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
  • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
  • C23C14/0021—Reactive sputtering or evaporation
  • C23C14/0036—Reactive sputtering
  • C23C14/0063—Reactive sputtering characterised by means for introducing or removing gases
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
  • H01J2237/02—Details
  • H01J2237/022—Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube

Definitions

• the present invention relates to an apparatus for manufacturing a metal thin film on a wafer for use in processing of semiconductor devices and more particularly to an apparatus for thin film metallization in semiconductor device manufacture comprising an improved means for injection of a gas into the interior of a vacuum chamber.
• the process of depositing a metal film is a very important process which connects various components and devices.
• Aluminum, tungsten and copper, etc. are metals which are typically used as wiring material. Since there is difficulty in the etching process when using copper and a separate process (for example, etch-back and sputter) is required in the case of the chemical deposition of tungsten, a process for depositing aluminum is widely applied.
• any improvement in the process of depositing a thin metal film is increasingly important to the process of manufacturing semiconductor devices.
• AISi is formed by a diffusion reaction of the two materials in a contact interface between the two materials during thermal treatment for deposition of a multi-layer metal thin film and due to an additional process for obtaining a high deposition rate, a spark is induced by contact of the two materials so that a leak or short circuit occurs during usage of manufactured device, e.g. a memory chip.
• the solid solubility of Si in an aluminum target is made to be in a saturated condition by increasing the silicon content in the aluminum target.
• Precipitation of Si occurs at the grain boundary of the aluminum thin film, and if the precipitation is substantive, then the sectional area of the connection line of aluminum decreases so that electron movement and stress concentration occur making the prevention of a spark difficult. Therefore, adequate temperature control based upon the addition of Si and a uniform distribution of Si precipitation are required. Therefore, to solve the above problem, a process is disclosed for depositing TiN,
• Fig 1 is a schematic drawing of a prior art apparatus for practicing a reactive sputtering method for forming thin film
• a heater block 12 having a heater 12a for heating a wafer 200, a sputtering source 13 installed above the heater block 12, a vacuum pump 16 for forming a vacuum in the vacuum chamber 11 and a target 14 composed of a particular material (for example, Ti) to be deposited are operatively positioned in the vacuum chamber as illustrated
• Gas supply pipes 15, 15' for injecting argon and nitrogen gases, and the like, respectively, are positioned at the side or bottom of the vacuum chamber 11
• the apparatus of the present invention solves the above described problems.
• the invention relates to an apparatus for manufacturing thin film on a wafer having a top and a bottom and comprises a vacuum chamber with a heater block positioned in the vacuum chamber for heating the wafer.
• a sputtering source having a first end and a second end with the second end positioned proximate the heater block is used.
• a clamp holds the bottom of the wafer against the heater block while a first gas supply directly provides a first gas along the second end of the sputtering source, and a second gas supply directly provides a second gas to the top of the wafer.
• This gas supply configuration ensures a separate and direct supply of the proper gas to a specific site within the vacuum chamber, rather than to a general or remote site as in prior art chambers.
• the inventive apparatus comprises a vacuum chamber, a heater block positioned inside the vacuum chamber, a sputtering source positioned above the heater block, an elevator means, which is for the most part, positioned below the vacuum chamber for elevating the heater block, a clamp for clamping a wafer positioned on the top of the heater block upon elevating the heater block by the elevator means, a gas supply means comprising a first gas supply positioned along the outer circumferential surface of the sputtering source for supplying a first gas, and a second gas supply positioned at the top of the clamp for supplying a second gas to the wafer from the top of the clamp at a constant angle, and a vacuum pumping means installed below the heater block for removing the different gases at the time of initial pump down of the vacuum chamber and during the process.
• Fig. 1 is a sectional view schematically showing a prior art apparatus for manufacturing thin film of a semiconductor
• Fig. 2 is a sectional view showing the apparatus for manufacturing thin film of a semiconductor according to the present invention
• Fig. 3 A is a perspective view of a second gas supply shown in Fig. 2;
• Fig. 3B is a detailed planar view of the second gas supply
• Fig. 4 is a perspective view of a first gas supply shown in Fig. 2;
• Fig. 5 is a side view of an elevator means of the apparatus for manufacturing thin film of a semiconductor according to the present invention.
