MATERIALS AND METHODS OF FORMING CONTROLLED VOID

• US 20080038934A1
• Filed: 03/29/2007
• Published: 02/14/2008
• Est. Priority Date: 04/18/2006
• Status: Active Grant

• Current Assignee: Versum Materials US, LLC (Merck & Co., Inc.)
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: BITNER, MARK, KARWACKI, EUGENE, LUKAS, AARON, O'NEILL, MARK, VINCENT, JEAN, WU, DINGJUN, VRTIS, RAYMOND
• Granted Patent: US 8,399,349 B2
• Time in Patent Office: Days
• US Class Current: 438/759
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02172 the material containing at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides materials containing silicon H01L21/02123; metal silicates H01L21/02142
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02263 deposition from the gas or vapour phase
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02282 liquid deposition, e.g. spin-coating, sol-gel techniques, spray coating
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: H01L 21/423 with high-energy radiation
• CPC Class Codes: H01L 21/764 Air gaps H01L21/76264 takes precedence
• CPC Class Codes: H01L 21/7682 the dielectric comprising air gaps
• CPC Class Codes: H01L 2221/1047 the air gaps being formed by pores in the dielectric

Abstract

The present invention is a process for forming an air gap within a substrate, the process comprising: providing a substrate; depositing a sacrificial material by deposition of at least one sacrificial material precursor; depositing a composite layer; removale of the porogen material in the composite layer to form a porous layer and contacting the layered substrate with a removal media to substantially remove the sacrificial material and provide the air gaps within the substrate; wherein the at least one sacrificial material precursor is selected from the group consisting of: an organic porogen; silicon, and a polar solvent soluble metal oxide and mixtures thereof.

Claims

1. A process for forming an air gap, the process comprising:

(a) providing a substrate;

(b) depositing a sacrificial layer with at least one organic precursor onto the substrate;

(c) depositing a composite layer with a porogen that is the at least one organic precursor in (b) and at least one silica-containing precursor or organosilicate glass (OSG) precursor onto the substrate;

(d) applying energy to the substrate having the sacrificial layer and the composite layer to remove both the sacrificial layer to provide air gaps and the porogen to form a porous layer;

(e) optionally, patterning a layer selected from the group consisting of the sacrificial layer, the composite layer, the porous layer and combinations thereof; and

(f) optionally, repeating steps (a)-(e) at least one time for making multilevel structures;

Wherein depositing steps (b) and (c) are via a process selected from the group consisting of chemical vapor depositions (CVD) and plasma enhanced chemical vapor depositions (PECVD).

2. The process for forming an air gap in claim 1, wherein the at least one organic precursor is at least one member selected from the group consisting of:

(1) at least one cyclic hydrocarbon having a cyclic structure and the formula C_nH₂n, where n is 4 to 14, a number of carbons in the cyclic structure is between 4 and 10, and the at least one cyclic hydrocarbon optionally contains a plurality of simple or branched hydrocarbons substituted onto the cyclic structure;

(2) at least one linear or branched, saturated, singly or multiply unsaturated hydrocarbon of the general formula C_nH<sub>(2n+2)−

2y</sub> where n is 2 to 20 and where y is 0 to n;

(3) at least one singly or multiply unsaturated cyclic hydrocarbon having a cyclic structure and the formula C_nH<sub>2n−

2x</sub>, where x is a number of unsaturated sites, n is 4 to 14, a number of carbons in the cyclic structure is between 4 and 10, and the at least one singly or multiply unsaturated cyclic hydrocarbon optionally contains a plurality of simple or branched hydrocarbons substituents substituted onto the cyclic structure, and contains endocyclic unsaturation or unsaturation on one of the hydrocarbon substituents;

(4) at least one bicyclic hydrocarbon having a bicyclic structure and the formula C_nH<sub>2n−

2</sub>, where n is 4 to 14, a number of carbons in the bicyclic structure is from 4 to 12, and the at least one bicyclic hydrocarbon optionally contains a plurality of simple or branched hydrocarbons substituted onto the bicyclic structure;

(5) at least one multiply unsaturated bicyclic hydrocarbon having a bicyclic structure and the formula C_nH<sub>2n−

