# US 6,265,781 B1 · Methods and solutions for cleaning polished aluminum-containing layers, methods for making metallization structures, and the structures resulting from these methods

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- Number: US 6,265,781 B1
- Document ID: US6265781B1
- Status: Granted
- Kind: B1
- Application number: 09/153,053
- Filed: 1998-09-15
- Granted: 2001-07-24
- Earliest claimed: 1996-10-19
- Assignees: Micron Technology, Inc.
- Inventors: Michael T. Andreas
- Web page: https://patentgrep.com/patent/US6265781B1

## CPC

- H10W 20/062: {by smoothing of conductive parts, e.g. by planarisation}
- H10P 52/403: {of conductive or resistive materials}
- H10P 70/277: {the processing being a planarisation of conductive layers}
- H10W 20/425: {Barrier, adhesion or liner layers}
- H10W 20/4407: {Aluminium alloys}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Methods for making an aluminum-containing metallization structure, methods and solutions for cleaning a polished aluminum-containing layer, and the structures formed by these methods. The methods for making the aluminum-containing metallization structure are practiced by providing a substrate, forming a metal layer with an upper surface containing aluminum over the substrate, polishing the metal layer, and contacting the polished surface of the metal layer with a solution comprising water and at least one corrosion-inhibiting agent. The method for cleaning the polished aluminum-containing layer is practiced by contacting a polished aluminum-containing layer with a solution comprising water and a corrosion-inhibiting agent. In these methods and solutions, the water may be deionized water, the corrosion-inhibiting agent may be citric acid or one of its salts, and the solution may contain additional additives, such as chelating agents, buffers, oxidants, anti-oxidants, and surfactants. These methods and solutions reduce the corrosion caused by DI water used in cleaning polished aluminum-containing layers and maintain a passivative environment which protects the exposed aluminum structures.

## Claims

### Claim 1

A metallization structure for an integrated circuit, comprising:
an integrated circuit substrate; and
an aluminum-containing conductive layer overlying the integrated circuit substrate and including a polished surface finish exhibiting no visible corrosion up to at least 150× magnification.

### Claim 2 (depends on 1)

The metallization structure of claim 1, wherein the integrated circuit substrate comprises an upper metal surface.

### Claim 3 (depends on 2)

The metallization structure of claim 2, including a dielectric layer disposed between the integrated circuit substrate and the aluminum-containing layer.

### Claim 4 (depends on 3)

The metallization structure of claim 3, wherein the dielectric layer contains at least one via therein.

### Claim 5 (depends on 4)

The metallization structure of claim 4, wherein the at least one via exposes the upper metal surface of the integrated circuit substrate.

### Claim 6 (depends on 5)

The metallization structure of claim 5, including at least one titanium-containing layer disposed between the aluminum-containing layer and the upper metal surface of the integrated circuit substrate and between the aluminum-containing layer and a sidewall of the at least one via.

### Claim 7 (depends on 6)

The metallization structure of claim 6, wherein the at least one titanium-containing layer comprises a layer of titanium underlying a layer of titanium nitride.

### Claim 8 (depends on 7)

The metallization structure of claim 7, wherein an aluminum concentration of the aluminum-containing layer is at least 50 wt %.

### Claim 9 (depends on 5)

The metallization structure of claim 5, wherein an aluminum concentration of the aluminum-containing layer ranges from 60 wt % to 90 wt %.

### Claim 10

A metallization structure for an integrated circuit, comprising:
a substrate including an upper metal surface;
a polished aluminum-containing layer overlying the substrate and exhibiting no visual corrosion up to at least 150× magnification, the aluminum-containing layer including an aluminum concentration ranging from 60 wt % to 90 wt %; and
a dielectric layer disposed between the substrate and the aluminum-containing layer, the dielectric layer containing at least one via therein, the at least one via exposing the upper metal surface of the substrate.

### Claim 11

A metallization structure for an integrated circuit, comprising:
a substrate including an upper metal surface;
a dielectric layer disposed over the substrate, the dielectric layer containing at least one via therein, the at least one via exposing the upper metal surface of the substrate; and
an aluminum-containing layer overlying the substrate and the dielectric layer including a polished surface finish exhibiting no visible corrosion up to at least 150× magnification.

### Claim 12 (depends on 11)

The metallization structure of claim 11, including at least one titanium-containing layer disposed between the aluminum-containing layer and the upper metal surface of the substrate and between the aluminum-containing layer and a sidewall of the at least one via.

### Claim 13 (depends on 12)

The metallization structure of claim 12, wherein the at least one titanium-containing layer comprises a layer of titanium underlying a layer of titanium nitride.

### Claim 14 (depends on 13)

The metallization structure of claim 13, wherein an aluminum concentration of the aluminum-containing layer is at least 50 wt %.