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(12) Patent Application Publication (10) Pub. No.: US 2012/0244690 A1 U0zumi (43) Pub

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(12) Patent Application Publication (10) Pub. No.: US 2012/0244690 A1 U0zumi (43) Pub US 2012O244690A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2012/0244690 A1 U0Zumi (43) Pub. Date: Sep. 27, 2012 (54) ION IMPLANTED RESIST STRIP WITH CD7C 309/06 (2006.01) SUPERACID BOSB I3/00 (2006.01) GO3F 7/42 (2006.01) (75) Inventor: Yoshihiro UoZumi, Somers, NY (52) U.S. Cl. ............... 438/514; 156/345.23; 156/345.21; (US) 134/3:510/176; 568/5:562/113; 423/467; 257/E21474 (73) Assignee: TOSHIBA AMERICA ELECTRONIC COMPONENTS, (57) ABSTRACT INC. Irvine, CA (US) According to certain embodiments, a resist is placed over the Surface of a semiconductor structure, wherein the resist cov (21) Appl. No.: 13/069,625 ers a portion of the semiconductor structure. Dopants are 1-1. implanted into the semiconductor structure using an ion (22) Filed: Mar. 23, 2011 implantation beam in regions of the semiconductor structure O O not covered by the resist. Due to exposure to the ion implan Publication Classification tation beam, at least a portion of the resist is converted by (51) Int. Cl. exposure to the ion beam to contain an inorganic carbonized HOIL 2L/426 (2006.01) material. The semiconductor structure with resist is contacted C23F I/08 (2006.01) with a Superacid composition containing a Superacid species COIB 7/46 (2006.01) to remove the resist containing inorganic carbonized materi C07F 5/02 (2006.01) als from the semiconductor structure. Patent Application Publication Sep. 27, 2012 Sheet 1 of 5 US 2012/0244690 A1 109 105 107105 Y 105E, 105 y Figure 1 105 Figure 2 Patent Application Publication Sep. 27, 2012 Sheet 2 of 5 US 2012/0244690 A1 As ion dose (atons.cfm?) Eas 16 essa x5 s son s E 1500 2OO law enumber (crir Figure 3 Patent Application Publication Sep. 27, 2012 Sheet 3 of 5 US 2012/0244690 A1 Figure 4 Patent Application Publication Sep. 27, 2012 Sheet 4 of 5 US 2012/0244690 A1 506 Figure 5 Patent Application Publication Sep. 27, 2012 Sheet 5 of 5 US 2012/0244690 A1 Placing A Resist Over The Surface Of A Semiconductor Structure Exposing The Resist To An Ion Implantation Beam 604 Contacting The Resist With A Superacid Composition 606 608 Recovering The Semiconductor Structure With The Resist Removed f Figure 6 US 2012/0244690 A1 Sep. 27, 2012 ION MIPLANTED RESIST STRIP WITH 0012. As shown in FIG. 2, impurity regions 205 are SUPERACID formed on the semiconductor structure 101 due to exposure to the ion implantation beam 109. Such doped regions can form FIELD the Source and drain regions of transistor structures or other 0001 Embodiments described herein generally relate to functional regions. Before additional processing acts can be methods and devices for removing carbonized materials from performed, the resist 105 typically needs to be removed. semiconductor structures. 0013 The resist 105 is typically formed from an organic polymer material. The resist can contain light-sensitive mate BACKGROUND rials to assist in patterning the resist; however, the methods 0002 Semiconductor devices are formed by combining disclosed herein are not dependent upon any specific compo materials having varying conductive properties. In general, sition for the resist. Exposure of the resist to an ion implan semiconductor structures and devices can contain electric tation beam introduces undesirable chemical changes to the insulators, electrical conductors and semiconductor materials resist 105 complicating removal of the resist 105. High-en that have electrical properties intermediate to insulators and ergy ion implantation beams can carbonize the resist. As conductors. The properties of semiconductor materials can be defined herein, carbonization refers to a portion of the resist adjusted through the introduction of dopants or impurities. containing inorganic carbon bonds. A material containing 0003 Impurities are added to semiconductor materials inorganic carbon bonds has at least of a portion of the carbon using ion implantation techniques. Ion implantation tech atoms contained in the resist bonded only to other carbon niques function through the production of ions of a desired atoms. That is, a portion of the carbon atoms in a carbonized element or molecule produced in an ion source. The ion is inorganic material are not bonded to organic bases such as accelerated to a high energy using magnetic fields, where methyl or ethylbases. However, it must be noted that carbon higher energy results in a greater depth of penetration. How hydrogen bonds can be present in the resist after exposure. ever, high-energy ion implantation can result in undesirable 0014 Carbonization is indicated by a portion of the carbon chemical changes to a resist used for selectively doping a atoms present being involved only in carbon-carbon inor semiconductor. ganic bonding. A carbonized material having inorganic car bon-carbon bonds can contain one or more of graphite or BRIEF DESCRIPTION OF DRAWINGS micro crystallized carbon. Graphite is an allotrope of carbon where carbon forms hexagonal rings of carbonatoms bonded 0004 FIG. 1 shows an embodiment semiconductor with a to three other carbon atoms. Mirco crystallized carbon is a resist present on a Surface thereof. material that contains sp. hybridized carbon, however, a full 0005 FIG. 2 shows an embodiment semiconductor struc three-dimensional lattice is not present. As examples, the ture with impurity doped regions. inorganic carbonized material can be one or more selected 0006 FIG. 3 shows Raman spectra of resists implanted from graphite, fullerene, graphene, carbon nano-tube and with varying ion doses. micro crystallized carbon, among others. 