`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1030
`Exhibit 1030, Page 1
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 1 of 7
`
`
`
`US 6,506,686 B2
`
`
`
`
`FIG. 1
`
`120
`
`2
`
`1
`
`
`
`a
`
`117
`
`104
`
`
`
`
`
`
`ei De
`123 oe oT 124
`
`
`
`126
`Ta
`PPL
`25
`
`113
`Si
`414.|115111112
`16
`101
`
`PLDTRIZE]
`|
`RSSSSSSSSSS
`
`
`
`(2 el
`
`
`
`
`
`iM \ 1d
`N\/) SSSESIDS
`
`
`
`
`
`
`
`
`
`4
`WNWLLLVZA
`FZZZ
`VorTRVSosIN
`eern=H
`
`
`
`C/\ VA eSSSSS
`
`ssTsa
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`102
`VIRNNAARANSIANSANA
`
`
`
`
`a aa
`
`
`ih
`HAS
`103
`
`
`
`
`
`KANNASNSAN
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`106
`
`
`
`
`
`
`
`
`
`
`Ex. 1030, Page 2
`
`Ex. 1030, Page 2
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 2 of 7
`
`
`US 6,506,686 B2
`
`
`
`
`FIG. 2
`
`
`
`
`
`
`
`
`
`
`
`
`
`a|@ =e-
`
`
`
`
`
`«|Lor -
`Tc
`
`118A |
`112
`118B
`
`
`
`
`
`
`4 18 llwi|veor iv | 100
`
`
`
`
`
`tt op HS
`
`
`ASSISAMKDNAJAAAN
`NVAPZLZIZeaeeEN
`
`
`
`\/Aieestaeiesn
`
`
`
` 121C
`
`
`
`
`
`
`
`
`
`
`116 sprefeerstereeePPEPeeePEPee W121B
`
`
`
`
`
`
`115A
`
`111A
`
`Ex. 1030, Page 3
`
`Ex. 1030, Page 3
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 3 of 7
`
`
`US 6,506,686 B2
`
`
`
`
`
`
`Si ETCHING RATE( um/h)
`
`
`
`
`FIG. 3
`
`
`
`@ 50-75°C
`
`
`A 100-105 °C
`
`
`
`© 125-130°C
`50
`
`
`0
`
`
`
`-100
`
`
`
`
`-200
`
`
`
`-300
`
`
`
`-400
`
`
`
`-500
`
`
`
`-600
`
`
`
`
`Vdc (V)
`
`
`FIG. 4
`
`
`TEMPERATURE (deg)
`
`
`
`200
`
`
`
`
`
`
`
`
`
`
`
`
`
`150
`
`100
`
`
`
`
`
`
`
`
`
`
`Oo
`
`
`
`
`10
`
`20
`
`
`
`30
`
`
`
`40
`
`TIME (min)
`
`
`50
`
`
`60
`
`
`
`70
`
`
`
`80
`
`
`
`Ex. 1030, Page 4
`
`Ex. 1030, Page 4
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 4 of 7
`
`
`
`US 6,506,686 B2
`
`
`
`
`
`DISCHARGE ON bo
`
`
`
`
`|
`:
`DISCHARGE OFF:
`
`
`
`
`
`
`
`GAS INTRODUCTION
`
`
`
`
`
`200
`
`
`
`150
`
`
`
`
`100
`
` TEMPERATURE(deg)
`
`50
`
`
`
`ON OFF ON OFF ON OEE ON OFF
`
`
`
`
`
`
`0
`
`
`10
`
`
`
`12
`
`
`
`14
`
`
`
`16
`
`
`
`
`
`
`18 20 22 24
`
`
`
`
`
`26 28 30
`
`
`
`
`TIME (min)
`
`
`
`
`TEMPERATURE (deg)
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`200
`
`150
`
`
`
`100
`
`
`
`50
`
`
`
`0
`
`
`10
`
`
`
`
`10
`
`
`20
`
`30
`
`
`
`40
`
`
`
`50
`
`
`
`
`TIME (min)
`
`
`
`
`
`
`60
`
`
`
`70
`
`
`
`80
`
`
`
`Ex. 1030, Page 5
`
`Ex. 1030, Page 5
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 5 of 7
`
`
`US 6,506,686 B2
`
`
`
`
`FIG, 7
`
`
`120
`
`121
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`110 LL
`
`
`
`
`117
`
`
`
`
`
`=| Lieae125
`Oo OL
`
`
`
`
`f 198
`112
`118A |
`
`
`wa
`[
`|S
`141 Ao
`'
`100
`Nebo:KAWKON
`NWPLZeaZA
`VAS‘ANSSSERSs DNiobstbeSleeeSra
`
`a
`
`
`ELT[TL
`115
`121B
`
`
`
`116
`
`115A
`
`Ex. 1030, Page 6
`
`Ex. 1030, Page 6
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 6 of 7
`
`
`US 6,506,686 B2
`
`
`
`
`FIG. 8
`
`
`TEMPERATURE(deg)
`
`
`
`
`
`
`
`200150 innit
`100 [eo50 fe
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`0
`
`
`
`0
`
`
`
`
`10
`
`20
`
`
`
`30
`
`
`
`40
`
`50
`
`
`
`TIME (min)
`
`
`
`
`60
`
`
`
`70
`
`
`
`80
`
`
`
`
`
`ETCHING DEPTH(nm)
`
`
`
`1600
`
`1400
`
`1200
`
`1000
`
`800
`
`600
`
`400
`
`200
`
`0
`
`
`
`
`
`0
`
`1
`
`2
`
`3
`
`4
`
`
`TIME (min)
`
`
`
`
`
`ETCH RATE(nm/min)
`
`
`
`800
`
`
`
`600
`
`400
`
`
`
`200
`
`0
`
`Ex. 1030, Page 7
`
`Ex. 1030, Page 7
`
`
`
`U.S. Patent
`
`
`
`
`Jan. 14, 2003
`
`
`
`
`
`Sheet 7 of 7
`
`
`US 6,506,686 B2
`
`
`
`
`FIG. 9
`
`
`
`OES INTENSITY (a.u.)
