Samsung Electronics Co., Ltd. v. Demaray LLC
`Samsung Electronic's Exhibit 1020
`Exhibit 1020, Page 1
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`

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`U.S. Patent
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`Nov.28, 2000
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`Ex. 1020, Page 2
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`U.S. Patent
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`Nov.28, 2000
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`U.S. Patent
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`6,153,068
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`Ex. 1020, Page 4
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`Ex. 1020, Page 4
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`U.S. Patent
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`Nov.28, 2000
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`U.S. Patent
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`Nov.28, 2000
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`Ex. 1020, Page 6
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`Ex. 1020, Page 6
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`U.S. Patent
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`Nov.28, 2000
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`U.S. Patent
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`6,153,068
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`1
`PARALLEL PLATE SPUTTERING DEVICE
`WITH RF POWERED AUXILIARY
`ELECTRODES AND APPLIED EXTERNAL
`MAGNETIC FIELD
`
`BACKGROUNDOF THE INVENTION AND
`DESCRIPTION OF RELATED ART
`
`1. Technical Field
`
`The present invention relates to a sputtering device, and
`in particular to a sputtering device provided with a meansfor
`introducing magnetic field which is horizontal to a target
`surface to be processed by sputtering, so as to enable to
`perform uniform sputtering all over the surface of the target.
`2. Background Art
`Recently, as chip sizes of DRAM, MPUetc. become
`larger, silicon substrates used as their base bodies tend to
`have larger diameters. For the case that a thin film is to be
`formed on a larger-diameter base body by sputtering, it is
`desired to develop a sputtering device which can use a target
`having a larger diameter corresponding to a size of a base
`body, and can form a homogeneous deposit film having
`uniform film thickness on the base body.
`Asa conventional sputtering device, is mentioned an RF
`sputtering device FIG. 6) which hasparallel plate electrodes
`andsputters a target while applying RFbiasto the target, or
`a magnetron sputtering device (FIG. 7) which has such
`structure that magneticfield is generated from a back surface
`of a target, and which applies RF bias to the target while
`applying that magnetic field, so as to generate higher-density
`plasma on the surface of the target.
`FIG. 9 showsa result of investigating sputtering capacity
`of the above-described RF sputtering device and magnetron
`sputtering device. Namely, after application of radio fre-
`quency power (13.56 MHz) to an Al target (150 mm@) for
`100 hours, scraped amounts of the target were investigated
`at 8 points on a surface of the target at intervals of 20 mm
`in the diametral direction to obtain the result. From this
`result,
`it
`is seen that a magnetron sputtering device has
`higher sputtering capacity than a RF sputtering device. As
`shown in FIG. 8, however,
`in the magnetron sputtering
`device, directions of the magnetic field generated on the
`target surface are not uniform,and accordingly,on the target
`surface, strong plasma is generated only in a limited space
`enclosed by magnetic flux.
`One method of avoiding this problem that is knownin the
`art utilizes a yoke structure design rotating a magnet mecha-
`nism on a back surface of a target, and the like. However,in
`the case that yoke structure design is employed,it leads to
`complication of the hardware, and in the case that
`the
`magnet mechanism is rotated, plasmais rotated and accord-
`ingly film substance grown on a substrate becomes weak in
`stress resistance. In addition, deposit film with uniform
`quality can not necessarily be obtained on a base body.
`OBJECT AND SUMMARY OF THE INVENTION
`
`An object of the present invention is to provide [provided]
`a sputtering device which provides a [can make] plasma
`with a uniform density [uniform for a target] and deposits a
`film with a [can form deposit film having] uniform film
`quality on a base body.
`The present invention provides a sputtering device pro-
`vided with two electrodes I and II of parallel plate type
`within a vessel
`inside which pressure can be reduced,
`wherein: a target to be sputtered is placed on said electrode
`I, and a base body on which a film is to be deposited is
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`placed onsaid electrodeII, with the target and the base body
`being opposed to each other; a process gasis introduced into
`said vessel from a gas supply system; radio frequency power
`is applied to said target throughat least said electrode I so
`as to excite plasma between the electrode I and the electrode
`II; characterized in that: outside said vessel, is provided a
`meansfor introducing magnetic field horizontalat least to a
`surface to be sputtered of said target.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a schematic sectional view showing an embodi-
`ment of the sputtering device according to the present
`invention;
`FIG. 2 is a schematic plan view showinga case that a pair
`of permanent magnets are used as a means for introducing
`magnetic field shown in FIG. 1;
`FIG. 3 is a schematic plan view showing a case that a
`dipole ring magnets (DRM) is used as the means for
`introducing magnetic field shown in FIG. 1;
`FIG. 4 is a graph showing a result of investigation of
`scraped amounts of the target in the sputtering device of the
`present invention;
`FIG. 5 is a graph showing specific resistance of the
`deposit film;
`FIG. 6 is a schematic sectional view showing an example
`of the conventional RF sputtering device;
`FIG. 7 is a schematic sectional view showing an example
`of the conventional magnetron sputtering device;
`FIG. 8 is a schematic sectional view showing a state of
`magnetic field generation in the magnetron sputtering device
`of FIG. 7; and
`FIG. 9 is a graph showing a result of investigation of
`scraped amounts of the target in the conventional sputtering
`device.
