JP3891627B2 - Workpiece placement table - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece mounting table incorporated in an apparatus or the like that performs plasma processing on a semiconductor wafer.
[0002]
[Prior art]
When performing processing such as etching or ashing on a semiconductor wafer, the wafer is placed and fixed on a mounting table disposed in the reaction chamber, and in this state, the reaction gas is introduced into the reaction chamber for processing. I have to.
[0003]
If there is unevenness on the mounting table due to a jig that transfers the wafer from the transfer system, the electric field is disturbed when plasma is applied, etching cannot be performed uniformly, and dust is also likely to be generated.
Therefore, there is a workpiece placing table having a structure proposed in Japanese Patent Laid-Open No. 5-175160 and Japanese Patent Laid-Open No. 5-217948.
[0004]
As shown in FIG. 9, the workpiece placement table disclosed in the above publication is provided with a holder 101 on the placement table 100, and a part of the holder 101 is an annular portion 102 that moves up and down relative to the upper surface of the table 100. The annular portion 102 is provided with a support portion 103 for supporting the peripheral edge of the lower surface of the wafer W, and a concave portion 104 into which the support portion 103 enters when the holder 101 is lowered on the upper surface of the table 100 is formed. The wafer W is inserted and transferred between the annular portion 102 and the support portion 103 while being raised from the upper surface of the table, and then the holder is lowered to place the wafer W on the upper surface of the table 100, and the further placed wafer The periphery of W is pressed against the upper surface of the table 100 by a part of the annular portion 102 and fixed.
[0005]
[Problems to be solved by the invention]
In the conventional structure described above, in the state where the holder 101 is lowered and the upper surface of the peripheral edge of the wafer W is pressed by the annular portion 102, the concave portion 104 becomes a gap as shown in FIG. The plasma around 104 becomes non-uniform.
In addition, electrostatic adsorption is an essential technology for recent etching equipment. However, sufficient adsorption force cannot be obtained, resulting in wafer misalignment and reduced cooling efficiency during etching. Troubles such as causing a transport error may occur.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a workpiece placing table according to the first invention of the present application includes a conveyance claw for transferring a workpiece between the table and a conveyance device, and the conveyance claw is arranged around the table. In addition, the ascending and descending movement is possible, the ascending limit position is used as the receiving / receiving position of the object to be processed, and the descending limit position is fitted into a recess formed on the peripheral edge of the table upper surface. Was to be the same.
[0007]
In addition, the workpiece placing table according to the second invention of the present application is further provided with a presser claw for pressing the upper surface of the peripheral edge of the workpiece placed on the table to the workpiece placing table according to the first invention. The presser claw is arranged around the table and can be moved up and down independently of the conveying claw.
This presser claw can avoid a serious damage when the electrostatic adsorption cannot be normally attached / detached. Further, since the lifting and lowering can be performed independently of the transfer claw, the wafer can be smoothly transferred on the table.
[0008]
Here, a ring member is fitted on the upper surface of the peripheral edge of the table, and a recess is formed in the ring member to which the conveying claw at the lower limit is fitted, and the peripheral edge of the workpiece is fitted on the upper surface of the conveying claw. It is possible to provide a structure in which a plurality of parts, a conveying claw and a pressing claw are provided, and these are arranged around the table with a phase shift.
[0009]
When there are multiple transport claws and presser claws, attach the transport claws and presser claws to a single support member, and form a slit in the table body for the support members to move up and down. The attached support member may be moved up and down by a drive source such as a cylinder unit, and the support member attached with the transport claw may be pushed up by the support member attached with the presser claw. It may be moved up and down by a drive source such as a unit, and the support member to which the presser claw is attached is pushed down by the support member to which the conveyance claw is attached.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a schematic configuration diagram of an ECR apparatus (plasma etching apparatus using electron cyclotron motion) incorporating a mounting table according to the present invention. It is housed in a waveguide 3 or cavity connected to a 45 GHz microwave oscillator 2, a magnetic field generating coil 4 is arranged around the waveguide 3, and the reaction chamber 1 is connected to a vacuum pump 5 and the reaction chamber 1. A mounting table 10 for the wafer W is provided below the inside.
