JPS58182829A - Dry etching device - Google Patents

Abstract

PURPOSE:To effectively cool a sample supporting mechanism without reducing the power for supporting the sample and thus contrive to speed up etching without causing resist deterioration, by providing an elastic member of good thermal conductivity which is pressed and pinched by the supporting mechanism and a cathode at the time of contact-fixing the sample on the cathode by the supporting mechanism. CONSTITUTION:The sample 2 is mounted on an insulation film 31 of Mylar or Kapton, etc. on the water-cooled cathode 3. The elastic member 41 constituted of e.g. Si rubber is interposed between the sample supporting mechanism 14 constituted of alumite and the cathode 3 resulting in the mechanical adhesion between the sample 2 and the cathode 3, and simultaneously the supporting mechanism 14 is cooled by the elastic member 41 of good thermal conductivity. By this constitution, the problem of bending during etching and further resist deterioration is completely solved. For the elastic member 41, rubbers are most effective.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to magnetron discharge? This paper relates to improvements to the dry etching equipment used.

[Technical background of the invention and its problems]

In recent years, integrated circuits have become increasingly finer, and very large scale integrated circuits with a minimum dimension of 1 to 2 μm have recently been prototyped. Parallel plate type electrodes are usually used for such microfabrication. A reactive gas such as CF, etc. is introduced into a reaction vessel containing 13.56 (MH
Glow discharge by applying high frequency power r of z)?
Positive ions in plasma? The ions are accelerated by the cathode drop voltage VDCVC generated on the surface of the pole (electrode for applying high-frequency power), and are incident perpendicularly to the sample, causing physical and chemical reactions to etch the sample, so-called reactive ion etching ( ReBctive IonEtch
However, due to the very low ionization efficiency (10-'~10''I) of the glow discharge,
For example, etching speed of CF'', +H2 gas using 7'j810!) or at most 300-400 (X/min)
It took more than 40 minutes to etch a 1 [μm] thick S10□kura. Therefore, it is desired to increase the etching speed because Ω is extremely disadvantageous in terms of Il productivity.

In contrast, the inventor A! A magnetic field generating means made of a permanent magnet is provided under the cathode to which high-frequency power is applied, and a magnetic field that is orthogonal to the electric field exerted by the high-frequency power is formed to generate electrons. (electric field)×(
Is it possible to cause the electrons to drift in the direction of the magnetic field, and to make this electron orbit a closed circuit?Is it possible to dissociate the electrons by collision with gas molecules?
Developed a dry etching device (utilizing magnetron discharge) which accelerated discharge efficiency and increased discharge efficiency (Patent Application No. 155 1).
7382.1).

Figure 1 1-1- Magnetron release 1! This is a schematic configuration diagram showing the dry etching apparatus fk used in the meeting. ○In the figure, 1 is a grounded vacuum vessel, and this vacuum vessel 1 ton is used for sample 2.
A cathode 3 placed in the chamber separates the area into a high vacuum area in which a magnetic field generating means consisting of a permanent magnet 4 and its drive system 5.6 are housed, and an etching area in which the sample 2 is placed. In order to prevent the discharge caused by the magnet 4, the high vacuum region is evacuated to, for example, a diffusion pump system through seven exhaust ports to a temperature of less than IXlO'-' (Torr). The connection is made by a gate valve 9 driven by a solenoid valve 8; during actual etching, the gate valve 9 is not closed, and the etching chamber is connected via an exhaust port 10'i to, for example, a mechanical booster or a rotary pump system. Exhausted by. Further, the discharge consists of a magnetron discharge 11 on the N-8 gap and a glow discharge 12 in the periphery, and etching is performed by scanning the permanent magnet 4 in one direction (
In this example, it is assumed that the rotational movement of the support rod 6 by the drive motor 13 causes the gear 5 to move in a direction perpendicular to the plane of the paper as a result of the linear movement of the gear 5).
Etching was performed on sample 2 while scanning, and etching with good uniformity was achieved. Furthermore, sample 2 during etching
is brought into close contact with the cathode 3 by a mechanical support mechanism 14,
The sample 2 is cooled down by the water cooling mechanism 15, thereby preventing the sample 2 from reaching a temperature of -1, 1. Also, at the end of etching, the sample 2 is guided by the mechanical support mechanism 14.
It quickly leaves the cathode 3, and conversely, the sample 1 to be etched next is also let into the cathode 3 in the same way.
is a high frequency vL source, 17 is a matching box, 1B is 0
Ring seal r shown, next 19. ~, 22 indicate insulators made of fluororesin, etc.0 Figure 2 shows this device using Eri C1 (Fsk and S10°?
Etching speed when etching, Vd.

