JPH0666300B2 - Dry etching equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer holding mechanism of a dry etching apparatus, and more particularly to a semiconductor wafer holding mechanism having a simple structure and suitable for a mass production type dry etching apparatus.

[Background of the Invention]

The fine pattern formation of a semiconductor integrated circuit by a dry etching apparatus is performed by forming a desired pattern on a semiconductor wafer, which is an object to be processed, by a resist exposure phenomenon, and using this as a mask, a high frequency glow of an etching gas introduced into a vacuum atmosphere. It is performed by transferring a resist pattern onto a semiconductor wafer by using electric discharge. At this time, the temperature of the semiconductor wafer rises due to the irradiation of the etching film with plasma or ion bombardment of the resist film, which may cause softening or deterioration due to heat, which may adversely affect the fine pattern formation. Therefore, below the softening point of the resist,
Cooling of the semiconductor wafer is indispensable to the dry etching apparatus when the high frequency power is increased in order to suppress the temperature rise of the semiconductor wafer, especially for the purpose of improving the etching rate.

Therefore, in order to improve the electric heating performance between the water-cooled electrode on which the semiconductor wafer is mounted and the semiconductor wafer, a technique of interposing an elastic sheet or grease between the semiconductor wafer and the electrode, a technique of mechanically pressing the semiconductor wafer against the electrode, Alternatively, a technique has been proposed in which a semiconductor wafer is brought into close contact with an electrode by utilizing electrostatic attraction.

As a technique for mechanically pressing the semiconductor wafer against the electrodes, there is a technique disclosed in, for example, JP-A-57-45240 and JP-A-55-127034. However, in these prior arts, since the semiconductor wafer is pressed by the screwing jig every time the semiconductor wafer is placed on the electrode, it is difficult to adopt in a mass production type dry etching apparatus, and the structure is complicated, Moreover, since the semiconductor wafer holding mechanism portion projects into the plasma from the mounting surface of the semiconductor wafer and disturbs the electric field around the semiconductor wafer, the incidence of ions that are perpendicular to the electric field and physically etch the semiconductor wafer Loses direction,
There is a drawback that the uniformity of etching on the semiconductor wafer surface is impaired.

[Object of the Invention]

The object of the present invention is to eliminate the drawbacks of the prior art, suppress the disturbance of the electric field around the semiconductor wafer mounted on the electrode, and have a simple structure, which is suitable for a mass-production type dry etching apparatus. Another object of the present invention is to provide a semiconductor wafer retainer mechanism for a dry etching apparatus capable of improving heat transfer performance between a semiconductor wafer retainer and an electrode, and to reliably separate an etched semiconductor wafer from a semiconductor wafer retainer body. An object of the present invention is to provide a semiconductor wafer pressing mechanism for a dry etching apparatus.

[Outline of Invention]

The present invention provides a processing chamber for processing a semiconductor wafer, electrode means for mounting the semiconductor wafer, cooling means inside the electrode means for cooling the electrode means and the semiconductor wafer, and the processing chamber. A semiconductor wafer pressing means for pressing the semiconductor wafer onto the electrode means, and a driving means outside the processing chamber for pressing or releasing the pressing of the semiconductor wafer onto the electrode means by the semiconductor wafer pressing means. A dry etching apparatus provided with an elastic support member that elastically supports the semiconductor wafer pressing means.

Further, the present invention provides the dry etching apparatus,
The semiconductor wafer holding means is provided with a releasing means for releasing the semiconductor wafer from the semiconductor wafer holding means when the pressing of the semiconductor wafer is released by the driving means.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an example of a parallel plate type dry etching apparatus to which the present invention should be applied and an embodiment of a semiconductor wafer pressing mechanism of the present invention applied to this.