(2+2x)</sub>, where x is a number of unsaturated sites, n is 4 to 14, a number of carbons in the bicyclic structure is from 4 to 12, and the at least one multiply unsaturated bicyclic hydrocarbon optionally contains a plurality of simple or branched hydrocarbons substituents substituted onto the bicyclic structure, and contains endocyclic unsaturation or unsaturation on one of the hydrocarbon substituents;

(6) at least one tricyclic hydrocarbon having a tricyclic structure and the formula C_nH<sub>2n−

4</sub>, where n is 4 to 14, a number of carbons in the tricyclic structure is from 4 to 12, and the at least one tricyclic hydrocarbon optionally contains a plurality of simple or branched hydrocarbons substituted onto the cyclic structure;

(7) at least one hydrocarbon structures containing one or more alcohol groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

z</sub>(OH)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of alcohol groups in the compounds and is between 1 and 4, and where the alcohol functionality can be exo- and/or endocyclic;

(8) at least one hydrocarbon structures containing one or more ether groups and having the general formula C_nH<sub>2n+2−

2x−

2y</sub>O_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of ether linkages in the structure and is between 1 and 4, and where the ether linkage(s) can be exo- and/or endocyclic;

(9) at least one hydrocarbon structures containing one or more epoxide groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>O_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of epoxide groups in the structure and is between 1 and 4, and where the epoxide groups can be attached to a cyclic ring or a linear chain;

(10) at least one hydrocarbon structures containing one or more aldehyde groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>O_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of aldehyde groups in the structure and is between 1 and 4;

(11) at least one hydrocarbon structures containing one or more ketone groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>O_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of aldehyde groups in the structure and is between 1 and 4, and where the ketone group(s) can be exo- and/or endocyclic;

(12) at least one hydrocarbon structures containing one or more carboxylic acid groups and having the general formula C_nH<sub>2n+2x−

2y−

3z</sub>(OOH)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of carboxylic acid groups in the structure and is between 1 and 4;

(13) at least one hydrocarbon structures containing an even number of carboxylic acid groups and in which the acid functionality is dehydrated to form a cyclic anhydride group where the structures have the general formula C_nH<sub>2n+2−

2x−

2y−

6z</sub>(O₃)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of anhydride groups in the structure and is 1 or 2;

(14) at least one hydrocarbon structures containing an ester group with the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>(O₂)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure, and where none of the unsaturated bonds are conjugated with the carbonyl group of the ester, and where z is the number of anhydride groups in the structure and is 1 or 2;

(15) at least one hydrocarbon structures containing an acrylate functionality consisting of an ester group and at least one unsaturated bond that is conjugated with the carbonyl of the ester group, and having the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>(O₂)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is greater than or equal to 1, and where at least of the unsaturated bonds are conjugated with the carbonyl group of the ester, and where z is the number of ester groups in the structure and is 1 or 2;

(16) at least one hydrocarbon structures containing both ether and a carbonyl functional groups and having the general formula C_nH<sub>2n+2−

2w−

2x−

2y</sub>(O)_y(O)_z where n is 1 to 12, and where w is the number of cyclic rings in the structure and is between 0 and 4, and where x is the number of unsaturated bonds in the structure and is between 0 and n, and where y is the number of carbonyl groups in the structure in which the carbonyl group can be ketones and/or aldehydes, and where z is the number of ether groups in the structure and is 1 or 2, and where the ether group(s) can be endocyclic or exocyclic;

(17) at least one hydrocarbon structures containing both ether and alcohol functional groups and having the general formula C_nH<sub>2n+2−

2w−

2x−

y</sub>(OH)_y(O)_z where n is 1 to 12, and where w is the number of cyclic rings in the structure and is between 0 and 4, and where x is the number of unsaturated bonds in the structure and is between 0 and n, and where y is the number of alcohol groups in the structure, and where z is the number of ether groups in the structure and is 1 or 2, and where the ether group(s) can be endocyclic or exocyclic;

(18) at least one hydrocarbon structures containing any combination of functional groups selected from the following list;

alcohol, ether, carbonyl, and carboxylic acid and having the general formula C_nH<sub>2n+2−

