JP2002231176A - Ion implanter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict generation of particles from a subject to implantation by holding the subject. SOLUTION: For material of contact parts with a silicon wafer 24 in a wafer chuck pin 30 and a wafer chuck plate 28 for holding the side surface side of the silicon wafer 24, one of tantalum material, silicon carbide material, and carbon material is used, thereby generation of particles from contact parts of a wafer holder 20 with the silicon wafer 24 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implanter, and more particularly, to a SIMOX (S) suitable for implanting oxygen ions into a silicon wafer with the silicon wafer as an implantation target.
evolution by Implanted Ox
ygen).

[0002]

2. Description of the Related Art Conventionally, as an ion implanter for implanting ions into a silicon wafer, there is known an ion implanter which irradiates an ion beam from an ion source into a processing chamber and implants oxygen ions and the like into the silicon wafer disposed in the processing chamber. Have been. This type of ion implanter employs a configuration in which a silicon wafer is supported on a disk-shaped wafer holder, and silicon or quartz is used as a material for the wafer holder. That is, the wafer holder is formed using the same silicon material or quartz material as the silicon wafer, and generation of particles from the wafer holder is prevented.

[0003]

Incidentally, in an ion implanter, particularly in an ion implanter for SIMOX, 50% is used.
Under a high temperature condition of 0 ° C. or more, the wafer holder connected to the rotating disk via the arm holder is rotated at 500 rpm and scanned, and in this state, oxygen ions are implanted into the silicon wafer on the wafer holder for about 4 hours. Therefore, it is necessary to suppress generation of foreign particles and particles. In this case, with respect to the former foreign matter contamination, foreign material contamination can be prevented by limiting the material of a member disposed near the silicon wafer to be irradiated with the ion beam. That is, by using the same silicon material or quartz material as the silicon wafer as the material of the wafer holder to be irradiated with the ion beam while holding the silicon wafer, foreign material contamination can be prevented.

However, even if the same silicon material or quartz material as the silicon wafer is used for the wafer holder, in view of the latter particle generation, the silicon material or quartz material has poor contact with the silicon wafer, and the contact between the silicon material and the quartz material is poor. There is a problem that particles are generated from the point.

[0005] An object of the present invention is to provide an ion implanter which can suppress generation of particles from an implantation target by holding the implantation target.

[0006]

In order to solve the above-mentioned problems, the present invention provides a processing chamber for forming a processing space for an object to be implanted in a vacuum atmosphere, and an ion beam emitted from an ion source. Ion beam incident means for incident on the substrate, holding means arranged in the processing chamber for movably holding the implantation target, and moving the holding means within a propagation region of the ion beam as a passage area for the implantation target. And a transporting means, wherein the contact portion of the holding means with the object to be implanted comprises an ion implanter made of a material having good contact with the object to be implanted.

Further, the present invention provides a processing chamber for forming a processing space for an implantation object in a vacuum atmosphere, an ion source for generating and emitting an ion beam, and a specific ion beam emitted from the ion source. Ion beam injection means for extracting an ion species and injecting an ion beam of a specific ion species into the processing chamber; holding means arranged in the processing chamber to movably hold the implantation target; and Transport means for moving the holding means in the propagation region of the ion beam as a passage area of the implantation target, a contact portion of the holding means with the implantation target is a material having good contact with the implantation target. This constitutes an ion implanter having the above configuration.

In configuring each of the ion implanters, the following elements can be added.

(1) The holding means is a disk-shaped holder base, a chuck plate fixed to the outer peripheral side of the holder base and a part of which is projected in a radial direction of the holder base, A chuck pin disposed on the outer peripheral side of the holder base so as to be movable in the radial direction of the holder base in opposition to the chuck plate, and a part of the chuck pin is projected in the radial direction of the holder base; The outer peripheral side of the injection target arranged on the holder base is held by the chuck plate and the chuck pins.

(2) The transporting means comprises a rotating disk driven to rotate by a driving source, and a plurality of holder arms connected to the rotating disk and radially arranged on the outer peripheral side of the rotating disk. The holder base is fixed to tip ends of the plurality of holder arms.

(3) The tip ends of the plurality of holder arms are bent in a direction perpendicular to the rotation surface of each holder arm, and the holder base is fixed to the tip of the bent portion.

(4) A V-groove is formed on a contact surface of the chuck plate which is to be in contact with the object to be injected.
One surface of the V-groove is formed in parallel with the holder base, and the other surface of the V-groove is formed on an inclined surface inclined toward the holder base with respect to the incident direction of the ion beam.

