JP3287222B2 - Dry etching method and dry etching apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dry etching method and a dry etching apparatus.

[0002]

2. Description of the Related Art In recent years, attempts have been made to perform fine processing on both surfaces of a substrate made of glass or the like using a dry etching apparatus. Some conventional dry etching apparatuses aim at processing a substrate made of a semiconductor such as silicon.

[0003]

By the way, in order to process a substrate on both sides, an unprocessed surface on the opposite side can be etched while the processed surface of the substrate is held in a non-contact manner. It is desirable.

[0004] In addition, when temperature unevenness occurs in the substrate, the result of etching varies. Here, when etching is performed, the temperature of an insulating substrate such as glass tends to rise more than that of a semiconductor such as silicon, so that a means for uniformly cooling the substrate is required.

Accordingly, an object of the present invention is to provide a dry etching method and a dry etching apparatus capable of etching an unprocessed surface on the back surface without contacting the processed surface and uniformly cooling the substrate.

[0006]

According to the dry etching method of the present invention, an upper electrode which is grounded in a reduced pressure atmosphere;
A dry etching method in which a substrate is positioned between a lower electrode connected to a high-frequency power supply and a substrate is etched by a process gas in a plasma state. A space whose upper part is covered by the lower surface of the substrate is formed above the substrate, and a cooling gas is introduced into the space from a plurality of outlets formed at the outer edge of the space, and the substrate is etched while being uniformly cooled. The lower surface of the substrate on the substrate supporting portion.
An annular substrate mounting surface for receiving is formed, and
A stepped flat surface is formed inside the substrate mounting surface.
The plate is designed to be supported on this flat surface without contact.
Up and down the board by going under the outer edge of the board
Lifter, a recess for storing the lowered lifter,
A substrate presser for pressing the upper surface of the plate, and connecting the space and the concave portion.
Providing a communication hole through which the cooling gas is filled in the space;
While discharging from the communication hole,
The cooling device cools the substrate pressed against the substrate mounting surface .

Further, the dry etching apparatus of the present invention comprises an outer cylinder forming an internal space shielded from the outside, an upper electrode disposed on the upper part of the outer cylinder and electrically grounded, and a lower electrode connected to a high frequency power supply. An inner cylinder on which electrodes are mounted and which is arranged below the outer cylinder, and a lower ring receiving the outer edge of the lower surface of the substrate
A substrate supporting portion having a substrate mounting surface formed between the upper electrode and the lower electrode, and forming a space in which an upper portion is covered by a lower surface of the substrate in a state where the substrate is received on the substrate mounting surface. A flat surface that is stepped down from the inside of the substrate mounting surface to provide a plurality of air outlets for introducing cooling gas into the space from the outer edge of the flat surface , and also go under the outer edge of the substrate
The lifter that lifts and lowers the substrate
A recess for holding the board, and a board holder for holding the top of the board.
Further, the space is communicated with the recess to fill the space.
A communication hole for discharging the cooled cooling gas is formed .

[0008]

According to a first aspect of the present invention, in a dry etching method, a substrate is positioned between a grounded upper electrode and a lower electrode connected to a high-frequency power supply in a reduced-pressure atmosphere, and a plasma state is established. A dry etching method for etching a substrate with a process gas, comprising: setting a substrate on a substrate support, forming a space above the substrate support, the upper surface of which is covered by a lower surface of the substrate; the outer portion formed a plurality of air outlet from the cooling gas to the space is introduced, so as to etching while uniformly cooling the substrate, the lower surface of the substrate on the substrate support portion
An annular substrate mounting surface for receiving is formed, and
A stepped flat surface is formed inside the substrate mounting surface.
The plate is designed to be supported on this flat surface without contact.
Up and down the board by going under the outer edge of the board
Lifter, a recess for storing the lowered lifter,
A substrate presser for pressing the upper surface of the plate, and connecting the space and the concave portion.
Providing a communication hole through which the cooling gas is filled in the space;
While discharging from the communication hole,
The cooling device cools the substrate pressed against the substrate mounting surface . Therefore, the substrate can be uniformly cooled by the cooling gas existing in the space. Further, most of the substrate is in contact with the cooling gas, not in contact with the solid member, and the etching can be performed in a non-contact state.