[0011]
Next, the mounting table 10 will be described with reference to FIGS. The mounting table 10 is placed in a cylindrical body 11 made of ceramic in order from the top, a ceramic support block 12, a ceramic support plate 13, an aluminum lower electrode 14, an aluminum electrostatic chuck plate 15, and a ceramic. The ring member 16 is laminated.
[0012]
In addition, the mounting table 10 includes a transfer claw 17 for transferring a workpiece between the table and a transfer device, and a presser claw 18 for pressing the upper surface of the peripheral edge of a wafer W (target workpiece) placed on the table. And.
[0013]
The conveying claw 17 and the presser claw 18 are arranged out of phase around the table, the conveying claw 17 is attached to the upper end portion of the column body 19, and the lower end portion of the column body 19 is an outer end portion of the support member 20 extending radially. The presser claw 18 is attached to the upper end portion of the column body 21, and the lower end portion of the column body 21 is attached to the outer end portion of the support member 22 that extends radially.
[0014]
A groove portion 23 into which the column bodies 19 and 21 enter is formed on the inner peripheral surface of the cylindrical body 11, and a slit 24 that allows the support members 20 and 22 to move up and down is formed in the support block 12. In the illustrated example, the slit 24 penetrates in the vertical direction. However, in order to prevent the support block 12 from falling apart, the support block 12 is fixed to the bottom plate 25, or the lower end portion or the upper end portion of the support block 12. A portion without a slit may be provided.
[0015]
A cooling water passage 26 is formed on the lower surface of the electrostatic chuck plate 15, and a cooling water introduction hole 27 and a cooling water discharge hole 28 communicating with the cooling water passage 26 are provided in the bottom plate 25, the support block 12, and the support plate. 13 and the lower electrode 14, and a He gas injection hole 29 for cooling the wafer W is formed in the center of the upper surface of the electrostatic chuck plate 15. A He gas introduction hole 30 connected to the He gas injection hole 29 is formed. The bottom plate 25, the support block 12, the support plate 13, and the lower electrode 14 are formed. A conductive wire 31 for applying a high frequency is connected to the lower electrode 14 through the bottom plate 25, the support block 12 and the support plate 13.
[0016]
The support member 22 is disposed below the support member 20, and the support member 22 is attached to a cylinder unit 32 as a drive source, and the support member 22 and the presser claw 18 are moved up and down by the cylinder unit 32 and supported. When the member 22 is raised to a predetermined position, the support member 20 and the conveyance claw 17 are raised together with the support member 22 and the presser claw 18.
[0017]
Further, the ring member 16 is formed with a stepped portion 33 into which the peripheral portion of the wafer W is fitted, and a similar stepped portion 34 is also formed on the transfer claw 17. Further, the ring member 16 is formed with a recess 35 into which the conveying claw 17 in the lowering limit is fitted. The depth of the recess 35 is substantially equal to the thickness of the conveying claw 17 so that the upper surface of the conveying claw 17 and the upper surface of the chuck plate 15 are flush with each other in the fitted state.
[0018]
7, the wafer W is inserted into the space between the transfer claw 17 and the presser claw 18 with the transfer claw 17 and the presser claw 18 raised by the operation of the cylinder unit 32. The wafer W is delivered onto the claw 17.
[0019]
Next, by compressing the cylinder unit 32, the support member 22 and the presser claw 18 are lowered, and the support member 20 and the conveyance claw 17 pushed up by the support member 22 are also lowered. Further, when the presser claw 18 is lowered, the wafer W and the transfer claw 17 can be brought into contact with each other. At this time, the conveying claw 17 is fitted into the recess 35. At this time, the wafer W is placed on the electrostatic chuck plate 15. Prior to this, the wafer W is uniformly cooled to about −60 ° C. by the He gas from the He gas ejection holes 29. Etching is performed using alternative chlorofluorocarbon or chlorine gas as the reaction gas.