(5) The V-groove of the chuck plate is formed to have a curvature according to the outer shape of the object to be injected.

(6) In the chuck pin, at least a contact portion with the injection target is formed in a columnar shape.

(7) The chuck pin has a cylindrical small-diameter portion serving as a contact portion with the injection target, and large-diameter portions formed on both sides of the small-diameter portion with a diameter larger than the small-diameter portion. And a tapered surface is formed between the small-diameter portion and each of the large-diameter portions so that the diameter gradually increases from the small-diameter portion toward each of the large-diameter portions.

(8) The material of the contact portion of the holding means with the object to be injected is a tantalum material.

(9) The material of the contact portion of the holding means with the object to be injected is a silicon carbide material.

(10) The material of the contact portion of the holding means with the object to be injected is a carbon material.

(11) The object to be implanted is a disk-shaped silicon wafer.

According to the above-mentioned means, by using a material having good contact with the injection target as a material of the contact portion with the injection target in the holding means, for example, under a high temperature condition of 500 ° C. or more, the injection target Is rotated at 500 rpm, and even when the ion beam is implanted for about 4 hours, it is possible to suppress the generation of particles from the contact area with the implantation target, which can contribute to the improvement of quality.

Further, a small-diameter portion is formed on a chuck pin which is to be in contact with the implantation target, or a V-groove is formed in a chuck plate which is to be in contact with the implantation target. Is prevented from being directly irradiated, foreign matter contamination can also be suppressed. Also,
When a silicon wafer is used as a material to be implanted, the material having good contact properties can be determined in consideration of hardness, surface shape (smoothness), wettability of the material, and metal contamination on the silicon wafer.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram of an ion implanter showing one embodiment of the present invention. 1, the ion implanter includes an ion source 10, a mass separator 12, a processing chamber (end station) 14, a rotating disk 16, a holder arm 18, a wafer holder 20, and the like.

The ion source 10 is connected to the mass separator 12 via a vacuum-evacuated pipe (not shown).
The ion beam 22 is generated by oxygen ions, and the generated ion beam 22 is emitted to the mass separator 12 side. The mass separator 12 is connected to the processing chamber 14 via a vacuum-evacuated pipe (not shown), and applies an electromagnetic force to the ion beam 22 from the ion source 10 to deflect the ion beam 22 by about 90 °. And an ion species having a required mass from the ion beam 22, for example,
The apparatus is configured as an ion beam incident means for separating and extracting only oxygen ions and injecting an ion beam 22 of oxygen ions as a specific ion species into the processing chamber 14. The processing chamber 14 is evacuated by a vacuum exhaust device (not shown) to form a processing space for a silicon wafer 24 to be implanted in a vacuum atmosphere. The rotating disk 1 is provided in the processing chamber 14.
6, a holder arm 18, a wafer holder 20, and the like are accommodated.

The rotating disk 16 holds the silicon wafer 2 in the propagation region of the ion beam 22 by a specific ion species.
As an element of the transfer means for moving the wafer holder 20 as a passage area of the silicon wafer 4, for example, the silicon held by the wafer holder 20 is connected to a driving source such as a motor and is driven to rotate and reciprocate along the arrow X direction. The wafer 24 is rotated and scanned. Four aluminum holder arms 18 are connected to the outer peripheral side of the rotary disk 16 at a 90 ° pitch, and each holder arm 18 can rotate about an axis.

As shown in FIG. 2, each holder arm 18 is bent at its distal end in a direction orthogonal to the rotation surface of each holder arm 18, and a wafer holder base 26 is provided at the distal end of the bent portion. Fixed. That is, the distal end side of the holder arm 18 is bent in a direction orthogonal to the irradiation direction of the ion beam 24. The wafer holder base 26 is formed in a disc shape using an aluminum material, and a wafer chuck plate 28 is fixed to an outer peripheral side of the wafer holder base 26. The wafer chuck pins 30 are arranged movably along the radial direction of the wafer holder base 26. A part of the wafer chuck plate 28 protrudes from the outer peripheral side of the wafer holder base 26 along the radial direction of the wafer holder base 26,
The outer peripheral side of the silicon wafer 24 on the wafer holder base 26 and a part thereof are formed in a plate-like shape. The wafer chuck plate 28 may be formed in, for example, an arc shape having a curvature that matches the external shape of the silicon wafer 24, or may be provided with a step on the contact surface side with the wafer 24. It is also possible to adopt a configuration of contacting.

