HK1076921B - Fluoropolymer interlayer dielectric by chemical vapor deposition - Google Patents

Description

Fluoropolymer dielectric interlayers by chemical vapor deposition

Background

Modern electronic thin film devices use conductor and insulator layers as current carrying structures in these devices. The dielectric (insulator) layer is often composed of silicon-containing materials such as silicon dioxide and silicon nitride. As the requirements in such devices become more demanding, there is a need for improved dielectric materials having a lower dielectric constant than silicon-containing materials.

Fluoropolymers have excellent dielectric properties. However, the deposition methods of these polymer films are limited. In some cases, the polymer may be made soluble in a selected solvent, such that a film may be formed by methods commonly used for, e.g., photoresist materials. However, the property of rendering the polymer soluble may not be most desirable for dielectric applications. In another case, an emulsion or slurry of fine particles of polymer may be applied to the device, a film created by removing the solvent carrier, and then heat treating the particles to create a film. However, it may not be easy to form a uniform film having desired properties by these methods.

Thus, alternative methods of forming fluoropolymer layers are needed. In particular, the thin film processing industry often employs chemical vapor deposition to deposit these dielectric materials. Thus, there is a particular need for a chemical vapor deposition apparatus for dielectric deposition of fluoropolymers.

Summary of The Invention

A method of forming a fluoropolymer layer on a thin film device has been discovered comprising:

a) contacting the thin film device with a gas phase fluoromonomer, and

b) initiating polymerization of the fluoromonomer with a free radical polymerization initiator, whereby the fluoromonomer polymerizes into the fluoropolymer layer on the thin-film device.

A method of forming a fluoropolymer layer on a thin film device has been discovered comprising:

a) delivering a gas phase fluoromonomer to the thin film device,

b) contacting said thin film device with said gas phase fluoromonomer, and

c) initiating polymerization of the fluoromonomer with a free radical polymerization initiator, whereby the fluoromonomer polymerizes into the fluoropolymer layer on the thin-film device.

A method of forming a fluoropolymer layer on a thin film device has been discovered comprising:

a) delivering a gas-phase fluoromonomer and a gas-phase radical polymerization initiator to the thin film device,

b) mixing the gas-phase fluoromonomer and the gas-phase free-radical polymerization initiator to form a gas-phase mixture of the fluoromonomer and the free-radical polymerization initiator,

c) contacting said thin film device with said gas phase mixture of said fluoromonomer and said free radical polymerization initiator, and

d) initiating polymerization of the fluoromonomer with the free radical polymerization initiator, whereby the fluoromonomer polymerizes into the fluoropolymer layer on the thin-film device.

Detailed Description

The present invention is a method for forming a fluoropolymer layer on a thin-film device comprising contacting the thin-film device with a gas-phase fluoromonomer and initiating polymerization of the fluoromonomer with a free-radical polymerization initiator, whereby the fluoromonomer polymerizes into the fluoropolymer layer on the thin-film device.

The fluoropolymer comprising the fluoropolymer layer formed by the method of the present invention is comprised of repeating units of fluoromonomers as defined herein and has a number average molecular weight greater than 10,000. The fluoropolymer layer produced by the process of the present invention has a uniform thickness, typically a thickness of from about 500 angstroms to about 50,000 angstroms.

Thin film devices on which the fluoropolymer layer is formed by the method of the present invention include devices known in the microelectronics industry such as semiconductor wafers, integrated circuits, flat panel displays, micromechanical devices, microelectromechanical systems, and thin film optical and optoelectronic devices. The surfaces of such thin film devices on which the fluoropolymer layer is formed by the method of the present invention include: silicon; silicon dioxide; silicon nitride; silicon oxynitride; silicon carbide; "carbon-doped" oxides (e.g., spin-on materials such as HSQ and MSQ and CVD materials such as Coral)^TMAnd Black Diamond^TM) (ii) a Phosphosilicate, borosilicate, and borophosphosilicate glasses; a polyimide; aluminum; copper; tungsten; molybdenum; titanium; tantalum; silicides and nitrides of aluminum, copper, tungsten, molybdenum, titanium, and tantalum; conductive alloys of aluminum, copper, tungsten, molybdenum, titanium, and tantalum, including aluminum doped with copper and/or silicon.

