JPS59178731A - Dry etching apparatus - Google Patents

Abstract

PURPOSE:To perform the etching of a sample uniformly at a high speed, without abnormal discharge between a ring shaped member and the sample to be etched, by providing a tapered part on the ring shaped member, which is arranged around a member to be etched. CONSTITUTION:A vacuum container 1 is divided into a high vacuum region, wherein a magnetic-field generator comprising a permanent magnet 4 and driving systems 5 and 6 for the generator are enclosed, and an etching region, where in a sample 2 is provided, by a cathode 3, on which the sample 2 is mounted. A ring shaped member 17 is attached to the lower side of the cathode 3 so as to surround the sample 2. The member 17 comprises, e.g., an aluminum plate, and a tapered part 17a is formed at the opening of the member. In this constitution, any abnormal discharge between the sample 2 and the member 17 does not occur, and the uniform, high-speed etching can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a dry etching apparatus that utilizes magnetron discharge.

[Technical background of the invention and its problems]

In recent years, integrated circuits have become more and more miniaturized, and recently, 1fil and dI with minimum dimensions of 1 to 2 [μm] have been prototyped (even up to 2). Normally, a reactive gas of 01゛ or 200 nm is placed in a reaction vessel P'1 having parallel plate electrodes, and a Shinoishi local wave force of, for example, 13.56 (1νiH, ) is applied to one pole on which the sample is placed. By applying it, a glow is caused, and the old ions in the plasma are accelerated by the pressure Vpc i2 on the surface of the polarized (high-class eL 7111 electrode) surface. These ions are incident on the sample (-perpendicularly) and the sample is
@So-called reactive ion etching, which etches from a physical and chemical reaction.
ng: RIE) is used. However, in RIB with parallel plate electrodes (-), for example CF, -(-H), due to the very low ionization efficiency of glow discharge (10' to io'''6).

The etching speed of S I 02 using gas is at most;
300-400CA,/min], I Cp
m : l thickness (7) 4 to etch SiO,
This takes more than 0 minutes, which is extremely inconvenient in terms of mass production.

Therefore, it is desired to increase the etching speed.

In response to this, the present inventors installed a magnetic field generating means consisting of two permanent IJ5 stones under the application of high-frequency 8-wave power, and formed a magnetic field that intersects with the electric field due to the high-level 8-wave power. Naruko (
By making Trit motion in the direction of ``magnetic field'' x (magnetic field) and making this electron orbit a closed circuit (Secondly, magnetron discharge that promotes collisional dissociation between electrons and gas molecules to improve radiation efficiency) We have developed a dry etching device (Japanese Patent Application No. 173,821/1982). By using this device, we were able to significantly improve the etching speed. For example, when using CF, +H, gas The etching rate of the Sin used was 1 [μm/min] on each side, and chlorine-based gas was used for poly SL and A/S (2 to 1).
An etching rate of [μm,/mi] was obtained, and notching with high mass productivity was achieved (-).

However, if the inventors of the present invention were to try their hand at etching, the following problems would arise in the etching that exited the above-mentioned apparatus.

Figure 1 shows a sample (100wnφ
FIG. 3 is a characteristic diagram showing the etching depth distribution within the wafer. The etching conditions at this time were Koshoha's power of 1100
[W] Etching pressure Q, l [Torr: l, gas i%
t15ft, 50 (SOOMI). Also, the sample position 50 indicates the center of the sample. From Fig. 1, the sample circle radius Rs = 501:zm] has a uniform etching depth, but only one peripheral area. As a result, it was found that the overall uniformity reached more than ±301 m%). Such non-uniformity of etching is undesirable because it leads to a decrease in the manufacturing yield of semiconductor chips.

The above-mentioned tendency for the peripheral etching speed to increase is normal RII! This is also observed in i.

In RIEi, an attempt has been made to improve the etching uniformity by arranging a ring-shaped member around the sample. However, in dry etching equipment that uses Madai-Tron discharge, the trace ionization efficiency described above is significantly reduced (-), so when a ring-shaped member is used, abnormal discharge may occur between the member and the sample. In addition, when using the above ring-shaped member, the sample lifting mechanism that moves the material up and down and places the sample on the cathode and the ring-shaped member make contact T.
There is a risk that To avoid this, if there is a sufficient distance between the ring-shaped member and the sample, the uniformity of etching will be reduced.

[Purpose of the invention]

An object of the present invention is to be able to etch a sample at high speed with good uniformity without causing abnormal discharge between the ring-shaped member and the sample to be etched, and to improve etching reliability and element manufacturing yield. To provide a dry etching device for obtaining

[Summary of the invention]

The gist of the present invention is to attach a ring-shaped member (-a taper 7) around the sample to be etched.

