JPS63300517A - Etching - Google Patents

Abstract

PURPOSE:To uniformly control temperature all over the surface of a semiconductor wafer for enabling the whole surface of the semiconductor wafer to be uniformly etched, by using an electrostatic chuck having a larger diameter than the diameter of the semiconductor wafer to be etched. CONSTITUTION:A path 21 for chuck cooling water and a path 22 for gas are provided inside one electrode 2, and this path 22 for gas is connected through to a path 31 for gas provided inside an electrostatic chuck 3 while this path 31 for gas is opened at the interface between the electrostatic chuck 3 and a semiconductor wafer 4 so as to introduce gas as shown by an arrow for improving thermal conduction between the semiconductor wafer 4 and the electrostatic chuck 3. The diameter of the electrostatic chuck 3 is made larger than the diameter of the semiconductor wafer 4. Accordingly, gas contacts even with peripheral part of the semiconductor wafer 4 so as to uniformly control temperature all over the surface of the semiconductor wafer 4 for enabling all over the surface of the semiconductor wafer to be uniformly etched.

Description

[Detailed Description of the Invention] [Summary] A gas supply path is provided through the main body, and a heat conduction gas is blown between the semiconductor wafer and the main body through the gas supply path. In this etching method, an electrostatic chuck body for semiconductor wafers having a diameter larger than the diameter of the semiconductor wafer to be etched is used for etching using a dry etching apparatus having an electrostatic chuck for semiconductor wafers.

[Industrial application field]

The present invention relates to improvements in etching methods.

In particular, an etching method using a dry etching device that introduces gas to the back side of a semiconductor wafer supported by an electrostatic chuck through a gas supply path provided through the electrostatic chuck body. Regarding improvements.

[Conventional technology]

In FIG. 0, a known dry etching apparatus 2 whose schematic structure is shown in FIG. do. 5 is a counter electrode, which is grounded in this example. 6 has an RF main power source, the ■ end is grounded, and the other end is connected to one electrode 2 in this example. In this one electrode 2, a chuck cooling water passage 21 and a gas passage 22 are provided, and this gas passage 22 is connected to a gas passage 31 provided in the electrostatic chuck 3.
This gas passage 31 communicates with the electrostatic chuck 3.
It is opened at the interface between the semiconductor wafer 4 and the semiconductor wafer 4, and debris is introduced in the direction of the arrow to improve heat conduction between the semiconductor wafer 4 and the electrostatic chuck 3. It goes without saying that the vacuum container 1 is provided with an etching gas supply port +1 and an exhaust port 12.

A dry etching device with such a structure (a dry etching device in which gas is introduced to the back side of a semiconductor wafer supported by an electrostatic chuck through a gas supply path provided through the electrostatic chuck body) I will talk about the development process.

Before this wafer temperature control method was developed, the third
As shown in the figure, an elastic heat transfer film 6 such as a silicone resin film is interposed between the electrostatic chuck 3 and the semiconductor wafer 4 to improve thermal contact between the semiconductor wafer 4 and the electrostatic chuck 3. 4 had good temperature control.

In such a dry etching apparatus having a structure in which elastic heat transfer l1516 is interposed between the semiconductor wafer 4 and the electrostatic chuck 2, the diameter of the electrostatic chuck 3 is made smaller than the diameter of the semiconductor wafer 4. I had no choice but to do it. This is to prevent the elastic heat transfer film 6 such as a silicone resin film from being exposed to plasma or the like.

Subsequently, a dry knee 7ing device was developed in which gas was introduced to the back side of the semiconductor wafer 4 supported by the electrostatic chuck 3 through a gas feed path 31 provided through the electrostatic chuck body 3. However, this type of dry kneading device (which supplies gas to the semiconductor wafer 4 supported by the electrostatic chuck 3 through a gas supply path 31 provided on the back surface of the electrostatic chuck body 3) Even in the type of dry etching apparatus M) to be introduced, the custom of making the diameter of the electrostatic chuck 3 smaller than the diameter of the semiconductor wafer 4 was maintained.

[Problem that the invention seeks to solve]

In a dry etching apparatus as described above, in which scum is introduced to the back surface of a semiconductor wafer supported by an electrostatic chuck through a gas supply path provided through the electrostatic chuck body, As mentioned above, mainly due to historical reasons, the diameter of the electrostatic chuck is made smaller than the diameter of the semiconductor wafer, so a sufficient amount of gas is not supplied to the peripheral area of the semiconductor wafer, and the semiconductor wafer is The disadvantage is that the temperature is not sufficiently controlled.

The purpose of the present invention is to eliminate this drawback, and to
In an etching method using a dry etching device that introduces gas through a gas supply path provided through the electrostatic chuck body, the entire surface of the semiconductor wafer can be uniformly temperature-controlled; semiconductor waeno λ
The object of the present invention is to provide an improvement that enables uniform etching of the entire surface of the surface.

[Means for solving problems]

The means taken by the present invention to achieve the above object is that a gas supply passage (31) is provided penetrating the main body (3), and through this gas supply passage (31), A semiconductor wafer (4) being etched during etching using a dry etching apparatus having an electrostatic chuck (3) for semiconductor wafers in which gas is introduced between the back surface of the semiconductor wafer (4) and the main body (3). The purpose is to use an electrostatic chuck body (3) for semiconductor wafers having a diameter larger than the diameter of the semiconductor wafer.

