JPH1131775A - Method for manufacturing resin-sealed semiconductor device, and lead frame used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent peeling off, drop, residue, etc., of resin burr from occurring by recovering with the remaining mold burr sticking to a frame body and a thin streak after a lead frame resin sealing process. SOLUTION: In this method, using a lead frame 1 comprising a frame body 6 which connects an external lead 5 drawn out of the one side of an inner lead part 2 and a frame body 8 which connects a thin streak 7 drawn out of the other side of the inner lead part 2, semiconductor substrates 3 and 4 are fixed to a required part of the inner lead part 2, and then molded by resin- sealing (9). After that, the thin streak 7 and the frame body 6 connecting the eternal lead 5 and the frame body 8 connecting the thin streak 7 are removed. When the thin streak 7 is provided with a tensile breakage part 7a and a resin burr reservoir part 7b for removing the thin streak 7 and the frame body 8 connecting the thin streak 7, the thin streak 7 is removed by the tensile breakage part 7a with a resin burr 9a sticking, while a tensile force in drawn out direction is acted on the thin streak 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

Description of the Field of the Invention The present invention relates to a method of manufacturing a resin-encapsulated semiconductor device (2) such as a power device capable of handling relatively large power or a so-called multi-chip module incorporating an IC and a power device. It relates to a lead frame used for this.

[0002]

2. Description of the Related Art In recent years, general resin-encapsulated semiconductor devices are often of the so-called full-mold type in which resin is molded on both surfaces of a support plate on which a semiconductor chip is fixed or internal leads. In this full mold type, after resin molding, unnecessary frames or strips of the lead frame are cut,
Alternatively, the method includes a step of breaking the pre-formed small cut portion by pulling and removing each. In particular, in the case of breaking due to tension, the fracture surface can be placed in the resin, so that when it is attached to an external heat radiator, the creeping distance with the external heat radiator is improved, and there is an advantage that the dielectric strength is improved. Such a resin sealing technology is disclosed in Japanese Patent Publication No. 3-778 and Japanese Patent Publication No. 4-51.
No. 974.

That is, a semiconductor chip is fixed to a support plate or an internal lead (inner lead) which constitutes a part of a lead frame, and the semiconductor chip is connected to an external lead by a thin wire or the like. Next, the lead frame is mounted on a mold, and the molten resin is pressed into the cavity. At this time, the external leads and strips connected to each side of the support plate are gripped by the mold. After the resin has solidified, the lead frame is removed from the mold.

[0004]

It is desirable that the above-mentioned molten resin does not flow out of the cavity to the outside, but oozes out at the portion of the lead frame gripped by the die, and after this portion is solidified, as shown in FIG. It remains as resin burr 10a.
The resin burrs 10a, when the strip 11 is pulled out, cause the attached resin burrs to peel off, fall, and scatter into the apparatus, causing problems such as product clogging and product damage. 4 (a) and 4 (b) are a plan view and a side view showing a conventional example. In the figures, reference numeral 10 denotes a resin sealing molded portion 12, 13 denotes a frame, and 14 denotes external leads.

[0005]

[Object of the invention]

(3) The present invention has been made in order to solve the above-mentioned disadvantages of the prior art, and has an object to keep mold burrs attached to a frame and a strip after a resin sealing step of a lead frame in close contact. , Collecting, and preventing the occurrence of problems such as peeling, dropping, and remaining resin burrs.

[0006]

According to the present invention, there is provided a frame for connecting external leads extending from one side of an inner lead portion,
A semiconductor substrate is fixed to a required portion of the inner lead portion by using a lead frame having a frame that connects strips derived from the other side of the inner lead portion, and after resin sealing and molding, A frame connecting the leads, the strip, and a step of removing the frame connecting the strips, wherein the strip is provided with a tensile break portion and a resin burr-retaining portion, and the frame is connected to the strips. In the step of removing the body, a step of applying a tensile force to the strip in a direction in which the strip is led out and removing the strip at the pull-rupture portion with resin burr adhered is provided.