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`-df-.-----LCF 230.5nmweeee- ---f.-..--
`
`1
`
`
`
`
`0
`
`1
`
`2
`
`
`
`3
`
`
`
`4
`
`
`
`
`
`BIAS Vpp
`
`
`TIME (min)
`
`
`
`2000
`
`1800
`
`1600
`
`1400
`
`1200
`
`1000
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`}----;o=SSSSSSno -400
`<BIAS-Vpp
`
`
`
`
`
`
`
`
`
`
`
`0
`
`1
`
`2
`
`3
`
`4
`
`TIME (min)
`
`Ex. 1030, Page 8
`
`Ex. 1030, Page 8
`
`
`
`
`1
`PLASMA PROCESSING APPARATUS AND
`
`
`PLASMA PROCESSING METHOD
`
`
`
`
`
`
`
`
`US 6,506,686 B2
`
`
`
`
`
`
`
`
`BACKGROUND OF THE INVENTION
`
`
`1. Field of the Invention
`
`
`
`
`
`
`
`
`
`
`The present
`invention relates to a plasma processing
`
`
`
`
`
`
`apparatus and processing method, particularly to a plasma
`
`
`
`
`
`
`processing apparatus and processing method suitable for
`
`
`
`
`formation of ultrafine pattern in semiconductor production
`process.
`
`
`
`
`
`2. Related Background Art
`
`
`
`
`
`
`In semiconductor production process, a plasma process-
`
`
`
`
`
`
`
`ing apparatus is widely used in fine processing such as
`
`
`
`
`
`
`
`
`etching, film formation and ashing. In plasma processing,
`
`
`
`
`
`
`
`process gas introduced into a vacuum chamber(reactor) is
`
`
`
`
`
`
`converted to plasma by a plasma generation means, and is
`
`
`
`
`
`
`made to react on the semiconductor wafer surface to provide
`
`
`
`
`
`
`
`
`fine processing, and volatile reaction products are exhausted,
`
`
`
`
`thus a predetermined process is performed.
`
`
`
`
`
`
`This plasma processing is strongly affected by tempera-
`
`
`
`
`
`
`
`
`
`
`ture of the reactor inner wall and wafer and deposition of
`
`
`
`
`
`
`
`
`reaction products on the inner wall. Furthermore,
`if the
`
`
`
`
`
`
`
`
`reaction products deposited inside the reactor have peeled
`
`
`
`
`
`
`off, partilcle may be produced, resulting in deterioration of
`
`
`
`
`
`
`
`device characteristics or reduction of yields. In the plasma
`
`
`
`
`
`
`processing apparatus, therefore, it is important to control
`
`
`
`
`
`
`
`
`temperature inside the reactor and deposition of reaction
`
`
`
`
`
`
`
`products on the surface, in order to ensure process stability
`
`
`
`
`and to prevent particle contamination.
`
`
`
`
`
`
`
`
`For example, Official Gazette of Japanese Patent Laid-
`
`
`
`
`
`
`
`Open NO. 144072/1996 discloses a dry etching apparatus
`
`
`
`
`
`
`
`
`which controls and maintains the temperature of each part
`
`
`
`
`
`
`
`inside the reactor to a high temperature of 150 to 300° C.
`
`
`
`
`
`
`
`
`
`(preferably 200 to 250° C.), at least 150° C. higher than that
`
`
`
`
`
`
`
`
`
`of etching stage, within the accuracy of +5° C., wherein the
`
`
`
`
`
`
`
`
`purpose is to improvethe selectivity in a silicon oxide dry
`
`
`
`
`
`
`
`etching process. This is intended to reduce deposition of
`
`
`
`
`
`
`
`plasma polymer on the inner wall of the reactor by control-
`
`
`
`
`
`
`
`
`
`ling eachpart inside the reactor to high temperature, thereby
`
`
`
`
`
`
`
`increase the deposition of plasma polymer on the semicon-
`
`
`
`
`
`
`
`ductor wafer, with the result of improved selectivity.
`
`
`
`
`
`
`
`Also, Official Gazette of Japanese Patent Laid-Open NO.