• Fig. 6 is a side view of the apparatus for manufacturing thin film of a semiconductor shown in Fig. 2; and Fig. 7 is an enlarged view of the second gas supply shown in Fig. 3.
• Fig. 1 relates to the prior art and is discussed above.
• the apparatus for manufacturing thin film of a semiconductor device deposits a film on the top of a wafer 200.
• the apparatus of the present invention comprises frame 21 which supports vacuum chamber 22.
• Heater block 23 is operatively positioned inside vacuum chamber 22 with sputtering source 24 positioned above heater block 23.
• Target 24a is positioned below sputtering source 24, i.e. between sputtering source 24 and heater block 23.
• the bottom of heater block 23 includes heating means 23a, which is well known in the art, for heating wafer 200 when placed on top of heater block 23.
• Elevator means 30 elevates heater block 23 in order that wafer to be heat treated is contacted by the heater block and is positioned below the heater block and extending into vacuum chamber 22 as illustrated at Fig. 2.
• Clamp 26 is positioned in vacuum chamber 22 below target 24a and above heater block 23. In operation, clamp 26 engages or clamps wafer 200 disposed on the top of heater block 23 when the heater block is elevated by elevator means 30.
• Gas supply means 40 supplies gas to specific sites in the interior of vacuum chamber 22, comprising a first gas supply 41 and a second gas supply 45. Gas supply means 40 separately supplies at least two kinds of gas to the interior of the vacuum chamber.
• First gas supply 41 directly supplies a first gas along the outer circumferential surface 40a of sputtering source 24 and second gas supply 45 directly supply a second gas to the wafer.
• Vacuum means 1 10 (Fig. 6) forms and maintains the interior of the vacuum chamber at a high degree of vacuum.
• First gas supply 41 is proximately disposed about the outer circumferential surface 40a of sputtering source 24 supplying a first gas, e.g. argon gas or the like, proximate to the sputtering source 24 as shown in Fig. 4.
• First gas supply 41 includes cylindrical shield 41a having a first end 43a and a second end 43b which surrounds and is spaced apart 41c from the outer circumferential surface of sputtering source 24.
• the first end 43 a of cylindrical shield 41 is sealed to prevent gas communication therethrough and the second end 43b, i.e.
• First gas supply 41 includes a first gas supply pipe 41b, preferably fabricated of electrolytically polished stainless steel, for conveying a first gas, e.g. argon gas, or the like, to opening 44, which is formed between the inner circumferential surface of shield 41a which is spaced apart from the outer circumferential surface of sputtering source 24.
• a first gas e.g. argon gas, or the like
• cylindrical shield 41a further includes lip 41aa which radially extends from the second end of cylindrical shield 41a at an acute angle relative to this cylindrical shield in order to prevent undesired arc discharge.
• the interior sectional area of first gas supply pipe 41b is smaller relative to the spaced apart cross-sectional area 41c of the gas discharge part between sputtering source 24 and shield 41a. The purpose of this configuration is to promote uniform pressure about opening 44.
• a first end 43 a of cylindrical shield 41a is closed to prevent gas communication therethrough and a second end 43b is spaced apart a predetermined distance from the outer circumferential surface 40a of sputtering source 24 in order to permit the first gas to flow therefrom, i.e. proximate the outer circumferential surface of sputtering source 24, as discussed above.
• the second end 43b of cylindrical shield 41a is spaced apart a predetermined distance from the outer circumferential surface 40a of sputtering source 24 and is closed except for a plurality of openings (not shown) formed therein to permit gases communication therethrough.
• clamp 26 defines an open-ended cylinder or a ring with an opening 26a formed therein, i.e. resembling a donut shape, including a top 27a and a bottom 27b.
• the interior space or opening 26a of the clamp being similar to the inner opening of said donut, exposes wafer 200 under the operation of clamp 26 as seen in Fig.
• Clamp 26 includes an inner circumferential flange 26b, preferably with an inclined edge 26c most preferably terminating in a notch 28 for receiving the peripheral edge of wafer 200, as shown at Fig. 3B.
