US-12628588-B2 - Wiring forming method and substrate processing apparatus

Abstract

A wiring forming method includes a loading step (Si), an etching step (S 3 ), and a reducing step (S 6 ). In the loading step (S 1 ), a substrate having a metal wiring portion formed thereon is loaded into a chamber. In the etching step (S 3 ), an oxidizing gas is supplied to the substrate to etch one part of the metal wiring portion. In the reducing step (S 6 ), a reducing gas is supplied to the substrate to reduce an oxide film of the metal wiring portion formed by the etching step (S 3 ).

Inventors

• Masaki Inaba
• Akihisa Iwasaki

Assignees

• SCREEN Holdings Co., Ltd.

Dates

Publication Date

20260512

Application Date

20211223

Priority Date

20201228

Claims (10)

1. 1 . A wiring forming method comprising: loading a substrate having a metal wiring portion formed on said substrate into a chamber; supplying an oxidizing gas to said substrate to etch one part of said metal wiring portion; and supplying a reducing gas to said substrate to reduce an oxide film of said metal wiring portion formed by supplying said oxidizing gas, wherein said metal wiring portion comprises: a wiring main body positioned in a trench of an insulating film in said substrate; and a barrier film provided between said wiring main body and said insulating film; and wherein an upper surface of the wiring main body is recessed from an upper surface of the barrier film; in supplying said oxidizing gas, etching a projecting portion of said barrier film projecting beyond an upper surface of said wiring main body; and in supplying said reducing gas, reducing said oxide film formed on said wiring main body by said supplying said oxidizing gas.
2. 2 . The wiring forming method according to claim 1 , wherein said barrier film includes ruthenium.
3. 3 . The wiring forming method according to claim 1 , wherein said wiring main body includes at least any one of copper, molybdenum, cobalt, tungsten, platinum, and indium.
4. 4 . The wiring forming method according to claim 1 , wherein further comprises: detecting a generated gas generated by supplying said oxidizing gas by a gas sensor, said generated gas generated by a reaction between said oxidizing gas and said metal wiring portion; and determining whether to terminate supplying said oxidizing gas based on a detection value of said gas sensor.
5. 5 . The wiring forming method according to claim 1 , further comprising: supplying an inert gas into said chamber to discharge said oxidizing gas from said chamber, supplying said inert gas is performed between supplying said oxidizing gas and supplying said reducing gas.
6. 6 . The wiring forming method according to claim 1 , wherein in supplying said oxidizing gas, supplying said oxidizing gas and supplying the inert gas are alternately repeated.
7. 7 . The wiring forming method according to claim 1 , wherein in supplying said oxidizing gas, said substrate is heated so that a temperature of said substrate is 50 degrees Celsius or more and 200 degrees Celsius or less.
8. 8 . The wiring forming method according to claim 1 , wherein in supplying said reducing gas, said substrate is heated so that a temperature of said substrate is 100 degrees Celsius or more and 300 degrees Celsius or less.
9. 9 . The wiring forming method according to claim 1 , further comprising: cooling said substrate after supplying said reducing gas; and unloading said substrate from said chamber after cooling said substrate.
10. 10 . A substrate processing apparatus comprising: a chamber; a substrate holder provided in said chamber that holds a substrate having a metal wiring portion formed on said substrate; an oxidizing gas supply unit that supplies an oxidizing gas to said substrate in said chamber to etch one part of said metal wiring portion; a reducing gas supply unit that supplies a reducing gas to said substrate to reduce an oxide film of said metal wiring portion formed by said oxidizing gas; and a controller performing operations according to claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a 35 U.S.C. §§ 371 national phase conversion of International Application No. PCT/JP2021/047788, filed Dec. 23, 2021, which claims priority to Japanese Patent Application No. 2020-219085, filed Dec. 28, 2020, the contents of both of which are incorporated herein by reference. The PCT International Application was published in the Japanese language. TECHNICAL FIELD The present application relates to a wiring forming method and a substrate processing apparatus. BACKGROUND ART Following the miniaturization of wiring in a semiconductor device, a short circuit between wiring becomes more likely to occur due to a deviation between the wiring and a via. That is, when a via formed on a certain first wiring is misaligned in a horizontal direction and one part of the via is also formed on an insulating film between the first wiring and a second wiring, a distance between the second wiring and the via is shortened, thus a short circuit can occur between the first wiring and the second wiring via the via. A self-alignment via has been proposed as a method for solving this problem (for example, Patent Document 1). In Patent Document 1, a metal film (for example, a copper wiring) serving as a wiring is formed inside each trench formed in the insulating film, and by etching an upper surface of the metal film, the upper surface of each metal film is caused to retract further than an upper surface of the insulating film. As a result, it is possible to lengthen a distance between the upper surface of the metal film and the upper surface of the insulating film. According to this, even when one part of the via is formed on the upper surface of the insulating film between a first metal film and a second metal film due to the via deviating from the first metal film in the horizontal direction, since the upper surface of the second metal film retracts further than the upper surface of the insulating film, it is possible to maintain a distance between the via and the second metal film. Accordingly, it is possible to suppress a short circuit between the first metal film and the second metal film via the via. PRIOR ART DOCUMENT Patent Document Patent Document 1: Japanese Patent Application Laid-Open No. 2019-61978 SUMMARY Problem to be Solved by the Invention Wiring (hereinafter referred to as a metal wiring portion) formed on a substrate is formed of a single metal film, or is formed of a plurality of metal films. Such a metal wiring portion is etched as appropriate in a manufacturing step thereof to adjust a shape of the metal wiring portion. For example, in Patent Document 1, the upper surface of the metal film is etched. In such etching, the metal wiring portion may be etched by oxidization. In this case, an oxide film may be partially formed on the metal wiring portion. Such an oxide film is not preferable as it increases a resistance value of the metal wiring portion. Therefore, an object of the present application is to provide a technique capable of etching one part of the metal wiring portion by oxidation while suppressing an increase in the resistance value of the metal wiring portion due to the oxide film formed by oxidation. Means to Solve the Problem A first aspect of a wiring forming method is a method for forming a wiring including a loading step of loading a substrate having a metal wiring portion formed thereon in a chamber, an etching step of supplying an oxidizing gas to the substrate to etch one part of the metal wiring portion, and a reducing step of supplying a reducing gas to the substrate to reduce an oxide film of the metal wiring portion formed by the etching step. A second aspect of a wiring forming method is the wiring forming method according to the first aspect, in which the metal wiring portion includes a wiring main body positioned in a trench of an insulating film in the substrate, and a barrier film provided between the wiring main body and the insulating film, in the etching step, one part of the barrier film is etched as the one part of the metal wiring portion, and in the reducing step, the oxide film formed on the wiring main body by the etching step is reduced. A third aspect of the wiring forming method is the wiring forming method according to the second aspect, in which, in the etching step, a projecting portion of the barrier film projecting from a surface of the wiring main body is etched as the one part of the metal wiring portion, and in the reducing step, the oxide film formed on the surface of the wiring main body by the etching step is reduced. A fourth aspect of the wiring forming method is the wiring forming method according to the second or third aspect, in which the barrier film includes ruthenium. A fifth aspect of the wiring forming method is the wiring forming method according to any one of the second to fourth aspects, in which the wiring main body includes at least any one of copper, molybdenum, cobalt, tungst