The fluoromonomers used to form the fluoropolymer layer in the present invention contain carbon-carbon unsaturation and may include the elements carbon, fluorine, hydrogen, oxygen, nitrogen, sulfur and phosphorus. The fluoromonomer preferably comprises the elements carbon, fluorine and oxygen, most preferably comprises the elements carbon and fluorine. Mixtures of fluoromonomers may be employed in the present invention to prepare binary, ternary, or quaternary fluorocopolymers. The fluoromonomer is preferably homopolymerizable, but non-homopolymerizable fluoromonomers may also be used with homopolymerizable fluoromonomers to modify the properties of the fluoropolymer layer.

The homopolymerizable fluorine-containing monomer of the present invention includes:

formula C₂H_xF_(4-x)Wherein x is 0to 3,

formula cyclo- [ - (C (R)¹)(R²))_xOCF＝CFO-]Wherein x is 1 or 2, R¹And R²Independently selected from fluorine (F) and formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula cyclo- [ -C (═ CF)₂)OC(F)(R¹)CF₂O-]Fluoro-1, 3-dioxolane of formula (I), wherein R¹Selected from fluorine (F) and formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula CF₂＝CFO(C(F)(R¹))_xCF＝CF₂A fluorodiene of formula (I), wherein x is 1 to 5, and wherein R¹Selected from fluorine (F) and formula-C_xF_(2x+1)The straight-chain and branched saturated perfluoroalkyl groups represented, wherein x is 1 to 5, and

formula CF₂＝CFOCH₂R¹A fluorovinylhydrofluoroalkyl ether of wherein R¹Is hydrogen (H) or formula-C_xH_yF_(2x+1-y)Straight and branched saturated radicals are indicated, where x is from 1 to 5 and y is from 0to 2x +1.

Specific examples of the homopolymerizable fluorine-containing monomer of the present invention include:

CF₂＝CF₂，CF₂＝CFH，CF₂＝CH₂cis or trans-CFH ═ CFH, CFH ═ CH₂Cyclo- [ -CF₂OCF＝CFO]Cyclo- [ -CF₂CF₂OCF＝CFO]Cyclo- [ -C (F) (CF)₃)OCF＝CFO]Cyclo- [ -C (CF)₃)(CF₃)OCF＝CFO]Cyclo- [ -C (CF)₃)(C₂F₅)OCF＝CFO]Cyclo- [ -C (C)₂F₅)(C₂F₅)OCF＝CFO]Cyclo- [ -C (═ CF)₂)OCF₂CF₂O]Cyclo- [ -C (═ CF)₂)OC(F)(CF₃)CF₂O]Cyclo- [ -C (═ CF)₂)OC(F)(C₂F₅)CF₂O]，CF₂＝CFOCF₂CF＝CF₂，CF₂＝CFOCF(CF₃)CF＝CF₂，CF₂＝CFOCF₂CF₂CF＝CF₂，CF₂＝CFOCF(CF₃)CF₂CF＝CF₂，CF₂＝CFOCF₂CF(CF₃)CF＝CF₂，CF₂＝CFOCH₂CF₃，CF₂＝CFOCH₂C₂F₅And CF₂＝CFOCH₂CF₂CF₂CF₃.

The preferred fluoromonomer for use in the process of the present invention is CF₂＝CF₂(tetrafluoroethylene). Preferably with CF₂＝CF₂And CO₂In the process of the invention, tetrafluoroethylene is used, which is a reaction product of CF₂＝CF₂Compositions that are safe to deliver and handle are described in U.S.5,345,013 to VanBramer et al, which is incorporated herein by reference. CF preferably used in the process of the present invention₂＝CF₂With CO₂The mixture contains equal weight of CF₂＝CF₂And CO₂。

The non-homopolymerizable fluoromonomers of the present invention include:

formula CF₂＝CFR¹A perfluoroalkene of formula (I), wherein R¹Is selected from the formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula F₂C＝CFOR¹A perfluoroalkyl perfluorovinyl ether of wherein R¹Is selected from the formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula F₂C＝CFO(CF₂)_xR¹Or F₂C＝CFOCF₂CF(CF₃)O(CF₂)_xR¹A functionalized perfluorovinyl ether of formula (I), wherein x is 1-3, R¹is-CH₂OP(＝O)(OH)₂，-CH₂OH，-CH₂OCN，-CN，-C(＝O)OCH₃and-SO₂F, and

formula CF₂＝CFO(C(F)(R¹))_xOCF＝CF₂A perfluorodivinyl ether of formula wherein x is 1 to 5 and R¹Selected from fluorine (F) and formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown where x is 1 to 5.

