Patent EP0814495A2 successfully refreshed from Google Patents.
EP0814495A2
Expired / Lapsed
EP
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Adjusting DC bias voltage in plasma chamber
Assignee: Applied Materials Inc
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Filing: 1997-06-19
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Granted: —
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Expires: 2017-06-19
Abstract
Abstract A method of adjusting the cathode DC bias in a plasma chamber for fabricating semiconductor devices. A dielectric shield (10) is positioned between the plasma and a selected portion of the electrically grounded components of the chamber, such as the electrically grounded chamber wall (20). The cathode DC bias is adjusted by controlling one or more of the following parameters: (1) the surface area of the chamber wall or other grounded components which is blocked by the dielectric shield; (2) the thickness of the dielectric; (3) the gap between the shield and the chamber wall; and (4) the dielectric constant of the dielectric material. In an apparatus aspect, the invention is a plasma chamber for fabricating semiconductor devices having an exhaust baffle (14, 16) with a number of sinuous passages (54, 72, 73). Each passage is sufficiently long and sinuous that no portion of the plasma within the chamber can extend beyond the outlet of the passage. By blocking the plasma from reaching the exhaust pump, the exhaust baffle reduces the deposition of unwanted particles on exhaust pump components. The exhaust baffle also reduces the cathode DC bias by reducing the effective surface area of the electrically grounded chamber wall which couples RF power to the plasma.
Inventors
- 👤 Hongching Shan
- 👤 Evans Yip Lee
- 👤 Michael D. Welch
- 👤 Robert W. Wu
- 👤 Bryan Pu
- 👤 Paul Ernest Luscher
- 👤 James David Carducci
- 👤 Richard Blume
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 03:41
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32798; H01J37/32816; H01J37/32834; H01J37/32458; H01J37/32477; H01J37/32623; H01J37/32697; H01J37/32706
Claims Analysis
Total Claims: 42
Claim 1
Independent Claim
108 words
A plasma chamber for fabricating semiconductor devices, comprising: a vacuum chamber; a gas inlet for receiving a gas into the chamber; plasma excitation means for exciting the gas to a plasma state; an exhaust port through which gas can be exhausted from the chamber; a vacuum pump, connected to the exhaust port, for exhausting gas from the chamber; and an exhaust baffle having a number of sinuous passages, wherein the baffle overlies the exhaust port so that gas exhausted from the chamber passes through the sinuous passages, and each passage is sufficiently long and sinuous that the plasma inside the chamber does not extend completely through the passage.
Claim 2
Dependent Claim
13 words
A chamber according to claim 1, wherein the exhaust baffle comprises dielectric material.
Claim 3
Dependent Claim
96 words
A chamber according to claim 1, wherein the exhaust baffle comprises: (a) a first baffle member including (i) a cylindrical wall, and (ii) an annular protrusion which extends radially outward from the cylindrical wall; and (b) a second baffle member, positioned coaxially with and encircling the first baffle member, including (i) a cylindrical wall, and (ii) an annular protrusion which extends radially inward from the cylindrical wall; (c) wherein the respective protrusions of the first and second baffle members are spaced apart in an axial direction and are at least partially overlapping in a radial direction.
Claim 4
Dependent Claim
51 words
A chamber according to claim 3, wherein: the vacuum chamber further comprises an electrically conductive chamber wall and a first electrode mounted inside the chamber and electrically insulated from the conductive wall; the first baffle member encircles the first electrode; and the second baffle member is mounted adjacent the chamber wall.
Claim 5
Dependent Claim
34 words
A chamber according to claim 3, wherein: the second baffle member is mounted close enough to the chamber wall to prevent the formation of said plasma between the second baffle member and the wall.
Claim 6
Dependent Claim
93 words
For use with a semiconductor processing plasma chamber, a method of reducing deposition of particles on exhaust pump components, comprising the steps of: providing a vacuum chamber; forming a plasma within the chamber; exhausting gases from the chamber through an exhaust port; and positioning over the exhaust port an exhaust baffle having a number of sinuous passages so that gas exhausted from the chamber passes through the passages of the exhaust baffle, wherein each passage is sufficiently long and sinuous that the plasma within the chamber does not extend completely through the passage.
Claim 7
Dependent Claim
160 words
For use with a semiconductor processing plasma chamber, a method of changing the DC bias voltage at a first electrode in a positive direction comprising the steps of: providing a vacuum chamber having a number of chamber components; connecting at least one component of the chamber to an electrical ground; providing within the chamber a first electrode which is electrically insulated from the electrical ground; forming a plasma within the chamber; applying RF electrical power between the first electrode and the electrical ground so as to create a DC bias voltage at the first electrode relative to the electrical ground; exhausting gases from the chamber through an exhaust port; and positioning over the exhaust port an exhaust baffle having a number of sinuous passages so that gas exhausted from the chamber passes through the passages of the exhaust baffle, wherein each passage is sufficiently long and sinuous that the plasma within the chamber does not extend completely through the passage.
