Co/Cu selective wet etchant
AssigneeVersum Materials US, LLC
InventorsChung-Yi Chang, Wen Dar Liu, Yi-Chia Lee
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Abstract
The disclosed and claimed subject matter relates to wet etchants exhibiting high copper and cobalt etching rates where the etching rate ratio between the two metals can be varied. The wet etchants have a composition comprising a formulation consisting of: at least one alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent with the amino and hydroxyl substituents attached to two different carbon atoms; at least one pH adjuster for adjusting the pH of the formulation to between approximately 9 and approximately 12; at least one chelating agent; and water.
Claims21
A formulation consisting of:
- (i) at least one alkanolamine having at least two carbon atoms, at least one amino substituent and at least one hydroxyl substituent with the amino and hydroxyl substituents attached to two different carbon atoms;
- (ii) at least one pH adjuster comprising an inorganic acid or an organic acid selected from the group consisting of citric acid, sulfuric acid, phosphoric acid, oxalic acid, malonic acid, lactic acid, adipic acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, toluenesulfonic acid and a halogen acids of the formula H—X wherein X═F, Cl, Br, or I;
- (iii) at least one chelating agent;
- (iv) water;
- (v) optionally at least one water miscible solvent;
- and
- (vi) optionally at least one organic wettability adjusting material,
- wherein the formulation has a pH between approximately 9 and approximately 12.
Dependencies are inferred from the claim text.