JP2000251828A - Substrate holding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate holding device suited for reducing dispersion of ion implantation requirements at each point on a substrate surface. SOLUTION: A process target substrate is held on the holding face of a pedestal 12. A revolving mechanism causes the pedestal 12 to revolve along a circular orbit around a revolution shaft 11. During a process period, from when the pedestal 12 approaches a processing region on this circular orbit to when is separates away from the process region, a rotation mechanism causes the pedestal 12 to rotate in the opposite direction of the revolution direction, so that the holding face of the pedestal translationally moves along the circular orbit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holding apparatus, and more particularly to a substrate holding apparatus suitable for mounting on an ion implantation apparatus.

[0002]

2. Description of the Related Art FIG. 6A shows a front view of a substrate holding disk 100 of a conventional ion implantation apparatus. Rotating shaft 101
A plurality of pedestals 102 are arranged at equal intervals along a circumference centered at. A substrate is held on each pedestal 102. A part of the disk 100 is provided with a slit 103 extending in the radial direction.

A substrate is placed on a pedestal 102 and a disk 10
When 0 rotates around the rotation axis 101, each substrate revolves on a circular orbit about the rotation axis 101. As the substrate passes through the intersection region 104 with the ion beam,
Ion implantation is performed on the substrate.

When the slit 103 crosses the path of the ion beam, a part of the ion beam passes through the slit 103. By monitoring the beam current of the ion beam that has passed through the slit 103, an abnormality of the ion beam during the ion implantation period can be detected.

[0005]

When performing ion implantation,
The substrate is fixed to the pedestal 102. For this reason, the magnitude of the angle between a certain virtual vector 105 in the substrate plane and the radial direction of the circular orbit of the pedestal 102 is always constant.

When ion implantation is performed on a substrate obliquely, the beam axis of the ion beam is inclined with respect to the substrate surface.
Consider a case where an image obtained by vertically projecting the beam axis onto the substrate surface is directed in the radial direction of the circular orbit of the pedestal 102.

FIG. 6B shows a vertical projection image of the beam axis on the substrate surface. The arrow 106a indicates a vertical projection image of the beam axis when the center of the substrate is located in the intersection region 104 with the ion beam. An arrow 106b shows a vertical projection image of the beam axis when the center of the substrate deviates from the intersection region 104 with the ion beam. Arrows 106a and 106b are not parallel because the substrate is fixed to pedestal 102. In other words, the tilt direction of the beam axis incident on each point on the substrate surface is not constant. For this reason, conditions for ion implantation vary for a plurality of chips arranged in the substrate surface.

An object of the present invention is to provide a substrate holding apparatus suitable for reducing variations in ion implantation conditions at each point on a substrate surface.

[0009]

According to one aspect of the present invention, a pedestal having a holding surface for holding a substrate to be processed, a revolving mechanism for revolving the pedestal along a circular orbit around a revolving axis, The pedestal is revolved so that the holding surface of the pedestal translates along the circular orbit during a processing period until the pedestal approaches a processing area on the circular orbit and separates from the processing area. There is provided a substrate holding device having a rotation mechanism for rotating in a direction opposite to the direction.

By performing the translational movement of the pedestal during the processing period, it is possible to perform uniform processing on the surface of the processing object held on the pedestal.

[0011]

FIG. 1 is a schematic view of an ion implantation apparatus to which a substrate holding device according to an embodiment of the present invention is applied.
Through a window 2 provided in a processing container 1 which can be evacuated,
An ion beam 3 is introduced into the processing chamber 1.

In the processing container 1, a substrate holding device 10 is disposed. The substrate holding device 10 rotates about the revolution axis 11 in the direction indicated by the arrow AR1. A plurality of pedestals 12 are arranged along a circumference around the revolution axis 11. When the substrate holding device 10 rotates, the pedestal 12 revolves on a circular orbit. When the substrate held on the pedestal 12 crosses the path of the ion beam 3, the substrate is irradiated with the ion beam and ion implantation is performed.

