Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
130 words
A method of forming solder bumps on a board for mounting IC chips on which conductor wiring has been formed, which method is characterized by forming a photosensitive first solder resist on the surface of the board on which the conductor wiring has been formed, forming first openings by photoetching in the sites of the first solder resist where the solder bumps are to be placed, next forming a second solder resist on the first solder resist, forming second openings that connect with the first openings by photoetching at sites of the second solder resist that correspond to the first openings, filling the first and second openings with solder, carrying out reflow treatment, and then etching in such a way that at least part of the first solder resist remains.
Claim 2
Independent Claim
111 words
A method of forming solder bumps on IC chip mounting boards on which conductor wiring has been formed, which method is characterized by coating a liquid first solder resist on the surface of the board on which the conductor wiring has been formed so that it fills the spaces between the conductor lines, forming a second solder resist on the first solder resist, forming openings by photoetching at the sites of the first and second solder resists where the solder bumps are to be formed, filling the openings with solder, carrying out reflow treatment, and then etching in such a way that at least part of the first solder resist remains.
Claim 3
Dependent Claim
24 words
The method of forming solder bumps of Claim 1 or 2 characterized by constructing the second solder resist from a film-like photosensitive solder resist.
Claim 4
Dependent Claim
40 words
The method of forming solder bumps of Claim 1 or 3 characterized by the fact that S₂/S₁ ≧ 1 , where S₁ is the opening area of the first openings and S₂ is the opening area of the second openings.
Claim 5
Independent Claim
41 words
The method of forming solder bumps of any of Claims 1 to 4 characterized by making the first solder resist from a material of slower etching rate than the material of the second solder resist with respect to a specific etchant.
Claim 6
Independent Claim
135 words
A method of forming solder bumps on IC chip mounting boards on which conductor wiring has been formed, which method is characterized by coating a liquid first solder resist on the surface of the board on which the conductor wiring has been formed so that it fills the spaces between conductor wires, forming a photosensitive second solder resist on the first solder resist, forming first openings at the sites of the second solder resist where the solder bumps are to be formed, forming a third solder resist on the second solder resist, forming second openings that connect with the first openings by photoetching at sites of the third solder resist that correspond to the first openings, filling the first and second openings with solder, carrying out reflow treatment, and then removing the third solder resist.
Claim 7
Dependent Claim
39 words
The method of forming solder bumps of Claim 6 which is characterized by establishing that S₂/S₁ ≧ 1 , where S₁ is the opening area of the first openings and S₂ is the opening area of the second openings.
Claim 8
Dependent Claim
19 words
The method of forming solder bumps of Claim 7 characterized by forming the said openings in a zigzag pattern.