`
`
`
`
`
`
`275385/1993 discloses a parallel plate plasma processing
`
`
`
`
`
`
`apparatus wherein a heating means is provided onat least
`
`
`
`
`
`
`
`
`one of a clamp ring (object holding means) or focus ring
`
`
`
`
`
`
`
`
`(plasma concentration means) to raise and keep the tem-
`
`
`
`
`
`
`
`perature in order to prevent deposition of plasma process
`
`
`
`
`
`
`reaction products. As a heating means,a resistance heater is
`
`
`
`
`
`
`
`used. Since deposition of reaction products can be prevented
`
`
`
`
`
`
`
`
`by heating, peeling off of reaction products and particles on
`
`
`
`
`
`the object surface are reduced.
`
`
`
`
`
`
`
`
`
`However, when the reactor inner wall is set to a high
`
`
`
`
`
`
`temperature of 200 to 250° C. or more as described above,
`
`
`
`
`
`
`
`
`a problem arises that etching characteristics becomes very
`
`
`
`
`
`
`
`
`
`sensitive to the temperature of the inner wall surface, and
`
`
`
`
`
`
`
`
`repeatability and reliability of the process can be reduced.
`
`
`
`
`
`
`
`For example, S. C. McNevin,et al., J. Vac. Sci. Technol.
`
`
`
`
`
`
`
`B15(2) March/April 1997, P.21, “Chemical challenge of
`
`
`
`
`
`
`
`
`submicron oxide etching” indicates that oxide film etching
`
`
`
`
`
`
`
`rate increases 5% or more, in the inductively coupled plasma
`
`
`
`
`
`
`
`
`
`whenside wall temperature changes from 200 to 170° C.,
`
`
`
`
`
`
`
`therefore, surface temperature inside the reactor is required
`
`
`
`
`
`
`
`to be kept to a high accuracy of 250 +2° C. in order to ensure
`
`
`
`
`stability of process characteristics.
`
`10
`
`15
`
`
`
`20
`
`25
`
`
`
`30
`
`35
`
`
`
`40
`
`
`
`45
`
`
`
`50
`
`
`
`55
`
`
`
`60
`
`
`
`65
`
`
`
`
`2
`
`
`
`
`
`
`Furthermore, since the surface of the processing chamber
`
`
`
`
`
`
`
`
`
`inner wall is exposed to high density plasma,it is not easy
`
`
`
`
`
`
`
`
`
`to control the wall surface temperature with high accuracy in
`
`
`
`
`
`
`
`
`the high temperature range. A highly accurate in-situ tem-
`
`
`
`
`
`
`
`perature measuring means and a heating means such as
`
`
`
`
`
`
`
`
`
`
`resistance heater or lamp are to be used for temperature
`
`
`
`
`
`
`
`control. However, the temperature control mechanism and
`
`
`
`
`
`
`
`
`means will be quite complicated and large in scale, resulting
`
`
`
`
`
`
`
`
`
`in complicated equipment with high cost. In a high tem-
`
`
`
`
`
`
`
`
`
`perature range of more than 200° C., another problem exists
`
`
`
`
`
`
`
`
`
`
`that the materials applicable for the inner wall are limited.
`
`
`
`
`
`
`
`
`
`In this respect,
`the present applicants discloses in the
`
`
`
`
`
`
`Japanese Patent Application No. 147672/1998 (Official
`
`
`
`
`
`
`Gazette of Japanese Patent Laid-Open NO. 340149/1999) by
`
`
`
`
`
`
`
`
`
`the same applicants that the process can be insensitive to
`
`
`
`
`
`
`
`temperature changes and stable process repeatability can be
`
`
`
`
`
`
`
`
`ensured despite the temperature accuracy of about +10° C.,
`
`
`
`
`
`
`
`when the temperature of the processing chamberinner wall
`
`
`
`
`
`
`
`
`
`
`
`is set
`to the temperature range of lower than 100° C.,
`
`
`
`
`
`
`
`
`wherein said applicants use a magnetic field UHF band
`
`
`
`
`
`
`
`electromagnetic wave radiation discharge type plasma etch-
`
`
`
`
`ing apparatus as one Embodiment.
`
`
`
`
`
`
`
`The same application discloses that, by applying bias at
`
`
`
`
`
`
`
`
`
`
`least partly to the components (or inner wall surface) in
`
`
`
`
`
`
`
`
`contact with plasma, and by reducing the thermal capacity of
`
`
`
`
`
`
`
`the components to keep component temperature in the range
`
`
`
`
`
`
`
`
`
`
`from 150 to 250° C., it is possible to come to the level that
`
`
`
`
`
`
`
`
`the temperature fluctuation of components does not affect
`
`
`
`the process substantially.
`
`
`
`
`
`
`
`The present applicants in the Japanese Patent Application
`
`
`
`
`
`
`
`No. 232132/1999 by the same applicants also disclose that,
`
`
`
`
`
`
`
`when higher bias power of no deposition occurrence is
`
`
`
`
`
`
`
`
`
`applied to the silicon-made focusring set outside the sample,
`
`
`
`
`
`
`
`
`and when the surface temperature is higher than 150° C.,
`
`
`
`
`
`
`surface reaction dependency upon temperature on the silicon
`
`
`
`
`
`
`
`surface is reduced and stable process repeatability can be
`ensured.