The parallel plate type dry etching apparatus shown in these figures is
It comprises a processing chamber 1, an electrode 3 placed on the upper side of the processing chamber 1, and an electrode 6 introduced into the processing chamber 1 through an electrode inlet 2 formed in the lower portion of the processing chamber 1. There is. The inside of the processing chamber 1 is kept airtight against the atmosphere. The electrode 3 is provided with a cylinder shaft 4 and a plurality of small holes 5,
An etching gas is introduced into the processing chamber 1 from the inside of the cylindrical shaft 4 through the small holes 5 in a vacuum atmosphere.
The electrode 6 is a vertical driving device (not shown) via a shaft 7.
It is configured to be movable to a fixed position facing the electrode 3 in the processing chamber 1 through the electrode introduction port 2. High frequency power is applied between the electrodes 3 and 6. Further, the electrode 6 is provided with an electrode cooling means and a semiconductor wafer cooling means. The electrode cooling means includes a cooling water introducing passage 8 provided from the inside of the shaft 7 to the inside of the electrode 6, and a cooling water chamber 9 formed in the electrode 6.
And a cooling water lead-out path 10 provided from the inside of the electrode 6 to the inside of the shaft 7, and the electrode 6 is cooled by circulating the cooling water. The semiconductor wafer cooling means supplies the refrigerant gas from the shaft 7 through the inside of the pipe 11 provided inside the electrode 6, and the semiconductor wafer 12
Is designed to be cooled.

On the other hand, as shown in FIGS. 1 to 4, the semiconductor wafer pressing mechanism elastically supports the semiconductor wafer pressing body 13 installed above the electrode inlet 2 formed in the processing chamber 1 and the same. A leaf spring 19 and a leaf spring 21 as a detaching means for detaching the etched semiconductor wafer 12 from the semiconductor wafer retainer body 13 are provided.

The semiconductor wafer retainer body 13 has a semiconductor wafer retainer plate 14 and a cushioning material 15. The semiconductor wafer holding plate 14 is formed of an electrically insulating material having excellent corrosion resistance and heat resistance, for example, a thin plate of ceramics or quartz in order to hold down the disturbance of the plasma state formed between the electrodes 3 and 6. Also, the semiconductor wafer holding plate 14
Is formed in a hollow disk shape, as shown in FIG. As can be seen from FIG. 3, the cushioning material 15 is combined with the semiconductor wafer pressing plate 14 in a concentric ring shape with a leaf spring 21 as the separating means sandwiched between arc-shaped cushioning material pieces. And the semiconductor wafer pressing plate
14 semiconductor wafer contact surfaces, that is, the surfaces on the electrode 6 side. Further, the cushioning material 15 is sandwiched between the semiconductor wafer pressing plate 14 and the cushioning material holder 16, and this cushioning material holder 16 together with the seat plate 17 and the leaf spring 19 for supporting the semiconductor wafer pressing body is circular. It is fastened together with the semiconductor wafer pressing plate 14 by a plurality of mounting bolts 18 provided at equal intervals in the circumferential direction. The cushioning material 15 directly contacts the semiconductor wafer 12 mounted on the electrode 6.

As can be seen from FIG. 3, the leaf spring 19 for supporting the semiconductor wafer retainer body is formed in a ring shape concentric with the semiconductor wafer retainer plate 14. And this leaf spring 19
Is bonded to the semiconductor wafer pressing plate 14 together with the cushioning material 15 by the mounting bolts 18 as described above, and at the peripheral portion of the electrode introduction port 2 formed in the processing chamber 1, as shown in FIG. A plurality of mounting bolts 20 provided between the mounting bolts 18 in the circumferential direction are coupled to each other, and support the semiconductor wafer pressing body 13 so as to elastically act.

As shown in FIG. 3, the leaf spring 21 as a means for removing the etched semiconductor wafer is formed in a strip shape, and as shown in FIG. 4, the half of the working side projects downward. It is bent into a shape that Further, a plurality of leaf springs 21 are arranged in the circumferential direction between the cushioning material pieces, and the root side of each leaf spring 21 is attached to the semiconductor wafer pressing plate 14 and the cushioning material by mounting pins 22. It is clamped and fixed between the holder 16 and the holder.

