JPS60193340A - Plasma-etching apparatus - Google Patents

Abstract

PURPOSE:To uniformize the etching speed, by arranging a lower electrode for carrying a semiconductor wafer and an upper electrode having a multiplicity of gas feed openings to be arranged facing to each other, providing a cover chamber over the upper electrode to enclose the same, and shifting nozzles provided in the chamber in parallel with the electrode so as to select a gas feed opening for blowing gas. CONSTITUTION:A stainless steel vacuum container 10 having a gas outlet 12 at one end and a port 14 for taking in and out a wafer 13 at the other end is provided therein with a lower electrode 16 for carrying a wafer 13 and an upper electrode 15 having a multiplicity of gas feed openings 19, the electrodes being faced to each other and enclosed with an insulator 17. A cover chamber 20 is arranged over the electrode 15 and a guide bar 21 is provided within the chamber movably in parallel with respect to the electrode 15. Nozzles 22 and 23 are fixed to a part of the bar 21 for connecting the same with a gas feed tube 24. For etching the wafer by operating the apparatus constructed in this manner, the bar 21 is shifted such that the position of the nozzles 22 and 23 are made variable, and gas is blown against the wafer 13 from a desired feed opening 19.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a plasma etching apparatus. It is used. For example, 5-inch and 6-inch wafers are used.

As the diameter of the wafer increases in this manner, it is required to make the etching rate uniform during plasma etching, which is a microfabrication technique. For this reason, sheet type plasma etching apparatuses have become mainstream instead of batch type ones. The etching rate is influenced by factors such as the type of etching gas, flow rate, partial pressure ratio, power, pressure, and temperature. In particular, the etching rate varies greatly depending on the method of supplying the reactive gas to the surface of the wafer to be processed. For example, as shown in Figure 1 (4), Weno 1
When the processed portion of wafer 1 is aluminum film 2,
When etching is performed by supplying the reactive gas 4 from the gas supply port 3 to approximately the center of the etching, the distribution of the etching depth after the treatment is shown by the characteristic lines (I) (n) shown in Figure 2 (3). expressed. A at both ends of the characteristic line (1) (If) in the figure,
B, C.

As shown in FIG. 3, D represents four points on the periphery of the surface of the wafer l in mutually perpendicular diametrical directions. As is clear from the characteristic lines (1) and (II), the etching rate is high immediately below the supply section of the reaction gas 4, so
The etching depth is large, and the etching depth is shallow at both ends away from the supply section. Similarly, Figure 1 (
6), when the gas supply ports 5 are located on the outside of both ends of the wafer 1, the characteristic line (as shown by II (turn) in FIG. In terms of depth, the etching depth becomes shallow at the center of the wafer 1. This tendency becomes more pronounced as the diameter of the wafer 1 increases.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a plasma etching apparatus with uniform etching speed.

[Summary of the invention]

The present invention is a plasma etching apparatus in which the position of the etching gas supply port can be varied to achieve a uniform etching rate.

[Embodiments of the invention]

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

FIG. 4 is an explanatory diagram showing a schematic configuration of an embodiment of the present invention. In the figure, 10 is a vacuum container made of stainless steel, for example. An exhaust port 12 for the reaction gas 11 is formed at one end of the vacuum container 10 . Vacuum container 10
An entrance/exit 14 for the wafer 13 is provided at the end of the wafer 13 .

