, in the tilt unit 15 of this embodiment, the first cam hole 154 is linear and extends in the vertical direction, and the second cam hole 155 is formed in a substantially arc shape.

[0023] A pair of support plates 134 spaced apart from each other are fixed to the sputtering electrode 131. A first pin 135 that serves as a rotation center and engages with a first cam hole 154, and a second pin 136 that engages with a second cam hole 155 are fixed to each of the support plates 134. In FIG. 4, the first pin 135 and the second pin 136 extend and are fixed in a direction perpendicular to the plane of the drawing. By engaging the first pin 135 and the second pin 136 with the first cam hole 154 and the second cam hole 155 formed in each of the pair of second plates 152, 152, respectively, the sputtering electrode 131 including the support plate 134 is supported so as to be tiltable with respect to the pair of second plates 152 along the direction along the first cam hole 154 and the second cam hole 155.

[0024] As shown in FIG. 3, the tilt unit 15 of the present embodiment has a feed screw mechanism including a feed screw 156 rotatably supported between a first plate 151 and a third plate 153, and a bush 157 including a nut screwed onto the feed screw 156. When the feed screw 156 is rotated in one direction by turning a handle (not shown), the bush 157 descends, while when the feed screw 156 is rotated in the reverse direction, the bush 157 ascends. A link plate 158 is attached between the bush 157 and the sputtering electrode 131. When the feed screw 156 is rotated in one direction, the bush 157 descends and the link plate 158 pushes one end of the sputtering electrode 131, so that the electrode unit 13 rotates clockwise in FIG. 4 about the first pin 135. Conversely, when the feed screw 156 is rotated in the reverse direction, the bush 157 ascends and the link plate 158 pulls one end of the sputtering electrode 131, so that the electrode unit 13 rotates counterclockwise in FIG. 4 about the first pin 135.

[0025] Here, the tilt angle θ of the sputtering electrode 131 can vary between 0 and 90°. When the tilt angle θ of the sputtering electrode 131 is 0°, the bellows tube 17 with both ends fixed to the first plate 151 and the sputtering electrode 131 hangs vertically as shown by the two-dot chain line in FIG. 5. In contrast to this state, as the tilt angle θ of the sputtering electrode 131 approaches 90°, since the bellows tube 17 with both ends fixed to the first plate 151 and the sputtering electrode 131 is a flexible pipe, it does not tilt linearly but bends at the tilt unit 15. Then, as shown in FIG. 5, when the bellows tube 17 bends, the length of the bellows tube 17 becomes longer compared to the case of tilting linearly, the cable 18 inserted inside is also pulled, and the high-frequency inductance fluctuates. That is, when the tilt angle θ fluctuates, the properties of the discharge plasma by the sputtering electrode 131 also fluctuate. Therefore, the tilt unit 15 of the present embodiment includes a cam slide mechanism in which the length of the bellows tube 17 (and as a result, the length of the cable 18) remains constant regardless of the tilt angle θ to be adjusted.

[0026] FIG. 5 is a diagram showing the operation of the cam slide mechanism of the tilt unit 15 of the present embodiment. The cam slide mechanism of the tilt unit 15 of the present embodiment includes a first cam hole 154 and a second cam hole 155 formed in the second plate 152 of the tilt unit 15, and a first pin 135 and a second pin 136 provided on the support plate 134 of the sputtering electrode 131. As described above, the first pin 135 and the second pin 136 are engaged with the first cam hole 154 and the second cam hole 155 formed in each of the pair of second plates 152, 152, respectively. Thereby, the sputtering electrode 131 including the support plate 134 is supported so as to be tiltable with respect to the pair of second plates 152 along the directions along the first cam hole 154 and the second cam hole 155.