`
`
`
`
`
`
`
`
`
`However, as for the plate installed on the top antenna (or
`
`
`
`
`
`
`
`
`upper electrode or top plate) opposite to the sample wafer,
`
`
`
`
`
`
`
`
`although the plate has a big influence on processstability,
`
`
`
`
`
`
`
`
`
`
`said application only states that the plate has a role of
`
`
`
`
`
`
`
`stabilizing the process by preventing reaction product from
`
`
`
`
`
`
`
`
`deposition by application of bias, and said applicants did not
`
`
`
`
`
`
`reach sufficient understanding of the mechanism nor succeed
`
`
`
`
`
`in quantifying the required conditions.
`SUMMARYOF THE INVENTION
`
`
`
`
`
`
`
`
`
`From said technological standpoint, the present inventors
`
`
`
`
`
`
`
`made a strenuous effort to solve said problems, and found
`
`
`
`
`
`
`
`temperature range and accuracy required to ensure
`out
`
`
`
`
`
`
`
`process stability and requirements for surface state control
`
`
`
`
`
`
`
`
`by bias application, regardingthe top plate installed opposite
`
`
`
`
`to the sample wafer.
`
`
`
`
`
`
`
`
`The present invention was developed on the basis of the
`
`
`
`
`
`
`aforementioned findings, and is intended to provide a
`
`
`
`
`
`
`
`plasma processing apparatus and processing method with
`
`
`
`
`
`excellent process stability and repeatability.
`
`
`
`
`
`
`The present invention provides a plasma processing appa-
`
`
`
`
`
`
`ratus comprising; a vacuum chamber, a process gas supply
`
`
`
`
`
`
`means to supply gas to said vacuum chamber, an electrode
`
`
`
`
`
`
`
`to hold a sample inside said vacuum chamber, a plasma
`
`
`
`
`
`
`generator installed in said vacuum chamberopposite to said
`
`
`
`
`
`
`sample, and a vacuum exhaust system to evacuate said
`
`
`vacuum chamber;
`
`
`
`
`
`
`wherein said plasma generatoris installed a silicon-made
`
`
`
`
`
`
`
`
`plate inside the processing chamber, and bias voltage of
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Ex. 1030, Page 9
`
`Ex. 1030, Page 9
`
`
`
`
`
`US 6,506,686 B2
`
`
`
`
`
`
`
`
`
`
`
`3
`
`
`
`
`Vdc=-50 to -300 V (i.e. -300 V=Vdc=-50 V) is
`
`
`
`
`
`
`
`
`applied to said silicon-made plate, and the surface
`
`
`
`
`
`
`
`
`temperature of said plate is kept in the range from 100
`to 200° C.
`
`
`
`
`
`
`
`
`
`Anothercharacteristic of the present inventionis that the
`
`
`
`
`
`
`
`
`fluctuation of the surface temperature of the silicon-made
`
`
`
`
`
`
`
`
`plate on said plasma processing apparatus is kept within
`#25° C.
`
`
`
`
`
`
`
`
`Still further characteristic of the present invention is that
`
`
`
`
`
`
`
`said plasma generator of plasma processing apparatus is
`
`
`
`
`
`
`
`
`based on magnetic field or non-magnetic field UHF band
`
`
`
`
`
`
`electromagnetic wave radiation discharge method in the
`
`
`
`
`
`
`
`
`
`frequency range from 300 MHz to 1 GHz, and that the
`
`
`
`
`
`
`
`resistivity of said silicon-madeplate is 1 to 10 Qcem,and that
`
`
`
`
`
`
`
`
`
`the thickness of said silicon-made plate is 5 to 20 mm,
`
`
`
`desirably up to 10 mm.
`
`
`
`
`
`
`According to the present invention, dependency ofreac-
`
`
`
`
`
`
`
`
`
`tion on temperature on the silicon surface decreases by
`
`
`
`
`
`
`
`temperature control and bias application for silicon-made
`
`
`
`
`
`
`
`
`
`plate installed opposite to the sample and plasma state and
`
`
`
`
`
`
`
`process characteristics are stabilized for surface temperature
`
`
`
`
`
`
`
`
`
`fluctuation of the plate within +25° C.,
`thus a plasma
`
`
`
`
`
`
`
`processing apparatus and processing method with excellent
`
`
`
`
`
`stability and repeatability can be provided.
