WO1989003584A1 - Chambre de traitement sous vide a electrodes multiples - Google Patents

Chambre de traitement sous vide a electrodes multiples Download PDF

Info

Publication number
WO1989003584A1
WO1989003584A1 PCT/AU1988/000401 AU8800401W WO8903584A1 WO 1989003584 A1 WO1989003584 A1 WO 1989003584A1 AU 8800401 W AU8800401 W AU 8800401W WO 8903584 A1 WO8903584 A1 WO 8903584A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
etching
electrodes
guard
target
Prior art date
Application number
PCT/AU1988/000401
Other languages
English (en)
Inventor
Christopher Max Horwitz
Stephen Boronkay
Mark Gross
Original Assignee
Unisearch Limited
Labtam Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Unisearch Limited, Labtam Limited filed Critical Unisearch Limited
Publication of WO1989003584A1 publication Critical patent/WO1989003584A1/fr

Links

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
    • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering
    • H01J37/3411—Constructional aspects of the reactor
    • H01J37/3438—Electrodes other than cathode
    • 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
    • H01J37/34—Gas-filled discharge tubes operating with cathodic sputtering

Definitions

  • the present invention relates generally to rf (radio frequency) sputter apparatus for use in integrated circuit manufacture, and substrate machining for computer f brication.
  • rf radio frequency
  • etching and deposition occur at the same time, however, in etching processes the etching rate is greater than the deposition rate, while in deposition processes the deposition rate is greater than the etching rate.
  • the relative etching and deposition rates are determined by the materials, the reactive gasses used, the geometry of the etched surface and discharge parameters.
  • Reactive sputtering is a versatile etch and deposition process that uses chemically reactive components of a low-pressure discharge to obtain well controlled and directional etching, often with high selectivity between materials or well controlled deposition of thin films. It is widely used in the fabrication of microelectronic devices, especially on Si wafers, both in "batch” and “single wafer” configurations. Vacuum sputter processing of integrated circuits does, however, result in some undesirable side-effects, both during controlled etching of the layers to expose underlying materials and during deposition of various thin-film materials. The following description relates to the etching of Si ⁇ 2 layers to Si underlayers in a CF4/H2 gas mixture.
  • United States patent No. 4,584,079 describes two opposing targets powered at radio frequencies which allow the deposition of material from one target to another. Control over deposited film topography is obtained by adjustment of the ratio of rf powers applied to the two targets.
  • United States patent No. 4,362,611 describes a variation upon United States patent No. 4,584,079, employing an electrically floating guard ring placed close to the upper target (material source) electrode. The floating ring is coated with material and requires periodic cleaning.
  • the present invention consists in a dry process etching or deposition chamber comprising: - a vacuum chamber; a pair of radio frequency electrodes, one of which is a target electrode; a first source of radio frequency potential connected between said pair of electrodes; one or more guard electrodes surrounding said target electrode; a second source of electric potential connected to said guard electrode or electrodes; inlet means for introducing a gas into the vacuum chamber, which gas becomes chemically reactive, when ionised by a radio frequency discharge, to perform etching and deposition processes upon target material positioned on said target electrode.
  • the target electrode of the chamber of the present invention comprises a pair of electrodes electrically connected as a hollow cathode and one guard electrode is provided about each of the electrodes of the hollow cathode.
  • Figure 1 schematically illustrates a first embodiment of a sputter etching chamber in accordance with the present invention
  • Figure 2 schematically illustrates a second embodiment of a sputter etching chamber in accordance with the present invention
  • Figure 3 graphically illustrates the effect of target separation on etch rate in hollow cathode chambers according to the present invention.
  • FIG. 4 graphically illustrates the effect of H2 flow on selectivity in chambers of the present invention.
  • Thin-film deposition often incorporates an etch process.
  • eptiaxial silicon films show improved purity and planarity when HC1 is used as an etchant during film growth. Improvements in the density of evaporated films and in the density and planarity of sputtered films are obtained with controlled sputter etching of the growing films.
  • a common example of the latter is the "bias-sputtered quartz" used in integrated circuits as an overcoat or a planarizing interlevel dielectric.
  • etch processes can benefit etch processes.