[0027] More specifically, when the inclination angle θ of the sputtering electrode 131 is 0°, the bellows tube 17 hangs vertically as shown by the two-dot chain line in FIG. 5. At this time, the first pin 135 engaged with the first cam hole 154 is located at the position M1 shown in FIG. 5, the second pin 136 engaged with the second cam hole 155 is located at the position M1 shown in FIG. 5, and the length of the bellows tube 17 is L. On the other hand, when the inclination angle θ of the sputtering electrode 131 is 90°, the bellows tube 17 is in a state of being bent at a right angle as shown by the broken line in FIG. 5. At this time, the first pin 135 engaged with the first cam hole 154 is located at the position M2 shown in FIG. 5, the second pin 136 engaged with the second cam hole 155 is located at the position M2 shown in FIG. 5, and the length of the bent bellows tube 17 is L. And when the inclination angle θ of the sputtering electrode 131 is between 0° and 90°, as the inclination angle θ increases, the bellows tube 17 gradually bends. However, as the second pin 136 moves from the position M1 to M2, the first pin 135 moves from the position M1 to M2, whereby the length of the bellows tube 17 always maintains L.

[0028] As a result, it is possible to suppress the tensile stress from acting on the cable 18 inserted inside the bellows tube 17, and it is possible to suppress the fluctuation of the high-frequency inductance. That is, even if the inclination angle θ fluctuates, the properties of the discharge plasma by the sputtering electrode 131 can be kept constant. Further, since the length L of the bellows tube 17 is kept constant and no extra load acts, the life of the bellows tube 17 can also be extended. FIG. 6 is a longitudinal sectional view of the main part for explaining the movable range of the electrode unit 13 in FIG. 1. The electrode unit 13 of the present embodiment is movable within a range where the inclination angle θ is 0° to 90°, the height Z is 0 to 350 mm, and the offset length X is 0 to 590 mm. In FIG. 6, the cases where the inclination angle θ = 0°, the height Z = 350 mm, and the offset length X = 0 mm and where the inclination angle θ = 90°, the height Z = 50 mm, and the offset length X = 590 mm are each shown by a two-dot chain line.

[0029] Next, a method for obtaining the optimum values of the offset length X, height Z, and tilt angle θ of the sputtering electrode 131 when forming a thin film on the substrate 2 using the sputtering apparatus 1 of the present embodiment described above will be described. FIG. 7 is a flowchart showing a procedure for determining the optimum values of the center coordinates (X, Z) and tilt angle θ of the sputtering electrode 131 using the support program according to an embodiment of the present invention.

[0030] The program of the present embodiment utilizes the Monte Carlo method (a method of performing simulations and numerical calculations using random numbers) that tracks and simulates the behavior of sputtered particles flying from the target to the substrate to obtain the film thickness distribution. On the premise that the pressure (vacuum degree) in the chamber 12 is kept constant and the material of the target 132 is set to a predetermined material, when sputtering is performed at arbitrary center coordinates (X0, Z0) and tilt angle θ0 using the sputtering apparatus 1 of the present embodiment described above, based on the measured value of the film thickness distribution of the film formed on the substrate 2, parameters including the center coordinates (X0, Z0), tilt angle θ0, and variables A, B, n, m of the emission angle distribution model of sputtered particles are obtained. Based on the obtained parameters, the flight of sputtered particles is simulated, and the film thickness distribution of the film formed on the substrate 2 is predicted.

[0031] Specifically, as shown in step ST1 of FIG. 7, using the sputtering apparatus 1 of the present embodiment described above, the pressure (vacuum degree) in the chamber 12 is made constant, the material of the target 132 is set to a predetermined material, and sputtering treatment is performed at arbitrary center coordinates (X0, Z0) and inclination angle θ0. Then, the film thickness distribution of the film formed on the substrate 2 under these film formation conditions is measured. The definition of the film thickness distribution of the film formed on the substrate is not particularly limited. For example, when the substrate is a circular substrate such as a silicon wafer, it can be defined as the film thickness at predetermined pitches along the radial direction of the circular substrate. Also, when the substrate is a rectangular substrate, it can be defined as the film thickness at predetermined pitches on a straight line passing through the center point of the rectangular substrate. This measured film thickness distribution is also referred to as the measured value of the film thickness distribution. As a general film formation quality, it is preferably that the film thickness distribution is small, that is, the variation in the film thickness in the plane is small.

[0032] In the subsequent step ST2, the center coordinates (X0, Z0) and inclination angle θ0 of the sputtering electrode 131 set in step ST1 and the measured value of the measured film thickness distribution are input into the program of the present embodiment.

