GB2256084A - Plasma deposition and etching of substrates. - Google Patents
Plasma deposition and etching of substrates. Download PDFInfo
- Publication number
- GB2256084A GB2256084A GB9206246A GB9206246A GB2256084A GB 2256084 A GB2256084 A GB 2256084A GB 9206246 A GB9206246 A GB 9206246A GB 9206246 A GB9206246 A GB 9206246A GB 2256084 A GB2256084 A GB 2256084A
- Authority
- GB
- United Kingdom
- Prior art keywords
- electrode
- chamber
- reactor
- reactor according
- column
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/3244—Gas supply means
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
- C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
- C23C16/50—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges
- C23C16/505—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using radio frequency discharges
- C23C16/509—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating using electric discharges using radio frequency discharges using internal electrodes
- C23C16/5096—Flat-bed apparatus
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
- H01J37/32082—Radio frequency generated discharge
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32458—Vessel
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32431—Constructional details of the reactor
- H01J37/32532—Electrodes
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Drying Of Semiconductors (AREA)
Abstract
A reactor for carrying out plasma deposition on, or etching of, substrates (particularly semiconductor substrates) includes an electrode 14 mounted on an elongate column 13, the electrode and column being at least partially surrounded by a continuous metallic shield 22 which is conductively connected to the chamber housing and spaced from the electrode and support column by a separation distance of dimensions to ensure that a gas plasma cannot form in the space between the shield and the electrode or column. <IMAGE>
Description
Plasma deposition and etching of Substrates
This invention relates to apparatus suitable for plasma deposition on and etching of substrates, in particular semiconductor substrates.
Many attempts have been made to provide improved apparatus for plasma assisted deposition of layers on substrates (such as semiconductor substrates) or etching thereof. Examples of such apparatus are disclosed in U.S. Patents 4262631 and 4849068.
A major problem with methods of low pressure plasma etching/deposition techniques (also known as reactive ion etching/deposition) is ensuring that there is uniformity of deposition or etch on the substrate, and that deposition or etching of, the apparatus itself is kept to a minimum.
We have now devised improved apparatus which alleviates some of the abovementioned difficulties.
According to the invention, there is provided a reactor for plasma deposition, or etching of substrates, which reactor includes a housing defining a reactor chamber, within which chamber is arranged an electrode mounted on an elongate column, the electrode and column being at least partially surrounded by a continuous metallic shield, which shield is electrically conductively connected to the chamber housing and spaced from the electrode and support column by a separation distance of dimensions to ensure that a gas plasma cannot form in the space between the shield and the electrode or column.
In a preferred embodiment of the invention, the electrode has a planar support surface upon which the substrate to be etched or deposited on is supported. In this embodiment it is preferred that the shield does not extend over the planar support surface, and that the shield should extend around the entire periphery of the support column and electrode apart from over the planar support surface of the electrode.
It is preferred that the column is hollow and advantageously arranged to extend outside said chamber, said hollow column being arranged to carry connections from the electrode to external electrode conditioning apparatus.
The electrode conditioning apparatus preferably comprises generation means suitable for applying an electrical potential to the electrode. Advantageously the generation means is in the form of an alternating current generator capable of generating a radio frequency signal.
The electrode conditioning apparatus also preferably includes heating means for selectively elevating the temperature of the electrode, and also cooling means for selectively cooling the electrode.
Typically the reactor comprises a further electrode arranged in the reactor chamber and spaced from the first mentioned electrode. It is preferred that the further electrode is provided with a plurality of apertures therethrough.
The reactor is provided with gas inlet means arranged to permit a gas to enter the chamber. Advantageously, a gas diffusion member, having a plurality of apertures therethrough is provided intermediate the gas inlet means and the further electrode.
It is preferred that the electrodes are arranged substantially parallel to one another within the chamber. It is also preferred that the further electrode and gas diffusion member have respective facing surfaces substantially parallel to one another.
Advantageously the apertures in the diffusion member have axes substantially parallel to one another and also substantially parallel to the axes of the apertures in the second electrode.
The axes of the apertures in both the second electrode and the diffusion member are substantially parallel to the direction of gas flow through the apertures.