`
`
`
`
`
`
`
`The present
`invention is still further characterized as
`
`
`
`
`
`
`
`
`follows: the skin depth of the UHF band electromagnetic
`
`
`
`
`
`
`
`
`wave transmitting inside the silicon-made plate and silicon
`
`
`
`
`
`
`
`
`
`plate thickness are almost equal, and current resulting from
`
`
`
`
`
`
`
`
`UHFband electromagnetic wave flows the entire plate. As
`
`
`
`
`
`
`
`
`a result, the plate is effectively heated by self-heat genera-
`
`
`
`
`
`
`
`
`
`tion due to the internal resistance of silicon itself, which
`
`
`
`
`
`
`
`enables to set surface temperature of the silicon-made plate
`
`
`
`
`
`
`
`
`in the range from 100 to 200° C. where dependency of
`
`
`
`
`
`
`
`surface reaction on temperature decreases. As a result
`
`
`
`
`
`
`
`
`plasmastate and process characteristics are stabilized, thus
`
`
`
`
`
`
`
`
`a plasma processing apparatus and processing method with
`
`
`
`
`
`
`excellent stability and repeatability can be provided.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`
`
`
`
`
`
`
`
`
`
`FIG. 1 is a schematic diagram representing the vertical
`
`
`
`
`
`
`
`
`section of the first Embodiment where the present invention
`
`
`
`
`
`
`
`is applied to a magnetic field UHF band electromagnetic
`
`
`
`
`
`
`
`wave radiation discharge type plasma processing apparatus;
`
`
`
`
`
`
`FIG. 2 is a schematic diagram representing the vertical
`
`
`
`
`
`section of the embodimentof an antennastructure according
`
`
`
`
`to the first Embodiment;
`
`
`
`
`
`
`FIG. 3 showsthe result of evaluating consumption rate of
`
`
`
`
`
`the plate in the first Embodiment;
`
`
`
`
`
`
`FIG. 4 represents the temperature fluctuation of the plate
`
`
`
`
`in the first Embodiment;
`
`
`
`
`
`
`FIG. 5 represents the temperature fluctuation of the plate
`
`
`
`
`
`
`
`
`in the steady state in the first Embodiment;
`
`
`
`
`
`
`FIG. 6 represents the temperature fluctuation where the
`
`
`
`
`
`
`
`
`plate has different resistivity in the first Embodiment;
`
`
`
`
`
`
`FIG. 7 is a schematic diagram representing the vertical
`
`
`
`
`
`
`
`
`section of the second Embodiment where the present inven-
`
`
`
`
`
`
`
`tion is applied to a magnetic field UHF bandelectromagnetic
`
`
`
`
`
`
`
`wave radiation discharge type plasma processing apparatus;
`
`
`
`
`
`
`
`FIG. 8 represents the temperature fluctuation of the plate
`
`
`
`
`in the second Embodiment;
`
`
`
`
`
`
`FIG. 9 represents the changes of plasmaoptical emission,
`
`
`
`
`
`
`
`
`discharge voltage and antenna bias voltage with time in the
`
`
`
`second Embodiment; and
`
`
`
`
`
`
`FIG. 10 represents the result of measuring the dependency
`
`
`
`
`
`
`
`
`
`
`of etching depth and etching rate upon etching time in the
`second Embodiment.
`
`
`
`
`4
`DETAILED DESCRIPTION OF PREFERRED
`
`
`EMBODIMENTS
`
`
`
`
`
`
`
`
`
`
`The following describes the embodiments according to
`
`
`
`
`
`
`
`the present invention with reference to the drawings.
`
`
`
`
`
`
`
`FIG. 1 shows an embodiment where the present invention
`
`
`
`
`
`
`
`
`is applied to the magnetic field UHF band electromagnetic
`
`
`
`
`
`
`
`wave radiation discharge type plasma etching apparatus.It is
`
`
`
`
`
`
`
`
`a cross sectional view of said plasma etching apparatus in
`schematic form.
`
`
`
`
`
`
`
`
`
`The processing chamber 100 in FIG. 1 is a vacuum vessel
`
`
`
`
`
`
`
`providing a vacuum of about 10-° Torr. An antenna 110,
`
`
`
`
`
`
`
`which radiates electromagnetic wave, is installed on the top
`
`
`
`
`
`
`
`thereof, and a bottom electrode 130 to mount a sample W
`such as a waferis installed on the bottom thereof. Antenna
`
`
`
`
`
`
`
`110 and bottom electrode 130 are installed so as to be
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`opposite to and in parallel with each other. A magnetic field
`
`
`
`
`
`
`forming means 101 composed of an electromagnetic coil
`
`
`
`
`
`
`
`
`and a yoke, for example, is installed around the processing
`
`
`
`
`
`
`
`
`chamber 100. Process gas introduced into the processing
`
`
`
`
`
`
`chamberis converted into plasma by interaction between the
`
`
`
`
`
`
`
`
`electromagnetic wave radiated from the antenna 110 and
`
`
`
`
`
`
`
`
`magnetic field produced by the magnetic field forming
`
`
`
`
`
`
`
`means 101, and plasmaP is generated to perform processing
`
`
`
`
`
`
`
`of the sample W on the bottom electrode 130.
