# US 5,702,980 A · Method for forming intermetal dielectric with SOG etchback and CMP

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- Number: US 5,702,980 A
- Document ID: US5702980A
- Status: Granted
- Kind: A
- Application number: 08/616,415
- Filed: 1996-03-15
- Granted: 1997-12-30
- Earliest claimed: 1996-03-15
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chen-Hua Douglas Yu; Sylin-Ming Jang
- Web page: https://patentgrep.com/patent/US5702980A

## CPC

- H10W 20/071: {of dielectric parts thereof}
- H10W 20/075: {of multilayered thin functional dielectric layers}
- H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)}
- H10W 20/098: {by filling between adjacent conductive parts}
- H10W 20/48: Insulating materials thereof
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A defect free intermetal dielectric, IMD, and method of forming the defect free IMD are described. The IMD uses spacers formed by means of etchback of a layer of spin-on-glass, SOG. In order to use an oxide layer formed by means of plasma enhanced tetra-ethyl-ortho-silicate, PE-TEOS, as part of the IMD an oxide cap layer formed using plasma enhanced chemical vapor deposition, PE-CVD, is used to isolate the SOG spacers from the PE-TEOS formed oxide layer. By isolating the PE-TEOS formed oxide layer from the SOG spacers a reliable and defect free IMD is achieved.

## Claims

### Claim 1

A method of forming intermetal dielectric, comprising the steps of:
providing a semiconductor substrate having devices formed therein;
providing a layer of base dielectric formed on said semiconductor substrate;
providing an electrode pattern formed on said layer of base dielectric;
forming an oxide underlayer over said layer of base dielectric and said electrode pattern;
forming a layer of spin-on-glass on said oxide underlayer;
etching back said layer of spin-on-glass wherein said spin-on-glass is removed from that part of said oxide underlayer directly over said electrode pattern;
forming an oxide cap layer over said oxide underlayer and that part of said layer of spin-on-glass remaining after etching back said layer of spin-on-glass, wherein said oxide cap layer is formed using plasma enhanced chemical vapor deposition with silane and oxygen;
forming an intermetal oxide layer over said oxide cap layer, wherein said intermetal oxide layer is formed using plasma enhanced deposition of tetra-ethyl-ortho-silicate; and
planarizing said intermetal oxide layer.

### Claim 2 (depends on 1)

The method of claim 1 wherein said oxide underlayer is silicon dioxide formed using plasma enhanced chemical vapor deposition with SiH.sub.4 and O.sub.2 precursors.

### Claim 3 (depends on 1)

The method of claim 1 wherein said oxide underlayer is silicon dioxide having a thickness of between about 500 and 2000 Angstroms.

### Claim 4 (depends on 1)

The method of claim 1 wherein said oxide cap layer is silicon dioxide.

### Claim 5 (depends on 1)

The method of claim 1 wherein said oxide cap layer is silicon dioxide having a thickness of between about 500 and 2000 Angstroms.

### Claim 6 (depends on 1)

The method of claim 1 wherein said intermetal oxide is silicon dioxide.

### Claim 7 (depends on 1)

The method of claim 1 wherein said intermetal oxide is silicon dioxide having a thickness of between about 6000 and 8000 Angstroms.

### Claim 8 (depends on 1)

The method of claim 1 wherein said planarizing of said intermetal oxide layer is carried out using chemical mechanical polishing.

### Claim 9 (depends on 1)

The method of claim 1 wherein said layer of spin-on-glass has a thickness of between about 2000 and 6000 Angstroms before said etching back of said spin-on-glass layer.

### Claim 10 (depends on 1)

The method of claim 1 wherein said etching back of said spin-on-glass layer uses CF.sub.4, CHF.sub.3, and O.sub.2.