Typically, the housing is substantially cylindrical in transverse cross section, in which case the diffusion member and second electrode are preferably both substantially circular in transverse cross section. Advantageously the diffusion apertures in the diffusion member are provided within a relatively small zone, preferably a substantially circular zone, of the diffusion member. Typically the apertures in the second electrode are provided in a relatively larger zone of the electrode, again typically substantially circular, with respect to the relatively smaller zone provided in the diffusion member. Typically therefore, the second electrode is provided with a significantly greater number of apertures than the diffusion member. Typically the ratio of apertures in the second electrode to apertures in the diffusion member is greater than 2:1.It is preferred that the cross sectional areas of the apertures in the diffusion member are larger than the cross sectional areas of the apertures in the second electrode, such that in use restriction of the gas flow is caused resulting in a slight pressure increase in the zone of the chamber intermediate the diffusion member and the second electrode. This aids uniform diffusion of the gas in the chamber. In one embodiment the
In one embodiment the reactor chamber may comprise a first housing element comprising at least one sidewall element and base element which together with said sidewall element are arranged to define a cavity, and a separable second housing element having a surface arranged to sealingly abut and be secured to the sidewall(s) so as to define the chamber.
Typically a first continuous sealing member is provided around the abutment interface of the second housing element and sidewall(s) of the first housing element. The first and second housing elements are preferably provided with communicating conduits arranged to define a gas flow path extending from an external gas inlet port, across the interface to the interior of the chamber. Advantageously, a second continuous sealing member is provided on abutting portions of the first and second housing elements surrounding the junction of the communicating conduits at the interface.
Typically the chamber has a single substantially cylindrical outer sidewall, although in other embodiments the chamber may be rectangular or square having four sidewalls. The base is typically connected to the sidewall(s) by means of fixing bolts with an intermediate seal (typically metallic) being provided.
The second housing element may be a flat closure plate having a central aperture through which an electrode assembly may project. Typically, however, the second housing element is in the form of a sealed housing for an electrode assembly with a peripheral flanged portion being provided for sealing abutment with the first housing element.
The first and second continuous sealing members are preferably of a resilient material such as a plastics material or a rubber, and typically are in the form of "0" ring seals. It will be appreciated that the circumferential dimension of the first sealing member will be significantly larger than that of the second sealing member.
The first and second housing elements may be securely held in sealing abutment with one another by suitable peripheral bolts, clamps or the like.
The invention will now be further described by way of example only with reference to the accompanying drawings which is a schematic sectional representation of a reactor according to the invention;
Referring to the drawing, the reactor generally designated 1 has a chamber 2, which is divided into two portions by a diffuser plate 11. The chamber is capable of sustaining a partial vacuum, within which an upper electrode 3 and lower electrode 4 are positioned. The chamber 2 is generally cylindrical in transverse cross section and formed of a unitary closed cylindrical body portion 17 comprising cylindrical sidewall 5 and cover portion 6. The closed cylindrical body portion 17 may be a unitary casting, or, and more preferably the cover portion 6 may be bolted and sealed to the sidewall 5.The other end of the chamber 2 is closed by a sealed flange portion 7 of the lower electrode support housing 8.
The reacting gases (which may be silanes when, for example, silicon deposition is required, or where gallium arsenide deposition is required, may be Ga(CH3)3 and AsH3) are fed into the chamber 2 from a gas inlet port 9 and along respective coaxially aligned transport conduits 21 in the flange 7 of the lower electrode support housing 8 and the sidewall 5 of the chamber 2 respectively. The gas enters the housing 2 and passes through a circular array of holes 10 in a primary gas diffusion plate 11 and then passes through a further array of holes 12 provided in the spaced upper electrode 3 which thereby acts as a secondary diffusion plate.
It is important to note that the axes of the holes 10 and holes 11 are notcoaxial, and therefore gas flow through the primary diffusion and secondary diffuser 3 is caused to be turbulent resulting in improved dispersion of the diffusing gas. The reactor therefore effectively has two gas diffusion stages which create an excellent gas distribution system thereby improving etch or deposition uniformity. Furthermore, the diameters of the holes 10 in the primary diffusion plate 11 are larger than the diameters of the holes 12 in the electrode 3. This difference in size of aperture causes slight build up of pressure in the zone of the chamber 2 intermediate the diffusion plate 11 and electrode 3 thereby resulting in more effective and uniform gas diffusion and distribution in the chamber 2.
