KR940005707B1 - Method of flattening aluminium electrode connectors - Google Patents

Abstract

No content.

Description

Planarization method of Al electrode wiring

1a to 1c is a cross-sectional structural view of an embodiment of the present invention.

2a to 2c is a cross-sectional structural view of another embodiment of the present invention.

3a to 3c are cross-sectional structural views of yet another embodiment of the present invention.

4a to 4c are cross-sectional structural views of yet another embodiment of the present invention.

5a to 5c are cross-sectional structural views of the prior art.

* Explanation of symbols for main parts of the drawings

11, 21, 41, 61, 81: substrate 12, 22, 42, 62, 82: LOCOS oxide film

13, 23, 43, 63, 83: gate oxide film 14, 24, 44, 64, 84: gate electrode

15, 25, 45, 65, 85: oxide film 16, 26, 46, 66, 86: N diffusion layer

17, 27, 47, 67, 87: PSG film 18, 28, 48, 68: refractory metal silicide film

19, 29, 50, 70, 71: Al alloy film 30: Cu film

49, 69 titanium nitride (TiN) film 88 Al film

The present invention relates to a method of planarizing an Al electrode wiring formed on a semiconductor substrate in connection with a semiconductor integrated circuit.

A multilayer film of Al and its alloy is commonly used for forming electrode wirings of VLSI. Generally, such a film is laminated by vapor deposition or sputtering. However, various problems have recently occurred in the VLSI integration process. Examples include electro-migration, stress migration, and connection through high aspect ratio via holes.

One way to solve the above problem without changing the electrode wiring material is to change the structure of the Al layer and put it into the via hole. This technique uses a laser beam to planarize the Al electrode wiring.

In this method, since the Al film is temporarily melted and then recrystallized again, the grain size becomes larger and the film density becomes higher, so that it has excellent electromigration characteristics and stress migration characteristics.

5A to 5C are cross-sectional structural diagrams of the prior art described below.

As shown in FIG. 5A, after a LOCOS (Local Oxidation of Silicon) oxide film 82 is selectively formed on a P-type single crystal Si substrate, a gate oxide film 83 is formed thereon, and the gate electrode 84 thereon. To form. Next, a thin oxide film 85 is formed by light oxidization, and ion implantation is carried out with phosphorus or arsenic thereon to form an N ⁺ diffusion layer 86. A PSG (Phosphosilicate Glass) film 87 is formed thereon, and the oxide film 85 and the PSG film 87 serving as connection regions are etched and removed. Thereafter, the Al film 88 is formed by the sputtering method.

The Al film 88 of the connecting hole portion is very well maintained unless any other processing is performed.

5C is a cross sectional structural view of a substrate heated to 300 ° C. and then irradiated with a laser beam. As can be seen from FIG. 5C, when the substrate is heated and irradiated with a laser beam, the Al film is completely reflowed, so that reflowing of the high aspect ratio via hole is possible, so that there is no cavity. However, when the substrate is heated to 300 ° C. or higher and irradiated with a laser beam, the temperature of the substrate surface becomes higher than necessary silver, so that a spike phenomenon 90 to the Si substrate by the Al film occurs. Typically, however, spikes occur at the edges of the connection holes and in the worst case pass through the N ⁺ diffusion layer and reach the substrate, causing leakage.

An object and object of the present invention is to solve the above-mentioned problems of the prior art by preventing the spike and leakage of the Si substrate by the Al film even when the Al film is completely reflowed by irradiating a laser beam after heating the substrate.

The means of the present invention form one of the following temperature stable thin films between the Al film and the substrate: one of refractory metal, one high melting point metal silicide film and one layer of refractory metal silicide combined with one layer of TiN film. This prevents the reaction of the Si substrate by the Al film and prevents the occurrence of defects that occur during the heating of the substrate and subsequent treatment with the laser beam.

