JPS63192247A - Wafer supporter - Google Patents

Abstract

PURPOSE:To implant ions by setting an angle with high accuracy by mounting a platen consisting of a holding mechanism holding a wafer between a base member and a fixing member and a rolling mechanism turning the wafer together with the holding mechanism. CONSTITUTION:A holding mechanism 10 placing a wafer 8 on a base member (a platen cup 26) and elevating and lowering the wafer and holding the wafer 8 between the base member and a fixing member (a clamping ring 30) and a rolling mechanism 23 (bearings 24, 34, gears 42, 48 and a motor 44) rotating the wafer 8 held to the holding mechanism 10 together with the holding mechanism 10 are installed. Accordingly, the wafer B placed onto the base member is held between the base member and the fixing member by the ascent and descent of the wafer by the holding mechanism 10, and turned by the rolling mechanism 23 together with the holding mechanism 10 under a held state, and the wafer 8 can be sustained at a fixed angle.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wafer support device that holds and rotates a semiconductor wafer.

[Conventional technology]

Conventionally, in ion implantation equipment that implants ions into wafers, the wafer to be ion-implanted is fixed on a platen, and the ion implantation angle with respect to the wafer is adjusted by rotating the wafer around its central axis with respect to the surface of the wafer. Ion implantation is performed multiple times at different angles to one wafer.

For such ion implantation, if a platen does not have a rotation mechanism, after the -th ion implantation, the wafer is taken out of the chamber from the platen, rotated to an arbitrary angle, and then put back into the chamber. The procedure of returning to the platen and performing ion implantation is repeated. In this case, the process of changing the wafer angle involves transport work, which tends to cause errors between the set angle and the actual ion implantation angle, and one wafer must be transported multiple times. Because of this, there is a high possibility that dust will adhere to the wafer, and
Since the processing time for one wafer becomes long, there is a drawback that the number of wafers processed within a certain period of time (throughput) is small.

For this reason, a platen equipped with a rotating mechanism has conventionally been used, but this platen has rotating top-shaped bumpers arranged in a horseshoe or V shape to hold the wafer, and the platen is placed at the lowest point. Rotate the two located in the same direction,
The edges of the wafer are rubbed, causing the wafer to rotate.

[Problem that the invention seeks to solve]

By the way, in conventional systems equipped with a rotation mechanism, the wafer is rotated by rolling friction, so there is a possibility of slipping during rotation, and it is not reliable that the wafer will be centered at the set angle. During rotation, the back side of the wafer is in contact with the platen and is rubbed directly by the drive wheel, which tends to generate dust. Also, since the wafer is not in close contact with the platen, the cooling capacity of the wafer is reduced. There were disadvantages such as inferiority.

Therefore, this invention integrates the holding and rotation of the wafer, performs holding and rotation without causing any friction during rotation when taking out the wafer, and performs ion implantation by setting a highly accurate angle. It is.

[Means for solving problems]

As shown in FIG. 1, the wafer support device of this invention has the following features:
A holding mechanism 10 that places a wafer 8 on an i1W member (platen cup 26) and moves it up and down, and holds the wafer 8 between the mounting member and a fixing member (clamp ring 30); and a wafer held by the holding mechanism 10. 8 together with the holding mechanism 10 (bearing 24, 34
, gears 42, 48, and a motor 44).

[For production]

According to the present invention, by doing so, the wafer 8 placed on the mounting member is held by the holding mechanism 10 while being sandwiched between the holding member and the fixing member as the wafer 8 is raised and lowered. The wafer 8 held by the holding mechanism IO is rotated by the rotation mechanism 23 together with the holding mechanism 10 in the held state, so that the wafer 8 can be held at a predetermined angle.

Furthermore, since a fixing member that rotates together with the wafer 8 is provided and the wafer 8 is closely attached to the platen side, there is no need to worry about positional displacement during rotation, and the cooling capacity is also lower than that of a conventional platen that does not have a rotating mechanism 23. It will be equivalent. Furthermore, when the wafer 8 rotates, there is no friction with other members, so no dust is generated.

