Development of full-fill bottom antireflective coatings for dual-damascene process

Abstract

ABSTACT Among the variety of dual damascene (DD) processes, the via-first approach has drawn much attention because of its reduced process steps and improved photolithography process window. The via-first process requires a layer of via-fill material to be applied beneath the photoresist layer. The primary function of this via-fill material is to act as an etch-block at the base of the vias to prevent over-etching and punch-through of the bottom barrier layer during the trench-etch process. However, such materials also help to planarize the substrate and may limit back reflection from the substrate as well, helping to control the critical dimension (CD) of the printed features. Based on this understanding, our research efforts have been focused on the advancement of DD-applicable bottom antireflective coatings (BARCs). A series of novel plananzing DUV BARCs with full-via-fill properties and enhanced etching selectivity to resists have been developed. They showed good full-fill, void-free performance in O.2Oim vias having an aspect ratio of five(5), also sufficient top coverage i.e., enough coating thickness, low surface variation, and little thickness bias of isolated-via (1:10) area versus dense-via (1:1) area. The resist sidewall profiles with feature sizes less than O.2Oim indicated that there was good compatibility of the BARCs with the resists. The thin film etching selectivity to commercial resists was about I .2: 1 under an HBr/02 atmosphere. A study of the BARCs described in this report allows further discussion of the impact of pattern density, feature size, and processing conditions on BARC coating performance.

Resist Poisoning Studies of Gap Fill Materials for Patterning Metal Trenches in Via-First Dual Damascene Process

“…At the present stage of lithography, the output of an ArF excimer laser at 193 nm is used for the 45 -90 nm patterning and metal interconnects by the dual damascene (DD) process. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The DD process etches a dielectric layer to form a pattern of a metal conductor wire, and then fills the pattern with metal. The DD process can be classified into two principal types, namely, trench-first DD and via-first DD.…”

Development of Developer-Soluble Gap Fill Materials for Planarization in Via-First Dual Damascene Process

“…Gap fill materials for planarization are needed to ensure that the trench-patterning process produces the best profiles and critical dimension (CD) control. [1][2][3][4][5][6][7][8][9][10] One important property of a gap fill material is the ability to fill gaps properly without forming any voids. Void formation causes nonuniform etching and leads to some vias being insufficiently protected by a gap fill material during trench etching.…”

Study of High Etch Rate Bottom Antireflective Coating and Gap Fill Materials Using Dextrin Derivatives in ArF Lithography

“…In particular, porous ultralow-k films are required by the microelectronics industry as interlayer dielectrics for a 65 nm node and below in dual damascene technologies. [9][10][11][12] These porous ultralow-k films have high etch rates in CF 4 gas compared with SiO 2 , SiOF, and nonporous low-k films (SiOC). The high etch rate of gap fill materials is needed to avoid crowning or fencing on top of the trench after the etch process in via-first dual damascene technologies.…”