1a to 1c, 2a to 2c, 3a to 3c, and 4a to

As shown in FIG. 1A, the LOCOS oxide film 12 is formed on the P-type single crystal Si substrate 11 with a thickness of 4000 kPa to 9000 kPa by the selective oxidation method. The gate oxide film 13 is formed to be 150 kPa to 400 kPa by vapor oxidation or thermal oxidation in an oxygen atmosphere. A gate electrode 14 made of doped N ⁺ polycrystalline silicon or polyside is formed thereon, and then a thin (about 150 kPa to 600 kPa) oxide film 15 is formed by weak oxidation. On top of that, in the case of phosphorus, the injection energy of 25Kev to 60Kev, the injection volume of 1 × 10 ¹⁵ cm ^-2 to 10 × 10 ¹⁵ cm ^-2 , the injection energy of 50Kev to 80Kev, 3 × 10 ¹⁵ cm ^-for arsenic ^The N ⁺ diffusion layer 16 is formed by implantation with an implantation volume of ² to 5 x 10 ¹⁵ cm ^-2 . Then, after weak oxidation, a PSG film 17 is formed thereon. Connection holes are formed by selectively photoetching the PSG film and the thermal oxide film in an N ₂ atmosphere. As shown in FIG. 1B, the refractory metal film or the refractory metal silicide film 18 is formed to be 500 kV to 3000 kV by the sputtering method. The Al alloy film 19 is formed thereon at 8000 kPa to 12000 kPa by the sputtering method.

As shown in FIG. 1C, when the substrate is heated to 150 ° C to 400 ° C and locally irradiated with a laser beam, the Al alloy film is melted and reflowed. This reflow keeps the Al alloy film well around the connection hole. At this time, since there is a refractory metal or a refractory metal silicide film at the bottom, it serves as a barrier to prevent Al from penetrating onto the Si substrate.

As shown in FIG. 2A, the LOCOS oxide film 22 is formed on the P-type single crystal Si substrate 21 by a selective oxidation method with a thickness of 4000 kPa to 9000 kPa. And, in the oxygen atmosphere ^{+ 15 -2 15 -2 15 -2 16 -2 +} ₂

As shown in FIG. 2C, when the substrate is heated to 150 ° C to 400 ° C and locally irradiated with a laser beam, the Al alloy film and the Cu film are turned into an alloy, and at the same time, the Al alloy film is melted and reflowed. This reflow keeps the Al alloy film well around the connection hole. At this time, since there is a refractory metal or a refractory metal silicide film at the bottom, it serves as a barrier to prevent Al from penetrating onto the Si substrate.

As shown in FIG. 3A, the LOCOS oxide film 42 is formed to have a thickness of 4000 kPa to 9000 kPa by the selective oxidation method on the P-type single crystal Si substrate 41. FIG. And, in the oxygen atmosphere ^{+ 15 -2 15 -2 15 -2 16 -2 +} ₂

As shown in FIG. 3C, when the substrate is heated to 150 ° C to 400 ° C and locally irradiated with a laser beam, the Al alloy film is melted and reflowed. This reflow keeps the Al alloy film well around the connection hole. At this time, since there is a refractory metal or a refractory metal silicide film and a TiN film at the bottom, it serves as a barrier for preventing Al from penetrating onto the Si substrate.

As shown in FIG. 4A, the LOCOS oxide film 62 is formed on the P-type polycrystalline Si substrate 61 by a thickness of 4000 kPa to 9000 kPa by the selective oxidation method. The gate oxide film 63 is formed to be 150 kPa to 400 kPa by steam oxidation or thermal oxidation in an oxygen atmosphere. ^{+ 15 -2 16 -2 15 -2 16 -2 +} ₂

As shown in FIG. 4C, when the substrate is heated to 150 ° C to 400 ° C and locally irradiated with a laser beam, the Al alloy film is melted and reflowed. This reflow keeps the Al alloy film well around the connection hole. A second refractory metal film or high melting point metal silicide film 71 is formed thereon, and wiring is formed by photo etching. At this time, since there is a refractory metal or a refractory metal silicide film and a TiN film at the bottom, it serves as a barrier for preventing Al from penetrating onto the Si substrate.

