Recovery of hydrophobicity of low-k and ultra low-k organosilicate films used as inter metal dielectrics

• US 7,687,913 B2
• Filed: 02/19/2007
• Issued: 03/30/2010
• Est. Priority Date: 09/03/2003
• Status: Expired due to Fees

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Dimitrakopoulos, Christos D., Purushothaman, Sampath, Pfeiffer, Dirk, Colburn, Matthew E., Nitta, Satyanarayana V., Chakrapani, Nirupama
• Primary Examiner(s): LINDSAY JR, WALTER LEE
• Application Number:
  US11/676,447
• Publication Number:
  US 20070138640A1
• Time in Patent Office: 1,135 Days
• Field of Search: 257/758, 257/759, 257/760, 257/774, 257/E21.242, 257/E21.261, 257/E21.579
• US Class Current: 257/758
• 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 21/31058 of organic layers
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Often used to reduce the RC delay in integrated circuits are dielectric films of porous organosilicates which have a silica like backbone with alkyl or aryl groups (to add hydrophobicity to the materials and create free volume) attached directly to the Si atoms in the network. Si—R bonds rarely survive an exposure to plasmas or chemical treatments commonly used in processing; this is especially the case in materials with an open cell pore structure. When Si—R bonds are broken, the materials lose hydrophobicity, due to formation of hydrophilic silanols and low dielectric constant is compromised. A method by which the hydrophobicity of the materials is recovered using a novel class of silylation agents which may have the general formula (R₂N)_XSiR′_Y where X and Y are integers from 1 to 3 and 3 to 1 respectively, and where R and R′ are selected from the group of hydrogen, alkyl, aryl, allyl and a vinyl moiety. Mechanical strength of porous organosilicates is also improved as a result of the silylation treatment.

Claims

1. An article of manufacture comprising:

an insulating material having a plurality of electrical conductors formed therein; and

an intermetal dielectric including an organosilicate film having hydrogen atoms or alkyl or aryl groups attached to silicon atoms;

a surface of the organosilicate film comprising a product of reaction with an aminosilane silylating agent and an organosilicate of said film, said aminosilane having the general formula (R₂N)_xSiR′

_yR″

_z where X, Y and Z are integers with x varying from 1 to 3, and Y and Z varying from 3 to 0 respectively but where x+y+z is always equal to 4, and where R, R′

, and R″

are any hydrogen, methyl, aryl, allyl, phenyl or vinyl moiety.

2. An article as recited in claim 1, wherein the aminosilane is bis (dimethylamino) dimethylsilane.

3. An article as recited in claim 1, configured as a semiconductor chip, a semiconductor chip carrier or a semiconductor wafer.

4. An article as recited in claim 1, wherein said surface in an external surface of said film.

5. An article as recited in claim 1, wherein said surface includes that of pores within said film.

6. An article of manufacture comprising:

an insulating material having a plurality of electrical conductors formed therein;

an intermetal dielectric including an organosilicate film having hydrogen atoms, alkyl or aryl groups attached to silicon atoms;

a surface of the organosilicate film comprising a product of a silylating agent and an organosilicate of said film, said silylating agent comprising an aminosilane having a general formula (R₂N)_xSiR′

_y where X and Y are integers from 3 to 2 and 1 to 2 respectively, and where R and R′

are selected from the group consisting of hydrogen, alkyl, aryl, allyl, phenyl and a vinyl moiety.

7. An article of manufacture comprising:

an insulating material having a plurality of electrical conductors formed therein;

an intermetal dielectric including an organosilicate film having hydrogen atoms, alkyl or aryl groups attached to silicon atoms;

a surface of the organosilicate film comprising a product of a silylating agent and an organosilicate film, the silylating agent having the general formula R_xH_ySi_zA where x, and Y are integers from 0 to 5, 6 to 1, and z is 2, respectively and where R is a hydrogen, alkyl, aryl, allyl, phenyl or vinyl moiety, and A is a silazane.

8. An article of manufacture comprising:

an insulating material having a plurality of electrical conductors formed therein; and

an intermetal dielectric including an organosilicate film having hydrogen atoms or alkyl or aryl groups attached to silicon atoms;

a surface of the organosilicate film comprising a product of reaction with an aminosilane silylating agent and an organosilicate of said film and said silylating agent has the form R_xH_ySi-A where X and Y are integers from 0 to 2 and 3 to 1, respectively and where R, is any hydrogen, alkyl, aryl, allyl, phenyl or vinyl moiety and where A is a chloro or alkoxy moiety.