[0033] In the subsequent step ST3, based on the center coordinates (X0, Z0) and inclination angle θ0 of the sputtering electrode 131 set in step ST1 and the measured value of the measured film thickness distribution, variables of the emission angle distribution model of sputtering particles are calculated using Bayesian optimization processing. Bayesian optimization is a method of quickly reaching the optimal solution by sampling points with a high probability of obtaining the optimal solution in order, and refers to a method of estimating the form of a function from limited observation data for a black box function y = f(x). In the case of this example, the variables of the emission angle distribution model of sputtering particles are set as the search range of the Bayesian optimization processing, and the variables of the emission angle distribution model that minimize the difference between the measured value of the film thickness distribution and the calculated value of the film thickness distribution are calculated.

[0034] Here, the probability distribution formula of the emission angle distribution model of sputtering particles is P(θ)=A·cos n (θ)-B·cos m(θ), where A, B, n, and m are the variables to be determined. The film thickness distribution of the sputtering particles is obtained from the center coordinates (X, Z) and the tilt angle θ of the sputtering electrode 131, and the emission angle distribution of the sputtering particles. Therefore, if the measured value of the measured film thickness distribution and the center coordinates (X0, Z0) and the tilt angle θ0 of the arbitrarily set sputtering electrode 131 are known, the probability distribution formula of the emission angle distribution model of the sputtering particles is P(θ)=A·cos n (θ)-B·cos m (θ), the variables A, B, n, and m can be determined.

[0035] Then, in the subsequent step ST4, using the probability distribution formula P(θ)=A·cos n (θ)-B·cos m (θ) of the emission angle distribution model of the sputtering particles obtained by substituting the variables A, B, n, and m obtained in step ST3, the optimum values of the center coordinates (X, Z) and the tilt angle θ of the sputtering electrode 131 are calculated using Bayesian optimization. That is, the center coordinates (X, Z) and the tilt angle θ of the sputtering electrode 131 are set as the search range of the Bayesian optimization, and the center coordinates (X, Z) and the tilt angle θ at which the calculated value of the film thickness distribution is minimized (the variation of the film thickness distribution is minimized) are calculated. As described above, the film thickness distribution of the sputtering particles is obtained from the center coordinates (X, Z) and the tilt angle θ of the sputtering electrode 131, and the emission angle distribution of the sputtering particles. Here, the probability distribution formula of the emission angle distribution of the sputtering particles is P(θ)=A·cos n (θ)-B·cos m (θ), and the variables A, B, n, and m are obtained in step ST3. Since the ideal form of the film thickness distribution is that there is no variation in the film thickness, that is, the film thickness distribution becomes the minimum value, the center coordinates (X, Z) and the tilt angle θ of the sputtering electrode 131 can be obtained, and the center coordinates (X1, Z1) and the tilt angle θ1 obtained at this time become the optimum values in the simulation.

[0036] In the subsequent step ST5, the center coordinates (X1, Z1) and the tilt angle θ1 obtained in step ST4 are displayed on a computer display or the like.

[0037] In the subsequent step ST6, using the sputtering apparatus 1 of the present embodiment described above, the pressure (degree of vacuum) in the chamber 12 is set to the same pressure as in step ST1, the material of the target 132 is set to the same material as in step ST1, and sputtering is performed at the center coordinates (X1, Z1) and the tilt angle θ1 displayed on a computer display or the like. Then, the film thickness distribution of the film formed on the substrate 2 under these film formation conditions is measured.

[0038] In the subsequent step ST7, it is determined whether the measured value of the film thickness distribution measured in step ST6 is a satisfactory value. If it is a satisfactory value, the process proceeds to step ST12. If it is not a satisfactory value, the process proceeds to step ST8. In step ST12, the center coordinates (X1, Z1) and the tilt angle θ1 of the sputtering electrode 131 obtained in step ST4 are set in the sputtering apparatus 1 of the present embodiment, and actual production is performed. Thereby, without performing experiments by trial and error that are complicated and require time and labor, the optimum center coordinates (X1, Z1) and tilt angle θ1 of the sputtering electrode 131 can be obtained by performing at least one experiment.