[0007]

1 (a), 1 (b) and 1 (c) are plan views (before resin sealing) and side views of a lead frame showing an embodiment of the present invention.
And a partially enlarged view. Reference numeral 1 denotes a plurality of lead frames formed by punching a plate-like metal plate, and is connected in the lateral direction. Reference numeral 2 denotes an inner lead portion, of which 2a,
2b is punched in a wide shape as a support plate for fixing the semiconductor chip and also as a heat radiator. Reference numerals 3 and 4 denote a power device (for example, a MOSFET) fixed to a wide portion of the inner lead, an IC chip having a control function, and the like. Reference numeral 5 denotes an external lead derived from one of the inner leads. It is articulated. 6a and 6b are holes, 7 is a strip (flippin) led out to the other side of the inner lead, 8 is the other frame connected to the strip, 8a
Is a hole.

Next, in the strip 7, 7a is processed so as to be narrow in the vicinity of the inner lead portion (base portion). (4) A tensile break portion that is broken by tension, and a cut is made in the outer base portion to facilitate breakage. It may be inserted, thinned, or threaded like a sewing machine. Reference numeral 7b denotes a hemispherical notch formed over the side surface of the frame body 8 above the narrow strip, and is formed by a resin burr reservoir described later. 9
Denotes a resin sealing molded part (mold resin).

FIGS. 2 (a) and 2 (b) are a plan view and a partially enlarged view showing an embodiment of the present invention after resin sealing.
And resin burrs formed on the side surfaces of the frame 8. The present invention is characterized in that a semicircular notch 7b is provided in a part of the strip 7 to have a resin dummy for increasing the adhesion strength of resin burrs generated after resin sealing. The shape of the notch may be trapezoidal or triangular. In addition, the side of the strip may be made uneven, or may be roughened. Next, the generation of resin burrs and the state in which the frame 8 is pulled out in the cutting step from the mold will be described. That is, as shown in FIG. 3, after the resin sealing molding, by pulling one of the frames 8 as shown by the arrow in the figure, the strip 7 can be easily removed with the resin burr 9a attached. Unnecessary portions such as the other frame 6 and the external lead connection portion are thereafter removed by machining or the like.

[0010]

As is apparent from the above description, according to the present invention, a resin burr is formed in a strip connecting the frames by notches or the like to increase the contact area of the burr and increase the bonding strength. The resin burr can be collected with the resin burr kept in contact during the drawing process, preventing the stoppage of the device due to product clogging in the processing device due to the occurrence of resin burr peeling, dropping, residue, etc., and preventing product damage. I can do it.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the present invention (before resin sealing). (5) (a) Plan view (b) Side view (c) Partial sectional view

FIG. 2 is a view of one embodiment of the present invention (after resin sealing) (a) Plan view (b) Side view

FIG. 3 is an explanatory view of an embodiment of the present invention.

FIG. 4 shows a conventional example (a) plan view (b) side view

[Brief description of reference numerals]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Inner lead part 3, 4 Semiconductor substrate (device) 5 External lead 6, 8 Frame 7 Narrow 7a Breaking part 7b Notch part (resin burr pool) 9 Resin sealing molding part 9a Resin burr

Claims (4)

[Claims] 1. A lead frame having a frame for connecting external leads derived from one side of an inner lead portion and a frame for connecting strips derived from the other side of the inner lead portion. Fixing the semiconductor substrate to a required portion of the inner lead portion, molding the resin, and then removing the frame and the strip connecting the external leads, and removing the frame connecting the strip. In the step of providing a tensile breaking portion and a resin burr-retaining portion on the strip and removing the frame connecting the strip and the strip, a tensile force is applied to the strip in a direction in which the strip is led out to attach the resin burr. A method for manufacturing a resin-encapsulated semiconductor device, comprising the step of removing the strip at the tensile break portion while keeping the tension. 2. An inner lead portion (or a semiconductor support plate).
A frame that connects external leads derived from one side of the
In a lead frame having a frame for connecting a strip led out from the other side of the inner lead part (or the semiconductor support plate), the strip is formed by a tensile break portion formed at a base in a lead-out direction, and A lead frame comprising a resin burr pool formed partially or over a frame. 3. The lead frame according to claim 2, wherein a notch is provided in a part of the narrow strip to form a resin burr pool. 4. A resin burr storing part formed by roughening a part of a thin strip or a part of a frame body.
Lead frame.