As critical dimensions in integrated circuit (IC) device fabrication continue to shrink to less than 90 nm, designing multi-functional organic bottom anti-reflective coating (BARC) materials has become a challenge. In this paper, we report novel high performance BARC materials which are simultaneously capable of controlling reflectivity, planarizing on substrate surface, low bias filling without forming voids, low outgassing, high etch selectivity with resists and broad compatibility with resists. The new materials comprise of a chromophore that absorbs at 193 nm to give anti-reflective properties. By intriguing design of the crosslinking system to minimize the amount of low molecular weight additives and the by-product formation in the curing process, low-bias and low sublimation filling without formation of voids are achieved. In addition, the performance of the high etch rate BARC material can be further enhanced by blending with a low k high etch rate (~2.4X) material to achieve ultra high etch rate for ArF lithographic process. The filling properties, etch selectivity, lithographic and outgassing data of the new BARC materials will be presented.
Substrate reflectivity control plays an important role in immersion lithography. Multilayer
bottom anti-reflective coatings (B.A.R.C.s) become necessary. This paper will focus on the
recent development in organic ArF B.A.R.C. for immersion lithography. Single layer low k ArF
B.A.R.C.s in conjunction with multilayer CVD hard mask and dual layer organic ArF B.A.R.C.
application will be discussed. High NA dry and wet lithography data will be presented. We will
also present the etch rate data, defect data and out-gassing property of these new B.A.R.C.
As the feature sizes of integrated circuits shrink, highly anisotropic etching process (i.e., ion-assisted plasma etch, or reactive ion etch (RIE)), becomes even more essential for successful pattern transfer in the fabrication of semiconductor devices. The stringent 193 nm lithography process necessitates the use of bottom anti-reflective coating (BARC) for controlling reflections and improving swing ratios. Prior to RIE of a patterned wafer, the BARC layer must first be opened to allow pattern transfer from the resist mask to the underlying films. As we enter the era of sub-90nm imaging, minimum loss of the photoresist during the BARC open step is becoming more critical, since the demand for higher optical resolution dictates the use of ever thinner resist films. This in turn requires higher etch rate of BARC materials. In this paper we report on the impact of etching gas chemistries on the etch rates of BARC materials. The correlation between the etch chemistry and BARC products will be discussed. Reactive ion etch rates for blanket BARC coatings and BARCs under resist patterns were measured. Etch rates of BARC products of various material compositions were measured with a typical ArF resist as reference. It is well known that the chemical composition and structure of organic materials essentially determine the etch rates under certain etch process conditions. The correlations between etch rates and BARC polymer chemistry are reported. Etch chemistries, (i.e. the chemical interaction of plasma reactive ions with BARC materials), may also have profound effects on etch rates. Here we report on results obtained using four etching gas chemistries to study how oxygen contents, polymerizing gases, and inert gas effect the etch rates of different ArF BARC products.
As the semiconductor industry sails into the 100nm node and beyond, enabled by the integration of ArF lithography, new Bottom Antireflective Coatings (B.A.R.C.s) are required to address challenges associated with this new technology. Of these challenges, higher etch rates and better compatibility with the over coated resist are of central importance. New polymer platforms and additives in B.A.R.C. formulations will be required to overcome these challenges. The intent of this publication is to introduce our newly developed B.A.R.C.s designed to addresses the challenges of ArF lithography. All are currently available for integration into mass production of sub 100nm integrated circuit devices.
Due to miniaturization of semiconductor devices, ArF (193nm) lithography is likely expected to be used for sub 100nm regime. For sub 100nm devices, high NA (>=0.70) exposure tools and various strong off-axis illumination (OAI) conditions should be used. But unlike KrF (248nm) lithography, resist pattern collapse becomes one of the most serious problems in ArF lithography. In order to solve pattern collapse problem, thin resist process is generally introduced but its poor etch resistance is an obstacle for being applied in real production process. Due to this reason, new kinds of organic BARC materials are investigated and optimized to avoid pattern collapse. As mentioned, the most important issue in ArF organic BARC is believed to be the pattern collapse problem. A number of organic BARCs were made by varying polymer, cross-linker, thermal acid generator, and additive. We tried to analyze the key factor in terms of pattern collapse. This paper is to compare the various elements of the organic BARC formulation and to discuss what brings and causes pattern collapse.
To have excellent compatibility with ArF resists is the goal in development of bottom antireflective coatings (B.A.R.C.) for 193nm lithographic application. We need to be able to adjust chemical compatibility and optical properties of ArF B.A.R.C. to accommodate various film stacks. We need to deliver ArF B.A.R.C. materials with excellent coating uniformity, long shelf life and ultra-low defect level. In the meantime, we also need to improve etch rate of the ArF B.A.R.C.s for shorter etch time. In this paper, we will focus on our recent efforts to optimize the organic ArF B.A.R.C.s' compatibility with ArF resists in the areas mentioned above.
Full and/or partial filling of 193 nm antireflective materials in contact holes is required for dual damascene applications. One of the major challenges for via filling is to minimize various fill bias associated with via size, via pitches and wafer size to an acceptable level. Toward this aim, various formulations were prepared and tested on different types of wafers using different processing conditions. It has been found that both the properties of the filling materials (e.g., molecular weights, glass transition temperatures, etc.) and processing conditions (e.g., spinning speed, dispense modes, baking temperatures, etc.) affect the filling behaviors. This paper presents our recent progress in the development of 193 nm B.A.R.C. materials designed for the dual damascene process. Through screening of the B.A.R.C. materials and optimization of the processing parameters, we have successfully developed two types of B.A.R.C. materials, namely, AZ EXP ArF-2P1 and AZ EXP ArF-2P5A, both of which show good filling performance.