For multilayer process, importance of carbon-based spin-on hardmask material that replaces amorphous carbon layer (ACL) is ever increasing. Carbon-based spin-on hardmask is an organic polymer with high carbon content formulated in organic solvents for spin-coating application that is cured through baking. In comparison to CVD process for ACL, carbon-based spin-on hardmask material can offer several benefits: lower cost of ownership (CoO) and improved process time, as well as better gap-fill and planarization performances. Thus carbon-based spin-on hardmask material of high etch resistance, good gap-fill properties and global planarization performances over various pattern topographies are desired to achieve the fine patterning and high aspect ratio (A/R). In particular, good level of global planarization of spin coated layer over the underlying pattern topographies is important for self-aligned double patterning (SADP) process as it dictates the photolithographic margin. Herein, we report a copolymer carbon-based spin-on hardmask resin formulation that exhibits favorable film shrinkage profile and good etch resistance properties. By combining the favorable characteristics of each resin – one resin with good shrinkage property and the other with excellent etch resistance into the copolymer, it was possible to achieve a carbonbased spin-on hardmask formulation with desirable level of etch resistance and the planarization performances across various underlying substrate pattern topographies.
Spin-on dielectric (SOD) is widely used in semiconductor industry, to form insulating layers including shallow trench isolation (STI) or inter-layer dielectrics (ILD). SOD has several advantages over high density plasma chemical vapor deposition (HDP-CVD) for manufacturing process, such as less defect and higher throughput. However, both SOD and HDP-CVD have a drawback, which is a high temperature curing process required to make pure silicon oxide layers. High temperature curing could cause high stress and thermal distortion. These disadvantages are becoming more problematic as the semiconductor device shrinks. To resolve the problem, we tested several additives to moderate the curing temperature. It was found out that amine compounds were effective to convert SOD polymer into silicon oxide, therefore the curing process could be performed at a lower temperature. We also observed that the SOD films containing amine additives have higher etch resistance during a wet etch process. These results, as well as the lower curing temperature, are beneficial for manufacturing insulating layers. Further investigation is ongoing to characterize other film properties of the SOD with additives, and to optimize the formulation conditions according to the requirements of manufacturing processes.
In the recent semiconductor industry, as the device shrinks, spin-on dielectric (SOD) has been adopted as a
widely used material because of its excellent gap-fill, efficient throughput on mass production and highly competitive
initial cost of ownership. Among various semiconductor applications, SOD is especially valued as the suitable gap-fill
material for shallow trench isolation (STI), because the previously adopted technology, high density plasma chemical
vapor deposition (HDP-CVD), has a significant problem with void-free gap-fill on patterns with high aspect ratios. As
SOD is spin-coated on those narrow patterns, planarization is one of the important requirements. On the course of our
efforts on developing novel modified SOD materials, we discovered that the reactivity of each SOD resins has
meaningful correlation with the degree of planarization. In this paper, three experiments have been illustrated to prove
this correlation, 1) step coverage test, 2) humid air bubble test, and 3) film thickness shrinkage upon prebake. The SOD
resin with lower reactivity turned out to exhibit 1) larger size of circle around silica-beads, 2) slower molecular weight
growth under humid bubble condition, and 3) higher shrinkage upon prebake.
In the recent semiconductor mass production, the tri-layer hardmask system has become crucial for successful patterning
in many applications. Silicon-based anti-reflective spin-on hardmask (Si-SOH), which can be built by spin-on coating, is
desirable in terms of mass production throughput and the overall cost of ownership. As the pattern size shrinks, the
thickness of photoresist also becomes thinner, which forces the thickness of Si-SOH to be thinner resulting in a tighter
thickness margin. In this case, controlling optical properties of Si-SOH becomes important in order to achieve low
reflectivity in the exposure process. In addition, the tri-layer system can be set up more easily when the etch properties
of Si-SOH can be controlled. Previously, we reported papers on silicon-based anti-reflective spin-on hardmask materials
for 193 nm lithography, immersion ArF lithography, and optimization of optical properties of Si-SOH. In this paper, the
technique for controlling etch properties of Si-SOH by a different type of monomer is described. To control etch
properties in the same resin platform, the synthesis method was modified. Characterization of the Si-SOH synthesized
by the new technique and the lithographic performance using this material are described in detail.
