This paper describes the research completed to qualify materials to be used as bottom anti-reflective coatings (BARCs) for dual damascene (DD) photolithography. Several problems have been identified in the DD process. Among them are low fill, iso-dense bias, meniscus shape, via wall coating, and void formation. The issue focused upon in this research is incomplete displacement or void formation in the vias. These voids will have detrimental effects and could ultimately cause chip failure.
Flash memory chips are playing a critical role in semiconductor devices due to increased popularity of hand held electronic communication devices such as cell phones and PDAs (personal Digital Assistants). Flash memory offers two primary advantages in semiconductor devices. First, it offers flexibility of in-circuit programming capability to reduce the loss from programming errors and to significantly reduce commercialization time to market for new devices. Second, flash memory has a double density memory capability through stacked gate structures which increases the memory capability and thus saves significantly on chip real estate. However, due to stacked gate structures the requirements for manufacturing of flash memory devices are significantly different from traditional memory devices. Stacked gate structures also offer unique challenges to lithographic patterning materials such as Bottom Anti-Reflective Coating (BARC) compositions used to achieve CD control and to minimize standing wave effect in photolithography. To be applicable in flash memory manufacturing a BARC should form a conformal coating on high topography of stacked gate features as well as provide the normal anti-reflection properties for CD control. In this paper we report on a new highly conformal advanced i-line BARC for use in design and manufacture of flash memory devices. Conformal BARCs being significantly thinner in trenches than the planarizing BARCs offer the advantage of reducing BARC overetch and thus minimizing resist thickness loss.
This paper describes the development of a new conformal i- line BARC. With the advent of flash memory deices the topography can be greater than 0.5 micrometers . Maintaining CD control through the BARC etch step over such a high topography can be a challenge. In order to meet these needs, Brewer Science has developed a highly conformal, spin bowl compatible BARC with increased baseline etch rate. This new BARC exhibits excellent coverage on high topographies and thus reduces the need for over-etch due to its conformality , and also increase the throughput due to its higher etch rate. As the circuit density on the chip increases copper is being implemented as the metal of choice for interconnects to reduce line resistance in semiconductor devices. This paper also describes the development of an organic BARC for applications in dual damascene processing. Via first dual damascene processes used for copper integration requires materials which can provide anti-reflection properties as well as act as etch blocks by filling the vias. The dual damascene BARC reported in this paper exhibits excellent via fill properties to reduce resist thickness variations as well as provide anti-reflective and via etch block properties. This paper outlines the design, development, and performance characterization of the new i-line BARC platforms for both high topography as well as dual damascene applications in sub 0.35 (Mu) m i-line lithography.
This paper presents the chemistries and properties of organic, spin-on, bottom antireflective coatings (BARCs) that are designed for 193 nm lithography. All of the BARCs are thermosetting and use dye-attached/incorporated polymers. A first generation product, NEXT, will soon be commercialized. NEXT is built form i-line and deep-UV chemistries with the polymeric constituent being a substitute novolac. This product provide outstanding resolution of 0.16 micrometers L/S with several 193 nm photoresists. Second generation chemical platforms under study include acrylics, polyesters, and polyethers with the 193 nm absorbing chromophore being an aromatic function. The performance of selected BARCs from the four platforms is described, including: optical properties, 193 nm litho, plasma etch rates, Prolith modeling data, spin-bowl and waste line compatibility, and ambient stability.