Examples of non-homopolymerizable fluoromonomers of the present invention include:

CF₂＝CFCF₃，CF₂＝CFC₂F₅，CF₂＝CFOCF₃，CF₂＝CFOC₂F₅，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂CH₂OP(＝O)(OH)₂，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂CH₂OH，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂CH₂OCN，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂CN，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂C(＝O)OCH₃，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂SO₂F，F₂C＝CFOCF₂CF(CF₃)OCF₂CF₂CF₂SO₂F，F₂C＝CFOCF₂CF₂SO₂F，CF₂＝CFOCF₂CF₂CF₃，CF₂＝CFOCF₂OCF＝CF₂，CF₂＝CFOCF(CF₃)OCF＝CF₂，CF₂＝CFOCF₂CF₂OCF＝CF₂and CF₂＝CFOCF(CF₃)CF₂OCF＝CF₂.

The free radical polymerization initiator of the present method comprises an initiator capable of forming free radicals which initiate polymerization of the fluoromonomer and result in the formation of a fluoropolymer layer on the thin film device. It is preferred to deliver the initiator to the thin film device in the gas phase, however it is envisaged that the initiator may be present on or integral with the surface of the thin film device.

Free radical polymerization initiators for the process of the present invention include peroxides, saturated alkyl halides, halogenated olefins, halogens, and inorganic halides.

The peroxide initiators of the present invention contain at least one peroxy functional group (-OO-) and may be represented by R¹OOR²Wherein R is¹And R²Independently selected from saturated hydrocarbon groups, which may also contain halogen, oxygen and nitrogen atoms. Hydrocarbon peroxides such as di-tert-butyl peroxide may be used as initiators in the process of the present invention. Perfluorodiacyl peroxides can be used as initiators in the process of the present invention, wherein R is¹And R²Is R_FC (═ O) -) and R_FIs a perfluorocarbon group that may contain oxygen.

Preferred perfluorodiacyl peroxide initiators are those prepared from hexafluoropropylene oxide, such as (CF)₃CF₂CF₂OCF(CF₃)CO₂)₂。

The saturated alkyl halide initiator of the process of the invention can be represented by R-X, wherein X is a halogen, preferably fluorine, and R is a hydrocarbon group and preferably branched (secondary or tertiary). R is preferably fluorinated, more preferablyAnd optionally R is perfluorinated. Saturated alkyl halide initiators include, for example, perfluorotetramethylbutane CF₃(C(CF₃)₂)₂CF₃And perfluorocarbon iodides such as F (C)₂F₄)_xI, wherein x is 1-4.

The haloolefin initiators of the present invention are represented by R¹R²C＝CR³R⁴Wherein R is¹-R⁴Independently selected from hydrogen; halogen; alkyl substituted with hydrogen, halogen, and heteroatoms such as oxygen and nitrogen; and an ether group represented by-OR, wherein R is an alkyl group substituted with hydrogen, halogen, and hetero atoms such as oxygen and nitrogen. Preferably, R¹-R⁴At least one of which is fluorine. In one embodiment of the method of the present invention, a fluoromonomer is used as a free radical polymerization initiator under conditions in which the fluoromonomer is contacted with the thin film device. In this embodiment, tetrafluoroethylene (CF) may be used₂＝CF₂) As the fluorine-containing monomer, a perfluoroalkyl vinyl ether such as perfluoropropyl perfluorovinyl ether (CF) may be used₂＝CFOCF₂CF₂CF₃) Used as a radical polymerization initiator. Without wishing to be bound by theory, it is believed that in this embodiment, a small portion of the fluoromonomer thermally decomposes under conditions in which the fluoromonomer contacts the thin film device and forms free radical species that initiate polymerization of the fluoromonomer.

Halogen initiators of the present invention include molecular fluorine, chlorine, bromine and iodine. Among the halogen initiators, fluorine is preferred, especially fluorine which is highly diluted in an inert gas such as nitrogen.

The inorganic halide initiators of the present invention include nitrogen trifluoride and sulfur hexafluoride.

The present invention is a method for forming a fluoropolymer layer on a thin film device comprising, in part, contacting the thin film device with a gas phase fluoromonomer.

The total pressure during contact of the vapor phase fluoromonomer with the thin film device is not critical and may range from about 101kPa (1 atmosphere) to about 10.1kPa (0.1 atmosphere), preferably from about 101kPa to about 70 kPa. The total pressure may comprise in part the partial pressures of carrier gases, purge gases, and other process gases such as nitrogen, carbon dioxide, and noble gases. In a preferred embodiment of the process of the present invention, the free-radical polymerization initiator is in the gas phase and reacts with the fluorine-containing monomer in the gas phase near or at the surface of the thin-film device and thus contributes to the total pressure build-up.

The molar ratio of free radical polymerization initiator to fluoromonomer necessary to initiate and maintain an acceptable rate of fluoromonomer polymerization is not critical and depends upon a number of parameters (e.g., contact conditions, chemical structures of fluoromonomer and free radical polymerization initiator used, desired properties of the fluoropolymer layer), but is generally from about 1: 100 to 1: 100,000.

The temperature during contact of the vapor phase fluoromonomer with the thin film device is not critical and is generally maintained at a temperature of from about 20 ℃ to about 500 ℃, and preferably at a temperature of from about 300 ℃ to about 500 ℃.

The present invention is a method for forming a fluoropolymer layer on a thin film device, comprising in part initiating polymerization of a fluoromonomer with a free radical polymerization initiator. Without wishing to be bound by theory, it is believed that the fluoromonomer polymerizes on the surface of the thin film device in a free radical chain growth mechanism, initiated by radicals formed by bond homolytic cleavage of the free radical polymerization initiator under the above-mentioned contact conditions.

In an embodiment of the process of the present invention wherein the free radical polymerization initiator is in the gas phase, the process comprises mixing a gas phase fluoromonomer with a gas phase free radical polymerization initiator to form a gas phase mixture of fluoromonomer and free radical polymerization initiator. The mixing of the gases may be carried out by any method, but is preferably carried out by diffusing into the same volume in the direction of the flow of the fluoromonomer and initiator gases. Mixing may be controlled to occur before or during contact of the gas with the thin film device.

In a preferred embodiment of the method of the present invention, the vapor phase fluoromonomer and vapor phase radical polymerization initiator may be delivered to the surface of the thin film device by a chemical vapor deposition apparatus. Dispensing a gas on the surface of the thin film device to react the fluoromonomer with radicals formed by the radical polymerization initiator to form a fluoropolymer layer on the surface of the device. The function of the chemical vapor deposition apparatus is to distribute the gas in a substantially controlled manner over the surface of the thin film device. The chemical vapor deposition apparatus preferably provides a substantially controlled gas flow profile at a controlled flow rate to a particular surface area of the thin film device. The chemical vapor deposition apparatus may further include features to control premixing of gases prior to contact with the thin film device. The controlled distribution of the gases facilitates a complete, efficient and uniform reaction of the gases at the surface of the thin film device. This controlled dispensing provides greater control over the properties and quality of the resulting fluoropolymer layer. For example, the controlled dispensing allows important fluoropolymer layer properties such as thickness and dielectric constant to be uniform throughout a large diameter thin film device. When the fluoropolymer layer is not uniform in composition and thickness, proper functioning or further functionalization of the thin-film device will be compromised.