  • Compounds formed from reactive etch gases can ensure directional etching of highly reactive substrate materials by forming "passivating" layers on the etched sidewalls. These compounds can also greatly enhance etch selectivity by preferentially forming on all materials except for the material to be etched.
  • a high-intensity- discharge is generated at low pressures which permits simultaneous high-rate etching and deposition.
  • Deposited films are subject to a high degree of ion bombardment during growth, and so in some respects are similar to bias-sputtered films.
  • Hollow cathode etching can use the same polymer deposition reactions as in other reactor designs to obtain high etch selectivity between materials.
  • a striking degree of etched angle control in Si and Si ⁇ 2 has been observed in hollow cathode etching; this was initially thought to be caused by polymer deposition processes, but it has now been shown that angle control is caused by metal film deposition, which can be made independent of the polymer film deposition.
  • the multitarget hollow cathode system of the present invention has easily adjusted uniformity and self-cleaning electrodes, making it a useful new tool for high-rate etching and deposition.
  • FIG. 1 there is shown generally at 10 a schematic illustration of a first embodiment of the invention wherein a circular target geometry is used with ring (guard) electrodes 15 surrounding a central main (target) electrode. While many benefits of the invention would be achieved with a single target structure, in the preferred embodiment a hollow cathode geometry is employed with two identical opposing target assemblies 11 and 12 enclosing a high-intensity low-pressure discharge.
  • the two targets 11, 12 form a hollow cathode etch system with the anode 13.
  • the target electrodes 11, 12 and the anode 13 are connected to a radio frequency generator 14.
  • Ring electrodes 15, 16 are provided to act as separate guard electrodes being powered by either a second radio frequency generator 17, or alternatively a DC source 18.
  • the anode 13 is provided with a gas inlet 19 and an outlet 20 for connection to a vacuum pump (not shown). It has been shown that during normal operation of prior art hollow cathode chambers with a CF4/H2 mixture for selective etching of Si ⁇ 2 to a Si substrate, a heavy polymer build-up will result in the areas of the guard surfaces close to the targets. In addition, angle control is not easily performed using prior art metal deposition techniques unless metal is present on one or both of the targets. In embodiments of the present invention, application of either the radio frequency generator 17 or the DC source 18 to the ring electrodes 15, 16 results in very little polymer deposition on the ring electrodes, while providing control of the etched angle which can be varied electrically. If two rf generators 14, 17 are used they should either be synchronised or operate at sufficiently different frequencies (e.g. 11 MHz and 13.5 MHz) so as to minimise interaction between the generators.
  • sufficiently different frequencies e.g. 11 MHz and 13.5 MHz
  • Fig. 2 at 33 Shown generally in Fig. 2 at 33 is a schematic illustration of a second embodiment of a processing chamber according to the invention.
  • the ring electrodes 21, 22 are electrically connected, as are the target electrodes 23, 24, following the schematic of Fig. 1. This embodiment differs from that of Fig. 1 in the mounting method used for the ring electrodes.
  • the ring electrodes 21, 22 are now mounted upon ring electrode supports 25, 26 located around the target electrode supports 30, 31.
  • the chamber 20 is closed by anode 32.
  • the ring electrodes 21, 22 are roughly flush with the target plane and in addition exhibit significant capacitance to both the targets 23, 24 and the anode 32 as represented by C2 and C ⁇ respectively shown in phantom.
  • the ring electrodes 21, 22 develop a rf voltage determined by voltage division in C]_ and C2 in parallel with c ⁇ and C2 if these external capacitors are present.
  • the target electrodes of Fig. 2 are provided with recesses 34, 35 which enable the surface of the substrate 36, 37 to be substantially flush with the outer surface of its respective electrode 30, 31 and the corresponding ring electrode 21, 22.
  • the geometry of this second embodiment has additional advantages to those mentioned in connection with Figure 1. With a CF4/H2 etch gas mixture at 0.5 to 5 Pa pressure. Si central targets surrounded by Al ring ⁇ electrodes and when c ⁇ is replaced by a short circuit, when c ⁇ is large, or when the DC power supply is shorted through the rf power input required for a given etch rate is as high as that achieved in prior art hollow cathode etching chambers.
  • the DC power supply acts only as a source of current (i.e., has internal rectifier components to prevent sinking of ring current through the power supply) it can exhibit a DC power flow only at voltages above the ring bias voltage.
  • rf input powers of as little as one quarter of the typical prior art values are required to obtain a given etch rate. For instance, for a 2 kW rf input power a 10 nm/s Si ⁇ 2 etch rate can be attained with c[ shorted, or with the DC power supply shorted.
