JP2002033306A5 - - Google Patents

Description

(1)
When generating discharge plasma in the vacuum chamber using at least a double loop antenna, while maintaining the intermediate portion between the diametrically opposed portions of adjacent loop antennas parallel to the surface of the workpiece, spatial distribution control method of inductively coupled plasma, characterized in that continuously changing the other gap portions were diametrically opposed to one of the spacing of the portion opposed diametrally.

(2)
And fixing one interval sites were diametrically opposed adjacent loop antenna, inductively coupled plasma according to claim 1, characterized in that the variable range of expected the other spacing of the portion opposed diametrally Spatial distribution control method.

(3)
A one of the fixed spacing 40mm sites were diametrically opposed adjacent loop antenna, inductive coupling according to claim 2, characterized in that the other variable spacing of the portion opposed on a diameter of 20mm~60mm A method for controlling the spatial distribution of plasma.

FIG. 17 shows a magnetic neutral discharge etching apparatus proposed by the present applicant in Japanese Patent Application Laid-Open No. 7-263192. In the device proposed above, a magnetic neutral wire 13 is formed inside the vacuum chamber 1 by three magnetic field coils 10, 11, and 12 mounted outside the dielectric cylindrical wall 2 on the upper portion of the vacuum chamber 1. A ring-shaped plasma is formed by applying a high-frequency electric field from the high-frequency power supply for antenna 4 to the single antenna 3 disposed inside the intermediate magnetic field coil 11 along the magnetic neutral line 13. Have been. The etching gas is introduced from around the upper top plate 5 through the flow controller, and the pressure is controlled by the aperture ratio of the contactance valve. High frequency power is applied from a high frequency power supply 9 for bias to a substrate electrode 7 below the vacuum chamber 1 .

In the magnetic neutral discharge, a high-density plasma is formed at a portion of the magnetic neutral wire 13 formed in a ring in a vacuum, so that an induction electric field formed along the ring magnetic neutral wire 13 is effectively used. Ru Oh utilizes. By this method, a plasma having a charged particle density of 10 ¹¹ cm ^{−3 is} easily formed.

As disclosed in Japanese Patent Application Laid-Open No. Hei 10-317174, the applicant of the present application uses a parallel multiple winding of a plasma generating antenna to apply high frequency power in order to sufficiently etch a fine hole. Has been shown to be valid.
18 to 20 of the attached drawings show examples in which the plasma generating antenna is double-wound.
The reactive ion etching apparatus shown in FIG. 18 is configured as an inductive coupling type. In the illustrated etching apparatus, reference numeral 1 denotes a vacuum chamber, which includes an upper plasma generating section 1a and a substrate electrode section 1b, and an exhaust port 1c is provided in the substrate electrode section 1b. The plasma generating section 1a has a cylindrical side wall 2. Outside the side wall 2, a double-winding antenna 3 for generating plasma in the vacuum chamber 1 is disposed. It is connected to a high-frequency power supply 4 so as to generate a discharge plasma in the plasma generation section 1a at the top of the vacuum chamber 1.

The top plate 5 of the plasma generating section 1a at the top of the vacuum chamber 1 is hermetically fixed to the upper flange of the side wall 2, and a gas inlet 6 for introducing an etching gas into the vacuum chamber 1 is provided around the top plate 5. is provided and coupled to the etching gas supply source through a gas flow controller for controlling the flow rate of the gas supply passage and an etching gas this gas inlet 6 is not shown.
Further, a substrate electrode 7 is provided in the substrate electrode portion 1b below the plasma generating portion 1a of the vacuum chamber 1 via an insulator member 8, and the substrate electrode 7 is connected to a high frequency power supply 9 for applying an RF bias. ing.

In the apparatus shown in FIGS. 18 and 19, the power of the plasma-generating high-frequency power supply 4 (13.56 MHz) is set to 2.OkW, the power of the substrate bias high-frequency power supply 9 (800 kHz) is set to 500 W, and Ar 90 sccm (90%). ), introducing the _{C 4 F 8 10sccm (10%} ), it was etched under 3mTorr pressure, etching of substantially vertical shape of 0.3μm on the silicon oxide film without etch stop was possible.