The dry etching apparatus according to claim 3 is
An outer cylinder that forms an internal space that is shielded from the outside, an upper electrode that is placed above the outer cylinder and that is electrically grounded, and a lower electrode that is connected to a high-frequency power supply are mounted and arranged below the outer cylinder. A circle having an inner cylinder and receiving the outer edge of the lower surface of the substrate
A substrate supporting portion having an annular substrate mounting surface is provided between the upper electrode and the lower electrode, and a space is formed in which the upper surface is covered by the lower surface of the substrate when the substrate is received on the substrate mounting surface. A flat surface that is stepped down from the inside of the substrate mounting surface to provide a plurality of air outlets for introducing cooling gas into the space from the outer edge of the flat surface , and also go under the outer edge of the substrate
The lifter that lifts and lowers the substrate
A recess for holding the board, and a board holder for holding the top of the board.
Further, the space is communicated with the recess to fill the space.
A communication hole for discharging the cooled cooling gas is formed .

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a dry etching apparatus according to one embodiment of the present invention. FIG. 1 shows a lower member of the dry etching apparatus. 2 and 3 are cross-sectional views of FIG. 1ABC.

In FIGS. 1 and 2, reference numeral 1 denotes an outer cylinder which blocks the internal space of the dry etching apparatus from the outside. An inner cylinder 20 holding an electrode 10 and a substrate support 2 disposed above the electrode 10 is disposed below the inner side of the outer cylinder 1. 2a of the substrate support 2 is a horizontal upper surface. In the center of the upper surface 2a, an annular substrate mounting surface 2b is formed at a position one step lower than the upper surface 2a. When the substrate 3 is set, the outer edge of the lower surface of the substrate 3 is received on the substrate mounting surface 2b.

Reference numeral 2c denotes a circular flat surface formed inside the substrate mounting surface 2b and at a position one step lower. Most of the lower surface of the substrate 3 is a flat surface 2c.
The substrate 3 is positioned higher than the substrate 3 and is supported in a non-contact manner.

The reference numeral 2d denotes a substrate mounting surface 2b and a flat surface 2c.
And a flat surface 2c
The groove is located one step lower than the groove. In the groove 2d, a plurality of outlets 2e communicating with a flow path described later are radially opened.

Reference numeral 21 denotes an intermediate plate having conductivity disposed between the substrate support 2 and the lower electrode 10, and has grooves or holes formed therein for forming the flow path 12 communicating with the outlet 2e.

Reference numeral 4 denotes a lifter formed so that the upper surface of the distal end portion can go under the outer edge of the lower surface of the substrate 3 and the rod 4a (see FIG. 2) can be moved up and down to move the substrate 3 up and down. . In this embodiment, three lifters 4 are provided radially from the center of the apparatus. Substrate support 2 and inner cylinder 2
On the upper surface of 0, a groove forming the concave portion 22 is formed. The concave portion 22 has a size to accommodate the lifter 4, and when the rod 4a is lowered and the lifter 4 is settled in the concave portion, the upper surface of the lifter 4 is larger than the upper surface 2a and the substrate mounting surface 2b. It is located below. Accordingly, when the lifter 4 on which the substrate 3 is mounted is lowered, the outer edge of the lower surface of the substrate 3 lands on the substrate mounting surface 2b and is set on the substrate support (see FIG. 6). In FIG. 6, a communication hole d for communicating the space S with the concave portion 22 is formed in the upper surface of the substrate support 2 by cutting.
Therefore, when the cooling gas is introduced from the flow path 12, the space S is filled with the cooling gas, and a part thereof is discharged through the communication groove d as indicated by an arrow N.

A recess 5 is formed in the upper surface 2a at a position off the lifter 4, as shown in FIG.
Inside, a conductive member 6 made of a conductor such as a spring material is fixed by screws 6a. At the tip of the conductive member 6, a plurality of bent pieces 7 which are once erected from the center of the device and then turned back to the outer peripheral side of the device are formed. Therefore, the bent piece 7 has flexibility and conductivity, and is electrically connected to the substrate support 2.