In a preferred embodiment of the present invention, the process of the present invention may be carried out using a chemical vapor deposition apparatus having a linear injector as taught by DeDontney et al, U.S. Pat. No.5,683,516, which is incorporated herein by reference. The linear injector comprises an elongate member with a distal surface and at least one gas delivery surface extending along the length of the member and which includes a plurality of elongate channels formed therein. A plurality of sub-distribution grooves are also formed in the member and extend between the elongate channel and the gas delivery surface. In another linear injector configuration, a plurality of metering tubes may be inserted in each elongate channel, spaced from the channel walls and extending between the ends. The metering tube may contain openings of various forms and sizes to direct them away from the dispensing channel. The metering tube receives gas conveyed therealong, whereby said gas flows out of the openings and is conveyed via the corresponding distribution grooves, guided in a substantially controlled manner along the gas conveying surface. In the case of multiple gases, such as fluoromonomers and free radical polymerization initiators, the distribution grooves direct the distribution of these gases to a controlled area on the surface of the thin film device where it is desired to mix the gases. In addition, the distribution channel prevents potential chemical fouling of the injector by preventing premature reaction of gases that are particularly reactive under the selected contact conditions. The gases are directed to a desired area on or above the thin film device where they mix, react and form a uniform fluoropolymer layer on the thin film device located below the injector.

In another embodiment of the present invention, the method of the present invention may be carried out using a chemical vapor deposition apparatus having an annular injector as taught in U.S. Pat. No.5,851,294 to Young et al, which is incorporated herein by reference. The annular injector comprises a positive pressure plenum body having at least one positive pressure plenum formed therein and a plurality of nozzles for injecting a fluoromonomer and an initiator gas into the process chamber. The nozzles are spaced from the plenum and are positioned and configured to provide uniform distribution of gases along the thin film device where the gases mix, react and form a uniform fluoropolymer layer on the thin film device.

In another embodiment of the process of the invention, the process of the invention may be carried out in a prototype plate reactor as taught by Mahawill in U.S. Pat. No. 4,834,022, which is incorporated herein by reference. The contoured plate reactor is substantially cylindrical. The base of the reactor is inclined at an angle of about 3 to 5 from vertical and has a central platform with a well. The thin film device is placed in the bath so that the surface of the device on which the fluoropolymer is to be deposited does not protrude above the mesa surface. The fluoromonomer and initiator gases are mixed and caused to flow radially inwardly along the surface of the device in the region adjacent the cylindrical wall of the reactor where they mix, react and form a uniform fluoropolymer layer on the surface of the thin film device.

In another embodiment of the invention, Multiblock is employed in a quasi-atmospheric tool as taught by Miller and Dobkin, U.S.6,022,414 (fig. 18)^TMThe syringe carries out the method of the invention, which patent is incorporated herein by reference. Such an injector is advantageous in that it has multiple injector components and exhaust components to increase throughput of a production type CVD tool.

Examples

In the following examples, slm is indicated in standard liters per minute; sccm refers to standard cubic centimeters per minute.

Example 1

A thin film of Polytetrafluoroethylene (PTFE) was deposited on an 8 "diameter, 750 μm thick, P-doped silicon Wafer, available from Wafer Net, inc. (San Jose, CA USA), using an atmospheric pressure CVD tool.

Monoblok described in U.S. patent No.5,683,516 was used^®(Monoblok is a trademark of ASML Thermal Division, Scotts Valley, Calif., USA.) A linear injector applies laminar flows of reactant and initiator gases to the wafer surface at precisely metered rates as the wafer moves under the injector body on a conveyor belt through a heated horizontal tunnel (muffle).

In this example, Tetrafluoroethylene (TFE) and CO₂The mixture of equal weight was passed through the Monoblok at a flow rate of 8slm^®The divider port of the linear injector was used simultaneously with a liquid bubbler system to deliver di-tert-butyl peroxide (tbpo) vapor to the central port of the injector. The tbpo vapor stream comprises about 5sccm tbpo vapor by passing N₂Gas was obtained at a controlled flow rate of 50sccm through a bubbler containing room temperature tbpo.

The syringe conveyor spacing was 11mm, the muffle set temperature was 400 ℃, and the belt speed was 0.5 inches per minute (ipm). A PTFE film having an average thickness of 3,645 angstroms was deposited on the wafer. The C-V plot at 1MHz shows a dielectric constant ('k') of 2.2, while the k for the thermal oxide "control" wafer is 4.0.