The wafer chuck pins 30 are formed in a cylindrical shape, and the bottom side thereof is fixed to a support plate 32.
The end of the support plate 32 is connected to the bottom of the wafer holder base 26 so as to be movable in the radial direction of the wafer holder base 26, and is fixed to the bottom of the wafer holder base 26 (not shown). Urged toward the center of the wafer holder base 26. The outer peripheral side of the silicon wafer 24 is held by the spring force (elastic force) of the spring. The support plate 32
Is connected to a pusher (not shown). When the wafer 24 is set on the wafer holder base 26, the pusher drives the support plate 32 away from the wafer holder base 26 against the spring force. The wafer 24 is set on the wafer holder base 26. When the driving by the pusher is stopped after the silicon wafer 24 is set, the silicon wafer 24 moves toward the wafer holder base 26 by a spring force.

That is, in the present embodiment, the wafer holder 20 as a holding means for movably holding the silicon wafer 24 to be injected is formed by a wafer chuck plate 28 and two wafer chuck pins 30.
At this point, the outer peripheral side of the silicon wafer 24 is held.

Further, in the present embodiment, the contact portions of the wafer chuck plate 28 and the wafer chuck pins 30 with the silicon wafer 24 are
For example, a material having good contact with a material such as a tantalum material, a silicon carbide material, and a carbon material (graphite) is used.

In the ion implanter having the above structure, 5
Under a high temperature condition of 00 ° C. or more, the rotating disk 16 is
to drive rotating at rpm, the ion beam 22 by the oxygen ions irradiated toward the silicon wafer 24, oxygen ions are implanted approximately 4 hours, then was annealed, according to the SiO ₂ in the silicon wafer 24 A crystal layer was formed as an insulating film. In this case, centrifugal force always acts on the silicon wafer 24 on each wafer holder 20, and friction occurs between the silicon wafer 24 and the wafer chuck plate 28 and the wafer chuck pins 30, but the wafer chuck plate 28 and the wafer chuck Since a material having good contact with the silicon wafer 24 is used for the contact portion of the pin 30 with the silicon wafer 24, generation of particles from the contact portion can be suppressed.

Further, according to the present embodiment, the distal end side of each holder arm 18 is bent, and the holder arm 18 and the silicon wafer 24 are arranged while maintaining the height H. Even if the ion beam 22 is irradiated and particles are generated from the holder arm 18,
The mixing of the particles into the silicon wafer 24 can be suppressed.

The base material of the wafer chuck plate 28 and the wafer chuck pins 30 is silicon, quartz,
Materials such as carbon which have little foreign matter and metal contamination are used.

The contact portions of the wafer chuck plate 28 and the wafer chuck pins 30 with the silicon wafer 28 are connected to the wafer holder base 26 via conductive lines made of tantalum material, so that the ion beam 22
Even if the silicon wafer 24 is charged with the implantation of the silicon wafer, the charged charge is transferred to the wafer holder base 26 and the holder arm 18.
And can flow to the ground side, thereby preventing generation of particles due to charging.

Next, another embodiment of the wafer chuck plate will be described with reference to FIGS. The wafer chuck plate 28a in the present embodiment is formed in a substantially rectangular parallelepiped shape, and a step 34 is formed on the bottom side.
A V-groove 36 is formed on a side surface facing the silicon wafer 24, that is, a contact surface serving as a contact portion with the silicon wafer 24. One surface 36 a of the V groove 36 is formed so as to be parallel to the wafer holder base 26, and the other surface 3 a
6b is formed as an inclined surface inclined by an angle θ toward the wafer holder base 26 with respect to the incident direction of the ion beam 22. That is, the ion beam 22 is
Is formed to prevent the light from directly entering.

Further, a rectangular tantalum material 38 formed in a rectangular shape is mounted substantially at the center of the V groove 36. That is, the base material of the wafer chuck plate 28a is
While it is made of silicon, quartz, carbon or the like which is less contaminated with foreign matter and metal, the portion of the wafer chuck plate 28a which is to be in contact with the silicon wafer 24 has a good contact property with the silicon wafer 24. A tantalum material 38 is mounted among tantalum materials, silicon carbide materials, and carbon (graphite), which are good materials.

In mounting the tantalum material 38 on the wafer chuck plate 28a, as shown in FIG. 4, the tantalum material 38 may be deposited on the surface of the step 34 and the entire side surface of the wafer chuck plate 28a.

