JPH0799231A - Holding device for processing object and processing device - Google Patents

Abstract

(57) [Abstract] [Purpose] When a peripheral edge of an object to be processed such as a wafer is pressed and held on a mounting table, a convex portion generated in the previous step is formed on the peripheral edge. Also, the yield is improved without causing cracks or cracks in the object to be processed. [Structure] A concave portion 26 is appropriately formed on a lower surface of a peripheral edge portion 25 of a clamp ring 21 that presses the peripheral edge portion of a wafer relative to a mounting table. Even if a convex portion generated in the previous step is formed on the peripheral portion of the wafer, the convex portion is stored in the concave portion 26, so that the convex portion is not loaded when pressed, and There are no cracks or cracks, and no particles that cause pollution are generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for holding an object to be processed,
And a processing device using the holding device.

[0002]

2. Description of the Related Art For example, a semiconductor wafer (hereinafter, "wafer")
The plasma etching apparatus configured to perform the etching process with plasma will be described as an example. In such a plasma etching apparatus, a wafer to be processed is held on a mounting table serving as a lower electrode. A holding device is provided. In a conventional holding device of this type, for example, an outer peripheral edge portion of a wafer mounted on a mounting table whose surface is convexly and gently curved upward is provided with, for example, an annular clamp ring from above over the entire circumference. The wafer is configured to be pressed against the mounting table to hold the wafer on the mounting table, and the contact surface of the clamp ring with the outer peripheral edge of the wafer is formed flat.

[0003]

By the way, the wafer may be subjected to another process as a pre-process of the etching process by the plasma etching apparatus. In that case, for example, the pre-process may be changed to another process. If it is an etching process, the clamp part that clamps the wafer at a plurality of places with nails or the like is not etched at that time, and as a result, the clamp part is directly formed as a convex part and the outer peripheral edge part of the wafer is processed. Will be formed.

When the wafer having such a convex portion formed on the outer peripheral edge thereof is pressed by the conventional clamp ring, the contact surface is formed flat, so that the convex portion on the wafer is formed. Only the load is applied, and as a result, the wafer may be cracked or cracked. When such cracks are generated, not only the wafer itself becomes defective, but also particles are generated from the cracked portions, which causes contamination. Then, for example, if the etching process is performed as it is, the yield immediately decreases.

The present invention has been made in view of the above point, and even if such a convex portion is formed on the outer peripheral edge of an object to be processed such as a wafer, the wafer is mounted on a mounting table by a pressing jig. An object of the present invention is to solve the above problems by providing a device for holding an object to be processed which does not cause the cracks and the like even when pressed against, and a processing device equipped with the device.

[0006]

In order to achieve the above object, according to claim 1, the outer peripheral edge portion of the object to be processed placed on the mounting table is relatively mounted by an appropriate pressing jig. A holding device for an object to be processed, which is configured to hold the object to be processed on the mounting table by pressing it to a side, and is provided on a contact surface of the pressing jig with an outer peripheral edge portion of the object to be processed. There is provided a device for holding an object to be processed, characterized in that a concave portion having a shape capable of accommodating a convex portion formed on the outer peripheral edge portion is formed.

According to a second aspect of the present invention, as a processing apparatus having the above-mentioned holding device, a processing table having an airtight structure is provided with a mounting table on which an object to be processed is mounted and held, and the processing table has a predetermined structure. A processing apparatus configured to process the object to be processed in a reduced pressure atmosphere, wherein the outer peripheral portion of the object to be processed placed on the table is relatively placed by an appropriate pressing jig. In a processing apparatus having a device for holding an object to be processed, which is configured to hold the object to be processed on the mounting table by pressing it to the side, contact with an outer peripheral edge portion of the object to be processed in the pressing jig. The surface is provided with a concave portion having a shape capable of accommodating the convex portion formed on the outer peripheral edge portion,
A processing device is provided.

[0008]

According to the holding device of the first aspect of the present invention, a concave portion having a form capable of accommodating a convex portion formed on the outer peripheral edge portion on a contact surface of the pressing jig with the outer peripheral edge portion of the object to be processed. Therefore, even if the outer peripheral edge of the object is pressed by the pressing jig, the convex portion is housed in the concave portion and no load is applied to the convex portion. Therefore, when pressed, the object to be processed is not cracked or cracked.