The semiconductor wafer pressing mechanism of the above embodiment is used and operates in the following manner together with the parallel plate type dry etching apparatus.

That is, as shown in FIG. 1, a semiconductor wafer to be processed on the electrode 6 at a position where the electrode 6 is lowered from the processing chamber 1.
12, the electrode 6 is introduced into the processing chamber 1 through the electrode introduction port 2 formed in the processing chamber 1, and the electrode 6 is raised to a fixed position facing the electrode 3 installed in the processing chamber 1.

While the electrode 6 is being raised, the semiconductor wafer 12 placed on the electrode 6 first comes into contact with a leaf spring 21 as a semiconductor wafer releasing means in the semiconductor wafer holding mechanism, and then the leaf spring 21 bends. The semiconductor wafer 12 contacts the cushioning material 15 of the semiconductor wafer holding mechanism. Subsequently, when the electrode 6 is raised, the semiconductor wafer is bonded to the semiconductor wafer pressing plate 14 via the mounting bolt 18 and is bonded to the peripheral portion of the electrode introduction port 2 of the processing chamber 1 via another mounting bolt 20. The leaf spring 19 for supporting the presser body bends, and the electrode 6
Is lifted to a fixed position facing the electrode 3 installed in the processing chamber 1, the semiconductor wafer pressing body 13 presses the semiconductor wafer 12 onto the electrode 6 with a pressing force corresponding to the deflection of the leaf spring 19. ,In close contact.

After raising the electrode 6 to a fixed position, an etching gas is introduced from a small hole 5 through the inside of the cylindrical shaft 4 of the electrode 3 in a vacuum atmosphere, and high frequency power is applied between the electrodes 3 and 6, so that a semiconductor wafer is obtained. 12 is etched.

Meanwhile, the electrode 6 is cooled by the cooling water circulated in the cooling water introduction passage 8, the cooling water chamber 9 and the cooling water discharge passage 10 which constitute the electrode cooling means. As the electrode 6 is cooled, heat is transferred from the electrode 6 to the semiconductor wafer 12.

On the other hand, a refrigerant gas is supplied through a pipe 11 as a semiconductor wafer cooling means, and the semiconductor wafer is supplied by this refrigerant gas.
12 is cooled directly. Since the outer edge portion of the semiconductor wafer 12 is held by the semiconductor wafer holding body 13,
The leakage of the refrigerant gas from the outer edge portions of the electrode 6 and the semiconductor wafer 12 is prevented.

After the etching process is completed, the electrode 6 is lowered with the processed semiconductor wafer 12 mounted thereon.

At that time, the leaf spring 21 acts as a means for separating the semiconductor wafer, and the polymer by etching adheres to the lower surface of the buffer material 15, and the semiconductor wafer 12 that has been subjected to the etching treatment adheres to the buffer material 15 and does not separate. However, the etched semiconductor wafer 12 can be reliably separated from the buffer material 15.

The electrode 6 is withdrawn from the processing chamber 1 while the semiconductor wafer 12 having been subjected to the etching treatment is placed, the semiconductor wafer 12 subjected to the etching treatment is taken out from the electrode 6, and one cycle of the etching treatment is completed.

The semiconductor wafer pressing mechanism of the above embodiment has the following effects.

(1) The semiconductor wafer pressing mechanism is the semiconductor wafer pressing body.
13 and a leaf spring 19 for supporting the same, the semiconductor wafer pressing body 13 is provided with a semiconductor wafer pressing plate 14
And a buffer material 15, the semiconductor wafer pressing plate 14 is formed of a thin plate of an electrically insulating material having excellent corrosion resistance and heat resistance such as ceramics and quartz, and the buffer material 15 is a semiconductor wafer of the semiconductor wafer pressing plate 14. It is arranged on the contact surface side, and a leaf spring 19 is arranged on the semiconductor wafer contact surface side of the cushioning material 15 to couple these members, and furthermore, the cushioning material 15 and the semiconductor wafer holding plate 14 form the semiconductor wafer 12 Since the outer edge portion is pressed, the semiconductor wafer pressing plate 14, the buffer material 15, and the leaf spring 19 are combined with each other while the semiconductor wafer 12 placed on the electrode 6 is pressed in the processing chamber 1. Since it slightly protrudes toward the plasma side, the plasma state formed between the electrodes 3 and 6 is not significantly disturbed, and therefore the semiconductor wafer 12 can be uniformly subjected to the etching process.