According to the present embodiment, the silicon wafer 24
Since the tantalum material 38 is mounted in a foil shape or vapor-deposited in the V-groove 36 in the process of holding the outer peripheral side of the V-groove with the V-groove 36, generation of particles from the contact portion with the silicon wafer 24 is suppressed. can do. Further, an inclined surface is formed in the V groove 36, and the ion beam 22 does not directly enter the V groove 36, so that scattering and contamination of the tantalum material can be prevented.

In this embodiment, the V-groove 36 is formed on a straight line. However, the shape of the V-groove 36 is the same as that of the silicon wafer 24 in accordance with the outer shape of the silicon wafer 24. Can be formed in an arc shape having

In the present embodiment, a shielding plate for shielding the ion beam 22 may be disposed above the V-groove 36, or the tantalum material 38 may be attached only to the deep portion of the V-groove 36. it can.

Next, another embodiment of the wafer chuck pin will be described with reference to FIGS. The wafer chuck pins 30a according to the present embodiment are formed in a columnar shape using a material having little foreign matter and metal contamination such as silicon, quartz, or carbon as a base material. A cylindrical tantalum ring 40 serving as a contact portion with the silicon wafer 24 is formed as a small-diameter portion on the upper side of the wafer chuck pin 30a, and the diameter of the tantalum ring 40 is larger than the tantalum ring 40 with the tantalum ring 40 interposed therebetween. A large diameter portion 42 and a wafer chuck pin main body (large diameter portion) are formed on both sides thereof, and between the tantalum ring 40 and each large diameter portion, gradually from the tantalum ring 40 toward each large diameter portion. A tapered surface having a large diameter is formed.

The wafer chuck pins 30a are made of a material having little foreign matter and metal contamination such as silicon, quartz, carbon, or the like as a base material. The tantalum ring 40 is made of a material having good contact with the silicon wafer 24. Is configured using a tantalum material. In forming the tantalum ring 40, a tantalum material can be deposited only on the surface of the tantalum ring 40 as shown in FIG.

According to the present embodiment, since the tantalum material is used in the portion of the wafer chuck pin 30a that contacts the silicon wafer 24, the wafer chuck pin 30a
Since it is possible to prevent the generation of particles from the contact portion of the silicon wafer 24 with the silicon wafer 24a and prevent the ion beam 22 from directly entering the tantalum ring 40 by the large diameter portion 42, Scattering and contamination of the tantalum material can be prevented.

Note that, instead of the tantalum ring 40, a wire made of a tantalum material can be wound around the tantalum ring 40.

Next, another embodiment of the wafer holder 20 will be described with reference to FIG. A plurality of wafer setting pins 44 are set on the wafer holder base 26 in the present embodiment, and each wafer setting pin 44 is configured using a tantalum material. Each of the wafer setting pins 44 has a substantially spherical shape on the tip side.
4 is fixed to the wafer holder base 26 via a support plate 46. Each wafer setting pin 44 is connected to the silicon wafer 2
When the wafer 4 is set on the wafer holder 20, the bottom side of the silicon wafer 24 is held.

According to the present embodiment, the outer peripheral side of the silicon wafer 24 is held by the wafer chuck plate 28 and the two wafer chuck pins 30, and the bottom side of the silicon wafer 24 is held by the respective wafer setting pins 44. Thus, the silicon wafer 24 can be held more reliably.

In forming the wafer chuck plate 28a, a tethered material 38 is connected to a strip-shaped ground line made of a tantalum material, and this ground line is connected to the wafer holder base 26, so that the charged charges are grounded. You can escape.

Here, an 8-inch silicon wafer 2 was formed using a conventional ion implanter and the ion implanter according to the present invention.
4 was irradiated with the ion beam 22 to measure the generation state of the particles. The number of particles was 0.2 μm or more per 8 inch silicon wafer 24 compared to 1000 or more in the conventional ion implanter. However, by using the ion implanter according to the present invention, the result was reduced to 200 or less.

[0047]

As described above, according to the present invention,
Since a material having good contact with the injection target is used as a material of a contact portion with the injection target in the holding means, generation of particles from the contact portion with the injection target can be suppressed, and quality is improved. Can be contributed to.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an ion implanter according to an embodiment of the present invention.

FIG. 2 is a perspective view for explaining a relationship between a wafer holder and a holder arm.

FIG. 3 is a perspective view showing another embodiment of the wafer chuck plate.