• the degree of incline on circumferential flange 26b is, preferably, about 15 to 45 degrees.
• FIGs. 3 A and 3B also illustrate second gas supply 45 positioned on top 27a of clamp 26 for supplying the second gas, e.g. nitrogen gas, to wafer 200 surface during treatment of the wafer at a constant angle (as shown by edge 26c)) which promotes even distribution of the nitrogen gas over the wafer surface.
• the first and second gas supplies 41, 45 separately supply two pure gases or a mixture of gases to two specific sites within the vacuum chamber, and a vacuum means (see Fig. 6) maintains the inside of the vacuum chamber 22 at a high vacuum state.
• a reaction gas supply conduit 45a conveys the second gas via gas supply opening 45e to the inner circumferential flange 26b of clamp 26, preferably having an inclined edge 26c, where the second gas flows along the inclined edge 26c of the clamp toward the top of wafer 200 as shown in Fig.
• the second gas supply 45 comprises a conduit 45a for conveying the second gas.
• the conduit 45a includes a top 47, a bottom 47a and an inner 47b and an outer 47c circumferential edge with at least one gas supply opening 45e formed in the inner circumferential edge for supplying the second gas to the top of the wafer.
• the inner circumferential opening 45e defines a plurality of gas supply holes 45ee, e.g. approximately 12, spaced a predetermined distance apart.
• the reaction gas is supplied uniformly through each of the plurality of gas supply holes 45ee to the top of the wafer.
• the mounting of the reaction gas supply conduit 45a to clamp 26 may be achieved by placing reaction gas supply conduit 45a on the top of clamp 26.
• the conduit 45a may be sealed to the clamp 26, but this is not necessary.
• the mere placing of the conduit 45a on the clamp 26 promotes uniform pressure about the wafer since most of the gas flows out the supply opening 45e or plurality of openings 45ee and only a small amount escapes between the common joint 46b formed when the conduit is operatively positioned on the clamp, i.e. between the top of the clamp 27a and the outer circumferential edge 47c of the conduit 45a. This small portion of gas also assists in promoting uniform pressure about the wafer.
• a flexible tube 45d conveys the second gas to the conduit 45a from an external supply of the second gas.
• vacuum chamber 22 encloses heater block 23 and sputtering source 24 positioned above heater block 23.
• Elevator means 30 is positioned below vacuum chamber 22 and opening 22b formed in vacuum chamber 22 enables entry and withdrawal of a manipulator 70 for supplying a wafer to and removing a wafer from the top of heater block 23.
• the elevator means 30 is secured to frame 21 and moves heater block 23 relative to clamp 26 positioned within vacuum chamber 22.
• Elevator means 30 comprises, as shown in Fig. 5, a first elevator member 32 connected through a plurality of rods 31 to the bottom of heater block 23, a bellows member 33 with both ends secured to the edge of opening 22a formed at the edge of first elevator member 32 and at the bottom of vacuum chamber 22.
• a second elevator member 35 is connected through a plurality of rods to first elevator member 32 and placed vertically below first elevator member 32.
• a guide member 36 which is slidingly installed at the edge of second elevator member 35 having both ends fixed to frame 21.
• a driving means 37 operatively positioned on the frame 21, elevates second elevator member 35.
• driving means 37 includes a ball nut member 37a secured to second elevator member 35, a ball screw 37b screwed to ball nut member 37a and rotatably installed vertically to frame 21, a worm wheel 37c installed below ball screw 37b, and a worm 37f installed on a driving shaft connected to a rotational shaft of motor 37d being secured to frame 21 and meshed to worm wheel 37c.
• a sensor 80 such as photosensor or limit switch, controls the elevation position of heater block 23 by controlling motor 37d being selectively operated according to the elevation of the second elevator member 35.