According to the second aspect of the present invention, since the processing apparatus is provided with such a holding device, even if an appropriate convex portion is formed in the previous step on the outer peripheral edge portion of the object to be processed, it is held. When the device holds the object to be processed, the object to be processed is not cracked or cracked. Therefore, particles are not generated in the processing chamber, and the predetermined processing can be performed as it is in a clean atmosphere, and the yield can be improved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG.
In order to show the structure of the etching apparatus for "wafer"), the section of the etching apparatus is schematically shown.
The processing chamber 1 which is configured to be airtightly closed, is formed in a substantially cylindrical shape, for example, of aluminum whose surface is anodized.

Below the bottom plate 2 in the lower part of the processing chamber 1, there is provided an elevating mechanism 3 composed of an air cylinder or the like, and a mounting table 4 in the processing chamber 1 serving as a lower electrode.
Is configured to be vertically movable in the processing chamber 1 by the lifting mechanism 2. In order to ensure airtightness inside the processing chamber 1, an expandable bellows 5 made of, for example, stainless steel is annularly provided between the bottom plate 2 and the lower peripheral edge of the mounting table 4. .

The inside of the processing chamber 1 is evacuated from an exhaust port 7 communicating with an exhaust means 6 such as a vacuum pump so that a predetermined reduced pressure atmosphere can be set and maintained.
Further, by the Teflon exhaust ring 13 arranged on the outer periphery of the side surface of the mounting table 4, the gas above the mounting table 4 in the processing chamber 1 is efficiently and uniformly so as not to hinder the etching process. It is configured to be exhausted from the exhaust port 7.

The mounting table 4 is made of, for example, aluminum whose surface is anodized, and has a ground wire 8
Grounded by. The mounting surface on which the wafer W, which is the object to be processed, is mounted has a size capable of mounting a wafer having a diameter of 8 inches, and has a shape that is gently curved upwardly.

Further, a space A is provided in the center of the inside of the mounting table 4 described above.
Further, in the space A, a plate-shaped member 9 and a coil spring 10 for urging the plate-shaped member 9 downward are provided. The plate-like member 9 is connected to an elevating mechanism 11 such as an air cylinder provided below, and the space A is formed on the upper surface of the plate-like member 9.
A plurality of, for example, four lifter pins 12 are provided that can be inserted through the through holes between the mounting table 4 and the surface of the mounting table 4. Therefore,
Each of the lifter pins 1 is driven by driving the lifting mechanism 11.
2 is capable of projecting upward from the mounting surface of the mounting table 4, and when the elevating mechanism 11 is not driven, the coil springs 10 cause the lifter pins 12 to move,
It is stored in the mounting table 4.

Above the mounting table 4 in the processing chamber 1, there is provided a clamp ring 21 configured to relatively press the outer peripheral edge of the wafer W. The clamp ring 21 is supported by, for example, four ceramic shafts 23 fixed to an upper plate 22 fixed to the upper portion of the processing chamber 1. For example, if the shaft 23 is connected to an appropriate cylinder, the vertical position of the clamp ring 21 can be easily adjusted by operating the cylinder.

The clamp ring 21 is made of an insulating material such as alumina ceramics,
It has a substantially annular shape as a whole, and an opening 24 similar in shape to the wafer W having a diameter slightly smaller than that of the wafer W is provided in the center thereof. As shown in FIG. 2, the peripheral portion 25 of the opening 24 has a shape projecting toward the opening 24, and its tip is rounded.

On the back surface of the peripheral edge portion 25, that is, the back surface of the mounting table 4 side, as shown by the hatched portion in FIG. 3, at a central angle of 30 °, a depth of about 0.2 mm, a length of about 15 mm, and a width of about 15 mm. The recesses 26 of about 1.5 mm are provided at 12 places in total. The positions where these recesses 26 are arranged are set so as to correspond to the clamping positions when the peripheral edge of the wafer W, which is the object to be processed, is clamped in the previous step.

From the base of the peripheral edge portion 25 to the lower peripheral edge portion 27 of the opening 24 of the clamp ring 21, the side wall thereof is tapered so as to conform to the shape around the mounting surface of the mounting table 4. Has been done.