  • the required input power falls to roughly 500 W for the same etch rate, for DC power supply current between 380 and about 500 mA at 500 V.
  • DC power supply current between 380 and about 500 mA at 500 V.
  • Uniformity of etching can be adjusted by adjusting the spacing distance between the opposing target assemblies, and by adjusting the (C]_ + ⁇ ' ) / ⁇ ⁇ 2 + c ) capacitance ratio.
  • etching of the ring targets prevents polymer buildup near the central targets, and enables electronic control of the etched angle by varying the amount of metal liberated into the discharge, while also allowing a lower input power density for a given etch rate.
  • the apparatus used here employed 100-mm central target silicon wafers clamped by a 90-mm-i.d., 188-mm-o.d. ring coated with polyimide resin. Ring targets of Al with an outer 160-mm diameter were powered from a dc supply with high output impedance. The outer chamber was 320-mm diameter with variable height.
  • the polyimide-coated wafer ring clamp permitted rear H- gas cooling in addition to being at wafer potential, hence improving etch uniformity at the edge.
  • the "trielectrode" hollow cathode configuration provides a source of metal close to the targets, while permitting etched angle control by adjustment of the metal ring target discharge current. These ring targets also contribute to discharge confinement and hence to discharge power efficiency.
  • the rf generator is shown connected only to the central targets, and only the dc supply to the ring targets, in fact a fraction of the central target rf voltage appears on the ring targets.
  • External capacitors can be connected between the ring targets and the chamber or central electrodes to adjust the value of this ring rf voltage; a high ring voltage results in low input power density for a given etch rate, but also in a high rate of metal supply to the discharge.
  • Etch rates were measured with patterned thermal oxide on silicon; partially etching the oxide for an oxide etch rate, and heavily overetching the oxide for a silicon etch rate. This enable the etch to be started at low selectivities ofA—30:1, and then to be taken to full selectivity before silicon etching commenced, preventing transient starting conditions from generating stable polymer films.
  • capacitors C-, C 2 (Fig. 2) and of the dc power supply impedance are very strong; low impedances can quadruple the power input needed to obtain a given Si0 2 etch rate. Here these impedances are kept relatively high.
  • the target spacings shown in Fig. 12 were obtained by varying the chamber height.
  • FIG. 3 shows that target height variation allows easy optimization of etch uniformity to within + 1% (roughly our measurement error) ' .
  • This uniformity has been obtained at the expense of power input, and of silicon etch uniformity. For instance, in a result not shown in Fig. 3, raising the outer metal targets by an additional 3 mm above the central target area, with the same input power, yields up to double the Si ⁇ 2 etch rate. The etch uniformity then degrades to + 10%,- however.
  • Silicon etch uniformity is affected not only by ion bombardment (the dominant Si ⁇ 2 etch mechanism), but by neutral fluorine concentration and by polymer deposition rate. At low polymer generation rates (i.e., with only CF4 etch gas) the electrode spacing for best silicon etch uniformity simply differs from that for Si ⁇ 2- With H2 added, silicon etch uniformity is controlled by polymer deposition which depends on metal ring target voltage more than on target spacing. The best uniformity is obtained when the metal ring voltage is close'to the central target voltage, and C2 C ⁇ (Fig. 2).
  • FIGs. 3 and 4 show how the selectivities at center and edge of the wafer vary with H2 input.
  • selectivities of 'vl ⁇ (center) and 10 (edge) are obtained, rising to 150-300 (center) and 50 (edge) at the highest H2 concentration shown.
  • the Si ⁇ 2 etch rate remains high at 15 nm/s (0.9 um/min) and uniform to within ⁇ 1% from center to edge.
  • the etched Si ⁇ 2 angle depends on metal ring target etch rates; with 200-mA ring dc power supply current and Al metal electrodes a 75° angle in the wafer center is obtained. Within our SEM measurement error of + 5° this etched angle is maintained on substrates as close as 5 mm to the wafer clamp edge, and is independent of sample orientation. Thus our Al-containing angle control species appear to have adequate range.
  • Chamber cleanliness is another benefit of ring target etching; no polymer formed on the ring targets in any of this work.
  • the polyimide wafer clamp etch rate can be inferred from resist etch rates to be 'V 0.1 of the oxide etch rate in pure CF4, and below our measuring capability with added H2- No polymer forms on this ring.
  • resist etch rates to be 'V 0.1 of the oxide etch rate in pure CF4, and below our measuring capability with added H2- No polymer forms on this ring.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physical Vapour Deposition (AREA)
  • Drying Of Semiconductors (AREA)