• Vacuum means 110 maintains the interior of vacuum chamber 22 at the appropriate degree of vacuum in order to carry out processing and to prevent any unnecessary flow of gas on the wafer by positioning the inlet port formed in the vacuum chamber at a lower portion of the vacuum chamber, being connected to the molecular pump 112 or a low temperature pump by way of pumping port 111. That is, the inlet port of the high vacuum pump (molecular pump or low temperature pump) is positioned at a place in the vacuum chamber which is lower than the position of the wafer when placed on the heater block for treatment, as shown in Fig. 6. Collimator 90 selectively deposits atoms discharged from the sputtering source onto the top of the wafer and is positioned between the sputtering source and the wafer as illustrated at Fig. 6.
• motor 37d of driving means 37 of elevator means 30 is operated to rotate worm 37f installed on drive shaft 37e.
• Ball screw 37b is then rotated by worm wheel 37c being meshed with the worm 37f, while ball nut member 37a is engaged with ball screw 37b so that second elevator member 35 is elevated. Therefore, as first elevator member 32 which is connected to the second elevator member 35, is elevated, heater block 23 is also elevated moving the top of the heater block to engage and contact the bottom of wafer 200 which is finally supported by the heater block. By this operation wafer 200 is operatively placed on top of heater block 23 for treatment.
• a first gas typically being argon gas for the generation of plasma as well as preventing the discharge of an arc between the sputtering source and the shield with a second gas typically being the reaction gas, e.g. nitrogen gas.
• a second gas typically being the reaction gas, e.g. nitrogen gas.
• plasma is generated by applying a voltage to the sputtering source.
• Argon gas is supplied at a predetermined pressure from first gas supply pipe 41b by first gas supply 41 and flows out of opening 44 between sputtering source 24 and shield 41a.
• first gas supply pipe 41b since a cross-sectional area of the opening between the sputtering source and the shield is greater than that of the first gas supply pipe 41b, the gas is rapidly diffused.
• the gas flows out from between sputtering source 24 and shield 41a to the outer circumference of sputtering source 24 to which the target is secured, the gas flows at a uniform distribution pressure.
• the supply of the reaction gas flows from second gas supply 45 to the inside of vacuum chamber 22, that is, the reaction gas is supplied to tube 45d and then to reaction gas supply conduit 45a being installed on top of clamp 26 where it passes through reaction gas supply conduit 45a to gas supply hole 45e and then flows out of gas supply hole 45e and along inclined surface 26c of clamp 26 to the top of wafer 200, as illustrated at Fig. 7.
• opening 45c formed in the bottom 47a of reaction gas supply conduit 45a includes a portion of the top of clamp 26, and thus, where the reaction gas is supplied through tube 45d at a higher pressure than a predetermined pressure, a portion of the reaction gas flows out between common joint 46b which is formed when the conduit is operatively positioned on the clamp, i.e. between the top of clamp 27a and the outer circumferential edge 47c of conduit 45a, thereby reducing the pressure difference between the pressure at the upper surface and the pressure at the lower surface of wafer 200 to maintain the pressure of the gas supplied to gas supply hole 45e at a constant level, i.e. the small portion of gas assists in promoting uniform pressure about the wafer.
• gas supply hole 45e is formed vertically downward relative to the surface of wafer 200 and thus the flow of the gas to inclined surface 26c is increased so that gas can be reacted under a low pressure so as to improve the efficiency of deposition for a highly integrated wafer.
• the formation of the nitrogen film by the reaction gas that is, the flow of nitrogen gas to the top of the wafer can be controlled so as to control the generation of particles and to improve the characteristics of the deposited film (TiN film) formed on top of the wafer.
• the apparatus for manufacturing a thin film on a semiconductor device in accordance with the present invention can obtain a high deposition rate and superior deposited film since it can prevent the unnecessary formation of film on top of the wafer by the reaction gas by separating the first and second gases which are being supplied to the inside of the vacuum chamber and by supplying them separately, mainly around the sputtering source and the wafer respectively.
• the apparatus of the present invention can greatly improve collimator processing for deposition of atoms having a specified directionality.

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• Physical Vapour Deposition (AREA)
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• 1995
  • 1995-08-29 WO PCT/US1995/011039 patent/WO1996007769A1/en not_active Application Discontinuation
  • 1995-08-29 JP JP8509570A patent/JPH09505356A/ja active Pending
  • 1995-08-29 EP EP95931033A patent/EP0728224A4/de not_active Withdrawn

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