FIG. 2 shows a state immediately before the setting of the substrate 3. In FIG. 3, reference numeral 8 denotes a top plate that closes the upper part of the outer cylinder 1, and a horizontal upper electrode 9 that is electrically grounded is mounted at the center of the top plate 8. In the present embodiment, a process gas such as a fluorocarbon gas can be introduced into the outer cylinder 1 via the upper electrode 9.

The inner cylinder 2 is provided with a lower electrode 10 connected to a high frequency power supply 11. Also, the lower electrode 10
Has a flow path 12 for introducing a cooling gas such as helium gas.
The leading end of the flow path 12 is connected to an outlet 2e in the groove 2d. Therefore, the cooling gas can be supplied from the outlet 2e. A space 10 a through which cooling water flows is formed in the lower electrode 10, and the cooling water flows by a cooling means (not shown) to forcibly cool the lower electrode 10, the intermediate plate 21, which is in close contact with the lower electrode 10, and the substrate support 2. I do.

A cylinder 13 is fixed to the top plate 8 downward. The cylinder 13 raises and lowers the substrate holder 14. The substrate holder 14 is located on the outer peripheral side of the apparatus, and includes an insulating part 14 a made of an insulator and an insulating part 1.
4a, and a conductive portion 14b which comes into contact with and separates from the outer edge of the lower surface of the substrate 3.

Next, the dry etching method of the present embodiment will be described with reference to FIGS.

First, as shown in FIG. 2, the substrate 3 is supplied into the outer cylinder 1, and the outer edge of the lower surface of the substrate 3 is placed on the lifter 4. At this time, the lifter 4 is at the raised position.

Then, the pressure inside the outer cylinder 1 is reduced by an exhaust means (not shown), and a process gas is supplied.

Next, as shown in FIG. 3, the lifter 4 is lowered, the outer edge of the lower surface of the substrate 3 is mounted on the substrate mounting surface 2b, and the cylinder 13 is driven to lower the substrate presser 14. ,
The outer edge of the upper surface of the substrate 3 is pressed from top to bottom by the conductive portion 14b.

Then, as shown enlarged in FIG. 4, the upper surface of the flat surface 2c and the groove 2d is covered by the lower surface of the substrate 3, and a space S (having a thickness of, for example, about 50 μm) is provided below the substrate 3. ) Is formed. That is, most of the lower surface of the substrate 3 does not come into contact with the inner cylinder 2. At this time, the conductive portion 14b descends to push down the bent piece 7. Therefore, the conductive portion 14b is electrically connected to the lower electrode 10 via the substrate support 2 and the intermediate plate 21. Further, the insulating portion 14a does not contact the upper surface of the inner cylinder 20, and a slight gap t is formed between the two.

When the high-frequency power supply 11 is operated in the state shown in FIG. 3, the process gas supplied into the outer cylinder 1 causes the process gas between the upper electrode 9 and the substrate 3 to be in a plasma state, and the etching proceeds. I do.

At this time, the temperature of the substrate 3 rises, but by supplying the cooling gas from the flow path 12 into the space S,
The substrate 3 can be cooled uniformly.

In general, in a vacuum or reduced-pressure atmosphere, there is almost no gas that acts as a heat medium, so that it is extremely difficult to cool a high-temperature object. However, in this embodiment, the substrate can be cooled by setting the space S in contact with the substrate 3 to be cooled to a high pressure (about 10 Torr) filled with the cooling gas. In addition, cooling gas is introduced from the outer peripheral side of the space S, and the thickness of the space S is reduced to, for example, 5
The cooling gas has a viscous flow in the space S, such as 0 μm, so that the pressure distribution in the space S does not decrease even in the outer peripheral portion and becomes uniform. When the pressure of a gas such as a cooling gas changes, the heat transfer coefficient also changes. Therefore, by making the pressure distribution in the space S uniform, the entire substrate 3 can be uniformly cooled. As a result, the substrate 3 is uniformly etched, and unevenness in etching can be suppressed.

Next, when the etching is completed, the substrate is returned to the state shown in FIG. 2 and the substrate 3 is carried out. Then, as shown in FIG. 7, after the substrate 3 is unloaded, the substrate holder 14 is brought into contact with the substrate supporting part 2, and the substrate holder 14 and the substrate supporting part 2,
That is, the temperature difference from the lower electrode 10 is reduced. By doing so, the substrate holder 14 whose temperature rises during the etching is
, The temperature of the outer edge of the substrate 3 does not rise abnormally when the substrate presser 14 comes into contact with the substrate 3 next time.