Abstract

Une chambre d'attaque et de dépôt électrolytique par voie sèche comprend une électrode anodique (32), au moins une électrode cathodique (23, 24) et une électrode de garde (21, 22) à laquelle on a donné la forme d'une électrode annulaire entourant chaque électrode cathodique. Une source de potentiel H.F (27) est connectée entre l'anode (32) et chaque cathode (23, 24), et une source de courant continu (29) est connectée entre l'anode (32) et chaque électrode de garde (21, 22). En fonctionnement, un substrat (36, 37) à attaquer est placé sur une ou plusieurs des cathodes (23, 24) et les électrodes de garde (21, 22) sont utilisées comme source d'ions métalliques et assurent une régulation améliorée de la gravure.
PCT/AU1988/000401 1987-10-14 1988-10-14 Chambre de traitement sous vide a electrodes multiples WO1989003584A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AU486987 1987-10-14
AUPI4869 1987-10-14

Publications (1)

Publication Number Publication Date
WO1989003584A1 true WO1989003584A1 (fr) 1989-04-20

Family

ID=3695319

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU1988/000401 WO1989003584A1 (fr) 1987-10-14 1988-10-14 Chambre de traitement sous vide a electrodes multiples

Country Status (1)

Country Link
WO (1) WO1989003584A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999039385A1 (fr) * 1998-01-30 1999-08-05 Pacific Solar Pty. Limited Procede de passivation a l'hydrogene et appareil cathodique creux a multiples chambres
JP2006057181A (ja) * 2004-08-20 2006-03-02 Jds Uniphase Corp スパッタ・コーティング用アノード
US7524532B2 (en) * 2002-04-22 2009-04-28 Aixtron Ag Process for depositing thin layers on a substrate in a process chamber of adjustable height
US8500973B2 (en) 2004-08-20 2013-08-06 Jds Uniphase Corporation Anode for sputter coating

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4070264A (en) * 1973-07-12 1978-01-24 International Business Machines Corporation R. F. sputtering method and apparatus
US4376692A (en) * 1979-12-15 1983-03-15 Anelva Corporation Dry etching device comprising a member for bringing a specimen into electrical contact with a grounded electrode
AU2543184A (en) * 1983-03-09 1984-09-20 Unisearch Limited Hollow cathode r.f. sputtering
US4482419A (en) * 1983-02-03 1984-11-13 Anelva Corporation Dry etching apparatus comprising etching chambers of different etching rate distributions
US4521286A (en) * 1983-03-09 1985-06-04 Unisearch Limited Hollow cathode sputter etcher
US4637853A (en) * 1985-07-29 1987-01-20 International Business Machines Corporation Hollow cathode enhanced plasma for high rate reactive ion etching and deposition

