Advanced Micro Devices Corporation

Globalfoundries Inc.

Robert C Chen

Jeffrey Allan Shields

Khanh Q Tran

Robert Louis Dawson

John A Iacoponi

David C Greenlaw

Takeshi Nogami

Guarionex Morales

Robert Dawson

Khanh Tran

Punch-through vias are filled by initially depositing a thin, conformal layer of titanium nitride by chemical vapor deposition to cover an exposed upper surface of a lower metal feature, e.g. portions exposed by penetrating and undercutting an anti-reflective coating. A metal such as tungsten is subsequently deposited to fill the punch-through via. Embodiments include thermal decomposition of an organic-titanium compound, such as tetrakis-dimethylamino titanium, and treating the deposited titanium nitride in an H /N plasma to lower its resistivity. Moreover, the thickness of the anti-reflective coating can be reduced and the process window for etching the via widened.

Punch-through via with conformal barrier liner

A dielectric interlayer is formed over a semiconductor substrate comprising at least one active region. The exposed upper surface of the dielectric interlayer is treated with nitrogen to form a nitrided barrier layer thereon. At least one hydrogen-containing dielectric layer is formed over the dielectric interlayer having the nitrided barrier layer thereon. The nitrided barrier layer serves as a barrier to diffusion of hydrogen from the at least one hydrogen-containing dielectric layer into the dielectric interlayer, thereby preventing a decrease in hot carrier injection reliability.

H2  diffusion barrier formation by nitrogen incorporation in oxide layer

H2 diffusion barrier formation by nitrogen incorporation in oxide layer

Borderless vias are filled by initially depositing a thin, conformal layer of titanium nitride by chemical vapor deposition to cover an undercut, etched side surface of a lower metal feature. A metal, such as tungsten, is subsequently deposited to fill the borderless via. Embodiments include thermal decomposition of an organic-titanium compound, such as tetrakis-dimethylamino titanium, and treating the deposited titanium nitride in an H.sub.2 /N.sub.2 plasma to lower its resistivity.

Borderless vias with CVD barrier layer

HSQ is employed for gap filling patterned metal layers. The surface of the deposited HSQ gap fill layer is modified to decrease its plasma etching rate. Embodiments include modifying the HSQ surface by exposure to a plasma, such as a nitrogen-containing plasma, e.g., a plasma containing ammonia or hydrogen/nitrogen, to form a nitrided surface region. Reduction of the plasma etching rate of HSQ enables formation of reliable low resistance borderless vias.

HSQ with high plasma etching resistance surface for borderless vias

A substantially inert capping layer of tungsten nitride is deposited on cobalt layers prior to silicidation, thereby avoiding any substantial interaction with cobalt. The tungsten nitride capping layer also functions as a diffusion barrier preventing oxygen from reaching the silicidation area. The resulting cobalt silicides layer exhibit lower resistivity than those formed employing a titanium capping layer. Embodiments include rapid thermal annealing to initially form a layer of cobalt monosilicide consuming a portion of the cobalt layer, removing the tungsten nitride and unreacted cobalt layer, and rapid thermal annealing again to convert the cobalt monosilicide layer to a low resistivity layer of cobalt disilicide.

Cobalt silicidation using tungsten nitride capping layer

Spin-on HSQ is employed to gap fill metal layers in manufacturing a high density, multi-metal layer semiconductor device. The degradation of deposited HSQ layers during formation of borderless vias, as from photoresist stripping using an O.sub.2 -containing plasma, is overcome by treating the degraded HSQ layer with an H.sub.2 -containing plasma to restore the dangling Si--H bonds, thereby passivating the surface and preventing moisture absorption, before filling the via opening with conductive material, such as a barrier layer.

Borderless vias with HSQ gap filled patterned metal layers

Patterned metal layers are gap filled with HSQ and passivated to stabilize the dielectric constant of the HSQ substantially at the as-deposited value prior to oxide deposition by PECVD and planarization. Passivation and stabilization are effected by treating the as--deposited HSQ layer in a silane (SiH.sub.4) containing plasma.

Method of prevention of degradation of low dielectric constant gap-fill

Leading and trailing metal features in a dense array of conductive lines bordering an open field are formed with side surfaces that gradually taper in the direction of the open field toward an underlying substrate. Each side surface bordering the open field is formed with a sufficient slope to reduce cracking of the subsequently deposited dielectric gap fill layer at high stress areas bordering the open field.

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Los Altos, CA, United States of America

Robert C Chen