? Figure 9 shows the strength of the magnetic field on the sample surface. 5
The etching rate of tO2 increases with increasing magnetic field despite the rapid decrease of VdQ, especially around 200 (G) @1. It turns out that L fc-o becomes faster.
CHFB<7) to pressure: 0.05 Torr, rf
Power density? r 1.6 w, “0th order as CIA,
Ionization efficiency? Let's estimate how much the ion current increases compared to normal RIE by replacing the incident ion current r on the sample surface.The value of 0 ion current.The approximate value of rf, power @ degree, VdC processing. ? When calculated, when there is a magnetic field of 1000 CG], the ion current density tmarf power density is 1.6 (W/ctA).

1 × 10” (lono/
cnt-sec). On the other hand, when there is no magnetic field, Vd
Ion current density as C = 17oo(v)) or IX
1016 (lona/c4-sec), so it is expected that the etching rate will increase by a factor of about 10. In fact, the etching rate up to t when the magnetic field is 1000 (G) in a static plasma state. ~3 [μrnA
nin], therefore, by using a magnetic field, the ionization efficiency of the discharge is increased, and a large amount of ion current incident on the sample is drawn out, thereby achieving high-speed etching. On the other hand, this increase in ion current is the biggest cause of the rise in temperature of the sample during etching, and in fact, if the sample is simply placed on the cathode and then etched, the resist deteriorates significantly due to temperature changes, making it difficult to put it into practical use. Although this poses a major barrier, thermal contact between the sample 2 and the water-cooled cathode 3 by, for example, electrostatic chuck means or mechanical means as shown in FIG. By taking a sufficient amount of etching, the etching can be performed normally without the above-mentioned deterioration of the resist.

However, the electrostatic chuck means has a complicated structure and has many unresolved problems, such as the need to take measures against damage to the device since it applies a high voltage r of about 1 KV. On the other hand, although the method using mechanical means shown in FIG. 1 is very simple, it currently lacks reliability and reproducibility as explained below.

FIG. 3 is an enlarged cross-sectional view of the sample support portion r in FIG. 1, shown in FIG. The sample 2? Cathode 3
A gap 32 exists in order to press down with uniform force.

In other words, this gap portion 32 is not cooled and the casing is etched right now. When this is done, as shown in FIG.
is gradually curved and therefore the sample support function? It will not be fulfilled. Furthermore, it has been found that this progression of curvature occurs extremely quickly and instantaneously due to the wraparound 33 of the plasma into the gap portion 32. The degree of the gap explained above is greatly influenced by the thickness of the sample 2, and the time and degree of bending also vary. However, as mentioned above, the function of pressing sample 2 against cathode 3 with uniform force? Considering, the gap 3
It is something that cannot be avoided because the existence of 2 is taken away.

[Purpose of the invention]

(objective of the present invention), sample from sample support mechanism VC? Power to support? Sample support mechanism without slowing down? Can it be effectively cooled and resist deterioration etc.? The object of the present invention is to provide a dry etching apparatus that can perform etching at a speed of 7 Jλ without causing problems.

[Summary of the invention]

The present invention consists of a vacuum vessel equipped with a cathode to which high-frequency power is applied and a sample placed on the surface of the cathode, and an anode placed opposite to the surface of the cathode, and a reaction gas introduced into the vacuum vessel. a magnet provided on the back surface of the ten-gap pole for applying a magnetic field onto the surface of the cathode through the closed-loop magnetic pole gap; means for scanning; - means for shielding the space in which the magnet is placed from the space in which the sample is placed; and means for supporting the sample and pressing the cough sample against the surface of the cathode so as to bring it into close contact with the surface of the cathode. Equipped with a sample support mechanism and a device, and a discharge plasma between each of the electrodes. Magnetron discharge along with generation? In a dry etching apparatus for etching the sample, a good heat source is applied to at least one of the cathode or the support mechanism, and is pressed and clamped between the support mechanism and the cathode when the support mechanism tightly fixes the sample to the cathode. A conductive elastic member [provided].

〔Effect of the invention〕

According to the present invention, it is possible to press the sample against the cathode surface with a sufficiently large force by using four elastic members with good thermal conductivity, and furthermore, the elastic member can be pressed against the surface of the cathode with a sufficiently large force. The sample support mechanism can be effectively cooled through the sample support mechanism. Therefore, high-speed etching can be performed without causing deterioration of the resist.