FIG. 4 is a perspective view showing another embodiment of the wafer chuck plate.

FIG. 5 is a perspective view showing another embodiment of the wafer chuck pin.

FIG. 6 is a perspective view showing another embodiment of the wafer chuck pin.

FIG. 7 is a side view showing another embodiment of the wafer holder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ion source 12 Mass separator 14 Processing chamber 16 Rotating disk 18 Holder arm 20 Wafer holder 22 Ion beam 24 Silicon wafer 26 Wafer holder base 28, 28a Wafer chuck plate 30, 30a Wafer chuck pin 36 V groove 38 Tantalum material 40 Tantalum ring 42 Large diameter part 44 Wafer setting pin

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 27/12 H01L 21/265 J F term (Reference) 4K029 AA06 AA24 BA32 CA10 5C034 CC09 5F031 CA02 HA02 HA24 HA42 HA45 HA58 HA59 MA31 PA26

Claims (13)

[Claims] 1. A processing chamber for forming a processing space for an implantation target in a vacuum atmosphere, an ion beam incident means for inputting an ion beam emitted from an ion source into the processing chamber, and disposed in the processing chamber. Holding means for movably holding the implantation target, and transport means for moving the holding means as a passage area for the implantation target within the propagation region of the ion beam, and An ion implanter in which a contact portion is made of a material having good contact with the implantation target. 2. A processing chamber for forming a processing space for an implantation target in a vacuum atmosphere, an ion source for generating and emitting an ion beam, and extracting a specific ion species from the ion beam emitted from the ion source. Ion beam injection means for injecting an ion beam of a specific ion species into the processing chamber; holding means disposed in the processing chamber to movably hold the implantation target; and propagation of the ion beam by the specific ion species Carrying means for moving the holding means as a passage area of the injection target in the area,
An ion implanter in which the contact portion of the holding means with the implantation target is made of a material having good contact with the implantation target. 3. The ion implanter according to claim 1, wherein said holding means is a disc-shaped holder base, and is fixed to an outer peripheral side of said holder base, a part of which is said holder base. A chuck plate protruding in the radial direction of the holder base is disposed on the outer peripheral side of the holder base so as to be movable along the radial direction of the holder base in opposition to the chuck plate, and a part of the chuck base is provided. An ion implanter comprising: a chuck pin protruding in a radial direction, wherein an outer peripheral side of an implantation target arranged on the holder base is held by the chuck plate and the chuck pin. 4. The ion implanter according to claim 3, wherein said transport means is connected to said rotating disk rotated by a driving source and is radially disposed on an outer peripheral side of said rotating disk. An ion implanter comprising: a plurality of holder arms provided, wherein the holder base is fixed to tip ends of the plurality of holder arms. 5. The ion implanter according to claim 4, wherein the plurality of holder arms have their distal ends bent in a direction orthogonal to the rotation surface of each of the holder arms, and the distal ends of the bent portions. The holder base is fixed to the ion implanter. 6. The ion implanter according to claim 3, wherein a V-groove is formed on a contact surface of the chuck plate that is to be in contact with the implantation target, and one surface of the V-groove is the holder. An ion implanter formed parallel to the base, wherein the other surface of the V-groove is formed on an inclined surface inclined toward the holder base with respect to the incident direction of the ion beam. 7. The ion implanter according to claim 6, wherein the V-groove of the chuck plate is formed with a curvature according to an outer shape of the object to be implanted. 8. The ion implanter according to claim 6, wherein the chuck pin has a columnar shape at least in contact with the implantation target. 9. The ion implanter according to claim 6, wherein the chuck pin includes a cylindrical small-diameter portion serving as a contact portion with the implantation target, and a small-diameter portion having a diameter larger than the small-diameter portion. A large diameter portion formed on both sides of the tapered surface between the small diameter portion and each of the large diameter portions has a tapered surface whose diameter gradually increases from the small diameter portion toward each of the large diameter portions. An ion implanter characterized by being formed. 10. The ion implanter according to claim 1, wherein a material of a contact portion of said holding means with said implantation target is a tantalum material. Injection machine. 11. The ion implanter according to claim 1, wherein a material of a contact portion of said holding means with said implantation target is a silicon carbide material. Ion implanter. 12. The ion implanter according to claim 1, wherein a material of a contact portion of said holding means with said object to be implanted is a carbon material. Injection machine. 13. The ion implanter according to claim 1, wherein the implantation target is a disk-shaped silicon wafer.