`(Symbols)
`100 vessel, 101 meansfor introducing magnetic field, 102
`electrode I,
`103 target, 104 auxiliary electrode A, 105 base body,
`106 electrode II, 107 auxiliary electrode B,
`108-110 band eliminators (B-E.), 111 and 112 low-pass
`filters,
`113-115 AC powersupplies, 116-118 matching circuits,
`119 and 120 DC power supply, 121 gas supply system,
`122 turbo-molecular pump, 123 dry pump, and 124
`exhaust system,
`200 vessel, 230a, 2305 permanent magnets, 300 vessel,
`303 target, 330 permanent magnet, 601 sputtering chamber,
`602 anode, 603 target, 604 shutter, 605 shield, 606 gas
`supply port, 607 exhaust port, 608 matching circuit, 609 RF
`power supply, 610 matching box, 703 target, 704 erosion
`position, 705 shield, 706 magnet, 707 magnet support, 708
`power supply line, 709 cooling water inlet, 710 cooling
`water exit, 711 insulating material, 803 target, 806 magnet,
`807 magnet support, 812 leakage flux
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT OF THE
`INVENTION
`(Best Mode for Carrying Out the Invention)
`FIG. 1 is a schematic sectional view showing an example
`of the sputtering device according to the present invention.
`In FIG. 1, reference numeral 100 refers to a vessel, inside
`which pressure can be reduced, 101 to a meansfor intro-
`ducing magnetic field, 102 to an electrode I, 103 to a target,
`104 to an auxiliary electrode A, 105 to a base body, 106 to
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`Ex. 1020, Page 11
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`Ex. 1020, Page 11
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`6,153,068
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`an electrode I, 107 to an auxiliary electrode B, 108-110 to
`band eliminators (B.E.), 111 and 112 to low-passfilters,
`113-115 to AC power supplies, 116-118 to matching
`circuits, 119 and 120 to DC power supply, 121 to a gas
`supply system, 122 to a turbo-molecular pump, 123 to a dry
`pump, and 124 to an exhaust system.
`In FIG. 1, the vessel 100 can be reduced in pressure to
`such a level that plasma process can be carried out in its
`inside. To that end, the gas supply system 121 introduces gas
`into the vessel 100 for plasma excitation, and the exhaust
`system 124 can reduce the pressure inside the vessel.
`As wall surface material of the vessel 100, Al alloy or the
`like may be used. Preferably, however, nitrided material (for
`example, AIN) may be used,taking it into consideration that
`water content released from the chamber wall surface etc.
`deteriorates adherence between material to be formed with
`
`film and the base body to be processed, and that other
`material than the target base body to be processed is sput-
`tered. This is not limited to the chamber wall surface, and,
`as the electrodes and other materials within the chamber,
`materials which do not release water content and have
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`rial employed in the conventional technique as a means for
`introducing magneticfield.
`The base body 105 is a substrate for receiving particles
`etc. sputtered from the target 103 and for depositing a film
`on it. As the base body 105, for example, Si substrate, SiC
`substrate, glass substrate, or the like may be used, although
`it is not limited to these.
`The electrode II 106 has a function of holding the base
`body 105, and is connected with the AC power supply 114
`through the matching circuit 117 as well as connected with
`the DC powersupply 120 through the low-passfilter (LPF)
`112. Thisis to give self-bias to the base body 105. In the case
`that the base body 105 is conductive and the material to be
`formed asthe film on the base body 105 is also conductive,
`only the DC power supply 120 maysuffice. In the case that
`either of them is insulating material, the DC power supply
`120 is not necessary and it is suffice that only the AC power
`supply 114 is connected.
`The auxiliary electrode B 107 is located in the area
`outside the outer peripheral end of the base body 105, and
`in the position spaced from the base body 105 and the
`electrode II 106. Further, the auxiliary electrode B 107 is
`connected with the AC power supply 115 through the
`matchingcircuit 118 to apply radio frequency power. Thisis
`provided for relaxing bias of the plasma due to application
`of the magnetic field.
`The band eliminators (B.E.) 108-110 are band-rejection
`filters, and suitably set in such a manner that only radio
`frequency power having desirable frequenciesare applied to
`the respective electrodes connected, so that the applied radio
`frequencies are not affect one another.