On the upper portion of the clamp ring 21 having the above structure, the upper electrode 31 is disposed so as to face the mounting table 4.
Is provided. The upper electrode 31 corresponds to the electrode support 3
2. A baffle plate 34 which is provided with a gap from the electrode support 32 and has a large number of ejection ports 33, and an electrode plate which is located below the baffle plate 34 and is supported by a shield ring 35 made of quartz or the like. It is composed of 36.

The etching gas and carrier gas supplied from the gas supply pipe 37 provided above the electrode support 32 are discharged from the discharge port 33 of the baffle plate 34.
It is configured to be discharged toward the mounting table 4 side and to be uniformly discharged to the wafer W held on the mounting table 4.

The electrode plate 36 has, for example, 13.56M.
A high frequency power supply 38 for applying a high frequency power of Hz is connected thereto, while the mounting table 4 serving as the lower electrode is grounded by the ground wire 8 as described above, so that the predetermined high frequency power supply 38 is used. High frequency power is applied to the electrode plate 3
6 is applied, plasma is generated between the electrode plate 36 and the mounting table 4, and the wafer W on the mounting table 4 is subjected to radical etching treatment.

If a high-frequency power source is connected to the mounting table 4 side and this is used as a power source electrode, and the electrode plate 36 is grounded, RIE (reactive ion etching) processing can be performed. It can be configured as a possible etching device.

The present embodiment is configured as described above,
Next, the operation will be described. First, the wafer W to be processed is placed in the processing chamber 1 by a transfer means such as a transfer arm (not shown) when the mounting table 4 is lowered. 4 and the upper electrode 31 and then received by the upper surface of the lifter pin 12 lifted by the lifting mechanism 11 as shown in FIG. Then, after the transfer means is retracted to the outside of the processing chamber 1, the lifter pins 12 are lowered and the wafer W is mounted on the mounting surface of the mounting table 4.

After that, the mounting table 4 is raised by the elevating mechanism 3, the peripheral edge of the wafer W abuts the lower surface of the peripheral edge 25 of the clamp ring 21, and overdrive is applied to the peripheral edge of the wafer W. The back surface of the peripheral edge portion of the clamp ring 21 presses the wafer W with a force of, for example, about 3 kgf, and as a result, the wafer W is held in close contact with the curved mounting surface of the mounting table 4.

At this time, even if a portion clamped at the time of the pre-process is formed on the peripheral portion of the wafer W as a claw-shaped convex portion, it is not contacted with the peripheral portion 25 on the side to be the contact surface. , The recesses 26 are provided, and the recesses 26 are arranged so as to correspond to the clamp locations. Therefore, the projections are accommodated in the recesses 26, and as a result, the wafer W is clamped by the clamp ring 21. The peripheral portion 2 of
It is pressed by the portion of the device 5 except the recess 26.

This will be described with reference to FIG. 4. The peripheral edge of the wafer W loaded into the processing chamber 1 has a shape and size corresponding to the clamping position at the time of clamping that occurs in the previous process. The convex portion 41 is formed. The convex portion 41 usually has a substantially triangular shape in plan view, although the shape thereof varies depending on the shape of the claw serving as the clamp portion of the clamp jig, and the maximum width L thereof is about 8 mm. And the height is slightly different depending on the degree of processing in the previous step, but is, for example, 0.1 to 0.1.
It has a size of 0.2 μm.

However, as described above, the recesses 26 having a depth of about 0.2 mm, a length of about 15 mm, and a width of about 1.5 mm are formed on the back surface of the peripheral edge portion 25 serving as the wafer pressing portion of the clamp ring 21. Since the protrusions 41 are arranged corresponding to the protrusions 41, when the wafer W is relatively pressed by the clamp ring 21, the protrusions 41 are accommodated in the recesses 26 as shown in FIG. It will be dressed as it is, and in the end, Fig. 4
The wafer W is clamped by the clamp ring 2 at the shaded portion of
It will be pressed by 1. The states of the clamp ring 21, the wafer W, and the mounting table 4 at this time are shown in FIGS. 6 and 7.

Therefore, even if the peripheral edge of the wafer W is pressed by the clamp ring 21 to hold the wafer W on the mounting table 4, no load is applied to the convex portion 41, and therefore the object to be processed is not affected. There is a crack in this wafer W,
It does not cause cracks.