Claim 8
Dependent Claim
31 words
A method according to claim 7, wherein the at least one component which is connected to the electrical ground in the connecting step includes an electrically conductive wall of the chamber.
Claim 9
Dependent Claim
20 words
A method according to claim 7, wherein the positioning step further comprises insulating the exhaust baffle from the electrical ground.
Claim 10
Dependent Claim
28 words
A method according to claim 7, wherein the positioning step further comprises including within the exhaust baffle a dielectric material positioned between the plasma and the electrical ground.
Claim 11
Dependent Claim
108 words
A plasma chamber for processing semiconductor devices, comprising: a vacuum chamber having first and second electrodes, the two electrodes being electrically insulated from each other; means for forming a plasma inside the chamber; an RF power supply connected between the first electrode and the second electrode so as to create a DC bias voltage at the first electrode relative to the second electrode; and a dielectric shield mounted between the plasma and a selected area of the second electrode so as to block direct contact between the plasma and said selected area of the second electrode, wherein the shield is mounted at a distance from the second electrode.
Claim 12
Dependent Claim
35 words
A chamber according to claim 11, further comprising: a seal between the second electrode and the perimeter of the dielectric shield for preventing plasma from entering the gap between the shield and the second electrode.
Claim 13
Dependent Claim
33 words
A chamber according to claim 11, wherein the distance between the shield and the second electrode is small enough to prevent the formation of said plasma between the shield and the second electrode.
Claim 14
Dependent Claim
42 words
A chamber according to claim 11, wherein both said distance between the shield and the second electrode and said selected area which the shield blocks from contacting the plasma are large enough to change the DC bias voltage in a positive direction.
Claim 15
Dependent Claim
18 words
A chamber according to claim 11, wherein the second electrode includes an electrically conductive wall of the chamber.
Claim 16
Dependent Claim
31 words
A chamber according to claim 15, wherein: the conductive wall is connected to an electrical ground; and the RF power supply is connected between the first electrode and the electrical ground.
Claim 17
Dependent Claim
114 words
For use in a semiconductor processing plasma chamber, a method of changing the DC bias voltage at a first electrode in a positive direction, comprising the steps of: providing a vacuum chamber having first and second electrodes, the two electrodes being electrically insulated from each other; forming a plasma inside the chamber; applying RF electrical power between the first electrode and the second electrode so as to create a DC bias voltage at the first electrode relative to the second electrode; and positioning a dielectric shield between the plasma and a selected area of the second electrode so as to block direct contact between the plasma and said selected area of the second electrode.
Claim 18
Dependent Claim
49 words
A method according to claim 17, wherein: the positioning step includes establishing the area of the second electrode blocked by the shield and the thickness of the shield so that both the area and the thickness are large enough to change the DC bias voltage in a positive direction.
Claim 19
Dependent Claim
52 words
A method according to claim 17, wherein: the positioning step includes, establishing the area of said portion of the second electrode blocked by the shield and the thickness of the shield so that both the area and the thickness are large enough to change the DC bias voltage in a positive direction.
Claim 20
Dependent Claim
70 words
A method according to claim 17, wherein: the step of providing a vacuum chamber further comprises providing the chamber with an electrically conductive wall, wherein the second electrode includes the wall; the step of applying RF power comprises providing said RF power between the first electrode and the wall; and the step of positioning a shield comprises positioning the shield between the plasma and a selected portion of the wall.
Claim 21
Dependent Claim
39 words
A method according to claim 20, further comprising the step of: connecting the conductive wall to an electrical ground; wherein the step of applying RF power comprises providing said RF power between the first electrode and the electrical ground.
Claim 22
Dependent Claim
22 words
A method according to claim 17, wherein the positioning step further comprises: positioning the shield at a distance from the second electrode.
Claim 23
Dependent Claim
56 words
A method according to claim 22, wherein the positioning step further comprises: establishing the area of said portion of the second electrode blocked by the shield and the distance between the shield and the second electrode so that the area and the distance are large enough to change the DC bias voltage in a positive direction.
Claim 24
Dependent Claim
36 words
A method according to claim 22, further comprising the step of: sealing between the second electrode and the perimeter of the shield to prevent plasma from entering the gap between the shield and the second electrode.