For example, when implanting ions into the wafer 8, it is necessary to tilt the wafer 8 nearly vertically, and therefore it is necessary to hold (clamp) the wafer 8 on the platen. Although it is necessary to rotate the wafer in a state in which the wafer is rotated, the use of the wafer support device of the present invention can meet such requirements.

In the wafer support device of the present invention, the holding mechanism 10 holds the wafer 8 between the clamp ring 30 fixed to the main body side and the platen cup 26 by lifting the platen cup 26 on which the wafer 8 is placed. By doing so, the wafer 8 can be held securely.

Further, in the wafer support device of the present invention, the holding mechanism 10 has a platen cup 2 attached to the edge of the platen cup 26.
If a locking member (arm 54, 56) is provided that rotates in response to the rise of the wafer 6 and faces onto the wafer 8, and the wafer 8 is held by the locking member, the locking member on the main body side can be placed on the wafer 8. Since it is only a member, it is possible to suppress the generation of dust and the like as much as possible.

〔Example〕

1 to 4 show a first embodiment of the wafer support device of the present invention.

In this embodiment, a wafer support device is implemented in a platen mechanism of an ion implanter. That is, a bellows plate 6 is attached to the platen mechanism via three supports 4 on the circumference of the lower surface of the platen main body 2 as a base, and is a lifting means for raising and lowering the wafer 8 to be held in the holding mechanism 10. A bellows 12 is supported.

A cup holder 14 is fixed to the upper part of the bellows 12. The cup holder 14 vertically passes through the platen body 2 so as to be vertically movable, and a guide shaft 18 is attached with a spring 16 that urges the platen body 2 downward.
is elastically supported in equilibrium by As shown in FIG. 2, this guide shaft 18 has bearings 19 disposed circumferentially at equal angles around the central axis of the cup holder 14 and press-fitted into the platen body 2.
The spring 16 is inserted between the lower surface of the platen body 2 and a plate 20 attached to the guide shaft 18.

A circular platen cup 26 is attached to the upper surface of the cup holder 14 along with the inner race 22 as an R-mounting member for rotatably mounting the wafer 8 via a bearing 24 in the rotation mechanism 23. The platen cup 26 has a circular shape as shown in FIG.
A recess 28 is formed for placing the wafer 8 at t2.

A clamp ring 30 as a fixing member attached to the platen body 2 is installed on the top of the platen cup 26, and the tip of the clamp ring 30 is used to hold down the wafer 8 placed on the platen cup 26. It is set so as to fit into the recess 28 of the platen cup 26.

The clamp ring 30 is rotatably attached to a clamp block 32 attached to the platen body 2 via a bearing 34, and a retainer 36 is provided on the upper edge thereof.

Then, the pressure fluid 40 is caused to flow into the space inside the bellows 12 from the fluid injection hole 38 provided at the center of the bellows plate 6, thereby promoting the expansion of the bellows 12, and the cup holder 14 and the platen cup configured above the bellows 12. 26
etc. can be raised vertically. At this time, the guide shaft 18 is also pulled up, and the guide shaft 1
The spring 16 inserted between the plate 20 and the platen body 2 is compressed by the receiver fixed to the lower end of the platen 8. The guide shaft 18 is guided by the bearing 19 of the platen body 2 and can move up and down smoothly.
It functions as a guide when raising and lowering the cup holder 14 and the platen cup 26.

Therefore, as the platen cup 26 rises, the wafer 8 is sandwiched between the clamp ring 30 and clamping is completed, as shown in FIG. In addition, when removing the wafer 8, the pressure fluid 40 in the bellows 12
By lowering the pressure, the reaction force of the compressed spring 16 acts to lower the cup holder 14, and the platen cup 26 fixed thereto lowers to complete unclamping.

Then, the platen cup 26 and the clamp ring 30
are rotatably fixed to the platen body 2 via bearings 24 and 34, respectively, and a gear 48 attached to a rotating shaft 46 of a motor 44 meshes with a gear 42 formed around the platen cup 26. has been done. That is, the rotation mechanism 23 for rotating the wafer 8 while holding it is composed of bearings 24, 34, gears 42, 48, and a motor 44.

Therefore, by such a rotation mechanism 23.