On the substrate holding surface of each pedestal 12, a substrate fixing mechanism 13 for fixing the substrate is provided. The detailed configuration of the substrate fixing mechanism 13 will be described later with reference to FIG. The substrate holding surface of each pedestal 12 is slightly inclined so as to face the revolving shaft 11 from the track surface of the pedestal 12. When the pedestal 12 revolves, the substrate placed thereon is pressed against the substrate holding surface by centrifugal force and fixed.

A beam current measuring means 50 is arranged downstream of the position where the pedestal 12 crosses the ion beam 3. As the beam current measuring means 50, for example, a Faraday cup can be used. Beam current measuring means 50
Can measure the current due to the incident ion beam. The measured current value is input to the control means 52.

Driving means 51 rotates the substrate holding device 10 so that the substrate holding device 10 rotates so that the distance from the revolution axis 11 to the beam irradiation point 4 where the ion beam 3 and the pedestal 12 intersect varies. The translation is performed in the direction indicated by the arrow AR2. The direction of the translation is within a plane including the beam axis of the ion beam 3 and the revolution axis 11 and is parallel to the surface of the substrate on which the ion beam 3 is irradiated.
Further, the driving means 51 moves the substrate holding device 10
It can be moved in the direction indicated by R3. Substrate holding device 10
Can be changed, so that the injection angle (incident angle) of the ion beam into the substrate can be changed. Substrate holding device 1
The rotation, translation, and tilting of 0 are controlled by a drive signal provided from the control unit 52 to the drive unit 51.

FIG. 2 is a front view of the substrate holding device 10 of FIG. The plurality of pedestals 12 are arranged at a certain interval along a circumference around the revolution shaft 11. Each pedestal 1
2 is supported on the revolving shaft 11 by the arm 17. Diameter 30
In the case of an apparatus for processing a substrate of 0 mm, the diameter L2 of each pedestal 12 is about 300 mm, the diameter L1 of a circular orbit drawn by the center of the pedestal 12 is 1300 mm, and the minimum distance L3 between the pedestals 12 adjacent to each other is about 11 mm.

The circular orbit of the pedestal 12 intersects the ion beam passage area (processing area) 14. When the pedestal 12 crosses the ion beam passage area 14, ions are implanted into the substrate held on the holding surface.

Consider a virtual vector 15 on the substrate holding surface of the pedestal 12. It is assumed that the direction of the virtual vector 15 is fixed to the substrate holding surface. The virtual vector 15 does not change its direction during the ion implantation period (processing period) until the pedestal 12 approaches the ion beam passage area 14 and moves away from the ion beam passage area 14. That is, the pedestal 12 translates during the ion implantation period. This translation is realized by rotating the pedestal 12 in a direction opposite to the direction of the revolution with respect to the radial direction of the circular orbit (the length direction of the arm 17).

When the pedestal 12 leaves the beam passage area 14, the pedestal 12 makes a complete circuit along the circular orbit, and then returns to the beam passage area 1.
Approaching 4. During a waiting period before reaching the beam passage area 14, the pedestal 12 rotates in the same direction as the revolving direction with respect to the arm 17 by the same angle as the angle rotated during the ion implantation period. By this rotation, virtual vector 1
The direction of 5 is the same as the direction during the previous ion implantation period.

During the period in which the pedestal 12 crosses the ion beam passage area 14, the direction of the virtual vector 15 on the substrate holding surface is constant, so that ion implantation can be performed on the entire surface of the substrate under almost the same conditions. The speed at which the pedestal 12 crosses the ion beam passage area 14 is the same at any position in the substrate surface. Therefore, if the beam current is constant,
When ion implantation is performed on the inner peripheral region of the circular orbit in the substrate surface, and when ion implantation is performed on the outer peripheral region,
There is no need to change the speed of revolution or the speed of translation of the substrate holding device 10.