In the etching under the same conditions in the conventional apparatus configuration, the etch stop occurred at a depth of about 0.5 μm, although there were some differences depending on the pattern width.
Compounds such as CF, CF ₂ , CF ₃ , C ₂ F ₂ , C ₂ F ₄ , C ₂ F ₅ , C ₃ F ₅ , C ₃ F ₆ , and the like which adhere to the wall surface and further decomposed C ₂ F _X, there is a C ₃ F _X, compounds such as _{C 4 F X (x = 1~2} ). These compounds adhere to the wall to form a polymer film.
If the surface potential of the antenna 3 is high, ion bombardment occurs, and these compounds and wall materials are sputtered and deposited in the gas phase as a substance that is not desirable for fine processing. However, when the ion bombardment is suppressed not only precipitation of undesired material is reduced, if not suppressed again been sputtered by a low potential CF, and Tsu Do useful radicals such as CF _2, CF ₃ gas Jump out into phase, and on the contrary, become a desirable etchant.
By effectively forming the induced magnetic field component in this manner, a submicron hole pattern can be etched without an etch stop even in a condition where an etch stop has occurred in the conventional apparatus configuration.

[0013]
[Problems to be solved by the invention]
However, from the viewpoint of the uniformity of the etching rate with respect to a large area, in the case of both the single-wound antenna and the double-wound antenna, the induction port, that is, the terminal portion is discontinuous, so that the inductive coupling is weak, as long as the horizontal plane of the antenna is to place the antenna so as to be parallel to the substrate, the etching rate in the vicinity of the terminal portion of the antenna is Tsu heterogeneity there that is lower than other regions.

According to the present invention, reducing the interval adjacent the opposite side, i.e. the side adjacent loop high frequency coil which faces the diameter in almost the introducing end portion than the distance (or pitch) between the input end of the loop-shaped high-frequency coil The etching rate at that portion is lower than that at the introduction end side. Therefore, by adjusting the interval in the direction to correct the non-uniformity of the etching rate in the case that had the same respective distance between the input end side thereof opposite uniform in front of the edge Ji packaging material etch You will gain speed.

Between the three magnetic field coils 22, 23, and 24 and the cylindrical side wall 21 of the plasma generating section 20a, a double-turned loop antenna 26 is arranged. It is supported on a desired fixed spacing (pitch) in a fixed support 27, and it is connected to not shown plasma generating high frequency power source. The portion of the loop-shaped antenna 26 substantially diametrically opposed to the leading end of the loop-shaped antenna 26 is supported by two antenna support members 28 and 29 as shown in detail in FIGS. The members 28, 29 are provided with screw taps 28a, 29a which are opposite to each other, the proximal ends 28b, 29b of the antenna support members 28, 29 are expanded laterally, and the longitudinal It is slidably supported by a guide groove 30a provided along the direction.

Screw tap 28a, 29 a of the respective antenna support members 28 and 29 are threadedly engaged to the threaded rod member 31 extending parallel to the guide support member 30. Therefore, by rotating the threaded rod member 31, the antenna support members 28 and 29 move in a direction away from or close to each other along the guide groove 30a of the guide support member 30, and thereby the distance between the loop antennas 26 ( Pitch) can be adjusted. For example, when the threaded rod member 31 is rotated clockwise, the antenna support members 28 and 29 move away from each other along the guide groove 30a of the guide support member 30, thereby reducing the interval between the loop antennas 26. On the other hand, when the threaded rod member 31 is rotated counterclockwise, the antenna support members 28 and 29 move in a direction approaching each other along the guide groove 30a of the guide support member 30, thereby forming a loop antenna. 26 can be reduced. In this case, the distance between the loop antennas 26 can be adjusted continuously from a minimum of 20 mm to a maximum of 60 mm, preferably 24 mm to 52 mm. In this configuration, an intermediate portion between the introduction ends of the upper and lower loop antennas 26 and a portion substantially diametrically opposed to the introduction end is kept parallel to the surface to be etched, that is, the substrate.

Dry etching condition A (operated by the IPC method without operating the three magnetic field coils 22, 23, and 24 in the apparatus shown in FIG. 1);
Vacuum chamber pressure: 0.68 Pa
Type of gas and flow rate: C _l 2 (160SCCM) and _O 2 (40SC
Mixed gas with CM) Power applied to antenna: 1 kW
Bias power: 40W
Three magnetic field coil currents: 0
Plasma-substrate distance: 150mm

Dry etching condition B (operated by magnetic neutral discharge (NLD) method);
Vacuum chamber pressure: 0.68 Pa
Type of gas and flow rate: C _l 2 (160SCCM) and _O 2 (40SC
Mixed gas with CM) Power applied to antenna: 1 kW
Bias power: 40W
Three magnetic field coil currents: coil 18.8A
Coil 23 is -16.4A
The coil 24 has 18.8A
(Only the coil 23 has a reverse current,
The radius of the generated magnetic neutral wire is about 80 mm
is there. )
Plasma-substrate distance: 150mm