In the current semiconductor industry, hardmasks have become essential for successful patterning in many applications. Silicon-based anti-reflective spin-on hardmask (Si-SOH), which can be built by spin-on coating, is desirable in terms of mass production throughput and cost of ownership. As the design rule shrinks, the thickness of photoresist also becomes thinner, which forces the thickness of Si-SOH to be thinner resulting in a tighter thickness margin. In this case, controlling of optical properties of Si-SOH is important in order to obtain low reflectivity in the exposure process. Previously, we reported papers on silicon-based anti-reflective spin-on hardmask materials for 193 nm lithography and immersion ArF lithography. In this paper, the technique for optimization of optical properties, especially n and k values, of Si-SOH is described. To control n and k values, several chromophores were screened and the ratio among them was optimized. Although the amount of chromophores increased and the silicon contents decreased, our etch resistance enhancement technique allowed Si-SOH to have sufficient etch resistance. Characterization of this Si-SOH and lithographic performance using these materials are described in detail.
In current semiconductor manufacturing processes, hardmasks have become more prevalent in patterning of
small features. A silicon-containing hardmask, which can be spun onto wafers, is desirable in terms of mass production
throughput and cost of ownership. Previously, we reported a paper on silicon-based anti-reflective spin-on hardmask
materials for 193 nm lithography. In this paper, hardmask materials for 45 nm pattern of immersion ArF lithography
are described. To achieve 45 nm patterning, a different base resin platform from the previous paper has been used.
Furthermore, we have improved the etch resistance by changing our synthesis method without modifying the resin
platform and silicon contents. Despite these changes, an excellent storage stability, which is one of the essential
requirements for the materials, is still maintained. Characterization and lithographic performance of 45 nm immersion
ArF lithography using our new materials are described in detail.
In ArF lithography for < 90nm L/S, amorphous carbon layer (ACL) deposition becomes inevitable process because thin
ArF resist itself can not provide suitable etch selectivity to sub-layers. One of the problems of ACL hardmask is surface
particles which are more problematic in mass production. Limited capacity, high cost-of-ownership, and low process
efficiency also make ACL hardmask a dilemma which can not be ignored by device makers. One of the answers to these
problems is using a spin-on organic hardmask material instead of ACL hardmask. Therefore, several processes including
bi-layer resist process (BLR), tri-layer resist process (TLR), and multi-layer resist process (MLR) have been investigated.
In this paper, we have described spin-on organic hardmask materials applicable to 70nm memory devices. Applications
to tri-layer resist process (TLR) were investigated in terms of photo property, etch property and process compatibility.
Based on the test results described in this paper, our spin-on hardmask materials are expected to be used in mass
As the feature sizes of integrated circuits shrink, thinner photoresist coating should be used in order to avoid
high aspect ratio which can cause pattern collapse. Especially for 193 nm lithography, photoresist coating is too thin to
subsequent etching step. One of the solutions to this problem is using hardmasks which have good etch selectivity to
adjacent layers. In this paper, silicon-based anti-reflective spin-on hardmasks (Si-SOH) are described. One of the
major problems of silicon based polymers in the hardmask compositions is poor storage stability because silanol group is
reactive enough to condense each other, which can instigate molecular weight increase to yield gel-type particles. The
storage stability of our hardmask materials have been improved by thermodynamically controlled synthesis and reactive
mask strategy. Especially the reactive masked silanol groups can take part in crosslinking reaction under the process
conditions without additional deprotection step. Although this strategy could encounter intermixing problems with
other layers, we can produce silicon-based hardmasks without any deleterious effects. These hardmasks show antireflective
properties and great etch selectivity to both photoresists and organic hardmasks (C-SOH).