`
`
`
`
`
`Evacuation of the processing chamber 100 is provided by
`
`
`
`
`
`
`
`vacuum exhaust apparatus 106 connected to vacuum cham-
`
`
`
`
`
`
`
`
`
`
`ber 105 and the inner pressure can be controlled by a
`
`
`
`
`
`
`
`
`pressure control means 107. The processing pressure is
`
`
`
`
`
`
`
`
`
`adjusted in the range from 0.1 to 10 Pa, more desirably from
`
`
`
`
`
`
`
`
`
`0.5 to 4 Pa. The processing chamber 100 and the vacuum
`
`
`
`
`
`
`
`
`chamber 105 are at the ground potential. A side wall inner
`
`
`
`
`
`
`
`unit 103 having a temperature control function is replace-
`
`
`
`
`
`
`
`
`ably installed on a side wall 102 of the processing chamber
`
`
`
`
`
`
`100. The temperature on the inner surface is controlled by a
`
`
`
`
`
`
`
`
`heat transfer medium suppliedin circulation to the side wall
`
`
`
`
`
`
`
`
`
`
`inner unit 103 from the heat transfer medium supply means
`
`
`
`
`
`
`
`104. Alternatively,
`the temperature can be feedback-
`
`
`
`
`
`
`controlled by a heater mechanism and a temperature detect-
`
`
`
`
`
`
`
`
`ing means. The temperature control range is from 0 to 100°
`
`
`
`
`
`
`
`
`C., desirably 20 to 80° C., and is controlled within +10° C.
`
`
`
`
`
`
`
`
`
`
`is desirable that
`the side wall 102 of the processing
`It
`chamber 100 and side wall inner unit 103 are made of
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`non-magnetic metallic material without containing heavy
`
`
`
`
`
`
`
`metal, featuring high thermal conductivity, for example
`
`
`
`
`
`
`
`
`aluminum, and that the surface is provided with surface
`
`
`
`
`
`
`
`process of anti-plasma, for example anodized aluminum
`oxide or the like.
`
`
`
`Antenna 110 installed on the vacuum vessel consists of a
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`disk formed conductor 111, a dielectric 112 and a dielectric
`
`
`
`
`
`
`
`
`
`ring 113, and is held by a housing 114 as a part of the
`
`
`
`
`
`
`
`vacuum vessel. Furthermore, a plate 115 is installed on the
`surface of the disk formed conductor 111 on the side in
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`contact with plasma. A outer ring 116 is installed further on
`
`
`
`
`
`
`
`
`the outside. The temperature of the disk formed conductor
`
`
`
`
`
`
`111 is kept at a predetermined value by a temperature control
`
`
`
`
`
`
`
`means(not illustrated), namely by heat transfer medium
`
`
`
`
`
`
`
`
`circulating inside, and the surface temperature of the plate
`115 in contact with the disk formed conductor 111 is
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`controlled. The process gas used to perform sample etching
`
`
`
`
`
`
`
`and film formation is supplied at a predetermined flow rate
`
`
`
`
`
`
`
`
`
`
`and mixing ratio from the gas supply means 117 and is
`
`
`
`
`
`
`
`introduced into processing chamber through numerousholes
`
`
`
`
`
`
`
`
`
`
`provided on the disk formed conductor 111 and the plate
`
`
`
`
`115, controlled to a designed distribution.
`
`
`
`
`
`
`The antenna 110 is connected to an antenna powersource
`
`
`
`
`
`
`
`
`121 and antenna bias power source 122 as an antenna power
`
`
`
`
`10
`
`
`
`15
`
`
`
`20
`
`25
`
`
`
`30
`
`35
`
`
`
`40
`
`
`
`45
`
`
`
`50
`
`
`
`55
`
`
`
`60
`
`
`
`65
`
`
`
`Ex. 1030, Page 10
`
`Ex. 1030, Page 10
`
`
`
`
`
`US 6,506,686 B2
`
`
`5
`
`
`
`
`
`
`
`
`system 120 through matching circuit-filter systems 122 and
`
`
`
`
`
`
`
`
`
`124,and is also connected to the ground througha filter 125.
`
`
`
`
`
`
`
`
`The antenna power source 121 supplies power at a UHF
`
`
`
`
`
`
`
`
`band frequency in the range from 300 MHz to 1 GHz. By
`
`
`
`
`
`
`
`
`setting diameter of the disk formed conductor 111 to a
`
`
`
`
`
`
`specified characteristic length,
`inherent excitation mode,
`
`
`
`
`
`
`
`such as TMO01 mode, is formed. In the present Embodiment,
`
`
`
`
`
`
`
`frequency of the antenna power source 121 is 450 MHz,and
`the diameter of the disk formed conductor 111 is 330 mm.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Meanwhile, the antenna bias power source 122 controls
`
`
`
`
`
`
`
`
`the reaction on the surface of the plate 115 by applying bias
`
`
`
`
`
`
`
`
`powerat a frequency in the range from several tens of kHz
`
`
`
`
`
`
`
`
`to several tens of MHz to the antenna 110. Particularly in
`
`
`
`
`
`
`
`
`
`case of oxide film etching using CF-series gas, use of high
`
`
`
`
`
`
`
`
`
`
`purity silicon as a material of the plate 115 enables the
`
`
`
`
`
`
`
`reaction of F radical and CFx radical to be controlled, thus
`
`
`
`
`
`
`
`
`radical composition ratio can be adjusted.