The lower electrode 4 comprises a hollow central column 13 having a planar table mount portion 14 at its uppermost end. The table mount 14 in use serves to support the semiconductor substrate which is to be etched or used as a deposition surface. The column 13 projects into the chamber 2 and is supported by the lower electrode support housing 8, a gas seal being effected therewith by the sealing "0" ring 15. The column 13 and sides of the table mount 14 are surrounded by a dark space shield 22 which prevents etching taking place on these surfaces when the device is used for etching substances located on the table mount 14. This is due to the fact that the separation gap between the dark space shield 22 and the column 13 and table mount 14 is of sufficiently small dimensions to ensure that the plasma generated in the chamber 2 cannot exist in the gap.The dark space shield is metallic, and constructed as a unitary casing which is profiled and shaped to extend around the sides of the mount 14 and column 13 and be conductively connected to the housing 8 in the region of the entry point of the column 13 into the housing; this is an important feature of the reactor since it ensures that a good electrical path to ground via the housing 8 is provided.
When used for etching a semiconductor substrate, the lower electrode 4 is connected to a radio frequency (RF) generating and tuning device 23, and also a heater and thermocouple assembly (not shown). It should be noted that since the column 13 is hollow, the R.F. and water cooling apparatus connections to the lower electrode are conveniently made with the electrode via the hollow internal cavity of the column 13, which aids greatly in the maintenance of the reactor 1. When used for deposition on a semiconductor substrate the polarity of the electrodes is reversed, with the R.F. generating device being connected to the upper electrode 3 via suitable couplings (not shown) in the base 6. In "etching mode", the lower electrode 4 is heated by heater apparatus (not shown) provided in the interior of the hollow support column 13.
Gas flow into the reactor chamber 2 is induced by means of connection to a vacuum pump (not shown) coupled to the vacuum connection part 16 in the lower electrode support housing 8.
An important feature of the reactor 1 is the manner in which the cylindrical body 17 is closed by and gas sealed to the flange portion 7 of the lower electrode support housing 8. A first cylindrical sealing ring 18 of conventional "0" ring type is located in a seat such that when the cylindrical body 17 is closed by the flange 7 of the lower electrode support housing 8 a gas tight seal is effected between the two.
A further sealing "0" ring 20 of substantially smaller diameter than the "0" ring 18 is also located in a seat at the sealing faces of the closed cylindrical body portion 17 and flange 7 such that it surrounds the conduits 21 in the region of their junction at the cylindrical body 17 and flange 7 interface. Typically the body portion 17, and flange 7 are secured in sealing engagement by suitable bolting arrangement or the like (or not shown).
In use, a vacuum pump is actuated causing the reacting gas to enter the chamber 2 via the conduits 21 in the manner outlined above. Flow of the gas through the holes 10 in the primary diffuser 11 and subsequently through the "non-aligned" holes 12 in the spaced upper electrode 3 (acting as a secondary diffuser) causes dispersion of the reacting gas which is important for deposition/etch uniformity. The upper electrode 3 is held at R.F.
ground potential, with the lower electrode being "hot" or energised by the RF source. The large potential difference created between the upper and lower electrodes 3,4 causes a plasma to be struck in the gas between the two electrodes, breaking down the gas reactants into ionised species. These ionised species are then uniformly etched on the surface of the semiconductor substrate (located on the lower electrode 3). As explained above, for deposition the polarity of the electrodes is reversed, with, typically, a heater being connected to the lower electrode as detailed above, and energised to raise the temperature of the lower electrode to 200"C or above to aid the deposition process.
Claims (14)
1. A reactor for plasma deposition, or etching of substrates, which reactor includes a
housing defining a reactor chamber, within which chamber is arranged an electrode
mounted on an elongate column, the electrode and column being at least partially
surrounded by a continuous metallic shield, which shield is electrically conductively
connected to the chamber housing and spaced from the electrode and support column
by a separation distance of dimensions to ensure that a gas plasma cannot form in the
space between the shield and the electrode or column.
2. A reactor according to claim 1, wherein the electrode has a planar support surface
upon which the substrate to be etched or deposited on is arranged to be supported.
3. A reactor according to claim 2, wherein the shield is arranged to extend around the
entire periphery of the support column and electrode apart from over the planar
support surface of the electrode.
4. A reactor according to any preceding claim, wherein the elongate column is
substantially hollow and arranged to extend to the exterior of the chamber.
5. A reactor according to claim 4, wherein the hollow column is arranged to carry
connections from the electrode to external electrode conditioning apparatus.
6. A reactor according to claim 5, wherein the electrode conditioning apparatus
comprises generation means for applying an electrical potential to the electrode.
7. A reactor according to claim 5 or claim 6, wherein the electrode conditioning
apparatus includes heating means arranged to selectively elevate the temperature of
the electrode and/or cooling means arranged to selectively cool the electrode.
