Search

We examined an environmentally friendly photoresist removal method using H radicals produced by decomposing hydrogen on a hot iridium catalyst. We examined the relationship between photoresist removal rate and its surface temperature using thin film interference and the removal properties using H radicals produced by the Ir catalyst. Decomposition behavior at polymer surface by radicals may be analyzed in further detail from the aspect of kinetics. Additionally, we investigated the oxygen addition effects on the removal rate. The photoresist removal rate increased with the oxygen additive amount and then decreased more gradually than in the case of using W filament. The increasing behavior was similar but there was a large difference between W and Ir catalyst in the decreasing behavior. [ABSTRACT FROM AUTHOR]

This paper proposes a photoresist removal process that uses multibubble microwave plasma produced in ultrapure water. A non-implanted photoresist and various kinds of ion-implanted photoresists such as B, P, and As were treated with a high ion dose of 5 × 1015 atoms/cm2 at an acceleration energy of 70 keV; this resulted in fast removal rates of more than 1 μm/min. When the distance between multibubble microwave plasma and the photoresist film was increased by a few millimeters, the photoresist removal rates drastically decreased; this suggests that short-lived radicals such as OH affect high-speed photoresist removal. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the removal characteristic of positive-tone novolak photoresists into which B, P. and As ions were implanted with doses of 5 x 1012-5 x 1015 atoms/cm2 at an acceleration energy of 70 keV using atomic hydrogen, and the hardening mechanisms for the photoresists. All of the ion-implanted photoresists with doses up to 5 x 1015 atoms/cm2 were removed without regard for ion species. The removal rates of the photoresists decreased with increasing ion-implantation dose due to hardening of the photoresist surfaces with implantation. The thickness of the surface-hardened layer of the photoresists decreased in the order of B → P → As, and the removal rate increased with decreasing thickness. The energy supplied from the ions to the photoresist concentrated on the surface side in the order of B → P → As, and the impact of the heavier ion on the photoresist was greater than that of the lighter ion. We deduced that the photoresists exhibited carbonization and cross-linkage attributable to the decrease in OH, CH, and 0 Is and the increase in C=C, C is, and if-conjugated systems. [ABSTRACT FROM AUTHOR]

Using environmentally friendly wet ozone instead of chemicals, we removed B-, P-, and As-ion-implanted positive-tone novolak photoresists with an implantation dose of 5 x 10 12-1 x 1016 atoms/cm2 at an acceleration energy of 70 keV. Ion-implanted photoresists with an implantation dose exceeding 5 x 1015 atoms/cm2 could not be removed, but photoresists implanted at doses below 5 X 1013 atoms/cm2 could be removed. Photoresist implanted with B ions at 5 x 1014 atoms/cm2 was removed slowly, but photoresists implanted with P and As ions were not removed at all. The hardness of the photoresist with B ions implanted at 5 x 1014 atoms/cm2 was 1.8 times greater than that of the nonimplanted photoresist (AZ6112), that of the P-ion-implanted photoresist was eight times greater, and that of the As-ion-implanted photoresist was five times greater. The B-ion-implanted photoresist was softer than the Pand As-ion-implanted photoresists. We also obtained the calculation results in which the energy supplied from the B ions to the photoresist was lower than that from P and As ions. We assumed that the ion-implanted photoresists were hardened by cross-linkage due to the energies supplied to the photoresists from the ions. Therefore, we determined that the hardness threshold of the photoresist that could be removed by using wet ozone was twice the hardness of AZ6112. [ABSTRACT FROM AUTHOR]

We sought to lower the dissolution rate of resists in unexposed areas, studying the chemical structure of dissolution inhibitor for a chemically amplified three-component (matrix resin, dissolution inhibitor, and acid generator) positive resist. As dissolution inhibitors, carbonic acid ester and carboxylic acid ester were evaluated and compared. In unexposed areas, the dissolution rate of the resist consisting of carboxylic acid ester is lower than that of the resist consisting of carbonic acid ester. Investigations by IR and TGA indicated that the carbonic acid ester became a dissolution promoter since part of the dissolution-inhibition group (tBOC group) is thermally decomposed and converted into a OH group during prebaking. This is due to the inferior thermal stability of the carbonic acid ester compared to the carboxylic acid ester. It is clear that, for high resolution of the chemically amplified resist, carboxylic acid ester is a desirable dissolution inhibitor since it can lower the dissolution rate in unexposed areas. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 2, 80(5): 31–39, 1997 [ABSTRACT FROM AUTHOR]

Mass spectrometry was used to identify the decomposition products of two typical photoresist polymers, Novolak and polymethylmethacrylate, by H atoms produced on hot wire surfaces. The production of CH 4 and CO was confirmed for both polymers. Other possible products are C 3 H 8 , C 4 H 10 or C 4 H 8 , and some esters such as CH 3 COOC 2 H 5 . The production of CO 2 , C 2 H 4 , C 2 H 6 , alcohols, and aromatics are minor. The possible decomposition mechanisms are discussed on the basis of density functional calculations of the energetics. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses the removal of chemically amplified negative-tone i-line resist SU-8 using hydrogen radicals generated by the catalytic decomposition of H2 molecules in H2/N2 mixed gas (H2:N2 =10:90vol.%) using a tungsten hot-wire catalyzer. SU-8 resists with exposure doses from 7 to 280mJ/cm2 were removed by hydrogen radicals, although the SU-8 removal rate was independent of the exposure dose. The SU-8 removal rate increased with both substrate and catalyzer temperature, in addition to a decrease in the distance between the catalyzer and substrate. A high removal rate for cross-linked SU-8 with an exposure dose of 14mJ/cm2 of approximately 4μm/min was achieved with a catalyzer to substrate distance of 20mm, and catalyzer and initial substrate temperatures of 2400 and 165°C, respectively. [Copyright &y& Elsevier]