The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 13, 2016
Filed:
Sep. 17, 2013
Lintec Corporation, Itabashi-ku, JP;
Tomochika Tominaga, Saitama, JP;
Kazuyuki Tamura, Phoenix, AZ (US);
LINTEC CORPORATION, Itabashi-ku, JP;
Abstract
The present invention relates to a back grinding sheet (BG sheet) () having an unevenness-absorbing layer () on a substrate (), in which the unevenness-absorbing layer is a layer formed of a film-forming composition containing (A) a urethane (meth)acrylate and (B) a polymerizable monomer except component (A) and the layer satisfies the following requirements (a) to (c): (a) a loss tangent at 70° C. measured at a frequency of 1 Hz is 1.5 or more, (b) a relaxation rate 300 seconds after a square (1 cm×1 cm) of the unevenness-absorbing layer is compressed at 25° C. and a compressive load of 10 N is 30% or less, and (c) a storage elastic modulus at 25° C. measured at a frequency of 1 Hz is 1.0 to 10.0 MPa. The BG sheet of the present invention has excellent absorptivity of uneven portions such as bumps in a semiconductor wafer and can suppress formation of gaps between bumps and the BG sheet and simultaneously suppress a phenomenon where the resin layer (unevenness-absorbing layer) of a BG sheet oozes from the edges of a roll when the BG sheet is wound up in the form of roll.