Method of positioning lead frame on molding die to seal semiconductor element with resin

A method of positioning a semiconductor lead frame with at least one positional adjustment hole, on a molding die prior to sealing said lead frame with resin, means for positioning said lead frame including a die member with a reference pin and at least one positional adjustment pin, holding means for releasably grasping said lead frame, a horizontal plate member with a reference hole, under which said holding means is located, an x-y driver for moving said horizontal plate member in x-y directions in the plane of said horizontal plate member, and an imaging system with imaging means and imaging circuitry means;

• said method comprising the steps of:
• (a) grasping said lead frame with said holding means;
• (b) operating said x-y driver to move said horizontal plate to a position above said die;
• (c) forming images of said reference pin and said reference hole with said imaging means;
• (d) processing said images with said image circuitry means to form a positional deviation signal representative of a positional difference between said reference pin and said reference hole;
• (e) enabling said x-y driver according to said positional deviation signal, so as to correctly position said horizontal plate with said die;
• and
• (f) lowering said lead frame on to said die.

A method of positioning lead frame on a molding die to seal said lead frame with resin, wherein a semiconductor element is bonded on said lead frame, said method comprising the steps of:

• (a) preparing a die having a top surface at an end position of which an anisotropic pin is planted;
• (b) preparing X-Y driver means provided with a horizontal plate member under which holding means for holding said lead frame is attached, wherein:
• said X-Y driver means is operable to two-dimensionally drive and move said plate member in horizontal X-Y directions and is operable to rotate in a horizontal plane;
• and
• said plate member has a vertical anisotropic through hole at an end region of said plate member;
• (c) holding said lead frame by said holding means;
• (d) carrying said X-Y driver means to a space on said die together with said plate member and said holding means holding said lead frame;
• (e) detecting respective two-dimensional images of said hole and said pin by a two-dimensional-image detector coupled to said plate member to generate an image signal representative of said respective two-dimensional images;
• (f) detecting two-dimensional translational deviation and rotational deviation between said respective images by comparing image portions based on said image signal with each other;
• (g) enabling said X-Y driver means in accordance with said translational deviation and said rotational deviation to two-dimensionally align respective positions of said anisotropic hole and said anisotropic pin in said horizontal directions and to adjust respective angles of said anisotropic hole and said anisotropic pin;
• and
• (h) releasing said lead frame from said holding means to place said lead frame on said die.