2u−

2v−

w−

2y−

3z</sub>(OH)_w(O)_x(O)_y(OOH)_z where n is 1 to 12, and where u is the number of cyclic rings in the structure and is between 0 and 4, and where v is the number of unsaturated bonds in the structure and is between 0 and n, and where w is the number of alcohol groups in the structure and is between 0 and 4, and where x is the number of ether groups in the structure and is between 0 and 4 and where the ether group(s) can be endocyclic or exocyclic, and where y is the number of carbonyl groups in the structure and is between 0 and 3 in which the carbonyl group can be ketones and/or aldehydes, and where z is the number of carboxylic acid groups in the structure and is between 0 and 2;

(19) at least one hydrocarbon structures containing one or more primary amine groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

z</sub>(NH₂)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of amine groups in the compounds and is between 1 and 4, and where the amine functionality can be exo- and/or endocyclic;

(20) at least one hydrocarbon structures containing one or more secondary amine groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

2z</sub>(NH)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of secondary amine groups in the compounds and is between 1 and 4, and where the amine functionality can be exo- and/or endocyclic;

(21) at least one hydrocarbon structures containing one or more tertiary amine groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

3z</sub>(N)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of tertiary amine groups in the compounds and is between 1 and 4, and where the amine functionality can be exo- and/or endocyclic;

(22) at least one hydrocarbon structures containing one or more nitro groups and having the general formula C_nH<sub>2n+2−

2x−

2y−

z</sub>(NO₂)_z where n is 1 to 12, and where x is the number of cyclic rings in the structure and is between 0 and 4, and where y is the number of unsaturated bonds in the structure and is between 0 and n, and where z is the number of nitro groups in the compounds and is between 1 and 4, and where the nitro functionality can be exo- and/or endocyclic;

(23) at least one hydrocarbon structures having both amine and ether functional groups having the general formula C_nH<sub>2n+2−

2u−

2v−

w−

2x−

3y−

z</sub>(NH₂)_w(NH)_x(N)_y(OH)_z where n is 1 to 12, and where u is the number of cyclic rings in the structure and is between 0 and 4, and where v is the number of unsaturated bonds in the structure and is between 0 and n, and where w is the number of primary amine groups, x is the number of secondary amine groups, y is the number of tertiary amine groups, and where 1<

w+x+y<

4, and where z is the number of alcohol groups in the compound and is between 1 and 4, and where the alcohol and/or amine groups can be exo- and/or endocyclic;

(24) at least one hydrocarbon structures having both amine and alcohol functional groups having the general formula C_nH<sub>2n+2−

2u−

2v−

w−

2x−

3y−

z</sub>(NH₂)_w(NH)_x(N)_y(OH)_z where n is 1 to 12, and where u is the number of cyclic rings in the structure and is between 0 and 4, and where v is the number of unsaturated bonds in the structure and is between 0 and n, and where w is the number of primary amine groups, x is the number of secondary amine groups, y is the number of tertiary amine groups, and where 1<

w+x+y<

4, and where z is the number of ether groups in the compound and is between 1 and 4, and where the ether and/or amine groups can be exo- and/or endocyclic; and

(25) at least one hydrocarbon structures having both amine and carbonyl functional groups having the general formula C_nH<sub>2n+2−

2u−

2v−

w−

2x−

3y−

2z</sub>(NH₂)_w(NH)_x(N)_y(O)_z where n is 1 to 12, and where u is the number of cyclic rings in the structure and is between 0 and 4, and where v is the number of unsaturated bonds in the structure and is between 0 and n, and where w is the number of primary amine groups, x is the number of secondary amine groups, y is the number of tertiary amine groups, and where 1<

w+x+y<

4, and where z is the number of carbonyl groups in the compound and is between 1 and 4, and where the carbonyl groups can be aldehyde(s) and/or ketone(s), and where the carbonyl and/or amine groups can be exo- and/or endocyclic.

3. The process for forming an air gap in claim 1, wherein the at least one organic precursor is at least one member selected from the group consisting of alpha-terpinene, limonene, cyclohexane, 1,2,4-trimethylcyclohexane, 1,5-dimethyl-1,5-cyclooctadiene, camphene, adamantane, 1,3-butadiene, substituted dienes, decahydronaphthelene, 1,5-cyclooctadiene, cyclooctane, cyclooctene, norbornadiene, 5-Ethylidene-2-norbornene, cyclopentene oxide and cyclopentanone.