8. A reactor according to any preceding claim, which comprises a further electrode
arranged in the reactor chamber and spaced from the first mentioned electrode.
9. A reactor according to claim 8, wherein the further electrode is provided with a
plurality of apertures therethrough.
10. A reactor according to claim 8 or claim 9, wherein a gas diffusion member having
a plurality of apertures is provided intermediate a region of gas entry into the
chamber and the further electrode.
11. A reactor according to any preceding claim, wherein the reactor chamber comprises
a first housing element comprising at least one sidewall element and base element
which together with said sidewall element are arranged to define a cavity, and a
separable second housing element having a surface arranged at an interface to
sealingly abut and be secured to the sidewall(s) so as to define the chamber.
12. A reactor according to claim 11, wherein the first and second housing elements are
provided with communicating conduits arranged to define a gas flow path extending
from an external gas inlet port, across the interface to the interior of the chamber.
13. A reactor according to claim 12, wherein a first continuous sealing member is
provided around the abutment interface of the second housing element and sidewall(s)
of the first housing element, a second continuous sealing member being provided at
the interface surrounding the junction of the communicating conduits.
14. A reactor substantially as herein described with reference to the accompanying
drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9206246A GB2256084A (en) | 1991-05-13 | 1992-03-23 | Plasma deposition and etching of substrates. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9110288A GB2255857A (en) | 1991-05-13 | 1991-05-13 | Plasma deposition and etching of semiconductor substrates |
| GB9206246A GB2256084A (en) | 1991-05-13 | 1992-03-23 | Plasma deposition and etching of substrates. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9206246D0 GB9206246D0 (en) | 1992-05-06 |
| GB2256084A true GB2256084A (en) | 1992-11-25 |
Family
ID=26298892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9206246A Withdrawn GB2256084A (en) | 1991-05-13 | 1992-03-23 | Plasma deposition and etching of substrates. |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2256084A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999057753A1 (en) * | 1998-05-01 | 1999-11-11 | Applied Materials, Inc. | Apparatus for improved biasing and retaining of a workpiece in a workpiece processing system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0012954A2 (en) * | 1978-12-22 | 1980-07-09 | International Business Machines Corporation | Bias sputter deposition apparatus and its method of use |
| EP0171949A2 (en) * | 1984-07-23 | 1986-02-19 | Fujitsu Limited | Microwave plasma etching apparatus |
| US4620893A (en) * | 1983-07-05 | 1986-11-04 | Nextral | Apparatus for the plasma treatment of disk-shaped substrates |
| EP0266288A2 (en) * | 1986-10-30 | 1988-05-04 | Nihon Shinku Gijutsu Kabushiki Kaisha | Vacuum processing method and apparatus |
| GB2209769A (en) * | 1987-09-16 | 1989-05-24 | Ion Tech Ltd | Sputter coating |
| US4921724A (en) * | 1987-06-12 | 1990-05-01 | Leybold-Aktiengesellschaft | Process for coating a substrate with an organic coating having gradated hardness |
-
1992
- 1992-03-23 GB GB9206246A patent/GB2256084A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0012954A2 (en) * | 1978-12-22 | 1980-07-09 | International Business Machines Corporation | Bias sputter deposition apparatus and its method of use |
| US4620893A (en) * | 1983-07-05 | 1986-11-04 | Nextral | Apparatus for the plasma treatment of disk-shaped substrates |
| EP0171949A2 (en) * | 1984-07-23 | 1986-02-19 | Fujitsu Limited | Microwave plasma etching apparatus |
| EP0266288A2 (en) * | 1986-10-30 | 1988-05-04 | Nihon Shinku Gijutsu Kabushiki Kaisha | Vacuum processing method and apparatus |
| US4921724A (en) * | 1987-06-12 | 1990-05-01 | Leybold-Aktiengesellschaft | Process for coating a substrate with an organic coating having gradated hardness |
| GB2209769A (en) * | 1987-09-16 | 1989-05-24 | Ion Tech Ltd | Sputter coating |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999057753A1 (en) * | 1998-05-01 | 1999-11-11 | Applied Materials, Inc. | Apparatus for improved biasing and retaining of a workpiece in a workpiece processing system |
| US6081414A (en) * | 1998-05-01 | 2000-06-27 | Applied Materials, Inc. | Apparatus for improved biasing and retaining of a workpiece in a workpiece processing system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9206246D0 (en) | 1992-05-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |