Image sensor having wave guide and method for manufacturing the same
An image sensor having a wave guide includes a semiconductor substrate formed with a photodiode and a peripheral circuit region; an anti-reflective layer formed on the semiconductor substrate; an insulation layer formed on the anti-reflective layer; a wiring layer formed on the insulation layer and connected to the semiconductor substrate; at least one interlayer dielectric stacked on the wiring layer; and a wave guide connected to the insulation layer by passing through the interlayer dielectric and the wiring layer which are formed over the photodiode.
1. A method for manufacturing an image sensor having a wave guide, comprising the steps of:
(a) forming an anti-reflective layer on a semiconductor substrate which is formed with a photodiode and a peripheral circuit region;
(b) forming an insulation layer on the anti-reflective layer;
(c) forming a conductive wiring layer on the insulation layer;
(d) forming at least one interlayer dielectric on the wiring layer;
(e) selectively etching the interlayer dielectric until the wiring layer, is exposed, so as to form a wave guide over the photodiode; and
(f) selectively etching the wiring layer exposed in the step (e) until a portion of the insulation layer formed over the photodiode is exposed;
wherein the wiring layer provides a conductor that allows plasma-charged ions in the wave guide to be discharged into the semiconductor substrate and not be introduced into the photodiode.
2. The method according to claim 1 , wherein the step (c) comprises the step of:
(c1) connecting the wiring layer to a well which is formed in the semiconductor substrate.
3. The method according to claim 2 , wherein the step (d) comprises the step of:
(d1) forming a passivation layer on an uppermost interlayer dielectric.
4. The method according to claim 2 , wherein the well is formed through N+/P junction when the semiconductor substrate is a P type substrate, and is formed through P+/N junction when the semiconductor substrate is an N type substrate.
5. The method according to claim 2 , wherein, in the step (c), the wiring layer is formed using tungsten (W), aluminum (Al), or titanium (Ti).
6. The method according to claim 2 , further comprising the step of:
(g) etching a portion of the insulation layer exposed in the wiring layer etching step.
7. The method according to claim 2 , further comprising the steps of:
(h) forming a color filter on the passivation layer; and
(i) forming a microlens on the color filter.
8. The method according to claim 1 , wherein the wiring layer acts as a etch stop layer in the course of forming a wave guide so that non-uniformity in etching depth can be avoided.
9. The method according to claim 2 , wherein the wiring layer allows plasma-charged ions in the wave guide to be discharged into the semiconductor substrate via the well formed in the semiconductor substrate.