That is, the present invention provides a vacuum vessel comprising: a cathode to which a force is applied and a sample to be etched placed on the surface thereof; a front surface of the cathode; In this vacuum container (4 people at a time), a means for applying a reactive gas to the surface side of the above-mentioned first pole (a two-branched loop-shaped magnetic field) is applied to the surface side of the Kagamishima cathode, This magnet is connected to the above-mentioned high-frequency power (=applied center field direction and (
2) The means for scanning in the direction of the father and the means for each of the above-mentioned mice:
Pole 1'i31 +'-) A dry etching device that generates ICt4 plasma and generates magnetron discharge to etch the sample. A thicker ring-shaped member is provided, and the opening (-
C2 is formed to form a taper that widens toward the anode side.

〔Effect of the invention〕

According to the present invention, by providing a ring-shaped member around the sample to be etched, it is possible to improve the uniformity of etching.Moreover, since a taper is formed at the first opening of the ring-shaped member, it is possible to improve the uniformity of etching. The anode-side corner of the ring-shaped member and the anode-side corner of the sample can be sufficiently separated, and the generation of differential discharge between the ring-shaped member and the sample can be prevented. , by forming the ascendant Theba.

Preventing contact between the sample vertical EM mechanism and the ring-shaped member 1-
Benefits include:

[First Embodiment of the Invention] FIG. 2 is a schematic diagram showing the structure of a dry etching apparatus according to an embodiment of the present invention. In the figure, I is a grounded vacuum vessel that acts as an anode, and this vacuum vessel I is the sample 2.
The cathode 3 (-) placed on the cathode 3 (-) shows a high empty area where the magnetic field generating means consisting of permanent 16 stones 4 and its drive system 5.6 are housed, and an etching area where the sample 2 is placed (
It is separated into two parts. Is there an exhaust port in the area around Takashinai to prevent the radiation caused by the excavated stone 4? For example, by a diffusion pop system,
The etching chamber is bleed air, and the preliminary connection with the etching chamber is performed through a gate valve 9 (2) driven by a solenoid valve 8. During actual etching, this gate valve 9 is closed, and the etching chamber is connected to the exhaust port IO. Through the first row is a mechanical booster ten rotary pump system (excluding the second).Then, a closed loop of the discharge is formed [7 and 8l:, ii gap, the mago-tron discharge II and the surroundings. The etching consists of a glow discharge Z2 and a unidirectional flooding of the permanent stone 4.
(In this example, the rotation of the forked rod 6 by the drive motor Z6 is linked to the gear 5 (from 2 to the gland control operation, and from 2 to the left and right in the paper) This is carried out while the magnetron discharge 11 is running over the sample 2. Furthermore, during etching test g2, the electrostatic chuck machine 7 groove 141-
The cathode 3 is then covered and cooled by the water cooling mechanism 15, thereby preventing the sample 2 from rising in temperature. Warm up,
At the end of etching (- indicates sample 2 is sample 1 vertical movable groove I
6, the sample immediately leaves the cathode 3, and conversely, the sample to be etched next is similarly set at the cathode 3 ('').

10,000, a ring-shaped portion 4o Z7 is housed on the top side of the 1jfK pole 3 so as to surround the sample 2.

This ring-shaped member Z7 is made of, for example, an alumina plate, and has a taper 17ja formed in its opening, as shown in a plan view in FIG. 4j3 and in a cross-sectional view in FIG. 4. Here, the dimensions of the ring-shaped member I7 are as shown in FIG.
3M, distance to sample 2 l) Arm 1 [■]. In addition,
Reference numeral 18 in FIG. 1 of City Journal 2 indicates a high-frequency illumination, I9 a matching circuit, 20 an oil ring, and 2Z to 24 each indicate an insulator made of fluororesin or the like.

The wooden f6L 'II' M (I,
Etched sample 2 with a diameter of 100 Cram],
As a result of etching phosphorus-added poly 8i with a thickness of 0.7 (will), no abnormal discharge was observed between the sample 2 and the ring-shaped member I7, and high-speed etching with good uniformity could be performed.Here, Upper We abnormal discharge is prevented by dj
Since the taper 17a is formed in the opening of the ring-shaped glS material 17, the ring-shaped part 1
This is because the corner 3I of 3' z y and the corner 32 of test p2 are sufficiently separated. It also enables etching with good uniformity.

Arrangement of ring-shaped member I7 and taper zy formed in the opening
By a, the surrounding area of sample 2 with high-density plasma 13
This is thought to be because the etching of the peripheral portion is suppressed, and as a result, the etching speed of the peripheral portion becomes approximately equal to the etching speed of the central portion.