`In this
`
`
`
`
`
`
`
`
`Embodiment, antenna bias power source 122 is set at a
`
`
`
`
`
`frequency of 13.56 MHzand a powerof 50 W to 600 W.In
`20
`
`
`
`
`
`
`
`
`
`
`this case, bias voltage Vdc is generated to the plate 115 due
`to self-bias. The Vdc value is about Vdc=-300 V to -50 V
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`(ie. -300 VSVdeS-50 V), although it may vary with
`
`
`
`
`
`
`
`plasma density and pressure. The present Embodiment is
`
`
`
`
`
`
`
`
`characterized in the point that the self-bias applied to the
`
`
`
`
`
`
`plate 115 is controlled independentof the plasma generation,
`
`
`
`
`
`
`
`unlike so-called parallel plate capacitively coupled plasma
`
`
`
`
`
`
`
`
`system. Especially, by setting the bias voltage to a low value
`
`
`
`
`
`
`
`
`of Vdc=-100 V or less (for example -10 V) (ie. -100
`
`
`
`
`
`
`
`
`V=Vdc=-10 V),
`it becomes possible to reduce silicon
`
`
`
`
`
`
`
`consumption,
`resulting in running cost
`reduction, and
`
`
`
`
`
`
`
`becomesalso possible to reduce silicon sputtering, which
`
`
`
`
`
`
`
`results in less etching residue on the sample W.
`
`
`
`
`
`
`
`
`
`
`The distance between the bottom of the plate 115 and the
`
`
`
`
`
`
`
`sample W (hereafter called “gap”) is in the range of 30 to
`
`
`
`
`
`
`
`
`
`150 mm,or desirably 50 to 120 mm. Since the plate 115
`
`
`
`
`
`
`
`
`having wide area is placed opposite to the sample W, it has
`
`
`
`
`
`
`
`
`
`the biggest influence to the process. The major point of the
`
`
`
`
`
`
`present invention is to stabilize surface reaction on the plate
`
`
`
`
`
`
`
`
`115, and to get process characteristics with excellent repeat-
`
`
`
`
`
`
`
`
`
`ability by bias application to the surface of the plate 115 and
`
`
`
`
`
`
`
`
`by temperature control within a specific range. This will be
`described later in details.
`
`
`
`
`
`
`
`
`
`
`Onthe bottom of the processing chamber 100, a bottom
`
`
`
`
`
`
`
`electrode 130 is installed opposite to the antenna 110. To the
`
`
`
`
`
`
`
`
`bottom electrode 130, a bias power source 141 is connected
`
`
`
`
`
`
`
`
`
`through matching circuit filter system 142. The bias power
`
`
`
`
`
`
`
`
`
`
`source 141 supplies bias power in the range from 400 kHz
`
`
`
`
`
`
`
`
`to 13.56 MHz,for example, and controls the bias applied to
`
`
`
`
`
`
`
`
`the sample W. The bottom electrode 130 is connected to the
`
`
`
`
`
`
`
`
`ground through filter 143.
`In the present Embodiment,
`
`
`
`
`
`
`
`
`
`frequency of the bias power source 141 is set to 800 kHz.
`
`
`
`
`
`
`
`
`On the top surface of the bottom electrode 130, namely,
`
`
`
`
`
`
`
`on the sample mounting surface, a sample W such as a wafer
`
`
`
`
`
`
`
`is mounted on an electrostatic chucking unit 131. Electro-
`
`
`
`
`
`
`
`static chucking dielectric layer (hereafter called “electro-
`
`
`
`
`
`
`
`
`
`
`static chucking film”) is formed on the surface of the
`
`
`
`
`
`
`
`electrostatic chucking unit 131. By applying hundreds of
`
`
`
`
`
`
`
`
`
`
`volts to several kilovolts (kV) of DC voltage from an
`
`
`
`
`
`
`
`electrostatic chucking DC power supply 144 throughfilter
`
`
`
`
`
`
`
`145, sample W is chucked and held on the bottom electrode
`
`
`
`
`
`
`130 by electrostatic chucking force. As for the electrostatic
`
`
`
`
`
`
`
`chucking film, dielectric of aluminum oxide or aluminum
`
`
`
`
`
`
`
`
`oxide mixed with titanium oxide is used. Surface tempera-
`
`
`
`
`
`
`
`ture of the electrostatic chucking umit 131 is controlled by
`
`
`
`
`
`
`
`
`temperature control means(notillustrated). Inactive gas, for
`
`
`
`
`
`
`
`
`
`example helium gas,set to a specified flow rate and pressure,
`
`
`
`
`
`
`
`
`is supplied to the surface of the electrostatic chucking unit
`
`10
`
`15
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`
`6
`
`
`
`
`
`
`
`
`
`131, and raise heat conductivity with the sample W. This
`
`
`
`
`
`allows surface temperature of the sample W to be controlled
`
`
`
`
`
`
`
`
`
`
`with high precision in the range from about 100 to 110° C.,
`
`
`
`
`
`
`for example. On the top surface of the electrostatic chucking
`
`
`
`
`
`
`
`
`
`unit 131, a focus ring 132, a ring formed member made of
`
`
`
`
`
`
`
`
`high purity silicon, is installed outside the sample W. The
`
`
`
`
`
`
`
`
`focus ring 132 is isolated from electrostatic chucking unit
`
`
`
`
`
`
`
`131 by an insulator 133. An electrode outer cover 134 is
`
`
`
`
`
`
`
`
`
`settled outside the electrode. Alumina and quartz are suitable
`for the insulator 133 and the electrode outer cover 134. In
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`this Embodiment, alumina is used for the insulator 133 and
`
`
`
`
`
`
`
`
`electrode outer cover 134. This configuration enables bias
`
`
`
`
`
`
`
`powerapplied to the bottom electrode to be applied to the
`
`
`
`
`
`
`
`
`
`focus ring 132 bypartial leakage through the insulator 133.