FIG. 3 is a schematic diagram for explaining the rotation mechanism of the pedestal 12. An arm 17 extends radially from the revolution shaft 11. The pedestal 12 is attached to the tip of the arm 17 so as to be able to rotate. The cam fixing portion 40 defines a cam surface 40 a that makes a round around the revolution shaft 11. As the cam surface 40a advances from the start point Ps on the cam surface 40a in the direction of revolution (clockwise in FIG. 3) to the end point Pe, the revolution axis 1
It gradually approaches 1. When the cam surface 40a further advances in the direction of the revolution from the end point Pe, the cam surface 40a gradually moves away from the revolution shaft 11 and returns to the start point Ps.

A cam follower 20 is attached to the arm 17 at a position outside the cam surface 40a. The cam driven member 20 includes a driven shaft 21, a driven roller 22, a driving roller 23, and a spring 24. One end of the driven shaft 21 is swingably attached to the arm 17. The drive roller 23 is fixed to this one end. Driven shaft 21
Swings, the driving roller 23 rotates according to the swinging motion of the driven shaft 21.

A driven roller 22 is rotatably attached to the other end of the driven shaft 21. The driven roller 22 defines a driven surface 22a. The spring 24 urges the driven shaft 21 to press the driven surface 22a against the cam surface 40a.

A rotation shaft 18 is provided at the tip of the arm 17, and the small diameter portion 16 of the pedestal 12 is arranged coaxially with the rotation shaft 18. A belt 30 is suspended between the small-diameter portion 16 of the pedestal 12 and the driving roller 23. When the drive roller 23 rotates, the rotational force is transmitted to the small diameter portion 16, and the pedestal 12 rotates.

From the state where the driven surface 22a is in contact with the cam surface 40a at the starting point Ps, the arm 17 is moved from the state shown in FIG.
Is rotated clockwise, the driven roller 22
Follows a and approaches the revolving shaft 11. As the driven roller 22 moves, the driven shaft 21 swings. That is, the angle between the radial direction of the circular orbit and the driven shaft 21 changes. Driven shaft 2
When 1 swings, the drive roller 23 rotates. When the drive roller 23 rotates, the rotational force is transmitted to the small diameter portion 16 by the belt 30, and the pedestal 12 rotates on the arm 17.

When the arm 17 is rotated by the angle θ from the state in which the driven surface 22a is in contact with the cam surface 40a at the start point Ps, the pedestal 12 is angled in the direction opposite to the revolving direction with respect to the arm 17. Suppose that it rotates by θ '. The relationship between the rotation angle θ of the arm 17 and the rotation angle θ ′ of the pedestal 12
a, the length of the driven shaft 21, the radius of the driven surface 22 a, the length from the point of attachment of the driven shaft 21 to the arm 17 to the revolving shaft 11, the ratio of the radius between the small diameter portion 16 and the drive roller 23, etc. It is determined. When these are appropriately configured, the rotation angle θ ′ of the pedestal 12 can be made equal to the rotation angle θ of the arm 17. In this case, the pedestal 12 translates along a circular orbit.

FIG. 4 is a sectional view of the tip of the arm 17 and the pedestal 12. As shown in FIG. The inside of the arm 17 is hollow, and at the tip,
A rotation shaft 18 is attached. The rotation axis 18 is the arm 1
7 protrudes from the inner surface of the arm 17 in a direction orthogonal to the length direction of the arm 17, and extends to the outside of the arm 17 through the opposing side wall. A disk portion 19 is attached to the tip of the rotation shaft 18. The disk portion 19 defines an opposing surface 19 a orthogonal to the axial direction of the rotation shaft 18.

The pedestal 12 is arranged so as to surround the disk portion 19. A gap is formed between the pedestal 12 and the disk portion 19. Back surface 12 of substrate holding surface 12a of base 12
b is arranged substantially parallel to the facing surface 19a. Back 12
A minute gap 70 is defined between b and the opposing surface 19a. A film 12d made of silicone rubber is in close contact with the substrate holding surface 12a. The substrate is closely held on the surface of the film 12d.