After holding the wafer 8 between the platen cup 26 and the clamp ring 30, by rotating the motor 44, the platen cup 26 can be rotated, and the wafer 8 can be set at an arbitrary angle. and,
Since the platen cup 26 and the clamp ring 30 are clamped and rotated via the wafer 8, the wafer 8 can be rotated without causing friction between the wafer 8 and other members.

Next, FIGS. 5 to 7 show a second embodiment of the wafer support device of the present invention.

As shown in FIG. 5, in the platen mechanism of this embodiment, the elevating means such as bellows 12 for holding the wafer 8 and the rotation mechanism 23 for rotating the wafer 8 are constructed in the same manner as in the first embodiment. However, the holding mechanism 10 for holding the wafer 8 is different.

That is, in the platen mechanism of this embodiment, as shown in FIG. 6, a pair of brackets 50.5°2 of the holding mechanism 10 are provided at a plurality of locations around the platen cup 26 at regular intervals. It is attached and shown in (A) in Figure 7.
) shows the state before the wafer 8 is held by the holding mechanism 10, and (B) in FIG. 7 shows the state after the wafer 8 is held.

Between the brackets 50.52, as shown in FIG. 7(E), an arm 54.56 serving as a locking member for fixing the wafer 8 is sandwiched between the brackets 50.52 and holds a bearing 58. It is supported rotatably around a pin 60 serving as a support shaft. As shown in FIG. 7(D), the upper part of the arm 54 is provided with a clamp piece 6 so as to be rotatable around a pin 64 via a bearing 62.
6 is fixed, and a spring 68 is provided between the clamp piece 66 and the back of the arm 54, as shown in FIG. 7(C), and the tension of the spring 68 causes the clamp piece to 66 is pressed against the rod 70.

The rod 70 is connected to the arm 5 as shown in FIG. 7(B).
4 through a bearing 71 so as to be able to move up and down smoothly, and its lower end is in contact with the arm 56.

As shown in FIGS. 7A and 7D, the end of the arm 56 is connected to the tension block 72 via a pin 74 with a bearing 73 interposed therebetween, and the connection point is connected to the tension block 72. The elongated hole 76 allows rotational movement and a certain degree of left-right movement, but vertical movement is restricted.

An inner race 80 fixed to the platen body 2 via a bearing 78 and a tension block 72 are connected by a tension screw 82. The bearing 78 is mounted so as to have the same rotation center as the bearing 24 for rotating the platen cup 26.

Therefore, before the wafer 8 is held as shown in FIG. It is tilted at an acute angle slightly toward the center of the platen body 2 from a right angle to the arm 56, and is stabilized in a state in contact with a stopper provided on the arm 56.

From this state, in order to clamp the wafer 8, by injecting pressure fluid 40 into the bellows 12 and expanding the bellows 12, the platen cup 26 is gradually raised, and the brackets 50 and 52 fixed thereto are also lifted. Similarly, the connecting point of the four parts, bracket 50.52 and arm 54.56, will also rise. As the connection point rises, the arm 56 connects the other end to the tension block 72.
Since the arm 54 and the clamp piece 66 are restrained by the arm 56, the inclination gradually changes around the connection point, and the arm 54 and the clamp piece 66 rotate together with the arm 56 while maintaining the above-mentioned state.

In this way, as shown in FIGS. 7B and 7C, when the angle of the arm 54 becomes vertical, the arm 5
Laterally projecting protrusions from both sides of the front part of the arm 54 contact the brackets 50, 52 and prevent the arm 54 from rotating any further.

At this moment, the arms 54 and 56, the clamp piece 6
6 remains the same, the arm 56 is tilted slightly outward from the angle parallel to the wafer 8, and the clamp piece 66 is also tilted in the same manner.
The tip of 6 does not touch the wafer 8.

Next, as the platen cup 26 attempts to rise, the arm 56 becomes parallel to the wafer 8. At this time, since the arm 54 continues to maintain its vertical state, the rod 70 is pushed up, and the other end of the door 0 pushes up the clamp piece 66. Therefore, clamp piece 6
6 is rotated to an angle parallel to the wafer 8, and as shown in FIG.
), the wafer 8 becomes fixed and the clamping is completed.