(2) Since the cushioning material 15 is brought into contact with and pressed against the semiconductor wafer 12, the impact force when pressing the semiconductor wafer 12 can be alleviated, and the pressing force applied to the semiconductor wafer 12 is reduced from zero by the leaf spring 19. Since it can be gradually and linearly increased, not only the impact force acting on the semiconductor wafer 12 can be reduced, but also when the semiconductor wafer pressing plate 14 is made of a fragile material, the semiconductor wafer pressing plate 14
The mechanical life of the can be extended.

(3) A ring-shaped leaf spring 19 is used to support the semiconductor wafer retainer body 13, and the leaf spring 19 is connected to the semiconductor wafer retainer body 13 by a plurality of attachment bolts 18, while a plurality of other attachment bolts are used. Since it is connected to the peripheral portion of the electrode introduction port 2 of the processing chamber 1 by 20, the rigidity in the lateral direction with respect to the vertical movement of the leaf spring 19, that is, the diametrical direction of the semiconductor wafer 12 to be pressed can be increased.
It is possible to reduce the lateral displacement of the pressing margin of 13, and thus improve the reproducibility of the etching region of the semiconductor wafer 12 that opens from the semiconductor wafer pressing body 13 to the plasma, and obtain a uniform product in mass production processing. it can.

(4) After the etching process, when the electrode 6 is lowered, the leaf spring 21 as a means for separating the etched semiconductor wafer is used to positively separate the etched semiconductor wafer 12 from the semiconductor wafer retainer body 13. Therefore, during the etching process, the polymer due to the etching adheres to the lower surface of the cushioning material 15, whereby the semiconductor wafer 12 that has been subjected to the etching treatment adheres, and the leaf spring 21 of the leaf spring 21 does not separate from the cushioning material 15. By the movement, the semiconductor wafer 12 subjected to the etching treatment can be reliably separated from the buffer material 15 and placed on the electrode 6.

(5) The semiconductor wafer pressing body 13 and the leaf spring 19 are made to work by utilizing the ascending operation of the electrode 6 into the processing chamber 1, and the semiconductor wafer 12 placed on the electrode 6 can be automatically pressed. .

Next, FIGS. 5 and 6 show another embodiment of the present invention. This embodiment is different from the embodiment shown in FIGS. 1 to 4 for supporting a half-body wafer holding body. The shape of the leaf spring is different.

That is, in this embodiment, instead of the ring-shaped leaf spring,
A plurality of strip-shaped leaf springs 23 are arranged below the semiconductor wafer retainer body 13 at circumferential intervals.

Then, one end of each leaf spring 23 is connected to the semiconductor wafer retainer main body 13 by a mounting bolt 24, and the other end is connected to the peripheral edge of the electrode introduction port 2 of the processing chamber 1 by another mounting bolt 25. ing.

Other configurations of the embodiment shown in FIGS. 5 and 6 are the same as those of the embodiment shown in FIGS. 1 to 4,
The operation and effect are the same as those of the embodiment shown in FIGS. 1 to 4 except that the leaf spring 23 has a simple shape and is easy to attach.