`
`
`
`
`
`
`
`
`
`
`Intensity of the bias applied to the focus ring 132 can be
`
`
`
`
`
`
`
`adjusted according to dielectric constant and thicknessof the
`
`
`
`
`
`
`
`
`
`insulator 133. The focus ring 132 is thermally isolated from
`
`
`
`
`
`
`
`
`
`the insulator 133, and is not in thermal contact. This enables
`
`
`
`
`
`
`
`highly efficient temperature rise through heating by plasma
`
`
`
`
`
`
`
`and bias. Furthermore, use of silicon as material of the focus
`
`
`
`
`
`
`
`
`
`ring 132 allows scavenging function of the silicon on the
`
`
`
`
`
`
`
`
`surface of focus ring 132 to adjust the reaction of F radical
`
`
`
`
`
`
`
`
`and CFx radical or radical composition. This makes it
`
`
`
`
`
`
`
`possible to adjust etching uniformity, especially on the outer
`
`
`
`periphery of the wafer.
`
`
`
`
`
`
`The plasma etching apparatus according to the present
`
`
`
`
`
`Embodimentis structured as described above. Regarding the
`
`
`
`
`
`
`
`
`temperature control of the side wall
`in the above
`
`
`
`
`
`
`Embodiments, the results disclosed in the Japanese Patent
`
`
`
`
`Application No. 14767/1998 by the applicants of the present
`
`
`
`
`
`
`
`invention can be used. Likewise, regarding the focus ring
`
`
`
`
`
`
`structure, what is disclosed in the Japanese Patent Applica-
`
`
`
`
`
`
`
`
`tion No. 232132/1999 by the applicants of the present
`
`
`
`invention can be employed.
`
`
`
`
`
`
`
`
`the following describes a
`With reference to FIG. 1,
`
`
`
`
`
`
`
`process of etching silicon oxide film as an example, using
`
`
`
`
`this plasma etching apparatus:
`
`
`
`
`
`
`Firstly, the wafer W as an object of processing is loaded
`
`
`
`
`
`
`
`
`into the processing chamber 100 from a sample loading
`
`
`
`
`
`
`
`mechanism (notillustrated) and is mounted on the bottom
`
`
`
`
`
`
`
`
`
`electrode 130 and chucked thereon. The height of the lower
`
`
`
`
`
`
`
`electrode is adjusted, and the gap is set to a predetermined
`
`
`
`
`
`
`
`
`value. Then gases required for sample W etching process,
`
`
`
`
`
`
`
`
`
`for example, C,F,, Ar and O, are supplied into the process-
`
`
`
`
`
`
`
`
`
`
`ing chamber 100 from gas supply means 117 through the
`
`
`
`
`
`
`
`
`plate 115 at a predetermined flow rate and mixing ratio. At
`
`
`
`
`
`
`
`
`
`the same time, the pressure inside the processing chamber
`
`
`
`
`
`100 is adjusted to a predetermined processing pressure by
`
`
`
`
`
`
`
`
`
`the vacuum exhaust system 106 and the pressure control
`
`
`
`
`
`
`
`
`
`
`means 107. Then 450 MHz UHFpoweris supplied from the
`
`
`
`
`
`
`
`antenna power supply 121, and electromagnetic wave is
`
`
`
`
`
`
`
`
`radiated from the antenna 110. Plasma is generated inside
`
`
`
`
`
`
`
`the processing chamber 100 by interaction with approxi-
`
`
`
`
`
`
`
`
`mately horizontal magnetic field of 160 gausses (electron
`
`
`
`
`
`
`
`
`cyclotron resonance magnetic field intensity for 450 MHz)
`
`
`
`
`
`
`
`
`formed inside the processing chamber 100 by the magnetic
`
`
`
`
`
`
`
`
`field forming means 101. Process gas is dissociated to
`
`
`
`
`
`
`
`
`
`generate ion and radical. Composition and energy of ion and
`
`
`
`
`
`
`
`
`radical in plasmaare controlled by antenna bias power from
`
`
`
`
`
`
`
`
`
`
`
`the antenna bias power source 122 and bias power from the
`
`
`
`
`
`
`
`
`
`bias power supply 141 of the bottom electrode, and etching
`
`
`
`
`
`
`
`processis performed to the wafer W. Then, upon completion
`
`
`
`
`
`
`
`
`
`of etching, supply of power, magnetic field and process gas
`
`
`
`
`
`
`are terminated, and etching process is completed.
`
`
`
`
`
`
`The plasma processing apparatus in the present Embodi-
`
`
`
`
`
`
`is structured as described above. The following
`ment
`
`
`
`
`
`
`describes a specific method for controlling the temperature
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Ex. 1030, Page 11
`
`Ex. 1030, Page 11
`
`
`
`
`7
`
`
`
`
`
`
`
`
`
`of the plate 115 by the system in the prese