The following 6-inch quartz mask substrate was used as a sample to be etched.
Material: Synthetic quartz glass Dimensions: 152 mm x 152 mm x 6.35 mm thickness Film composition: resist (AZP1350 about 500 nm thickness) / low reflection tag
Ip double layer chromium film (about 105nm thickness) / quartz glass

[0042]
【The invention's effect】
As described above, in the method for controlling the spatial distribution of the inductively coupled plasma according to the present invention, when the discharge plasma is generated in the vacuum chamber using at least the double loop antenna, the diameter of the adjacent loop antenna is reduced. while an intermediate portion between the site and the upper face is maintained parallel to the plane of the workpiece, by continuously changing the other gap portions were diametrically opposed to one of the spacing of the portion opposed diametrally Therefore, the spatial distribution of the plasma can be arbitrarily controlled.

[Brief description of the drawings]
FIG.
FIG. 1 is a schematic diagram showing one embodiment of the present invention.
FIG. 2
FIG. 2 is an enlarged sectional view showing a main part of the device shown in FIG. 1.
FIG. 3
FIG. 2 is an enlarged plan view illustrating a main part of the device illustrated in FIG. 1.
FIG. 4
2 is a graph showing in-plane uniformity of an etching rate when an antenna pitch is 24 mm when the apparatus shown in FIG. 1 is operated by an ICP method.
FIG. 5
Data for evaluating the in-plane uniformity of the etching rate at an antenna pitch of 24 mm when the apparatus shown in FIG. 1 is operated by the ICP method.
FIG. 6
2 is a graph showing in-plane uniformity of an etching rate when an antenna pitch is 40 mm when the apparatus shown in FIG. 1 is operated by an ICP method.
FIG. 7
Data for evaluating the in-plane uniformity of the etching rate at an antenna pitch of 40 mm when the apparatus shown in FIG. 1 is operated by the ICP method.
FIG. 8
2 is a graph showing in-plane uniformity of an etching rate when an antenna pitch is 52 mm when the apparatus shown in FIG. 1 is operated by an ICP method.
FIG. 9
Data for evaluating the in-plane uniformity of the etching rate at an antenna pitch of 52 mm when the apparatus shown in FIG. 1 is operated by the ICP method.
FIG. 10
Graph showing the in-plane uniformity of the etching rate of the antenna pitch 24mm in the case where the apparatus shown in FIG. 1 and operating in NL D scheme.
FIG. 11
Data for evaluating in-plane uniformity of the etching rate of the antenna pitch 24mm in the case where the apparatus shown in FIG. 1 and operating in NL D scheme.
FIG.
Graph showing the in-plane uniformity of the etching rate of the antenna pitch 40mm in the case where the apparatus shown in FIG. 1 and operating in NL D scheme.
FIG. 13
Data for evaluating the in-plane uniformity of the etching rate at an antenna pitch of 40 mm when the apparatus shown in FIG. 1 is operated by the NLD method.
FIG. 14
2 is a graph showing in-plane uniformity of an etching rate when an antenna pitch is 52 mm when the apparatus shown in FIG. 1 is operated by an NLD method.
FIG.
Data for evaluating the in-plane uniformity of the etching rate at an antenna pitch of 52 mm when the apparatus shown in FIG. 1 is operated by the NLD method.
FIG.
FIG. 3 is a schematic diagram showing a conventional inductively coupled discharge type etching apparatus using a single antenna.
FIG.
The schematic diagram which shows the conventional magnetic neutral-ray-discharge type etching apparatus which used the single antenna.
FIG.
FIG. 2 is a schematic diagram showing a conventional inductively coupled discharge type etching apparatus using a dual antenna.
FIG.
FIG. 2 is a schematic diagram showing a conventional magnetic neutral line discharge type etching apparatus using a double antenna.
FIG.
FIG. 4 is a diagram showing a calculation position of a vector potential in the etching apparatus.
FIG. 21
4 is a graph showing a radial distribution of a vector potential.
FIG.
9 is a graph showing the radial distribution of the vector potential in the Z direction at R = 0.8.
[Explanation of symbols]
20: vacuum chamber
20a: Plasma generation unit
20b: substrate electrode part
20c: Exhaust port
21: Cylindrical side wall
22: Magnetic field coil
23: Magnetic field coil
24: Magnetic field coil
25: Frame
26: Double wound loop antenna
27: Fixed support
28: Antenna support member
29: Antenna support member
30: Guide support member
30a: guide groove
31: Threaded rod member
32: Top plate
33: Gas inlet
34: substrate electrode
35: Insulator member
36: High frequency power supply

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