Porogens, Porogenated Precursors and Methods for Using the Same to Provide Porous Organosilica Glass Films With Low Dielectric Constants

• US 20110143032A1
• Filed: 02/21/2011
• Published: 06/16/2011
• Est. Priority Date: 04/17/2002
• Status: Active Grant

• Current Assignee: Versum Materials US Inc.
• Original Assignee: Air Products and Chemicals Incorporated (Linde Plc)
• Inventors: O'Neill, Mark Leonard, Xiao, Manchao, Lukas, Aaron Scott, Vincent, Jean Louise, Vrtis, Raymond Nicholas, Norman, John Anthony Thomas
• Granted Patent: US 8,293,001 B2
• Time in Patent Office: Days
• US Class Current: 427/243
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/56 After-treatment
• 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 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]

Abstract

A porous organosilica glass (OSG) film consists of a single phase of a material represented by the formula Si_vO_wC_xH_yF_z, where v+w+x+y+z=100%, v is from 10 to 35 atomic %, w is from 10 to 65 atomic %, x is from 5 to 30 atomic %, y is from 10 to 50 atomic % and z is from 0 to 15 atomic %, wherein the film has pores and a dielectric constant less than 2.6. The film is provided by a chemical vapor deposition method in which a preliminary film is deposited from organosilane and/or organosiloxane precursors and pore-forming agents (porogens), which can be independent of, or bonded to, the precursors. The porogens are subsequently removed to provide the porous film. Compositions, such as kits, for forming the films include porogens and precursors. Porogenated precursors are also useful for providing the film.

Claims

1. A chemical vapor deposition method for producing a porous organosilica glass film, said method comprising:

providing a substrate within a vacuum chamber;

introducing into the vacuum chamber gaseous reagents including at least one precursor selected from the group consisting of an organosilane and an organosiloxane, and a porogen which is distinct from the precursor;

applying energy to the gaseous reagents in the chamber to induce reaction of the gaseous reagents to deposit a preliminary film on the substrate, wherein the preliminary film contains the porogen; and

removing from the preliminary film substantially all of the porogen to provide the porous film with pores and a dielectric constant less than 2.6,

wherein (i) the at least one silicon containing precursor has the formula R¹_n(OR²)_p(O(O)CR⁴)<sub>3−

n−

p</sub>Si—

R⁷—

SiR³_m(O(O)CR⁵)_q(OR⁶)<sub>3−

m−

q</sub>, wherein R¹ and R³ are independently H or C₁ to C₄ linear or branched, saturated, singly or multiply unsaturated, cyclic, partially or fully fluorinated hydrocarbon;

R², R⁶ and R⁷ are independently C₁ to C₆ linear or branched, saturated, singly or multiply unsaturated, cyclic, aromatic, partially or fully fluorinated hydrocarbon, R⁴ and R⁵ are independently H, C₁ to C₆ linear or branched, saturated, singly or multiply unsaturated, cyclic, aromatic, partially or fully fluorinated hydrocarbon, n is 0 to 3, m is 0 to 3, q is 0 to 3 and p is 0 to 3, provided that n+m≧

1, n+p≦

3, and m+q≦

3 and optionally diethoxymethylsilane; and

(ii) the at least one porogen is selected from the group consisting of;

(a) at least one cyclic hydrocarbon having a cyclic structure and the formula C_nH_2n, 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;

(b) 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=2−

20 and where y=0−

n;

(c) 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; and

(d) 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.

2. The method of claim 1, wherein the dielectric constant is less than 1.9.

3. The method of claim 1, wherein most of the hydrogen in the porous film is bonded to carbon.

4. The method of claim 1, wherein the porous film has a density less than 1.5 g/ml.

5. The method of claim 1, wherein the pores have an equivalent spherical diameter less than or equal to 5 nm.

6. The method of claim 1, wherein the porous film has a dielectric constant at least 0.3 less than a reference dielectric constant of the reference film.

7. The method of claim 1, wherein the porous film has a density at least 10% less than a reference density of the reference film.

8. The method of claim 1, wherein the porous film has an average weight loss of less than 1.0 wt %/hr isothermal at 425°

C. under N₂.

9. The method of claim 1, wherein the porous film has an average weight loss of less than 1.0 wt %/hr isothermal at 425°

C. under air.

10. The method of claim 1, wherein said at least one precursor is a mixture of a first organosilicon precursor with two or fewer Si—

O bonds with a second organosilicon precursor with three or more Si—

O bonds, and the mixture is provided to tailor a chemical composition of the porous film.

11. The method of claim 1, wherein the porogen is at least one member selected from the group consisting of alpha-terpinene, limonene, cyclohexane, cyclooctane, cymene, 1,3-butadiene, substituted dienes, decahydronaphthalene, and 1,2,4-trimethylcyclohexane, 1,5-dimethyl-1,5-cyclooctadiene

12. A composition comprising at least one precursor and a porogen distinct from the precursor, wherein the precursor is a compound of the formula R¹_n(OR²)_p(O(O)CR⁴)₃₋

n−

pSi—

R⁷—

SiR³_m(O(O)CR⁵)_q(OR⁶)<sub>3−

m−

q</sub> where R¹ and R³ are independently H or C₁ to C₄ linear or branched, saturated, singly or multiply unsaturated, cyclic, partially or fully fluorinated hydrocarbon;

R², R⁶ and R⁷ are independently C₁ to C₆ linear or branched, saturated, singly or multiply unsaturated, cyclic, aromatic, partially or fully fluorinated hydrocarbon, R⁴ and R⁵ are independently H, C₁ to C₆ linear or branched, saturated, singly or multiply unsaturated, cyclic, aromatic, partially or fully fluorinated hydrocarbon, n is 0 to 3, m is 0 to 3, q is 0 to 3 and p is 0 to 3, provided that n+m≧

1, n+p≦

3, and m+q≦

3.

13. The composition of claim 12, wherein the porogen is selected from the group consisting of:

a) at least one cyclic hydrocarbon having a cyclic structure and the formula C_nH_2n, 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;

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

2y</sub> where n=2−

20 and where y=0−

n;

c) 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;

d) 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;

e) 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; and

f) 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.

14. The composition of claim 13 wherein the porogen is selected from the group consisting of:

alpha-terpinene, limonene, cyclooctane, and cymene.

15. The composition of claim 13 wherein the porogen is norbornadiene.

16. The composition of claim 13 wherein the silicon precursor and porogen precursor are maintained in separate vessels prior to delivery to the deposition chamber, or in a single vessel with a means of separation therein.

17. The composition of claim 13 wherein the precursors are maintained in stainless steel electropolished containers suitable for the electronics industry.