Example 2

By using F₂AsInitiator, use of Monoblok^®The linear syringe deposits the PTFE membrane at atmospheric pressure. In this case, 5% F is used₂In N₂The commercially available mixture of (1). To obtain a detectable flow through the injector, additional N is used₂(referred to as D1N₂) The flow dilutes the low flow of fluorine-containing nitrogen gas. Mixing 8slm of Tetrafluoroethylene (TFE) and CO₂Into a central (inner) port with an outer port of 50sccm containing 5% F₂Nitrogen +7.95slmD 1N₂Gas flow, Monoblok^TMLinear syringe separator port with N of 16slm₂And (4) air flow. The muffle furnace is heated to a set point of 250 ℃ sufficient to thermally crack the fluorine molecules into atomic F. The belt speed was 0.5 ipm.

ESCA analysis was performed on PTFE films deposited on the wafers. The elemental composition was confirmed to be 31.4% of C and 68.6% of F.

A ratio of 2: 1F: C indicates polytetrafluoroethylene. No other elements were detected by ESCA. Furthermore, the chemical shifts indicate that all fluorine is bonded to a C atom, and that carbon is bonded to other carbon atoms or fluorine atoms, consistent with that expected for PTFE.

Example 3

In this example, NF was used₃PTFE was deposited as an initiator. NF₃The thermal cracking of (a) requires temperatures in excess of 700 ℃ to generate F atomic radicals. Heater located upstream of injector to inject inflowing NF₃Heating to above 700 ℃. Although self-contained, the heater was structurally similar to the commercially available Watlow Starflow^TMThe heater is similar. The F atoms generated by the heating react with the TFE gas flowing from the injector tank, causing polymerization at the wafer surface.

The test is specifically as follows: TFE flow rate 5slm, 50sccmNF through internal port₃+1.00slm of D1N₂Flow through the outer port while 1.00slm separator N₂Flow through Monoblok^®A separator port of a linear injector. The upstream heater was set at 740 ℃ and the muffle set point was 500 ℃.

In this case, the wafer placed under the injector was statically deposited for a total of 20 minutes. This test resulted in an average thickness of 174 angstroms and a maximum thickness of 1194 angstroms.

Example 4

The PTFE deposition example employed a deposition with Monoblok^®Atmospheric Pressure Chemical Vapor Deposition (APCVD) apparatus using linear injectors using 30% H in a bubbler₂O₂For initiating proprietary TFE gas mixtures. In this case, 4.4slm of TFE was controllably flowed through the center port, 1.2slm of bubbler N₂Flow through the external port (entrainment H)₂O₂) Separator N using 1.0slm₂. The muffle set point was 500 ℃ and a 60 minute static deposition was performed. A PTFE film was deposited with a maximum thickness of 2575A and a refractive index (n) of 1.376 as measured by Rudolph ellipsometry.

Example 5

In this example, Trigonox-C was used at atmospheric pressure^TMA PTFE film was deposited as an initiator. This is a product of Akzo Nobel Polymer Chemicals LLC. Employs Monoblok^®A linear injector. Tetrafluoroethylene (TFE) and CO₂The gas of the equal weight mixture was passed through the separator port of the linear injector at a rate of 8slm, while the liquid bubbler system used N₂Trigonox-C was introduced at a flow rate of 3slm using gas as a carrier gas^TMThrough the central port of the syringe.

The syringe conveyor spacing was 11mm, the muffle furnace set temperature was 400 ℃, the belt speed was 0.25ipm, and the discharge (exhaust) set point was 0.25 inch H₂And O. A coating of 3005 angstroms, refractive index (n) 1.37 was formed in a single pass through the deposition zone.

Example 6

To illustrate the effect of line speed on PTFE deposition, an experiment similar to example #1 was performed except that the line speed was increased to 1 inch/minute with a discharge set point of 0.25 for a total of 3 passes to compensate for the reduced residence time in the deposition zone. 1844 angstrom films were deposited at this higher line speed; moreover, film quality (as measured by Rudolph Spectrophotometer fitness test) is improved over films produced at lower line speeds.