[0039] In step ST7, when the measured value of the film thickness distribution measured in step ST6 is not a satisfactory value, in step ST8, the center coordinates (X1, Z1) and the tilt angle θ1 of the sputtering electrode 131 obtained in step ST4 and the measured value of the film thickness distribution measured in step ST6 are input into the program of the present embodiment.

[0040] In the subsequent steps ST9 to ST10, the same processing as in steps ST3 to ST4 described above is executed. Then, in step ST11, after the center coordinates (X2, Z2) and the tilt angle θ2 obtained in step ST10 are displayed on a computer display or the like, the process proceeds to step ST6. Hereinafter, in step ST7, steps ST8 to ST11 and ST6 to ST7 are repeated until the measured value of the film thickness distribution measured in step ST6 becomes a satisfactory value.

[0041] Note that the Monte Carlo method used in the program of this embodiment is a method using random numbers for simulating the behavior of sputtering particles flying from the target to the substrate. Therefore, it includes a step of generating a random number sample for expressing the emission angle distribution model of sputtering particles. Specifically, the step of generating this random number sample sets the emission angle range to 0 to π / 2 radians (corresponding to the tilt angle θ of 0 to 90°), and generates an angle list for each arbitrary angle within this emission angle range. Then, based on the probability distribution formula P(θ)=A·cos n (θ)-B·cos m (θ), the probability density for each angle in the angle list is calculated, and the calculated probability density is normalized.

[0042] Next, in order to generate a random number sample, an angle is randomly selected according to a uniform distribution within the emission angle range of 0 to π / 2 radians, and the normalized probability density corresponding to the selected angle is compared with a uniform random number. When the probability density is greater than the uniform random number, the angle is accepted as a sample. The above steps are repeated until a predetermined number of samples is obtained.

[0043] Note that the probability distribution formula P(θ)=A·cos n (θ)-B·cos m (θ) of the emission angle distribution model of sputtering particles is adjusted by parameters A and B, and the shape of the distribution is determined by parameters n and m. Also, the selection of the angle sample is performed using the acceptance-rejection method, and sampling is performed based on the maximum probability value obtained by normalizing the probability density.

[0044] In the sputtering apparatus 1 of this embodiment, when a circular target is used as the target 132, it is known that the annular region (doughnut-shaped region) on the surface of the target 132 becomes the emission source of sputtering particles. Therefore, the program of this embodiment includes a step of generating the emission source of sputtering particles as a point source within the annular region.

[0045] And the step of generating as point sources within this annular region receives (inputs) the inner radius, outer radius, and density of a plurality of annular regions, calculates the area of each annular region, determines the number of point sources generated based on the area and density of each annular region, divides the angle at equal intervals to evenly arrange the point sources, generates a random radius, calculates the coordinates of the point sources based on the radius and angle, and the coordinates of a specific axis of the point source are set to unique values.

Explanation of Signs

[0046] 1…Sputtering apparatus 11…Housing 111…Exhaust port 112…Exhaust device 113…Side wall panel 114…Bottom panel 115…Ceiling panel 116…Slide plate 12…Chamber 121…Film formation chamber 122…Porous quartz plate 123…Porous metal plate 124…Gas supply device 13…Electrode unit 131…Sputtering electrode 132…Target 133…Movable panel 134…Support plate 135…First pin 136…Second pin 137…Bracket 14…Shaft 141…Lifting plate 142…Feed screw mechanism 15…Tilt unit 151…First plate 152…Second plate 153…Third plate 154…First cam hole 155…Second cam hole 156…Feed screw 157…Bush 158…Link plate 16…Susceptor 161…Rotating shaft 162…Drive device 163…Heater 17…Bellows tube 18…Cable 2…Substrate C1…Susceptor center point C2…Target center point X…Offset length (distance in the X-axis direction from the susceptor center point C1 to the target center point C2) Z…Height (distance in the Z-axis direction from the susceptor center point C1 to the target center point C2) PL1…Plane parallel to the surface of the substrate PL2…Plane parallel to the surface of the target θ…Inclination angle (angle formed by PL1 and PL2)