`Embodiments
`In the following, the sputtering device according to the
`present
`invention will be described referring to the
`drawings, although the present invention is not limited to
`these embodiments.
`(Embodiment 1)
`In this embodiment, the sputtering device shown in FIG.
`1 was used with various means for introducing magnetic
`field 101 to investigate sputtering capacities. Sputtering
`capacity was evaluated by scraped amounts of an Al target
`(150 mm) at eight points on the surface of the target at
`intervals of 20 mm in the diametral direction, after applying
`radio frequency power (13.56 MHz) for 100 hours.
`As the meansfor introducing magnetic field 101, a case
`of magnetic arrangement shown in FIG. 2 and a case of
`magnetic arrangement shownin FIG. 3 were investigated. In
`the magnetic arrangement of FIG. 2, a pair of permanent
`magnets 230a, 2305 are positioned in parallel so that the
`vessel 200 of the sputtering device is located between them.
`In the magnetic arrangement of FIG. 3, a plurality of
`permanent magnets 330 are positioned so as to surround the
`vessel 300 of the sputtering device, which is a case using
`“so-called” dipole ring magnets (DRM). In FIG. 3, direction
`of arrow sign depicted in each permanent magnet shows
`direction of magnetization.
`In the present embodiment, however, the auxiliary elec-
`trodes A 104 and B 107 shownin FIG. 1 werenotinstalled.
`FIG. 4 is a graph showing scraped amounts ofthetarget.
`As a comparison example, a result for conventional mag-
`netron sputtering device shown in FIG. 6 is shown in FIG.
`4.
`
`Following facts have been found from FIG. 4.
`(1) By introducing the horizontal magnetic field on the
`surface of the target, the scraped amounts become more
`uniform than the conventional technique.
`(2) The arrangement of magnets of FIG. 3 is further more
`uniform in the scraped amounts than the arrangement of
`magnets of FIG. 2.
`
`Ex. 1020, Page 12
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`higher plasma resistance should be used as far as possible.
`Candidates of conductive material are glassy carbon, SiC,
`etc. and candidates of insulating material are AIN, SiN, etc.
`Selection of material is decided taking into consideration
`thermal conductivity, ratio of electric field strength on a
`surface, and the like.
`The meansfor introducing magnetic field 101 is installed
`outside the vessel 100, can be moved in upward and down-
`ward directions and in rotational direction, and produces
`uniform magnetic field on the target 103 by introducing
`magnetic field horizontal to a surface to be sputtered of the
`target 103.
`The electrode I 102 has a function of holding the target
`103, while it
`is an electrode for exciting plasma. This
`electrode I 102 is electrically connected with the AC power
`supply 113 through the matching circuit 116, and with the
`DC powersupply through the low-pass filter (LPF). This is
`provided for controlling energy of ions radiated onto the
`target 103. When the target is not conductive material, this
`energy is controlled by varying frequency and powerof the
`radio frequency power supply.
`The target 103 is a parent material to form a deposit film
`on a base body 105 placed in an opposite position. As the
`target 103, semiconductor material such as Si, metal mate-
`rial such as W, Ta, and insulating material such as SiO, can
`be used preferably, for example. Further, the material used
`as the target 103 is not limited to one to be directly formed
`as a film. Material which is different in chemical composi-
`tion or which is to constitute a part of composition of the :
`material of the aimed film may be used andreacted with gas
`existing within the plasma, so at to form the desired deposit
`film. By carrying out such a method of forming deposit film,
`Le., a reactive sputtering method,it is possible, for example,
`to form SiN film by using Si as the target 103 and N,as the
`gas for producing plasma.
`The auxiliary electrode A 104 is provided in the area
`outside the outer peripheral end of the target, and is con-
`tacted with the electrode I 102. The connection between the
`electrode I 102 and the auxiliary electrode A 104 may be of
`an electrical conductive state, or, alternatively, may be
`connected through a condenserto have electrical capacity. In
`particular, in the latter case, the auxiliary electrode A 104is
`not easily sputtered. The auxiliary electrode A 104 has an
`effect of enlarging generation space for the plasma excited
`on the target 103 toward the inside of the surface, and is
`greatly different in function from a yoke of magnetic mate-
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`Embodiment 2)
`In the present embodiment, as the means for introducing
`magnetic field 101 in the sputtering device shownin FIG. 1,
`the magnet arrangement shownin FIG. 3 wasused,and film
`qualities of deposit films were investigated for a case that the
`auxiliary electrodes A 104 and B 107 werenotinstalled and
`for a case that the auxiliary electrodes A 104 and B 107 were
`installed.