8. The process for forming an air gap in claim 1, wherein the sacrificial layer and the composite layer are deposited together in one chemical vapor deposition (CVD) stem or in one plasma enhanced chemical vapor deposition (PECVD) step.

9. The process for forming an air gap in claim 1, wherein the energy in the applying step (d) includes at least one selected from the group consisting of α

-particles, β

-particles, γ

-rays, x-rays, high energy electron, electron beam, visible light, infrared light, microwave frequency, radio-frequency, plasma, and combinations thereof.

10. The process for forming an air gap in claim 1, wherein the applying energy step (d) is preformed under conditions selected from the grout consisting of

(1) an ultraviolet light energy having a power in the range of 0 to 5000 W;

an atmospheric condition selected from the group consisting of inert, oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours; and

(2) a thermal energy;

a pressure in the range of 10 mtorr to the atmospheric pressure;

an atmospheric condition selected from the group consisting of inert, oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours.

14. The process for forming an air gap in claim 1, further comprising of filling pores in the porous layer with a polymizable organic species which can be activated towards polymerization.

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19. A process for forming an air gap, the process comprising:

(a) providing a substrate, optionally with an etch stop layer to protect bare layer of the substrate;

(b) depositing a sacrificial layer comprising silicon;

(c) depositing a composite layer with a porogen and at least one silica-containing precursor or organosilicate glass (OSG) precursor;

(d) applying energy to the substrate having the sacrificial layer and the composite layer to remove the porogen to form a porous layer;

(e) contacting the substrate having the sacrificial layer and the porous layer with a fluorine containing reagent under reduced pressure capable of diffusing through the porous layer to selectively remove the sacrificial layer to form air gaps;

(f) optionally, patterning a layer selected from the group consisting of the sacrificial layer, the composite layer, the porous layer and combinations thereof; and

(g) optionally, repeating steps (a)-(f) at least one time for making multilevel structures;

wherein depositing step (b) is via a process selected from the group consisting of a chemical vapor deposition (CVD) and a plasma enhanced chemical vapor deposition (PECVD); and

depositing step (c) is via a process selected from the group consisting of chemical vapor deposition (CVD), spin-on coating, dip coating and mist deposition.

20. The process for forming an air gap in claim 19, wherein the fluorine containing reagent is XeF₂ or BrF₃;

the etch stop layer for a silicon substrate is a SiO₂ layer formed via thermally oxidizing the silicon substrate; and

the sacrificial layer comprising poly-silicon or amorphous-silicon.

21. The process for forming an air gap in claim 19, wherein the fluorine containing reagent is a gas selected from the group consisting of HF, noble gas halides, inter-halogens, ClF₃ and mixtures thereof.

30. The process for forming an air gap in claim 19, wherein the energy in the applying step (d) includes at least one selected from the group consisting of α

-particles, β

-particles, γ

-rays, x-rays, high energy electron, electron beam, visible light, infrared light, microwave frequency, radio-frequency, plasma, and combinations thereof.

31. The process for forming an air gap in claim 19, wherein the applying energy step (d) is performed under conditions selected from the group consisting of

(1) an ultraviolet light having a power in the range of 0 to 5000 W;

an atmospheric condition selected from the group consisting of inert oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours; and

(2) a thermal energy;

a pressure in the range of 10 mtorr to the atmospheric pressure;

an atmospheric condition selected from the group consisting of inert oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours.

35. The process for forming an air gap in claim 19, further comprising of filling pores in the porous layer with a polymizable organic species which can be activated towards polymerization.

