Gap-filling process

Details Gap-filling process Gap-filling process

2002-11-20

2004-12-21

Fourson, George (Department: 2823)

Semiconductor device manufacturing: process

Coating with electrically or thermally conductive material

To form ohmic contact to semiconductive material

C438S633000, C438S634000, C438S638000

Reexamination Certificate

active

06833318

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to a process for forming semiconductor devices. More particularly, the present invention relates to a gap-filling process for forming semiconductor devices.
2. Description of Related Art
Gap-filling process is a technique that has many applications in semiconductor production. In semiconductor manufacturing, the gap-filling process is often used after openings are formed. Different material is deposited into the openings according to the type of structure desired. For example, insulating material is deposited into the trenches of a shallow trench isolation (STI) structure and conductive material is deposited into the contact window of an inter-metal dielectric (ILD) structure, the via of an inter-metal dielectric (IMD) structure or the metallic interconnect opening of a dual damascene structure.
FIGS. 1A
to
1
D are schematic cross-sectional views showing the progression of steps for forming a gap-filled material layer in the via opening of a via first dual damascene (VFDD) structure using a conventional gap-filling method. As shown in
FIG. 1A
, a substrate
100
having a conductive line
102
thereon is provided. A protective layer
104
, a dielectric layer
106
, an etching stop layer
108
, a second dielectric layer
110
, a cap layer
112
are sequentially formed over the substrate. A via opening
114
that passes through the cap layer
112
, the second dielectric layer
110
, the etching stop layer
108
, the dielectric layer
106
and exposes the protective layer
104
is formed.
As shown in
FIG. 1B
, a gap-filling material is deposited into the via opening
114
to form a gap-filling material layer
116
.
As shown in
FIG. 1C
, a polishing or etching process is conducted to remove excess gap-filling material from the gap-filling material layer
116
and expose the cap layer
112
. Hence, a gap-filled material layer
118
is formed inside the via opening
114
.
As shown in
FIG. 1D
, a bottom anti-reflection coating (BARC)
120
is formed over the cap layer
112
and the gap-filled material layer
118
.
However, the aforementioned method of forming a gap-filling material layer
118
inside the via opening
114
has a few problems. When the gap-filling material layer
116
is formed over the substrate
100
, a downward caving surface is formed near the mouth of the via opening
114
leading to the formation of a recess cavity in the gap-filling material layer
118
even after polishing or etching. The presence of this recess cavity in the gap-filling material layer
118
results in the production of a similar cavity in the subsequently formed bottom anti-reflection coating
120
and photoresist layer above the gap-filling material layer
118
. A non-planar profile is a major factor that intensifies the so-called striation effect. The striation effect contributes to a worsening of thickness uniformity in an overlying photoresist layer. Ultimately, critical dimensions (CD) and the dimensions measured in the after etching inspection (AEI) may deviate too much from the desired range because an accurate pattern is no longer reproduced.
In addition, the gap-filling material layer
118
may also be subjected to the damaging effects caused by the overlying bottom anti-reflection coating
120
or photoresist layer. In other words, the material in the bottom anti-reflection coating
120
or the photoresist layer and the material in the gap-filling material layer
118
may intermix leading to a loss of gap material. As a result, there is a further intensification of the striation effect and/or a distortion of the pattern profile after etching the inter-metal dielectric layer rendering the formation of an accurate pattern difficult.
SUMMARY OF INVENTION
Accordingly, one object of the present invention is to provide a gap-filling process capable of producing a gap-filling material layer with an improved surface planarity so that a subsequently formed bottom anti-reflection coating or photoresist layer over the gap-filling material layer also has a better surface planarity.
A second object of this invention is to provide a gap-filling process capable of preventing the loss of gap-filling material from a gap-filling material layer due to contact with a bottom anti-reflection coating or a photoresist layer. Consequently, the gap-filling material layer and the bottom anti-reflection coating or the photoresist layer can have a better surface planarity.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a gap-filling process. A substrate having a dielectric layer thereon is provided. An opening is formed in the dielectric layer. A gap-filling material layer is formed over the dielectric layer and inside the opening. A portion of the gap-filling material layer is removed to expose the dielectric layer. The gap-filling material layer and the surface of the dielectric layer undergo a gap-filling material treatment.
The gap-filling material treatment may include etching the dielectric layer and the gap-filling material layer to planarize the gap-filling material layer.
In addition, the gap-filling material treatment may also include performing a plasma processing, an ultraviolet curing or a chemical immersion of the gap-filling material layer to form a protective layer over the gap-filling material layer.
Furthermore, the gap-filling material treatment may involve etching the dielectric layer and the gap-filling material layer to planarize the gap-filling material layer and then performing a plasma processing, an ultraviolet curing or a chemical immersion of the gap-filling material layer to form a protective layer over the gap-filling material layer.
In this invention, the gap-filling material layer is etched to form a planar surface. Hence, any layer deposited over the gap-filling material layer can have a high level of planarity that facilitates the formation of a correct pattern in subsequent photolithographic and etching operation.
Since a protective layer is formed over the gap-filling material layer, intermixing of material between the bottom anti-reflection coating or the photoresist layer with the gap-filling material layer is stopped. Thus, the gap-filling material layer and the bottom anti-reflection coating or the photoresist layer can have a high degree of surface planarity. Ultimately, an accurate pattern is reproduced after a photolithographic and etching operation.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.


REFERENCES:
patent: 6100184 (2000-08-01), Zhao et al.
patent: 6184138 (2001-02-01), Ho et al.
patent: 6274499 (2001-08-01), Gupta et al.
patent: 6294460 (2001-09-01), Subramanian et al.
patent: 6316351 (2001-11-01), Chen et al.
patent: 6352921 (2002-03-01), Han et al.
patent: 6541367 (2003-04-01), Mandal
Ogure et al., U.S. patent application Publication U.S. 2002/0111022 A1, Pub. Date: Aug. 15, 2002.*
Lu et al., U.S. patent application Publication U.S. 2002/0137337 A1, Pub. Date: Sep. 26, 2002.*
Jiang et al., U.S. patent application Publication U.S. 2002/0139771 A1, Pub. Date: Oct. 3, 2002.

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