In the present embodiment, the intermediate plate 21 and the substrate support 2 are separately formed on the electrode 10, but may be formed integrally with the same material as the electrode 10. Further, the substrate 3 is not necessarily limited to a substrate processed on both sides.

[0030]

According to the present invention, by introducing a cooling gas into the space below side of the substrate supported on the substrate support, since the etching while uniformly cooling the substrate, cooling gas filled in the space This makes it possible to eliminate unevenness in temperature of the substrate and to perform etching uniformly. In addition, with respect to a substrate to be processed on both sides, the substrate can be set on the substrate support without contacting the processed surface, so that the processed surface is not likely to be damaged.

[Brief description of the drawings]

FIG. 1 is a plan view of a dry etching apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG. 1ABC.

FIG. 3 is a cross-sectional view of FIG. 1ABC.

FIG. 4 is a partially enlarged view of a dry etching apparatus according to an embodiment of the present invention.

FIG. 5 is a partially enlarged view of a dry etching apparatus according to an embodiment of the present invention.

FIG. 6 is a partially enlarged view of a dry etching apparatus according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of FIG. 1ABC.

[Explanation of symbols]

 3 Substrate 9 Upper electrode 10 Lower electrode 11 High frequency power supply S space

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-86385 (JP, A) JP-A-4-23431 (JP, A) JP-A-11-31680 (JP, A) JP-A-5-86 144777 (JP, A) JP-A-2-312223 (JP, A) JP-A-6-53207 (JP, A) JP-A-7-228985 (JP, A) JP-A-60-115226 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) C30B 1/00-35/00 C23F 4/00 H01L 21/3065

Claims (4)

(57) [Claims] 1. A dry etching method in which a substrate is positioned between a grounded upper electrode and a lower electrode connected to a high frequency power supply in a reduced pressure atmosphere, and the substrate is etched by a process gas in a plasma state. And setting a substrate on the substrate support to form a space above the substrate support where the upper part is covered by the lower surface of the substrate,
Annular This introduces a plurality of cooling gas into this space from the air outlet formed on the outer edge portion of the space, so as to etching while cooling the substrate, the said substrate supporting portion for receiving the lower lower surface of the substrate Base
A plate mounting surface is formed, and inside the substrate mounting surface
A flat surface with a step is formed, and the substrate is not in contact with this flat surface.
It is supported by touch, and the outer edge of the substrate
A lifter that goes under and lifts the substrate,
And a board presser that holds the top of the board.
Um, a communication hole for communicating the space and the concave portion is provided,
The cooling gas filled in the space is discharged from the communication hole.
While pressing against the substrate mounting surface by the substrate holder
A dry etching method characterized by cooling a substrate that has been shaken . 2. The dry etching method according to claim 1, wherein the cooling gas has a viscous flow in the space. 3. An outer cylinder forming an internal space which is shielded from the outside, an upper electrode which is disposed on the outer cylinder and is electrically grounded, and a lower electrode which is connected to a high frequency power supply is mounted on the outer cylinder. An inner cylinder disposed at a lower portion of the cylinder, and a substrate support portion having an annular substrate mounting surface for receiving an outer edge of a lower surface of the substrate is provided between the upper electrode and the lower electrode. Forming a flat surface that is stepped down inside the substrate mounting surface so as to form a space in which the upper surface is covered by the lower surface of the substrate, with the substrate placed on the substrate mounting surface; A plurality of air outlets for introducing cooling gas into the space from the outer edge of the substrate are provided .
The lifter that raises and lowers the substrate and the lifter that moves down are stored.
A concave portion and a substrate holder for pressing the upper surface of the substrate are provided.
The space filled with the concave portion communicates with the space to fill the cold space.
A dry etching apparatus characterized in that a communication hole for discharging a cooling gas is formed . 4. The dry-type dry storage device according to claim 3, wherein an annular groove is formed in an outer peripheral portion of the flat surface, and the plurality of outlets are formed so as to open to the groove. Etching equipment.