Multiple photolithographic exposures with different clear patterns
AssigneeMosel Vitelic, Inc.
InventorJohn Cauchi
Life of this patent
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Abstract
A photoresist layer is exposed two or more times. At least one exposure is conducted through a regular mask, and at least one exposure through a modified mask with a clear region overlapping the position of a non-clear region of the first mask. The radiation dose used with the modified mask is insufficient by itself to create a resist pattern on the substrate. The exposure through the modified mask alleviates the resist underexposure in concave corners of the opaque pattern of the regular mask. Instead of the modified mask, an exposure without a mask can be performed.
Claims14
A method for processing a layer of material sensitive to radiation, the layer being formed on a substrate, the method comprising:
- irradiating the material with said radiation;
- and
- developing the material to remove a portion of the material and expose a portion of the substrate, creating a pattern defined by the exposed portion of the substrate;
- wherein the irradiating operation comprises:
- (a) irradiating said material with said radiation through a first mask, wherein the first mask has a clear region and a non-clear region;
- and
- (b) irradiating said material with said radiation without a mask, or through a second mask which has a clear region at a position of at least a portion of the non-clear region of the first mask, wherein a radiation dose in the operation (b) is insufficient by itself to enable the developing operation to create a pattern with a portion of the substrate exposed and a portion of the substrate not exposed.
Dependencies are inferred from the claim text.