A small-diameter portion 16 fixed to the pedestal 12 is arranged coaxially with the rotation shaft 18 so as to surround the rotation shaft 18. The small diameter portion 16 is introduced to the inside of the internal cavity of the arm 17. A main bearing 60 is arranged between the outer peripheral surface of the tip of the rotation shaft 18 and the inner surface of the pedestal 12. At the center of the disk portion 19, a columnar concave portion 19b having a common axis with the rotation axis 18 is formed.
On 2b, a convex portion 12c that matches the concave portion 19b is formed. An auxiliary bearing 61 is arranged between the inner peripheral surface of the concave portion 19b and the outer peripheral surface of the convex portion 12c. Rotation axis 1
An auxiliary bearing 62 is disposed between the outer peripheral surface of the inner surface 8 and the inner peripheral surface of the small diameter portion 16. The main bearing 60 and the auxiliary bearings 61 and 62 allow the pedestal 12 to
It is supported rotatably.

A sealing member 65 is mounted on the portion where the small diameter portion 16 penetrates the side wall of the arm 17, and the internal cavity of the arm 17 and the space outside the arm 17 are separated while maintaining airtightness. Pedestal 1
The gap defined between the disk 2 and the disk portion 19 and the internal cavity of the arm 17 are airtightly separated by a sealing member 66. The sealing members 65 and 66 are configured by combining, for example, an O-ring and a ring made of polyethylene.

A belt 30 is suspended between the outer peripheral surface of the small diameter portion 16 and the driving roller 23 shown in FIG. The rotational force of the drive roller 23 is transmitted to the small diameter portion 16 by the belt 30, and the pedestal 12 rotates around the rotation shaft 18.

The heat conduction medium flow path 67 is provided inside the rotation shaft 18.
Are formed. One end of the heat conduction medium flow path 67 is open to the bottom surface of the recess 19c. The other end of the heat transfer medium flow path 67 is connected to an external heat transfer medium supply source through the inside of the side wall of the arm 17. The heat transfer medium is supplied into the gap 70 through the heat transfer medium flow path 67. The heat conduction medium is, for example, nitrogen gas, argon gas, or the like.

Since the gap between the disk portion 19 and the pedestal 12 is sealed by the sealing member 66, the gap is filled with the heat transfer medium. The internal cavity of the arm 17 is evacuated, and the heat transfer medium leaking from the sealing member 66 into the internal cavity of the arm 17 is discharged to the outside.

A cooling medium passage 68 is formed inside the rotation shaft 18 and the disk portion 19. The disk portion 19 can be cooled by flowing a cooling medium, for example, cooling water through the cooling medium passage 68. When the disc portion 19 is cooled, the substrate holding surface 12a of the pedestal 12 and the film 12d made of silicone rubber are cooled through the heat conduction medium filling the gap 70. By cooling the silicone rubber film 12d, it is possible to prevent a temperature rise during the ion implantation period of the substrate held tightly on the surface thereof.

FIG. 5 is a side view of the substrate fixing mechanism. The substrate holding device 10 is supported on the revolution shaft 11. Pedestal 1
Two fixed protrusions 13a are provided on the inner peripheral side of the circular orbit on the two substrate holding surfaces. When the end surface of the substrate 75 held on the substrate holding surface contacts the side surface of the fixed protrusion 13a, the movement of the substrate 75 to the revolving center is restricted.

Two movable members 13b are attached to a portion on the outer peripheral side of the circular orbit on the substrate holding surface. The movable member 13b swings about a fulcrum 13c fixed to the base 12. One end of the movable member 13b protrudes above the substrate holding surface, and a weight 13d is attached to the other end. When the pedestal 12 revolves, centrifugal force acts on the weight 13d, and the weight 13d is swung outward. The portion protruding from the substrate holding surface is swung inward on the opposite side. At this time, the protruding portion of the movable member 13b comes into contact with the outer peripheral end surface of the substrate 75. The position of the substrate 75 can be fixed by sandwiching the substrate 75 between the fixed protrusion 13a and the movable member 13b.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0038]

As described above, according to the present invention,
When the substrate to be processed is held and revolved, the substrate can be rotated in accordance with the revolving motion. By adjusting the speed of revolution and the speed of rotation, it becomes possible to translate the substrate along a circular orbit.

