Browse Prior Art Database

Fabrication of High Resolution Embossing Dies

IP.com Disclosure Number: IPCOM000061188D
Original Publication Date: 1986-Jul-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 67K

Publishing Venue

IBM

Related People

Krongelb, S: AUTHOR [+3]

Abstract

This article describes a process for fabricating a high resolution embossing die having very deep patterns with desired wall profile in a hard, abrasion-resistant material such as Mo, Ti, SiC, TiC or WC, which can be subsequently used to press patterns into polymers containing Al2O3, gamma - Fe2O3 or similar abrasive particles. Critical conditions for carrying out the process so as to achieve the desired results are also described.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 40% of the total text.

Page 1 of 3

Fabrication of High Resolution Embossing Dies

This article describes a process for fabricating a high resolution embossing die having very deep patterns with desired wall profile in a hard, abrasion-resistant material such as Mo, Ti, SiC, TiC or WC, which can be subsequently used to press patterns into polymers containing Al2O3, gamma - Fe2O3 or similar abrasive particles. Critical conditions for carrying out the process so as to achieve the desired results are also described. Requirements for a high resolution embossing die are that: (a) the die be made of a sufficiently hard material so that it will not wear excessively in the intended application; (b) patterns in the range of 5 to 10 microns must be faithfully replicated; (c) the pattern walls must have a small but definite taper to facilitate release of the die after the impression is made; and (d) the fabrication process must be capable of producing high aspect ratio patterns since the required depth of the die may be as much as 25 microns. Appropriate materials for a hard die include Mo, Ti, W, SiC, TiC and WC. Reactive ion etching or reactive ion milling through a photolithographically-defined plated Ni etch mask is an appropriate means for forming patterns of the desired dimensions. All of the above materials can be etched in a CF4 plasma using an etch mask of Ni or similar non-reactive material following the principles, as taught by Krongelb [1]. It will be noted that, for the mask thickness needed to make useful dies, the mask is best formed by electroplating. Since electroplating cannot be done directly on the materials which are appropriate for the die, it is in turn necessary to deposit an electroplating base on the die blank. The choice of the plating base and the generally required adhesion layer must be consistent with the subsequent requirements of the process. Particularly, these layers, which form a blanket deposition over the entire die surface, must not interfere with the reactive ion etch step. An Au plating base with a Ti adhesion layer meets this requirement since Au is readily eroded by physical sputtering even in a CF4 plasma and Ti is, of course, reactively etched in this environment. The use of Au has a further advantage in that its nobility relative to Ni facilitates the chemical removal of any residual layer of this material and protects the underlying die surface during the process. A brief etch in a suitable etchant, such as potassium iodide (KI) - iodine (I2), will remove the Au. The thickness of the required etch mask is governed by the relative etch rates of the mask and die materials. Obviously, it is desired that the etch rate ratio of the die material to the masking layer be as high as possible and that the etch rate of the die also be high. Reactive ion etching in a CF4 plasma achieve the high etch rate for materials such as Mo, W, Ti, SiC, TiC and WC. The materials, such as Ni, Co, Cu and NiFe, are etched relatively slowly in CF4; these mate...