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(11) | EP 0 841 167 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method of producing a through-hole, silicon substrate having a through-hole, device using such a substrate, method of producing an ink-jet print head, and ink-jet print head |
| (57) The invention provides a method of producing a through-hole, a substrate used to
produce a through-hole, a substrate having a through-hole, and a device using such
a through-hole or a substrate having such a through-hole, which are characterized
in that: a through-hole can be produced only by etching a silicon substrate from its
back side; the opening length d can be precisely controlled to a desired value regardless
of the variations in the silicon wafer thickness, and the orientation flat angle,
and also regardless of the type of a silicon crystal orientation-dependent anisotropic
etchant employed; high productivity, high production reproducibility, and ease of
production can be achieved; a high-liberality can be achieved in the shape of the
opening end even if temperature treatment is performed at a high temperature for a
long time; and a high-precision through-hole can be produced regardless of the shape
of a device formed on the surface of a substrate. The method of producing a through-hole
comprises the steps of: (a) forming a dummy layer on the principal surface of the
substrate at a location where the through-hole will be formed, the dummy layer being
capable of being selectively etched without etching the material of the substrate;
(b) forming a passivation layer having resistance to an etching process on the substrate
in such a manner that the dummy layer is covered with the passivation layer; (c) forming
an etching mask layer on the back surface of the substrate, the etching mask layer
having an opening corresponding to the dummy layer; (d) etching the substrate by means
of a crystal orientation-dependent anisotropic etching process until the dummy layer
is exposed via the opening; (e) removing the dummy layer by etching the dummy layer
from the part which has been exposed in the step of etching the substrate; and (f)
partially removing the passivation layer so as to form a through-hole. |