`When the auxiliary electrode B 107 was installed, fre-
`quency dependency was investigated with respect to radio
`frequencyapplied to the auxiliary electrode B 107 from the
`ACpowersupply 115. As the frequency, four kinds, 30 kHz,
`13.56 MHz, 40 MHz, and 100 MHz,wereused.
`As the base body 105, a plurality of single crystal Si
`wafers (33 mmd) were placed onthe electrode II 106. Asthe
`target 103, N-type Si (P-doped) was sputtered using Ar gas
`so as to deposit Si film on the base body 105. As the film
`quality of the deposit film, specific resistance was evaluated.
`FIG. 5 is a graph showing results of measurements of
`specific resistancestogether. In FIG. 5, the symbol © shows
`the result in the case that the auxiliary electrode A 104 and
`the auxiliary electrode B 107 were not installed, the symbol
`A shows the result in the case that radio frequency of 40
`MHz wasapplied to the auxiliary electrode B 107, and the
`symbol A showsthe result in the case that radio frequency
`of 100 MHz wasapplied to the auxiliary electrode B 107.
`Values of specific resistance shown in the ordinate axis of
`FIG. 5 are expressed being standardized by a value of
`specific resistance measured for a base body No. 1.
`From FIG. 5, following facts have been found.
`(1) In comparison with the case that the auxiliary electrodes
`A 104 and B 107 were not installed (shown by symbols
`©), dispersion of the specific resistances was smaller in
`the cases that the auxiliary electrodes A 104 and B 107
`were installed (shown by symbols A and A).
`(2) The dispersion of the specific resistances was further
`smaller in the case that the frequency fc applied to the
`auxiliary electrode B 107 wassufficiently large relative to
`the frequency f (13.56 MHz)applied to the target through
`the electrode I 102 (namely, the case of fe=40 MHz had
`smaller dispersion of the specific resistances than the case
`of fc=100 MHz).
`(3) The dispersion of the specific resistances was not
`improved whenthe frequency fc applied to the auxiliary
`electrode B 107 is smaller (380 kHz) than or equal (13.56
`MHz) to the frequency f (13.56 MHz) appliedto the target
`103 through the electrode I 102, and the results were
`similar to the case that the auxiliary electrodes A 104 and
`B 107 were notinstalled (shown by symbols ©).
`(4) In particular, in the case that the frequency fe (13.56
`MHz) appliedto the target 103 through the electrode I 102
`was equal to the frequency fc (13.56 MHz)appliedto the
`auxiliary electrode B 107, plasma interfered and electric
`discharge became unstable.
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`Thus, it is considered that the frequency fc of the radio
`frequency power applied to the auxiliary electrode B is
`larger than the frequency f of the radio frequency power
`applied to the above-described target through the above-
`described electrodeI, film quality of the deposit film can be
`made uniform.
`Effects of the Invention
`
`As described above, according to the present invention,
`by introducing magneticfield horizontal to a target’s surface
`to be sputtered, there is obtained the sputtering device in
`which scraped amounts of the target are uniform.
`Further, film quality of the deposit film can be uniformed,
`by providing the auxiliary electrode A in contact with the
`electrode I and in the area outside the outer peripheral end
`of the target, and by providing the auxiliary electrode B in
`the area outside the outer peripheral end of the base body
`and in a location spaced from the base body and the
`above-described electrode II. In that case, it is more pref-
`erable if the frequency fe of the radio frequency power
`applied to the auxiliary electrode B is larger than the
`frequency f of the radio frequency power applied to the
`above-described target through the above-described elec-
`trode I.
`Whatis claimedis:
`1. Asputtering device provided with two electrodes I and
`II of parallel plate type within a vessel inside which pressure
`can be reduced, wherein:
`
`a target to be sputtered is placed on saidelectrode I, and
`a base body on whicha film is to be deposited is placed
`on said electrode II, with the target and the base body
`being opposed to each other;
`a process gas is introduced into said vessel from a gas
`supply system;
`a meansfor generating a magnetic field with a particular
`magnetic field oriented horizontal to a sputterable sur-
`face of the target;
`a radio frequency poweris applied to said target through
`at least said electrode I so as to excite plasma between
`the electrode I and the electrodeII;
`an auxiliary electrode B is supplied; and
`a frequency fe of a radio frequency poweris applied to
`said auxiliary electrode B, said frequency being higher
`than a frequencyf of the radio frequency powerapplied
`to said target through said electrode I.
`2. The sputtering device according to claim 1, wherein:
`said auxiliary electrode B to which said radio frequency
`poweris applied is provided in an area outside an outer
`peripheral end of said base body and in a position
`spaced from said base body andsaid electrode II.
`*
`*
`*
`*
`*
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`Ex. 1020, Page 13
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`Ex. 1020, Page 13
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