[Brief description of the drawings]

FIG. 1 is a schematic view of an ion implantation apparatus equipped with a substrate holding device according to an embodiment of the present invention.

FIG. 2 is a front view of the substrate holding device according to the embodiment.

FIG. 3 is a schematic view showing a configuration of a pedestal rotation mechanism.

FIG. 4 is a cross-sectional view of the tip of the arm and a pedestal.

FIG. 5 is a side view schematically showing a substrate fixing mechanism.

FIG. 6 is a front view of a substrate holding device used in a conventional ion implantation apparatus, and a conceptual view showing a state of oblique ion implantation into a substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing container 2 Window 3 Ion beam 4 Beam irradiation point 10 Substrate holding device 11 Revolution axis 12 Pedestal 12a Substrate holding surface 12b Back surface 12c Convex part 12d Silicone rubber film 13 Substrate fixing mechanism 14 Ion beam passage area 15 Virtual vector 16 Rotation Shaft 17 Arm 18 Rotating shaft 19 Disk portion 19a Opposing surface 19b Depression 20 Follower member 21 Follower shaft 22 Follower roller 22a Follower surface 23 Drive roller 24 Spring 30 Belt 40 Cam fixing portion 40a Cam surface 50 Beam current measuring means 51 Drive means 52 Control means 60 Main bearing 61, 62 Auxiliary bearing 65, 66 Sealing member 67 Heat conduction medium flow path 68 Cooling medium flow path 70 Gap 75 Substrate

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/68 H01L 21/265 603D

Claims (5)

[Claims] A pedestal having a holding surface for holding a substrate to be processed; a revolving mechanism for revolving the pedestal along a circular orbit around a revolving axis; and a pedestal in a processing area on the circular orbit. A rotation mechanism for rotating the pedestal in a direction opposite to the direction of revolution so that the holding surface of the pedestal translates along the circular orbit during the processing period until approaching and leaving the processing area; A substrate holding device. 2. The revolving mechanism includes: an arm that supports the pedestal and defines a rotation axis of the pedestal; and a driving unit that rotates the arm around the revolving axis. 2. The substrate holding device according to claim 1, wherein the pedestal rotates in accordance with the rotation of the arm. 3. The rotation mechanism comprises: a cam surface that circles around the orbital shaft; and a driven member attached to the arm and defining a driven shaft, the driven surface having one end contacting the cam surface. In accordance with the rotation of the arm, the driven member that changes the angle between the radial direction of the circular orbit and the driven shaft according to the principle of a cam, and the driven shaft of the driven member and the radial direction of the circular orbit. 3. The substrate holding device according to claim 2, further comprising: a rotational force transmitting unit that transmits a rotational force of the driven member due to a change in the angle to the pedestal and rotates the pedestal. 4. The pedestal has a back surface parallel to the holding surface on the back side of the holding surface, and the revolving mechanism has an opposing surface facing the back surface, and the back surface is opposed to the opposing surface. A cooling medium flow that is arranged with a gap therebetween, and the gap and the space on the holding surface side are isolated from each other so as to maintain airtightness; The semiconductor holding device according to claim 1, further comprising a path and a heat conduction medium flow path for supplying a heat conduction medium into the gap. 5. A movement restricting means provided on a holding surface of the pedestal, for restricting movement of the substrate held on the holding surface in the direction of the center of revolution. A movable member attached to an outer peripheral portion, the movable member being swingably attached to the pedestal, and when the pedestal revolves, one end of the swing member swings out of a circular orbit by centrifugal force. The substrate holding device according to any one of claims 1 to 4, further comprising: the movable member that presses the substrate, the other end of which is held on the holding surface, toward the center of revolution.