JP3334523B2 - Dry etching method - 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 A dry etching method for etching a substrate includes an upper electrode electrically grounded and a lower electrode connected to a high frequency power supply. Then, a substrate is set on the lower electrode, and after reducing the atmosphere, a process gas is supplied to generate plasma.

Since the substrate to be set must maintain a horizontal posture, it is necessary to press the outer edge of the substrate against the lower electrode with a substrate holder during etching. When the etching is completed, a process of removing the substrate holder from the substrate and carrying out the substrate from the upper surface of the lower electrode is performed.

[0004]

The temperature of the substrate holder itself rises as a result of the etching. However, in the conventional dry etching apparatus, no countermeasures have been taken against the temperature increase of the substrate holder. By the way, the substrate holder is present in a reduced-pressure atmosphere, and in the reduced-pressure atmosphere, there is almost no gas as a medium for diffusing heat. The heat is hardly radiated out of the substrate holder.

For this reason, in the conventional dry etching method, the temperature of the substrate holder keeps increasing every time the etching is repeated, and accordingly, the temperature of the portion of the substrate that contacts the substrate holder also increases. I was Therefore, there has been a problem that the etching result for the substrate varies.

Accordingly, an object of the present invention is to provide a dry etching method and a dry etching apparatus which can suppress the variation in etching.

[0007]

According to the dry etching method of the present invention, a substrate is placed on the upper surface of a lower electrode cooled by cooling means, and the edge of the substrate is pressed against the lower electrode with a substrate holder and fixed. A step of applying a high-frequency power to the lower electrode to cause a process gas to be in a plasma state to etch the upper surface of the substrate, and a step of releasing the fixing of the substrate by the substrate holder and removing the substrate from the upper surface of the lower electrode. And cooling the substrate holder by lowering the substrate holder to make contact with the lower electrode.

[0008]

[0009]

According to the dry etching method of the present invention, the substrate is placed on the upper surface of the lower electrode cooled by the cooling means, and the edge of the substrate is pressed against the lower electrode with a substrate holder and fixed. A step of applying a high-frequency power to the lower electrode to cause a process gas to be in a plasma state to etch the upper surface of the substrate, and a step of releasing the fixing of the substrate by the substrate holder and removing the substrate from the upper surface of the lower electrode. The substrate holder that has been etched is
A step of contacting the lower electrode after being removed and cooling the substrate holder.

[0010]

Therefore, if the etching is completed
If the substrate presser is lowered, it contacts the cooled lower electrode.
By doing so, the temperature of the substrate holder, which has been raised in temperature by the etching , can be almost returned to the initial state, so that variations in the individual temperatures of the substrate can be reduced, which can contribute to uniform etching.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a dry etching apparatus according to one embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a vacuum vessel whose internal space is depressurized by a pressure control means P. Reference numeral 2 denotes an entrance through which the substrate 9 enters and exits the vacuum vessel 1. The entrance 2 is closed by a gate 3 during operation.

Reference numeral 4 denotes an upper electrode disposed above the vacuum vessel 1. The upper electrode 4 is electrically grounded, and a plurality of gas outlets 5 are opened on the lower surface for discharging a plasma generating gas. And in the gas outlet 5,
A plasma generation gas such as helium gas is supplied from a plasma generation gas supply unit 6.

An upper electrode 4 is provided below the vacuum vessel 1.
The lower electrode 7 is arranged so as to face. The lower electrode 7 is connected to a high-frequency electrode 8 for supplying high-frequency AC power. Further, a channel 10 is formed inside the vacuum vessel 1 for flowing cooling water to forcibly cool the entire lower electrode 7, and a cooling unit 11 for supplying cooling water is connected to the channel 10. ing. The substrate 9 placed in the vacuum vessel 1 is placed on the upper surface 7a of the lower electrode 7.

Reference numeral 12 denotes a substrate holder for fixing the substrate 9 by pressing the outer edge of the substrate 9 placed on the upper surface 7a of the lower electrode 7 against the lower electrode. The substrate holder 12 is fixed to a lower end of a rod 14 of a cylinder 13 fixed to an upper part of the vacuum vessel 1. That is, when the cylinder 13 is driven, the substrate holder 12 can be moved up and down.

The dry etching method according to the present embodiment has the above-described configuration, and its operation will be described below.

First, the gate 3 is opened, and the substrate 9 is set on the upper surface 7a of the lower electrode 7 of the vacuum vessel 1. Next, the gate 3 is closed, the cylinder 13 is driven, and the edge of the substrate 9 is pressed against the lower surface 7 a by the substrate presser 12.

Next, the vacuum vessel 1 is controlled by the pressure control means P.
The inside is decompressed, and a plasma generation gas is supplied from the plasma generation gas supply unit 6 into the vacuum vessel 1 through the gas outlet 5. Further, the high-frequency current 8 is operated to supply high-frequency AC power to the lower electrode 7. Further, the lower electrode 7 is forcibly cooled by the cooling means 11.

Then, plasma is generated near the upper surface of the substrate 9, the substrate 9 is dry-etched, and the temperature of the substrate 9 rises. Further, a substrate presser 12 pressing the substrate 9 is provided.
Also rises in temperature.

When the dry etching of the substrate 9 is completed, the gate 3 is opened and the substrate 9 is discharged out of the vacuum vessel 1. Here, as described in the section of the prior art, at this time, the substrate holder 12 is at a considerably high temperature.

Therefore, as shown in FIG. 2, while the lower electrode 7 is being forcibly cooled, the substrate holder 12 is lowered and brought into contact with the cooled upper surface 7a of the lower electrode 7. Thereby, the heat of the substrate holder 12 is transmitted to the lower electrode 7 and the substrate holder 12
Is substantially reduced to a temperature before the etching is performed.

Therefore, when the next etching is performed, the temperature of the substrate 9 does not change due to the substrate presser 12, so that the variation in the etching result can be suppressed.

[0024]

The present invention is configured as described above.
The etching result can be made uniform by eliminating the historical temperature rise of the substrate holder.

Since the substrate holder is cooled by bringing the substrate holder into contact with the lower electrode, no special modification for cooling is required for the substrate holder, and the substrate holder can be cooled by a relatively simple mechanism.

[Brief description of the drawings]

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

FIG. 2 is an operation explanatory diagram of a dry etching method according to one embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 4 Upper electrode 7 Lower electrode 8 High frequency power supply 9 Substrate 11 Cooling means 12 Substrate holding

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/3065 C23F 4/00 H01L 21/68

Claims (1)

(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. A step of placing the substrate on the upper surface of the lower electrode cooled by the cooling means, pressing the edge of the substrate against the lower electrode with a substrate holder, and fixing the lower electrode, and applying high-frequency power to the lower electrode. Etching the upper surface of the substrate by bringing the process gas into a plasma state; releasing the substrate from the upper surface of the lower electrode by releasing the fixing of the substrate by the substrate holder; and removing the substrate from the upper surface of the lower electrode. A dry etching method comprising a step of contacting the removed lower electrode to cool the substrate holder.