Electric heating – Metal heating – By arc
Reexamination Certificate
2001-05-30
2003-03-04
Dunn, Tom (Department: 1725)
Electric heating
Metal heating
By arc
C219S121700
Reexamination Certificate
active
06528757
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for and a method of processing a gate portion in a semiconductor manufacturing apparatus. More particularly, the present invention relates to an apparatus for and a method of processing a gate portion in a semiconductor manufacturing apparatus, which remove a gate correspondence portion from a semiconductor package connected to a lead frame, and a resin burr deposited on a lead portion associated with the semiconductor package.
2. Description of the Related Art
A semiconductor manufacturing apparatus includes the steps of: sealing many semiconductor parts in a lead frame, which is continuously extending in a direction in a form of band, with resin by an injection molding operation, and assembling as a semiconductor package, and then cutting and removing a gate portion resulting from the molding operation, and a resin burr deposited on a runner portion and a lead portion.
FIG. 1
shows the schematic shape of a lead frame
101
and the arrangement of many semiconductor packages
102
assembled on the surface of the lead frame.
FIGS. 2A and 2B
show the gate portion deposited on one semiconductor package
102
and the resin burrs deposited on a runner portion and a lead portion, mainly with regard to an upper half. The semiconductor package
102
has a lead portion
104
extending to an outer side from an inner side, as a part of a lead frame that short-circuits a peripheral portion of a hole
103
formed in the lead frame
101
. When the semiconductor package
102
is formed, a gate correspondence portion
105
formed in a runner and a gate of a molding member of a transfer mold (an injection molding machine), and a runner correspondence portion
106
formed in the runner connected to the gate are left after the molding operation. The gate correspondence portion
105
is deposited on one side of a central portion located at a center in a thickness direction of the semiconductor package
102
. A resin burr
109
is left after the molding operation at a thickness equal to that of the lead portion
104
on the surface around the lead portion
104
.
FIG. 3
shows a cutting mold
107
for cutting and removing the gate correspondence portion
105
and the runner correspondence portion
106
. As shown in
FIG. 4
, one of the semiconductor packages flowing in series in the sheet of the lead frame
101
is cut away at a particular point by a punch
108
and a die
110
of the cutting mold
107
. It is cut away by the action that the punch
108
pushes the gate correspondence portion
105
and the runner correspondence portion
106
under an integral condition in one direction. The resin burr
109
is removed by making a pressure of a solution, in which abrasive material and water are mixed, higher at a next process, and spraying it onto the entire semiconductor package, and then dropping.
The semiconductor package has been made further thinner and smaller. High filling resin is used as resin. Only by using the high filling resin, it is difficult to protect the occurrence of a sealing defect (non-filling and generation of void). It is necessary to provide a thickness equal to or greater than a certain value as a thickness of the gate. As the package is made thinner and smaller so that a rate of the gate thickness is greater with respect to the package thickness, the pushing and cutting operation of a known cutting method has the fear of an occurrence of a broken piece
111
at a side position of the lead portion
104
of the package, as shown in FIG.
5
. So, this may bring about a reduction in a yield. On the other hand, the known method of removing the resin burr
109
has the problem that the abrasive material is clogged between the leads in which an interval is made narrower as the semiconductor package is made further thinner and smaller. Also, it has the problem that the mold is damaged since the resin burr is drawn into the cutting mold, at a next step at which a part of the lead portion is cut away by the mold, and the package is sliced.
A technique for solving such problems is known from Japanese Laid Open Patent Application (JP-A-Heisei, 7-201898). This technique radiates a laser to a gate correspondence portion, cuts and separates the gate correspondence portion away from a main body of a package, or forms a notch in the gate correspondence portion, and accordingly makes the pushing and cutting operation using the mold proper. The employment of such laser technique proposes an approach to solve the above-mentioned problems. However, the cut result and the notch formation may be improper depending on the kinds of lasers having various wave lengths and strengths. Also, the cut result and the notch formation may be improper depending on the laser radiation manner. Thus, it is desirable to establish the actually using manner of the laser.
Japanese Laid Open Patent Application (JP-A-2000-21220) discloses the following method of manufacturing a light guide plate. The method of manufacturing a light guide plate is the method of injecting melt synthetic resin from a gate placed in a casting mold into a cavity, and molding a light guide plate portion and a gate portion protruding from the light guide plate portion, and then removing the gate portion from the light guide plate portion, and accordingly manufacturing the light guide plate, wherein the removal of the guide plate portion is done by using an energy beam.
SUMMARY OF THE INVENTION
The present invention is accomplished in view of the above mentioned problems. Therefore, an object of the present invention is to provide an apparatus for and a method of processing a gate portion in a semiconductor manufacturing apparatus, which can establish an actual application technique of a laser in order to properly cut a gate.
In order to achieve an aspect of the present invention, an apparatus processing a gate portion in a semiconductor manufacturing apparatus, includes: a laser beam scanner unit disposed along a carrying line on which a lead frame is carried; and a cutter, and wherein the laser beam scanner unit has an optical scanner unit second-dimensionally scanning laser beams, and a lens unit collecting the laser beams, and wherein the cutter has a punch, the punch mechanically pushing and cutting a gate correspondence portion which is perfectly cut away or almost cut away from a semiconductor package body by the laser beams.
In this case, the laser beams are YAG laser beams.
Also in this case the optical scanner unit includes: a first scanner unit scanning a light collection point of the laser beams in an X-axis direction; and a second scanner unit scanning the light collection point of the laser beams in a Y-axis direction substantially orthogonal to the X-axis direction, and wherein the laser beam scanned in the Y-axis direction cuts away the gate correspondence portion, and wherein the laser beam scanned in the Y-axis direction removes resin burrs deposited on lead portions exposed from the semiconductor package body.
Further in this case, scan lines of the laser beams scanned in the X-axis direction includes two scan lines oriented in the X-axis direction and a micro scan line which connects the two scan lines to be oriented in the Y-axis direction.
In this case, the apparatus processing a gate portion in a semiconductor manufacturing apparatus further includes: a picture inspector calculating a distance between a boundary line between the gate correspondence portion and the semiconductor package body, which is equivalent to a cut line by the cutting operation of the cutter, and an end plane of the semiconductor package located on a side opposite to the cut line, based on a picture to be photographed to judge whether or not the distance is within a set range.
Also in, this case, the picture inspector includes a CCD camera having a pixel address on a photographic plane.
A method of processing a gate portion in a semiconductor manufacturing apparatus, includes: scanning a radiation point of a laser beam in a X-axis direction; scan
Dunn Tom
Johnson Jonathan
Katten Muchin Zavis & Rosenman
NEC Corporation
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