[Effect]

The disadvantages mentioned above (in dry etching equipment of the type that introduces gas to the back side of the semiconductor wafer supported by the electrostatic chuck through a gas supply path provided through the electrostatic chuck body), The reason for the failure of the semiconductor wafer (temperature control) and (defect) is that the semiconductor wafer temperature control gas does not come into contact with the periphery of the semiconductor wafer, as shown in FIG.

On the other hand, in a dry etching apparatus of the type in which gas is introduced to the back surface of a semiconductor wafer supported by an electrostatic chuck through a gas supply passage provided through the electrostatic chuck body, as shown in FIG. Since there is no need to interpose the elastic heat transfer film 6 between the semiconductor wafer 4 and the electrostatic chuck 3, there is no need to protect the elastic heat transfer film 6 from plasma.

Therefore, in the present invention, by using an electrostatic chuck with a diameter larger than the diameter of the semiconductor wafer I\, gas contacts the entire surface of the semiconductor wafer up to the periphery, and the semiconductor wafer is uniformly distributed over the entire surface. temperature controlled,
The entire surface of the semiconductor wafer is etched uniformly.

〔Example〕

Hereinafter, a kneeling method according to an embodiment of the present invention will be further described with reference to the drawings.

Referring to FIG. 1, 1 is a vacuum container, 2 is one electrode, and supports an electrostatic chuck 3 that supports a semiconductor wafer 4. Reference numeral 5 denotes a counter electrode, which is connected to the vc ground in this example. 6 is an RF main power source, one end is grounded and the other end is connected to one electrode 2 in this example. A chuck cooling water passage 21 and a gas passage 22 are provided in one electrode 2, and this gas passage 22 communicates with a gas passage 31 provided in the electrostatic chuck 3.
This gas passage 31 opens at the interface between the electrostatic chuck 3 and the semiconductor wafer 4, and introduces gas as indicated by the arrow to improve heat conduction between the semiconductor wafer 4 and the electrostatic chuck 3. The vacuum container 1 has an etching gas supply port 11.
Needless to say, an exhaust port 12 is provided.

In this embodiment, the diameter of the electrostatic chuck 3 is made larger than the diameter of the semiconductor wafer 4.

Therefore, the gas comes into contact with the periphery of the semiconductor wafer 4, the temperature of the entire surface of the semiconductor wafer 4 is uniformly controlled, and the entire surface of the semiconductor wafer is uniformly etched.

Below is a semiconductor wafer 4 with a diameter of 5 inches (125 mm).
An example (example) in which a semiconductor wafer 4 with a diameter of 5 inches (125 mm) is attached to an electrostatic chuck 3 with a diameter of 142 mm (comparative example) Regarding the semiconductor wafer 4
The burnt degree of the surface, the PSG etching rate, and the variation in the PSG etching rate are compared and described below using RF power as a parameter.

1 difference J RF power IKW 1.5KW 2KW Burning condition No burnt No burnt Only 5mm of periphery has burnt Etching rate (unit - input/5in) 9.000
12,300 14.200 Same as above variation (unit: %
) ±845 ±10.2 ±11.3 Ratio" L example RF power IKW 1.5KW 2KW Burnt condition No burnt Peripheral LOSm Total solidity Burnt Etching rate (unit 2 people/win) 8.880
11.700 13.800 Same as above variation (unit: %
) ±11.8 ±12.0 ±17.3 The object to be etched is a PSG film covered with a 73MR8800 mask manufactured by Tokyo Ohka Co., Ltd., and the knee two-layer is methane tetrafluoride and methane trifluoride. The internal pressure is 0.3 Torr.

As is clear from the experimental results, in this example, there is little burntness, little variation in etching rate, and the temperature of the entire surface of the semiconductor wafer is uniformly controlled to a low temperature.

〔Effect of the invention〕

As explained above, in the present invention, a dry etching method is employed in which a gas is introduced to the back surface of a semiconductor wafer supported by an electrostatic chuck through a gas supply path provided through the electrostatic chuck body. When performing knee etching using the device, an electrostatic chuck with a diameter larger than the diameter of the semiconductor wafer to be etched must be used. Gas is supplied and the temperature is uniformly controlled over the entire surface of the semiconductor wafer, so that the entire surface of the semiconductor wafer is uniformly etched.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an etching method according to an embodiment of the present invention. FIG. 2 shows the configuration of a conventional dry etching device that sprays gas onto the back surface of a semiconductor wafer supported by an electrostatic chuck through a gas supply path provided through the electrostatic chuck body. It is a diagram. FIG. 3 is a block diagram of an etching device according to the prior art. FIG. 4 is a diagram illustrating this drawback of the etching device according to the prior art. l...Vacuum container, 11-...Etching gas supply port, 12-0 gas discharge port, 2...One electrode, 21--Chuck cooling water passage, 31φ electrostatic chuck, 31- ...Chuck cooling water passage, 4*a@semiconductor wafer, 5..9 counter electrode, 6. --RF power supply. Prior art Figure 4 Present invention Figure 1 Prior art Figure 2 Follow IS technique? Figure 3

Claims (1)

[Claims] A gas supply path (31) is provided passing through the main body (3), and the back surface of the semiconductor wafer (4) and the main body ( In an etching method using a dry etching apparatus having an electrostatic chuck for semiconductor wafers (3) into which gas is introduced during step 3), a semiconductor wafer having a diameter larger than the diameter of the semiconductor wafer to be etched (4) is used. Electrostatic chuck body (3
).