Claim 25
Dependent Claim
35 words
A method according to claim 22, wherein the positioning step further comprises: positioning the shield close enough to the second electrode to prevent the formation of said plasma between the shield and the second electrode.
Claim 26
Dependent Claim
19 words
A method according to claim 17, further comprising the step of: mounting a semiconductor substrate on the first electrode.
Claim 27
Dependent Claim
27 words
A method according to claim 17, wherein the positioning step further comprises including in the shield a dielectric material having a substantially higher thermal conductivity than quartz.
Claim 28
Independent Claim
170 words
A method of adjusting the DC bias voltage at a first electrode in a semiconductor processing plasma chamber, comprising the steps of: providing a vacuum chamber having first and second electrodes, the two electrodes being electrically insulated from each other; forming a plasma inside the chamber; applying RF electrical power between the first electrode and the second electrode so as to create a DC bias voltage as the first electrode relative to the second electrode; and positioning a first dielectric shield between the plasma and a first selected portion of the second electrode so as to block direct contact between the plasma and said selected portion of the second electrode; wherein the positioning step further includes adjusting said DC bias voltage by adjusting at least one of the parameters within the group consisting of (i) the area of said portion of the wall blocked by the shield, (it) the thickness of the shield, (iii) the spacing between the shield and the wall, and (iv) the dielectric constant of the shield.
Claim 29
Dependent Claim
19 words
A method according to claim 28, further comprising the step of: mounting a semiconductor substrate on the first electrode.
Claim 30
Dependent Claim
34 words
A method according to claim 28, wherein the positioning step further comprises: positioning the shield close enough to the second electrode to prevent the formation of plasma between the shield and the second electrode.
Claim 31
Dependent Claim
18 words
A method according to claim 28, wherein the second electrode includes an electrically conductive wall of the chamber.
Claim 32
Dependent Claim
49 words
A method according to claim 31, further comprising the step of: connecting the conductive chamber wall to an electrical ground; wherein the step of applying RF electrical power between the first electrode and the second electrode comprises applying RF electrical power between the first electrode and the electrical ground.
Claim 33
Dependent Claim
26 words
A method according to claim 28, wherein the positioning step further comprises: positioning the dielectric shield directly against the wall so that said spacing is zero.
Claim 34
Dependent Claim
53 words
A method according to claim 28, wherein the positioning step further comprises: positioning the shield away from the wall so as to create a gap between the shield and the wall; and sealing between the wall and the perimeter of the shield so as to prevent the formation of plasma in the gap.
Claim 35
Dependent Claim
41 words
A method according to claim 28, wherein the positioning step further comprises: positioning the shield away from the wall so that said spacing between the shield and the wall is sufficient to change the DC bias voltage in a positive direction.
Claim 36
Dependent Claim
32 words
A method according to claim 28, wherein the positioning step further comprises: adjusting the bias voltage by relating the first dielectric shield with a second dielectric shield having a different physical dimension.
Claim 37
Dependent Claim
32 words
A method according to claim 28, wherein the positioning step further comprises: adjusting the bias voltage by replacing the first dielectric shield with a second dielectric shield having a different dielectric constant.
Claim 38
Dependent Claim
48 words
A method according to claim 28, further comprising the steps of: performing in the chamber a first plasma process while the first dielectric shield is positioned in the chamber; and performing in the chamber a second plasma process while the first dielectric shield is absent from the chamber.
Claim 39
Dependent Claim
32 words
A method according to claim 38, wherein the first plasma process is a process for etching a non-dielectric material and the second plasma process is a process for etching a dielectric material.
Claim 40
Dependent Claim
84 words
A method according to claim 28, further comprising the steps of: performing in the chamber a plasma process for etching a non-dielectric material while the first dielectric shield is positioned in the chamber; and performing in the chamber a plasma process for etching a dielectric material while a second dielectric shield is positioned in the chamber, wherein the second shield has physical characteristics different from those of the first shield so as to produce a more negative DC bias voltage on the first electrode.
Claim 41
Dependent Claim
80 words
A method according to claim 28, further comprising the steps of: performing in the chamber a first plasma process while both the first dielectric shield and a second dielectric shield are positioned in the chamber, the second shield being positioned between the plasma and a second selected portion of said wall; and performing in the chamber a second plasma process while the first dielectric shield is positioned in the chamber and the second dielectric shield is absent from the chamber.
Claim 42
Dependent Claim
32 words
A method according to claim 41, wherein the first plasma process is a process for etching a non-dielectric material and the second plasma process is a process for etching a dielectric material.
References Cited (Backward Citations)
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