Method of forming an opening in a dielectric layer through a photoresist layer with silylated sidewall spacers
First Claim
1. A method for forming an opening in a dielectric layer formed over a semiconductor substrate, comprising the steps of:
- coating a base photoresist layer over the dielectric layer;
performing a photolithographic process to remove a selected part of the base photoresist layer lies directly over the part of the dielectric layer where the intended opening is located;
performing a conformational coating process to coat a silylatable photoresist layer over the base photoresist layer to a controlled predefined thickness;
performing a silylation process on the silylatable photoresist layer so as to form a silylated photoresist layer over all the exposed surfaces of the base photoresist layer;
performing a first etching process on the silylated photoresist layer, with the remaining part of the silylated photoresist layer serving as silylated sidewall spacers on the base photoresist layer;
with the combined structure of the base photoresist layer and the overlying silylated sidewall spacers serving as mask, performing a second etching process on the dielectric layer to etch away the unmasked part of the dielectric layer to form the intended opening in the dielectric layer; and
removing the combined structure of the base photoresist layer and the overlying silylated sidewall spacers.
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Abstract
A semiconductor fabrication method is provided for forming an opening in a dielectric layer, which can help downsize the critical dimension of the resulting opening through the use of a photoresist layer with silylated sidewall spacers. By this method, the first step is to coat a base photoresist layer over the dielectric layer. Next, a photolithographic process is performed to remove a selected part of the base photoresist layer. Then, a conformational coating process is performed to coat a silylatable photoresist layer over the base photoresist layer to a controlled predefined thickness. Subsequently, a silylation process is performed on the silylatable photoresist layer so as to form a silylated photoresist layer over all the exposed surfaces of the base photoresist layer. After this, a first etching process is performed on the silylated photoresist layer, with the remaining portions of the silylated photoresist layer serving as silylated sidewall spacers on the base photoresist layer. Then, with the combined structure of the base photoresist layer and the overlying silylated sidewall spacers serving as mask, a second etching process is performed on the dielectric layer to etch away the unmasked part of the dielectric layer to form the intended opening in the dielectric layer.
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Citations
11 Claims
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1. A method for forming an opening in a dielectric layer formed over a semiconductor substrate, comprising the steps of:
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coating a base photoresist layer over the dielectric layer; performing a photolithographic process to remove a selected part of the base photoresist layer lies directly over the part of the dielectric layer where the intended opening is located; performing a conformational coating process to coat a silylatable photoresist layer over the base photoresist layer to a controlled predefined thickness; performing a silylation process on the silylatable photoresist layer so as to form a silylated photoresist layer over all the exposed surfaces of the base photoresist layer; performing a first etching process on the silylated photoresist layer, with the remaining part of the silylated photoresist layer serving as silylated sidewall spacers on the base photoresist layer; with the combined structure of the base photoresist layer and the overlying silylated sidewall spacers serving as mask, performing a second etching process on the dielectric layer to etch away the unmasked part of the dielectric layer to form the intended opening in the dielectric layer; and removing the combined structure of the base photoresist layer and the overlying silylated sidewall spacers. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of defining a photoresist mask on a semiconductor wafer, comprising the steps of:
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coating a base photoresist layer over the wafer; performing a photolithographic process to remove a selected part of the base photoresist layer so as to form an opening in the base photoresist layer; forming a silylated sidewall spacer to a controlled thickness on the sidewall of the opening in the base photoresist layer, wherein the combined structure of the base photoresist layer and the silylated sidewall spacer serve as the intended photoresist mask. - View Dependent Claims (9, 10, 11)
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Specification