〔The invention's effect〕

According to the first aspect of the present invention described above, there is provided a semiconductor wafer retainer main body which is made of an electrically insulating material having corrosion resistance and heat resistance in a thin plate shape and which presses the outer edge portion of the semiconductor wafer placed on the electrode. Since the semiconductor wafer retainer body is elastically supported by a leaf spring and can be formed into a thin plate as a whole, the semiconductor wafer held on the electrode does not project to the plasma side slightly. Disturbance of the plasma state formed between them can be suppressed to a small extent, so that there is an effect that the semiconductor wafer can be uniformly etched, so that the semiconductor wafer retainer body is supported by the leaf spring, and the semiconductor retainer body is elastically operated. Therefore, the mass production type dry etching apparatus is performed by relatively moving the electrode on which the semiconductor wafer is mounted and the processing chamber in which the other electrode is installed. There is an effect that the semiconductor wafer can be automatically brought into close contact with the electrode by using the moving member. Since the semiconductor wafer is held in close contact with the electrode by the body for holding the semiconductor wafer through the leaf spring, There is an effect that the heat transfer performance can be improved, and since the structure is simple, there is also an effect that the maintenance can be easily performed.

Further, according to the second aspect of the present invention, since the detaching means for detaching the etched semiconductor wafer from the semiconductor wafer retainer body is provided, the polymer due to etching adheres to the semiconductor wafer retainer body, and Even when the etched semiconductor wafer is attached to the holding body, there is a particular effect that the semiconductor wafer can be reliably separated.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention applied to a flat plate type dry etching apparatus. FIG. 1 shows immediately before introducing an electrode on which a semiconductor wafer to be processed is placed into a processing chamber. 2 is a vertical sectional front view showing the arrangement state of each member of FIG. 2, FIG. 2 is a vertical sectional front view showing the arrangement state of each member during the etching process, and FIG. 3 is a cross-sectional plan view taken along the line III-III of FIG. Is an enlarged sectional view taken along the line IV-IV in FIG. 3, FIGS. 5 and 6 show another embodiment of the present invention, FIG. 5 is a cross-sectional plan view, and FIG. 6 is FIG. 6 is a sectional view taken along line VI-VI of FIG. 1 …… Processing chamber 2 …… Electrode inlet 3,6 …… Electrode 12 …… Semiconductor wafer 13 …… Semiconductor wafer retainer body 14 …… Semiconductor wafer retainer plate 15 …… Cushioning material 18 …… Cushioning material and leaf spring Mounting bolts for tightening together 19 ...... Plate springs for supporting semiconductor wafer retainer body 20 ...... Mounting bolts for connecting plate springs to the peripheral edge of the electrode introduction port 21 ...... Plates as means for removing processed semiconductor wafers Spring 22 ...... Plate for mounting leaf spring 23 ...... Plate spring for supporting semiconductor wafer retainer body 24 ...... Mounting bolt for leaf spring and semiconductor wafer retainer body 25 ...... Plate spring and peripheral edge of electrode inlet Mounting bolts to join

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Serizawa, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Within the Institute of Industrial Science, Hitachi, Ltd. (56) Reference JP-A-56-78457 (JP, A) Kai 54-29576 (JP, A)

Claims (4)

[Claims] 1. A processing chamber for processing a semiconductor wafer, electrode means for mounting the semiconductor wafer, cooling means inside the electrode means for cooling the electrode means and the semiconductor wafer, and the processing. A semiconductor wafer pressing means for pressing the semiconductor wafer onto the electrode means in a chamber, and a driving means outside the processing chamber for pressing or releasing the pressing of the semiconductor wafer onto the electrode means by the semiconductor wafer pressing means. And an elastic support member that elastically supports the semiconductor wafer pressing means, and is configured to perform etching on the semiconductor wafer. 2. The semiconductor wafer pressing means has a semiconductor pressing plate for pressing the semiconductor wafer against the electrode means, and a cushioning material attached to the contact surface side where the semiconductor pressing plate contacts the semiconductor wafer. The dry etching apparatus according to claim 1, wherein: 3. The semiconductor wafer pressing means has a separating means for separating the semiconductor wafer from the semiconductor wafer pressing means when the pressing of the semiconductor wafer is released by the driving means. The dry etching apparatus according to claim 1. 4. The dry etching apparatus according to claim 3, wherein the detaching means comprises an elastic member supported by the semiconductor wafer pressing means.