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40. A process for forming an air gap, the process comprising:

(a) providing a substrate;

(b) depositing a polar solvent soluble metal oxide sacrificial layer with a metal precursor;

(c) depositing a composite layer with a porogen and at least one silica-containing precursor or organosilicate glass (OSG) precursor;

(d) applying energy to the substrate having the sacrificial layer and the composite layer to remove the porogen to form a porous layer;

n

(e) contacting the substrate having the sacrificial layer and the porous layer with a polar solvent, optionally with a surfactant, capable of diffusing through the porous layer to remove the sacrificial layer to form air gaps;

(f) optimally, patterning a layer selected from the group consisting of the sacrificial layer, the composite layer, the porous layer and combinations thereof; and

(g) optionally, repeating steps (a)-(f) at least one time for making multilevel structures;

wherein the deposition of a polar solvent soluble metal oxide sacrificial layer in (b) and the deposition of a composite layer in (d) are via a process selected from the group consisting of a chemical vapor deposition, spin-on coating, dip-coating and mist deposition

42. The process for forming an air gap in claim 40, wherein the polar solvent soluble metal precursor is a germanium (Ge) based precursor selected from the group consisting of tetramethyl germane, germane tetramethoxy germanium and tetraethoxy germanium or a boron (B) based precursor selected from the group consisting of trimethyl boron, trimethoxy borane, triethoxy borane and diborane;

and the polar solvent soluble metal oxide sacrificial layer is a GeO₂ layer or a B₂O₃ layer.

44. The process for forming an air gap in claim 40, wherein the polar solvent in step (e) is selected from the group consisting of alcohols, ethers, heteroatom containing molecules, esters, ketones, aldehydes and mixtures thereof.

45. The process for forming an air gap in claim 40, wherein the polar solvent in step (e) is water.

48. The process for forming an air gap in claim 40, wherein the energy in the applying step (d) includes at least one selected from the group consisting of α

-particles, β

-particles, γ

-rays, x-rays, high energy electron, electron beam, ultraviolet light, visible light, infrared light, microwave frequency, radio-frequency, thermal, plasma, and combinations thereof.

49. The process for forming an air gap in claim 40, wherein the applying energy step (d) performed under conditions selected from the group consisting of

(1) an ultraviolet light having a power in the range of 0 to 5000 W;

an atmospheric condition selected from the group consisting of inert, oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours; and

(2) a thermal energy;

a pressure in the range of 10 mtorr to the atmospheric pressure;

an atmospheric condition selected from the group consisting of inert oxidizing and reducing;

a temperature in the range of ambient to 500°

C.; and

an exposure time in the range of 0.01 minute to 12 hours.

53. The process for forming an air gap in claim 40, further comprising of filling pores in the porous layer with a polymizable organic species which can be activated towards polymerization.

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58. A process for forming an air gap, the process comprising:

(a) providing a substrate;

(b) depositing a polar solvent soluble metal oxide sacrificial layer with a metal precursor;

(c) depositing a composite layer with a porogen that is the polar solvent soluble metal oxide in (b) and at least one silica-containing precursor or organosilicate glass (OSG) precursor;

(d) contacting the substrate having the sacrificial layer and the composite layer with a polar solvent, optionally with a surfactant to facilitate the diffusion of the polar solvent through the sacrificial layer and the composite layer, to remove the porogen to form a porous layer and to remove the sacrificial layer to form air gaps.

(e) optionally, patterning a layer selected from the group consisting of the sacrificial layer, the composite layer, the porous layer and combinations thereof; and

(f) optionally, steps (a)-(e) at least one time for making multilevel structures;

wherein the depositing steps (b) and (d) are processes selected from the group consisting of a chemical vapor deposition (CVD), spin- or coating, dip-coating and mist deposition.

60. The process for forming an air gap in claim 58, wherein the polar solvent soluble metal precursor is a germanium (Ge) based precursor selected from the group consisting of tetramethyl germane, germane, tetramethoxy germane and tetraethoxy germanium or a boron (B) based precursor selected from the group consisting of trimethyl boron, trimethoxy borane, triethoxy borane and diborane;

and the polar solvent soluble metal oxide sacrificial layer is a GeO₂ layer or a B₂O₃ layer.

62. The process for forming an air gap in claim 58, wherein the polar solvent in step (e) is selected from the group consisting of alcohols, ethers, heteroatom containing molecules, esters, ketones, aldehydes and mixtures thereof.

63. The process for forming an air gap in claim 58, wherein the polar solvent in step (e) is water.

66. The process for forming an air gap in claim 58, further comprising of filling pores in the porous layer with a polymizable organic species which can be activated towards polymerization.

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