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4070264A (en) * 1973-07-12 1978-01-24 International Business Machines Corporation R. F. sputtering method and apparatus
US4376692A (en) * 1979-12-15 1983-03-15 Anelva Corporation Dry etching device comprising a member for bringing a specimen into electrical contact with a grounded electrode
US4482419A (en) * 1983-02-03 1984-11-13 Anelva Corporation Dry etching apparatus comprising etching chambers of different etching rate distributions
AU2543184A (en) * 1983-03-09 1984-09-20 Unisearch Limited Hollow cathode r.f. sputtering
US4521286A (en) * 1983-03-09 1985-06-04 Unisearch Limited Hollow cathode sputter etcher
US4637853A (en) * 1985-07-29 1987-01-20 International Business Machines Corporation Hollow cathode enhanced plasma for high rate reactive ion etching and deposition

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999039385A1 (fr) * 1998-01-30 1999-08-05 Pacific Solar Pty. Limited Procede de passivation a l'hydrogene et appareil cathodique creux a multiples chambres
US7524532B2 (en) * 2002-04-22 2009-04-28 Aixtron Ag Process for depositing thin layers on a substrate in a process chamber of adjustable height
JP2006057181A (ja) * 2004-08-20 2006-03-02 Jds Uniphase Corp スパッタ・コーティング用アノード
EP1628323A3 (fr) * 2004-08-20 2009-04-22 JDS Uniphase Corporation Anode de revêtement par pulvérisation
US7879209B2 (en) 2004-08-20 2011-02-01 Jds Uniphase Corporation Cathode for sputter coating
US8500973B2 (en) 2004-08-20 2013-08-06 Jds Uniphase Corporation Anode for sputter coating

Similar Documents

Publication Publication Date Title
US4681653A (en) Planarized dielectric deposited using plasma enhanced chemical vapor deposition
JP5502756B2 (ja) べベル端部エッチングを行うプラズマエッチング処理チャンバ、及び、そのエッチング方法
US8500953B2 (en) Edge ring assembly with dielectric spacer ring
EP1161309B1 (fr) Procede de traitement repetitif par faisceau d'ions au moyen d'un faisceau d'ions au carbone
EP0049272B1 (fr) Fabrication de dispositifs microminiatureses par gravure au plasma du silicium avec des composes gazeux qui contiennent du fluor
US4599135A (en) Thin film deposition
EP1090407B1 (fr) Electrode d'enceinte de traitement de semi-conducteur
EP0702391B1 (fr) Procédé de gravure et réacteur à plasma pour la mise en oeuvre dudit procédé
US4496448A (en) Method for fabricating devices with DC bias-controlled reactive ion etching
JP2603217B2 (ja) 表面処理方法及び表面処理装置
JPH05308062A (ja) ドライエッチング方法
EP0184220B1 (fr) Appareil et procédé pour effectuer une gravure sèche
KR20050016080A (ko) 탄소-도우핑된 저유전체들의 선택적 식각
KR20040007210A (ko) 중풀루오르화탄소 에칭 가스를 이용한 전자기 강화플라즈마 에칭 방법
US11784042B2 (en) Carbon hard masks for patterning applications and methods related thereto
JP2004111779A (ja) 有機系絶縁膜のエッチング方法及び半導体装置の製造方法
WO2002050885A1 (fr) Procede de gravage pour film isolant
US6815369B2 (en) Method for monitoring deposition reaction during processing the surface of a semiconductor substrate
WO1989003584A1 (fr) Chambre de traitement sous vide a electrodes multiples
JPH11186229A (ja) ドライエッチング方法及び半導体装置の製造方法
US5110410A (en) Zinc sulfide planarization
JPH0429221B2 (fr)
JP3779277B2 (ja) 半導体装置の製造方法
JPH0121230B2 (fr)
JPS59124135A (ja) 反応性イオンエツチング方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AU JP US