0007 FIG. 4 shows an embodiment semiconductor struc ture after contact with a Superacid composition in accordance 0015. As discussed, exposure of the organic polymer with some embodiments. material of the resist converts at least a portion of the organic material in the resist to a carbonized inorganic material. The 0008 FIG. 5 shows an embodiment apparatus for strip extent of carbonization increases as the exposure of the resist ping a resist from a semiconductor structure. to the ion implantation beam increases. A measure of the 0009 FIG. 6 shows a flow chart for an exemplary meth extent of exposure of the resist is the energy of the ion implan odology for removing a carbonized resist in accordance with tation beam. In one embodiment, the ion implantation beam Some embodiments. has energy from about 1 to about 1000 keV. In another embodiment, the ion implantation beam has energy from DETAILED DESCRIPTION about 1 to about 100 keV. In yet another embodiment, the ion 0010. According to one embodiment, a resist is placed implantation beam has energy greater than about 3 keV. over the surface of a semiconductor structure, wherein the 0016. Another measure of exposure of the resist to the ion resist covers a portion of the semiconductor structure. implantation beam is the ion dose delivered to the exposed Dopants are implanted into the semiconductor structure using regions of the semiconductor structure. Although regions of an ion implantation beam in regions of the semiconductor the semiconductor structure covered by the resist do not structure not covered by the resist. The resist is exposed to the receive an ion dose, the resist receives the same exposure as ion implantation beam in the process of blocking deposition the regions of the semiconductor structure actually implanted of dopants into regions of the semiconductor structure cov with ions. In one embodiment, the semiconductor structure ered by the resist. Due to exposure to the ion implantation including a resist is exposed to anion implantation beam Such beam, at least a portion of the resist is converted by exposure that at least one region of the semiconductor device has impu to the ion beam to contain an inorganic carbonized material. rities at a concentration from about 1x10' to about 1x10'7 The resist is contacted with a Superacid composition contain atoms/cm. In another embodiment, the semiconductor struc ing a Superacid species to affect the removal of the resist from ture including a resist is exposed to an ion implantation beam the semiconductor structure. Such that at least one region of the semiconductor device has 0011. As shown in FIG. 1, a resist 105 is placed over a impurities at a concentration from about 1x10' to about portion of a semiconductor structure 101. Openings 107 in the 1x10' atoms/cm. In yet embodiment, the semiconductor resist—regions where the resist does not cover the semicon structure including a resist is exposed to an ion implantation ductor structure—allow for an ion implantation beam 109 to beam Such that at least one region of the semiconductor contact the surface of the semiconductor structure 101. device has impurities at a concentration more than about US 2012/0244690 A1 Sep. 27, 2012 1x10" atoms/cm. Carbonization can occur regardless of the “below' and similar terms indicate that the subject element is identity of the implanted ion including both p-type and n-type closer to the plane of the semiconductor substrate than impurities. another element referred to as a spatial reference. The terms 0017. The presence of inorganic carbonized material in “on.” “above.” “below,” and "over, etc. only indicate a rela the resist after exposure to anion beam can be determined and tive spatial relationship and do not necessarily indicate that measured through the use of Raman spectroscopy. Inorganic any particular elements are in physical contact. The preceding carbonized material produces light scattering intensity at a definitions apply throughout this document. As used through wavenumber shift of about 1600 cm, where organic poly out this disclosure, similar reference numbers refer to similar mer material produces minimal scattering intensity at a wave number shift of 1600 cm. FIG.3, reported by G. G. Totiret structures and features.
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