After the wafer W is held on the mounting table 4 by the clamp ring 21 as described above, the inside of the processing chamber 1 is set to a predetermined depressurized atmosphere, for example, several hundred mTorr, and a predetermined etching is performed from the discharge port 33. When a gas, for example, a halogen-based gas is introduced into the processing chamber 1 and then high frequency power is applied to the electrode plate 36 by the high frequency power supply 38, the wafer W is subjected to a predetermined etching process.

In this case, even if the wafer W, which is the object to be processed, has the convex portion 41 generated in the previous step on the peripheral portion thereof, the clamp ring is not loaded on the convex portion 41. Since it is pressed by 21, there is no possibility that particles will be generated from the pressing portion during processing, and the inside of the processing chamber 1 will not be contaminated. Therefore, the etching process on the wafer W is appropriately performed, and as a result, the yield is improved.

Further, although the above embodiment is an example in which the present invention is applied to an etching apparatus, the present invention is not limited to this, and the present invention is not limited to the plasma CVD apparatus and other semiconductor processing apparatuses such as an ashing apparatus and a sputtering apparatus. It is possible to apply to such.

[0032]

According to the holding device of the first aspect, when the outer peripheral edge of the object to be processed is pressed to the mounting table side by the pressing jig, the outer peripheral edge of the object to be processed is generated by the process of the previous step. Even if the convex portion is formed, the pressing does not cause cracks or cracks in the object to be processed.

According to the second aspect of the present invention, since the processing apparatus is provided with such a holding device, even if the object to be processed having the convex portion formed on the peripheral portion is held in the previous step, the processing chamber is held. Particles are not generated in the above, and it is possible to perform a predetermined process as it is in a clean atmosphere. Therefore, the yield can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a cross section of an etching apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view of the peripheral edge portion of the clamp ring in the embodiment of the present invention.

FIG. 3 is a bottom view of the clamp ring according to the embodiment of the present invention.

FIG. 4 is an explanatory plan view of a wafer showing a pressed portion of the wafer that is the object to be processed.

FIG. 5 is a cross-sectional explanatory view showing a state when the peripheral edge portion of the wafer is pressed by the clamp ring in the example of the present invention.

6 is an explanatory view showing a state of a side cross section showing a state when a peripheral edge portion of a wafer is pressed by a clamp ring in an example of the present invention, in accordance with a cross section taken along line P-P of FIG. 4. FIG.

7 is an explanatory view showing a state of a side cross section showing a state when a peripheral edge of a wafer is pressed by a clamp ring according to an example of the present invention, according to a cross section taken along the line QQ of FIG. 4. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing chamber 3 Lifting mechanism 4 Mounting table 6 Exhaust means 7 Exhaust port 21 Clamp ring 25 Peripheral part 26 Recessed part 31 Upper electrode 36 Electrode plate 37 Gas supply pipe 38 High frequency power supply 41 Convex part W Wafer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kosuke Imafuku 1st 2381 Kitashitajo, Fujii-cho, Nirasaki-shi, Yamanashi Tokyo Electron Yamanashi Co., Ltd.

Claims (2)

[Claims] 1. An outer peripheral edge portion of an object to be processed placed on the mounting table is relatively pressed against the mounting table by an appropriate pressing jig to hold the object to be processed on the mounting table. An apparatus for holding an object to be processed configured as described above, wherein a convex portion formed on the outer peripheral edge portion can be housed in a contact surface of the pressing jig with the outer peripheral edge portion of the object to be processed. A holding device for an object to be processed, characterized in that a recess is formed. 2. A processing apparatus having a mounting table in which an object to be processed is mounted and held in an airtight processing chamber and configured to process the object in a predetermined reduced pressure atmosphere. Further, the outer peripheral edge portion of the object to be processed placed on the mounting table is relatively pressed to the mounting table side by an appropriate pressing jig so as to hold the processing object on the mounting table. In a processing apparatus having a configured object holding device, a configuration in which a convex portion formed on the outer peripheral edge portion can be housed in a contact surface of the pressing jig with the outer peripheral edge portion of the object. The processing device is characterized in that a recess is formed.