In accordance with the present invention, because there is a temperature stable refractory metal suicide of further bond between the Al film and the substrate and the refractory metal, the temperature of the stable, refractory metal silicide or even more of the TiN film ⁺

Claims (6)

a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the element by selectively etching the insulating film, and c) forming a refractory metal film on the semiconductor substrate. And d) forming an Al film on the semiconductor substrate, and e) forming an Al wiring by etching the Al film and the refractory metal film. Wherein, between steps d) and e), the semiconductor substrate is heated to 150 ° C to 400 ° C and the Al film is reflowed by irradiating the Al film with a laser beam, and the refractory metal film has a thickness of 500. To 3000 kPa, and the aluminum wiring thin film has a thickness of 8000 to 12000 kPa. a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the element by selectively etching the insulating film, and c) forming a refractory metal film on the semiconductor substrate. A method of planarizing an AB electrode wiring on a semiconductor substrate, the method comprising: d) forming an Al film on the semiconductor substrate; and e) forming a Cu film on the semiconductor substrate. Heating the Cu film and the Al film with a laser beam to change the Cu film and the Al film into an Al-Cu alloy film and to reflow the Cu film and the Al film; and g) forming an Al-Cu alloy wiring by etching the Al-Cu alloy film and the refractory metal film, wherein the refractory metal film has a thickness of 500 to 3000 kPa. Planarizing method of group AI electrode wiring, characterized in that AI film is 8000 to 1200Å thick. a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the device by selectively etching the insulating film, and c) forming a refractory metal silicide film on the semiconductor substrate. A method of planarizing an Al electrode wiring on a semiconductor substrate comprising the step of forming and d) forming an Al film on the semiconductor substrate, the method comprising: e) heating the semiconductor substrate to 150 ° C to 400 ° C and Reflowing the Al film by irradiating with a laser beam; and f) forming an Al wiring by etching the Al film and the refractory metal silicide film, wherein the refractory metal silicide film has a thickness of 500 to 3000 kPa, And the Al film has a thickness of 8000 Å to 1200 Å. a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the device by selectively etching the insulating film, and c) forming a refractory metal silicide film on the semiconductor substrate. A method of planarizing an Al electrode wiring on a semiconductor substrate, the method comprising: forming a film; d) forming an Al film on the semiconductor substrate; and e) forming a Cu film on the semiconductor substrate. Changing the Cu film and the Al film to an Al-Cu alloy film and reflowing the Cu film and the Al film by irradiating the Cu film and the Al film with a laser beam at a light temperature of 150 ° C. to 400 ° C. And g) forming an Al—Cu alloy wiring by etching the Al—Cu alloy film and the refractory metal film, wherein the refractory metal silicide film has a thickness of 500 μm. 3000Å, and the planarizing method of the AI wiring electrode, characterized in that the AI film thickness of 8000 to 12000Å. a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the element by selectively etching the insulating film, and 7) forming a refractory metal film on the semiconductor substrate. A method of planarizing an Al electrode wiring on a semiconductor substrate, the method comprising: d) forming titanium nitride on the semiconductor substrate; and e) forming an Al film on the semiconductor substrate. Reflowing the Al alloy film by heating a substrate from 150 ° C. to 400 ° C. and irradiating the Al film with a laser beam; and g) Al alloy by selectively etching the Al alloy film, the titanium nitride film and the refractory metal film. And forming a wiring, wherein the refractory metal film has a thickness of 500 to 3000 kPa, and the titanium nitride film has a thickness of 200 to 100 0 Å, and the Al film has a thickness of 8000 to 120000 Å. a) forming an insulating film on the semiconductor substrate after forming the element, b) forming a connection hole for connecting with the element by selectively etching the insulating film, and c) forming a refractory metal film on the semiconductor substrate. And d) forming a titanium nitride film on the semiconductor substrate; and e) forming an Al alloy film on the semiconductor substrate. Reflowing the Al alloy film by heating the semiconductor substrate to 150 ° C to 400 ° C and irradiating the Al film with a laser beam; g) forming a second refractory metal film or a refractory silicide film on the semiconductor substrate; h) forming an AI alloy wiring by etching the first refractory metal film, the silicide film, the AI alloy film, the titanium nitride film and the second refractory metal film. Further comprising a process, wherein the refractory metal film and the refractory silicide film have a thickness of 500 to 3000 mW, the titanium nitride film has a thickness of 200 to 1000 mW, and the AI film has a thickness of 8000 to 12000 mW. Way.

Images