Opposing walls at the center of the vacuum container 10 are provided with an upper electrode 15.
and a lower electrode 16. The vacuum vessel 10, the upper electrode 15, and the lower electrode 16 are electrically insulated by an insulating member 17 made of a Teflon ring. Vacuum container 10
A wafer installation portion is formed on the surface of the lower electrode 160 inside. A cooling hole 18 is embedded in the lower electrode J6 to maintain the lower electrode 16 at a predetermined temperature. The upper electrode 15 has a large number of gas supply ports 19 opened at predetermined intervals and communicating with the inside of the vacuum vessel l. A cover chamber 20 is attached to the outside of the vacuum container 1 so as to isolate the gas supply port 19 from the outside world. Cover chamber 2
0, a guide bar 21 is provided substantially parallel to the upper electrode 15. Guide bar 21, reaction gas 1
A gas supply nozzle 23 having one ejection port 22 is slidably attached so as to communicate with the inside of the vacuum container 10 via a predetermined gas supply port 19 . The gas supply nozzle 23 is connected to a gas supply pipe 24 that penetrates the cover chamber 20 and is connected to a gas source (not shown). The upper electrode 15 and the lower electrode J6 are connected to the changeover switch 21 via matching boxes 25 and 26. The changeover switch 27 is connected to an RF power source 28. The upper electrode 15 and the lower electrode 1 are connected so that the electrode to which no high frequency voltage is applied is grounded.
6 is connected to a ground terminal via a changeover switch 29. Further, the vacuum container 10 is also grounded.

According to the plasma etching apparatus SO configured in this way, a J5 At film is formed by sputtering on the surface of the 5-inch silicon single crystal wafer 13, for example, and a resist film with a predetermined pattern is formed on the M film. The formed material was placed on a wafer placement section, and etching was performed under the following etching conditions while sliding the gas supply nozzle 23, and the results shown in FIG. 5 were obtained.

The etching conditions were carbon tetrachloride (cc) as the reaction gas J1.
t4) at a supply rate of 1008 CCM to the gas supply nozzle 23.
and the pressure inside the vacuum vessel 10 is Q, l Tor
r, the applied RF power was 0.6 W/car, and the high frequency power source was applied to the lower electrode 16.

FIG. 5 shows that after the resist film is peeled off from the surface of the wafer 130 using 02 asher after etching for 1 minute, At
The etching depth of the film surface was measured with a step needle, and the variation in the etching depth up to each point on the wafer 1 shown in FIG. 3 is expressed by a characteristic line cv)cv. As is clear from the characteristic line (V) (VD) in the figure, in the plasma etching apparatus 30 of the embodiment, the reaction gas 11 is supplied while moving the gas supply nozzle 23 depending on the type of wafer 13, etc. to perform the etching process. Therefore, it is possible to maintain a uniform etching speed and perform etching at a constant etching depth.Incidentally, when the standard deviation is σ and the average value is ma, the value of 3σ/i of the etching depth is as follows. It was ~0.05.

〔Effect of the invention〕

As explained above, according to the plasma etching apparatus according to the present invention, the etching rate can be made uniform.

[Brief explanation of drawings]

FIGS. 1(A) and 1(B) are explanatory diagrams showing the relationship between the supply positions of reactive gases with respect to the wafer, FIG. 2(A) 01) is a characteristic diagram showing variations in etching depth, and FIG. FIG. 4 is an explanatory diagram showing the position on the wafer, FIG. 4 is an explanatory diagram showing the schematic configuration of an embodiment of the present invention, and FIG. 5 is a characteristic diagram showing the effects of the embodiment. 10... Vacuum container, 11... Reaction gas, 12...
Exhaust port, 13... Wafer, 14... Entrance/exit, 15.
... Upper electrode, 16... Lower electrode, 17... Insulating member, 18... Cooling pipe, 19... Gas supply port, 2
o...Cuckoo chamber, xi...Guide bar, 22...
・Ejection port, 23... Gas supply nozzle, 24... Gas supply pipe, 2.5, 26... Matching device, 27.29...
- Selector switch, 28...RF power supply, 30...Plasma etching device.

Claims (1)

[Claims] A vacuum container having a wafer entrance/exit at one end and an exhaust port at the other end, and an upper electrode and a lower electrode forming a wall of the vacuum container and provided facing each other. , a wafer installation part formed in the lower electrode, a plurality of gas supply ports opened in the upper electrode so as to communicate with the inside of the vacuum container, and a gas supply port formed in the vacuum container so as to isolate the gas supply port from the outside world. a cover chamber formed on the outside of the upper part; and a cover chamber inserted through the cover chamber, one end of which is connected to a reactant gas supply source, and the other end of which has an ejection port sequentially communicated with the gas supply port. 1. A plasma etching apparatus comprising: a gas supply nozzle slidably provided on an electrode.