By the way, when the wafer 8 fixed in this way is rotated, the holding mechanism 10 is fixed to the platen cup 26 by the brackets 50 and 52, so the wafer 8 is rotated.
Since the tension screw 82 is fixed to the inner race 80 which can rotate freely, a constant tension, that is, clamping force is maintained even during rotation. Therefore, since the wafer 8 does not generate friction with other members during rotation, no dust is generated due to rotation.

Further, the wafer 8 can be removed by an operation completely opposite to that of clamping.

When the wafer support device of the present invention is used in an ion implantation device, after interrupting ion implantation, the platen can be rotated by a certain angle (for example, 90°) to perform re-implantation. It can be done multiple times during a single injection.

In this case, generally during ion implantation, the ion beam and wafer are at a certain angle (usually around 7 degrees) to prevent channeling, and when implanting ions into a pattern with a certain aspect ratio, the ridges may cause the wall or bottom surface to A shadow will appear (an unfilled area will appear on the wall), but if the platen is
By indexing and implanting ions in degrees, it is possible to eliminate unimplanted areas and also implant ions into the ridges and sides of the pattern, which is effective in improving device insulation and characteristics.

Further, by using a mechanism for tilting the platen, it is also possible to implant an arbitrary amount of ions into the side surface of the pattern. Further, by rotating during implantation, the above effects can be expected, while the dose uniformity is significantly improved.

For example, when the wafer 8 is rotated, the dose uniformity is 1.03% to 0.33% compared to when it is not rotated.
It was confirmed that

In addition, in ion implantation, the angle formed between the crystal lattice and the ion beam has a certain relationship, so the direction of the crystal lattice is indicated by a flat surface called the orientation flat on the wafer's periphery, but the positional accuracy of the flat surface is is required to be within ±1@, and in the case of compound semiconductors,
Even stricter precision is being required. Conventionally, the wafer is transferred onto the platen after aligning the orientation flat on a stage other than the platen, and the wafer may shift during this time, so the accuracy on the platen cannot necessarily be said to be accurate. However,
When the wafer support device of the present invention is used, such inconveniences can be eliminated.

A photosensor is built into the platen body to accurately measure the orientation flat position.
There is no need to consider errors during wafer transport, and the orientation flat can be set at any angle.

Although the ion implantation apparatus has been described in the embodiments, the wafer support apparatus of the present invention can be widely used in ion etching apparatuses and the like in addition to ion implantation apparatuses when rotating a wafer while holding it.

〔Effect of the invention〕

As explained above, according to the present invention, a wafer to be processed is held and rotated, the rotation angle is arbitrarily set,
The rotation angle can be easily set, and uniform ion implantation into a wafer can be realized using, for example, an ion implantation device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of the wafer support device of the present invention, FIG. 2 is a diagram showing the positional relationship between the guide shaft and motor of the platen mechanism in the wafer support device shown in FIG. 1, and FIG. The figure is a plan view of the platen mechanism of the wafer support device shown in FIG. 1, FIG. 4 is a diagram showing a state in which a wafer is fixed by the platen mechanism of the wafer support device shown in FIG. 1, and FIG. 6 is a cross-sectional view showing a second embodiment of the wafer support device; FIG. 6 is a plan view showing the holding mechanism of the platen mechanism of the wafer support device shown in FIG. 5;
FIG. 7 is a diagram showing the configuration and operating mechanism of the holding mechanism shown in FIG. 6. 8... Wafer, 10... Holding mechanism, 12... Bellows, 23... Rotating mechanism, 24. 34... Bearing, 26... Platen cup (mounting member), 30...
...Crumble ring (fixed member), 42.48...Gear, 44...Motor. Figure 2

Claims (3)

[Claims] (1) a holding mechanism that places a wafer on a mounting member and raises and lowers it, and holds the wafer between the mounting member and the fixing member;
A wafer support device including a platen and a rotation mechanism that rotates the wafer held by the holding mechanism together with the holding mechanism. (2) The wafer support according to claim 1, wherein the holding mechanism holds the wafer between a clamp ring fixed to the main body side and the platen cup by raising the platen cup on which the wafer is placed. Device. (3) The holding mechanism includes a locking member on the edge of the platen cup that rotates as the platen cup rises and faces onto the wafer, and the holding mechanism holds the wafer by the locking member. The wafer support device described.