[0020]
In the illustrated example, the workpiece placement table including the presser claw 18 is shown, but the presser claw 18 may be omitted.
[0021]
【The invention's effect】
As described above, according to the present invention, the conveying claw for transferring the workpiece between the table and the conveying device is arranged around the table and can be moved up and down, and the ascent limit position of the workpiece is set. At the transfer position, it is fitted into a recess formed on the periphery of the table upper surface at the lower limit position, and the upper surface of the conveying claw and the table upper surface are flush with each other in the fitted state, so that the plasma becomes uniform. .
[0022]
In addition to the above configuration, by providing a presser claw for pressing the upper surface of the peripheral edge of the workpiece, the workpiece can be reliably fixed to the table upper surface.
[0023]
Further, by providing a ring member in which a concave portion into which the conveying claw is fitted is provided on the upper surface of the peripheral edge portion of the table, it is possible to replace a place that is most easily eroded by plasma, thereby extending the life of the plasma processing apparatus.
[0024]
In addition, by providing a step portion in which the peripheral edge of the object to be processed is provided in the conveying claw, the object to be processed is automatically positioned, and the positional deviation is less likely to occur.
[0025]
Furthermore, the transfer claw and the presser claw are attached to the respective support members, and a space is provided between the transfer claw ascending limit position and the presser claw ascent limit position so that the wafer can be taken in and out. If the support of the conveyance claw is raised by the body, the conveyance claw and the press claw can be moved up and down independently by using a single drive source such as a cylinder.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a plasma processing apparatus incorporating a mounting table according to the present invention. FIG. 2 is an exploded perspective view of the mounting table according to the present invention. 4 is a cross-sectional view of the mounting table. FIG. 4 is a cross-sectional view of the mounting table based on the direction BB in FIG. 2. FIG. 5 is a vertical section of the mounting table based on the direction CC in FIG. FIG. 6 is a longitudinal sectional view of the mounting table based on the direction DD in FIG. 4. FIG. 7 is a longitudinal sectional view of the mounting table based on the direction EE in FIG. FIG. 9 is a view similar to FIG. 7 showing a state in which the wafer is being pressed onto the table. FIG. 9 is a cross-sectional view of a conventional workpiece mounting table. Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Mounting table, 11 ... Cylindrical body, 12 ... Support block, 13 ... Support plate, 14 ... Lower electrode, 15 ... Electrostatic chuck plate, 16 ... Ring member, 17 ... Conveying claw, 18 ... Pressing claw, 19, DESCRIPTION OF SYMBOLS 21 ... Column body, 20, 22 ... Support member, 24 ... Slit, 33, 34 ... Step part, 35 ... Recessed part, W ... To-be-processed object.

Claims (3)

In a table for placing an object to be processed such as a semiconductor wafer, a transfer claw for transferring the object to be processed between the table and a transfer device, and a presser for pressing the upper surface of the peripheral part of the object to be processed placed on the table The claw is disposed around the table and can be moved up and down by a drive source such as a cylinder unit . The upper limit position is set as a transfer position of the workpiece, and the upper surface of the table is set at the lower limit position. fitted in a recess formed in the periphery of, fitted in the conveying claw top and table top state flush with, also the pressing pawl wherein independently of the conveying claw while being arranged around the table by a drive source configured to be moved up and down, and wherein the allowed to rise earlier than conveying nail pressing nails with and pushing up by the support member mounted to the pressing claw support member mounted said conveying claw The object to be processed placed on the table that.  The workpiece mounting table according to claim 1, wherein a plurality of the conveying claws and the presser claws are provided, and are arranged around the table at different phases. The workpiece mounting table according to claim 2 , wherein each of the plurality of transport claws and presser claws is attached to one support member, and a slit is formed in the table body for the support members to move up and down. A workpiece placement table characterized by comprising:

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