Claims

1. a decompressible chamber for forming a film on a substrate; an electrode unit provided inside the chamber and including a sputtering electrode; The electrode unit is supported by a shaft via a tilt unit, the shaft is movable relative to the chamber in a first axis direction parallel to a surface of the substrate in a film deposition position and in a second axis direction perpendicular to the surface of the substrate in a film deposition position; The tilt unit is a sputtering apparatus capable of adjusting an inclination angle of a surface of a target attached to the sputtering electrode with respect to a surface of the substrate at a film formation position, a bellows tube is fixed between the shaft and the sputtering electrode; a cable for supplying high frequency power to the sputtering electrode is inserted from the outside of the chamber through the inside of the shaft and the bellows tube, and connected to the sputtering electrode; The tilt unit includes a cam slide mechanism that keeps the length of the cable constant regardless of the adjusted tilt angle.

2. The diameter of the sputtering electrode is 190 mm or more, The tilt unit is capable of adjusting the tilt angle in the range of 0° to 90°. The sputtering apparatus of claim 1, wherein the shaft is movable in the second axis direction within a range of 0 to 350 mm relative to the surface of the substrate at a film formation position such that the center coordinates of the sputtering electrode are movable in the first axis direction within a range of 0 to 590 mm relative to the center coordinates of the surface of the substrate at a film formation position such that the center coordinates of the sputtering electrode are movable in the first axis direction within a range of 0 to 590 mm relative to the center coordinates of the surface of the substrate at a film formation position.

3. 3. A program for assisting in determining optimal values ​​of a central coordinate and an inclination angle of the sputtering electrode in the sputtering apparatus according to claim 1, comprising: A program for causing a computer to execute a step of: determining parameters including variables of a center coordinate, the tilt angle, and a sputtering particle emission angle distribution model based on actual measurements of a film thickness distribution of a film formed on a substrate when a predetermined vacuum level and a predetermined target material are sputtered at any center coordinate and tilt angle using the sputtering apparatus; simulating the flight of sputtering particles based on the determined parameters, and predicting a film thickness distribution of a film formed on the substrate; The steps include: calculating variables of the emission angle distribution model that minimizes a difference between the measured film thickness distribution value and the calculated film thickness distribution value by Bayesian optimization with the variables of the emission angle distribution model of the sputtering particles as a search range; a step of calculating, by Bayesian optimization using the calculated variables of the emission angle distribution model and with the center coordinate and the tilt angle as search ranges, the center coordinate and the tilt angle at which the calculated value of the film thickness distribution is minimized.

4. The steps include generating random number samples to represent a model of the emission angle distribution of the sputtering particles; The step of generating the random number sample comprises: A range of emission angles is set to 0 to π / 2 radians, and an angle list is generated for each arbitrary angle within the emission angle range; calculating a probability density for each angle in the list of angles based on a probability distribution formula P(θ)=A·cosn(θ)−B·cosm(θ); normalizing the calculated probability density; randomly selecting angles according to a uniform distribution in the range of emission angles to generate the random number sample; Comparing the normalized probability density calculated by the probability distribution formula based on the selected angle with a uniform random number, and accepting the angle as a sample when the normalized probability density is greater than the uniform random number; 4. The program according to claim 3, wherein the above steps are repeated until a predetermined number of samples are obtained.

5. The probability distribution formula is adjusted by parameters A and B, and the shape of the distribution is determined by parameters n and m.

5. The program of claim 4, wherein the angle samples are selected using an acceptance / rejection method, and sampling is performed based on a maximum probability value obtained by normalizing the probability density.

6. generating the sputtering particle emission source as a point source within an annular region; The step of generating as a point source receiving an inner radius, an outer radius and a density of a plurality of annular regions; Calculate the area of ​​each toric region; determining a number of point sources to be generated based on the area and density of each annular region; Dividing the angle into equal intervals to evenly space the point sources; generating a random radius and calculating coordinates of the point source based on the radius and the angle; 4. The program of claim 3, wherein the coordinate of a particular axis of the point source is set to a unique value.

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