[Embodiments of the invention]

FIG. 5 is a sectional view showing the main structure of an embodiment of the present invention. It should be noted that the same parts as in FIG. 3 are given the same reference numerals as those in FIG. A sample 21 is placed on an insulating film 3 made of mylacetic fluoroton or the like on a water-cooled cathode 3.

Furthermore, a sample support mechanism 14 made of alumite or the like
An elastic member 4 made of, for example, silicone rubber is interposed between and the cathode 3, so that the sample 2 and the cathode 3 are mechanically bonded, and at the same time, the elastic member 4 with good thermal conductivity is vinegar,
The support mechanism 14 is also cooled.

With this structure, the problems of curvature during etching and resist deterioration as described above can be completely solved. As for the elastic member 41, a rubber-based material is most effective. For example, when using silicone rubber and pasting this elastic part 41'f over the entire area of the copper wire part as shown in Figure M6, the thermal resistance is R! When we calculate 'l' and look at 'C, we get the following. Thermal conductivity P of silicon rubber; 0.043 CVJ/crd, °C], thickness 'j
't: 0.05 (rental) *Area S; 520 [c
7A], then R2t/PS =:= 0.0023 C°C/W), and if 1. Even if RF power of (KW) is applied, the temperature -L rises by 2 [°C], resulting in extremely good cooling. Therefore, the sample 2 is supported without the sample support mechanism 14 being bent. . The reason why rubber bullets and curved objects are excellent is that their elastic modulus of expansion and contraction is extremely small. Gap 32? This results in complete thermal contact between the sample 2 and the cathode 3. Further, according to this embodiment, the support machine 4
% 14 is sufficiently cooled, it is also possible to paste an insulating film such as My 2 on the support mechanism 14,
It is also possible to prevent metal contamination from the support mechanism 14 during etching.

Note that the present invention is not limited to the above-mentioned embodiments, but is limited to the gist thereof. Various modifications can be made without departing from the scope. For example, the elastic member 41 is not limited to silicone rubber, but may be any material that has good thermal conductivity and elasticity. In addition, the elastic member 41 is attached to the sample support mechanism 1 as shown in FIG. 7(a) VC.
The process is not limited to 4 and 11, but may be applied to the cathode 3 (specifically, the insulating film 31) as shown in FIG. 4(b). Furthermore, the elastic member 4 may be applied to the entire surface of the cathode 3.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing a dry etching apparatus using a magnetron discharge chamber, and Fig. 2 to Fig. 1 are for explaining the operation of the above-mentioned apparatus.
□Etching speed and Vdc when etching
Figure 4 is a cross-sectional view showing the main parts of the sample support mechanism, and the fifth factor 1 is the main points of an embodiment of the present invention. 6 is a sectional view showing the structure of the parts, FIG. 6 is a scaled view illustrating the operation of the embodiment, and FIGS. 7(a) and 7(b) are sectional views illustrating a modified example. J...^ Empty container, 2... Sample, 3... Cathode, 4...
...Permanent magnet, 5...Gear, 6...Support rod, 7.1
0... Exhaust [-1, 8... Solenoid valve, 9... Gate valve,
1)...Magnetron discharge, 12° glow discharge,
13...Motor, 14...Sample support mechanism, 15...
・Water cooling mechanism, 16...High frequency wL source, Noah...Matching box, 1B...O ring seal, 19-2
2...Insulator, 31...Absolutely film, 32...Gap,
4. Elastic member.

Claims (1)

[Claims] A vacuum vessel is provided with a cathode to which a high frequency power is applied and a sample is placed on the surface thereof, and nine anodes disposed opposite to the surface of the cathode, and a reactant gas inside the vacuum vessel. A magnetic field is generated on the surface of the cathode by a closed loop magnetic pole gap provided on the back surface of the cathode. The magnet to be applied and this magnet? Means for scanning in a direction perpendicular to the direction of the electric field generated by the high-frequency power, and a skin space in which the magnet is arranged? Means for shielding the sample from the space in which it is placed, and the sample? Support the sample? Is the sample support mechanism that presses against the surface of the cathode and brings it into close contact with the surface of the cathode? Equipped with discharge plasma between each electrode? Magnetron discharge along with generation? Said sample occurring? In a dry etching apparatus for etching, an elastic material having good thermal conductivity is applied to at least one of the cathode acid or the support mechanism, and is pressed and clamped between the support mechanism and the cathode when the support mechanism tightly fixes the sample to the cathode. Is it possible to set up a component? Dry etching equipment with special features.