It has been found that the uniformity of etching is improved by providing the taper 17a on the ring-shaped member 17 as described above. The sixth thickness is the thickness of sample 2: 0.7 Cms] The thickness of the ring-shaped member is 2
FIG. 3 is a characteristic diagram illustrating measured changes in etching uniformity when the angle θ is rotated. In addition, the O mark in the figure is a ring shape) 3 The distance between material I7 and sample 2 Alk D
= i Ctmn].

Δ mark is l) = 3 C+nm: I, mark is D =
The case of 5 Cwn:l is shown. From this figure, select the taper angle θ in the range of distance 1) = 1 to 5 [between]
From the second figure, it can be seen that good uniformity in the number of man-hours can be obtained. The seventh factor is instead of distance (- J of ring-shaped member I7
FIG. 3 is a characteristic diagram showing measurement results when ν size T is used as a parameter. Please note that the distance is 2 [throats].

In the figure, the ψ mark indicates the thickness of the ring-shaped member 17, T=1 [coral], and the mu mark indicates the thickness T=2[, body: 1. The mark ll indicates the case of T = 31° [Kuji] and 1. l) From this figure, it can be seen that even if the thickness T is varied, it is not possible to obtain good uniformity in the number of steps [%] by selecting an appropriate value for the taper angle θ.

In this way, C-wooden mounting
(2) By arranging the ring-shaped member I7 and forming an appropriate taper 17a in the opening of the ring-shaped member 17 (2), it is possible to significantly improve etching uniformity. Formation (-) Even when the ring-shaped part I/ and sample 2 are in close proximity, the angles Be3t and a2, which are considered to be severe or concentrated, can be kept far enough apart, and this can prevent the formation of a foreign compound. There is also an advantage to the above-mentioned formation of Theba zya (from -, @Note 4)
Figure (- As shown, the ring-shaped member 17 and the sample vertical movement mechanism 16
This has the advantage of preventing contact with other people.

Note that the present invention is not limited to the embodiments described above (for example, I]'lJ hc2!J The material of the ring-shaped member is not limited to alumina, but may be etching-resistant such as silicon, silicon compounds, or organic materials). The surface of the ring-shaped member may be coated with the material having strong etching resistance.Furthermore, (2).

! The thickness, taper angle, etc. of the ring-shaped member may be appropriately determined depending on conditions such as the thickness of the sample, the outer diameter, and the distance from the sample. Moreover, it is of course applicable to etching not only poly-JISi but also Si and other materials. (2) The present invention can be implemented with various modifications within the scope without departing from the gist thereof.

[Brief explanation of the drawing]

Figure 1 is for explaining the problems of the conventional device, and the characteristics showing the relationship between the sample position and the etching depth, and Figures 2 to 7N are for explaining one embodiment of the present invention. , Fig. 2 is a schematic configuration diagram showing a dry etching device using mago-tron discharge, Fig. 3 is a plan view showing the main part β configuration of the above device, and the fourth part is a cross section taken along arrow A-A in Fig. 3. Figure 5 is an enlarged cross-section of the main part of the ring-shaped member.
1. Figures 6 and 7 respectively show the relationship between the taper angle and etching uniformity.
・Cathode, 4... Gravity stone, 5... Gear, 6... Grip rod, 7゜10... Exhaust port, 8... Patch valve, 9... Gate valve, II. ...Macnetron discharge, "...Kero-release, z 3...Motor, 14...Still chuck, I5...Water cooling mechanism 16...Specimen vertical movement mechanism, II...Ring Shape member, 1B...Koshang etun i prefecture, I9...Matching 100th road, 20...0 ring seal, 2I, ~, 24...K Baerukyumono, 31.32.
...Corner. Dispatcher's agent Bengashi Suzue Takehiko 3 spears, 4 spears, 5 spears, 6 spears

Claims (2)

[Claims] (1) A vacuum vessel containing a cathode to which a high frequency generating force is applied and a sample to be etched placed on the surface thereof, and an anode disposed opposite to the surface of the cathode, and the inside of this vacuum vessel; means for introducing a reactive gas, m1 is provided on the surface side of the cathode, and a closed-loop aH field is applied on the surface side of the cathode (two applied magnets, and this magnet = iJ).
The application 1 by the self-improving wave force is also carried out in a direction perpendicular to the field circulation (a means for eclipsing the field and a means provided on the front i4+2 cathode so as to surround the sample placed on the cathode). The ring-shaped member marked ``1'' is formed thicker than the thickness of the sample, and has a tapered opening that widens toward the anode side. dry etching equipment. (2) The link ring-shaped member described in rrli is made of silicon, a silicon compound, an organic substance, or alumina, or is coated with any of the above. Dry etching equipment.