Printed circuit board and electric device configured to facilitate bonding

A circuit board, for mounting an electric device which comprises a package, a semiconductor device being provided in the package and a plurality of leads each having one end portion extending out from the package, the circuit board comprising:

• an insulating substrate having a flat upper surface;
• and
• a pad electrode formed on the flat upper surface of the insulating substrate and having a thinner portion and a thicker portion, wherein a portion of a lead contacts the thicker portion, thereby forming a gap, filled with bonding material, between the thinner portion of the pad electrode and one end portion of the lead, each of the thinner and thicker portions comprises an upper surface facing upward away from the insulating substrate and a flat lower surface contacting the flat upper surface of the insulating substrate, and at least one of the upper surfaces is a linearly inclined sloped surface that inclines in the direction from the thinner portion toward the thicker portion.

A circuit board, for mounting an electric device which comprises a package, a semiconductor chip being provided in the package, and a plurality of leads each having one end portion extending out from the package, the circuit board comprising:

• an insulating substrate;
• and
• a plurality of pad electrodes formed on a same side of the insulating substrate, the plurality of pad electrodes including at least one thinner pad electrode and at least one thicker pad electrode, at least one lead being mounted on a corresponding thinner electrode among the plurality of pad electrodes to thereby form a gap, filled with solder, between the lead and the corresponding thinner electrode.

The circuit board according to claim 11, wherein at least three thicker pad electrodes and at least one thinner pad electrode are formed on the insulating substrate, and a bonding material fills the gap formed between the thinner pad electrode and one end of the lead.

An electric device mounted on a circuit board which has a plurality of pad electrodes each having a surface contacting a same side of the circuit board, the plurality of pad electrodes including at least one thinner pad electrode and at least one thicker pad electrode, and the electric device comprising:

• a packaging including a semiconductor device;
• and
• a plurality of leads, at least three of the leads being longer than other ones of the leads, each of the longer leads having one end portion which is bonded to a corresponding thinner pad electrode among the plurality of pad electrodes, each of the other leads having one end portion which is bonded to a corresponding thicker pad electrode among the plurality of pad electrodes, and a bonding material filling a gap formed between each of the other leads and its corresponding thicker pad electrode.

A circuit board for mounting an electric device having a plurality of leads, the circuit board comprising:

• an insulating substrate;
• and
• a pad electrode formed on the insulating substrate, the pad electrode including an upper portion and a lower portion, wherein the lower portion is configured to be bonded to a lead, and wherein the lower and upper portions comprise sloped planes, and the slope of the lower portion is greater than the slope of the upper portion.

An electric device mounted on a circuit board which has a plurality of pad electrodes each having a surface contacting the circuit board, the electric device comprising:

• a package including a semiconductor device;
• and
• a plurality of leads, each having one end portion which is bonded to a corresponding pad electrode among the plurality of pad electrodes, at least three of the leads being longer than other ones of the leads, and a bonding material filling a gap formed between each of the other leads and its corresponding pad electrode, wherein the three leads and the pad electrodes corresponding to the three leads are, respectively, dummy leads and dummy pad electrodes that are electrically unconnected.

A circuit board for mounting an electric device having at least one lead, the circuit board comprising:

• an insulating substrate having a flat upper surface;
• and
• a stepped slope pad electrode formed on said flat upper surface of the insulating substrate, said pad electrode including an upper portion, a lower portion, and an intermediate portion located between said upper and lower portions, wherein each of said upper, lower, and intermediate portions comprises an upper surface facing upward away from said insulating substrate and a flat lower surface contacting the flat upper surface of the insulating substrate, and at least one of said upper surfaces is a sloped surface.