Example 7

In this example, APNext was used^TM(APNext is a trademark of ASML thermal division, Scotts Valley, Calif., USA.) A quasi-atmospheric CVD tool deposits a PTFE film. The tool employs a thermal vacuum chuck to hold the 8 "silicon wafer while the chuck translates under a fixed syringe body to improve film uniformity. Deposition was performed in a process chamber at 600Torr using 2 syringes (two syringes loaded into a rack) using the following conditions:

● "monomer" flow rate (1: 1 weight ratio of TFE: CO)₂)＝12slm

● bubbler N₂Flow rate (Di-tert-butylperoxide as a room temperature initiator) 50sccm

● chuck temperature 400 deg.C

● chuck translation speed is 0.4 mm/s

● chuck-injector gap distance 6mm

● # passage times 1 (deposition time 27.5 min)

●N₂Chamber purge ═ 4slm

●N₂Counterweight (ballast) flow rate 40slm (inlet pump foreline)

● groove N₂Purge flow 8slm (internal)/4 slm (external)

5 wafers were coated using the above method, with the following results:

1. average thickness of the deposit 2731 angstroms (1 σ 206 angstroms)

2. Average refractive index 1.33(1 sigma 0.04)

3. After 10' anneal (380 ℃, in vacuum), the average thickness was 2638 angstroms (1 σ 256 angstroms).

Claims (8)

1. A method of forming a fluoropolymer layer on a thin film device, comprising:

a) delivering a gas-phase fluoromonomer and a gas-phase radical polymerization initiator to the thin film device,

b) mixing the gas-phase fluoromonomer and the gas-phase free-radical polymerization initiator to form a gas-phase mixture of the fluoromonomer and the free-radical polymerization initiator,

c) contacting said thin film device with said gas phase mixture of said fluoromonomer and said free radical polymerization initiator, and

d) initiating polymerization of said fluoromonomer with said free radical polymerization initiator, whereby said fluoromonomer polymerizes into said fluoropolymer layer on said thin-film device.

2. The method of claim 1, wherein the vapor phase fluoromonomer and the vapor phase free radical polymerization initiator are delivered to the thin film device by a chemical vapor deposition apparatus.

3. The method of claim 1 wherein the fluoropolymer layer has a thickness of 500 angstroms to 50,000 angstroms.

4. The method of claim 1 wherein the fluoromonomer is selected from the group consisting of:

formula C₂H_xF_(4-x)Wherein x is 0to 3,

formula cyclo- [ - (C (R)¹)(R²))_xOCF＝CFO-]A fluorodioxole of the formula wherein x is 1 or 2 and R¹And R²Independently selected from fluorine and formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula cyclo- [ -C (═ CF)₂)OC(F)(R¹)CF₂O-]Fluoro-1, 3-dioxolane of formula (I), wherein R¹Selected from fluorine and the formula-C_xF_(2x+1)Straight and branched saturated perfluoroalkane groups are shown, where x is 1 to 5,

formula CF₂＝CFO(C(F)(R¹))_xCF＝CF₂A fluorodiene of wherein x is 1 to 5, and wherein R¹Selected from fluorine and the formula-C_xF_(2x+1)The straight-chain and branched saturated perfluoroalkyl groups represented, wherein x is 1 to 5, and

formula CF₂＝CFOCH₂R¹A fluorovinylhydrofluoroalkyl ether of wherein R¹Is hydrogen or formula-C_xF_(2x+1)Straight-chain and branched saturated radicals are indicated, where x is from 1 to 5.

5. The process of claim 1 wherein the fluoromonomer is tetrafluoroethylene.

6. The process of claim 1 wherein the free radical polymerization initiator is selected from the group consisting of peroxides, saturated alkyl halides, halogenated olefins, halogens, and inorganic halides.

7. The process of claim 1, wherein the initiating step is carried out at a pressure of from 101kPa to 10.1kPa, a temperature of from 20 ℃ to 500 ℃, and the molar ratio of the radical polymerization initiator to the fluoromonomer is from 1: 100 to 1: 100,000.

8. The method of claim 2, wherein the chemical vapor deposition apparatus is selected from the group consisting of a linear injector, a ring injector, a special plate reactor, and a reactor using Multiblock^TMA quasi-atmospheric tool of a syringe.