JPH036050A - Lead frame - Google Patents

Abstract

PURPOSE:To prevent inner leads from being stuck together when lead frames are piled up and to prevent the inner leads from being deformed when the stuck inner leads are separated from each other by a method wherein a protrusion is formed in a region other than a noble metal layer formed at a tip part of an inner lead. CONSTITUTION:An island 1 for element mounting use is provided with the following: suspension pins 2 supported by a frame 2; pad parts 5 which are arranged around the island 1 and which are installed at tip parts of inner leads 4 supported by the frame 2 by plating an Au layer or the like; and protrusion 7 which are installed in regions other than regions where the pad parts 5 have been installed and which are installed in sections at the inner leads 4 at the inside of a sealing region 6 by a stamping operation. Consequently, even when lead frames are in a stacked state, the pad parts 5 do not come into contact with each other because of the protrusions 7 which have been installed at the inner leads 4. Thereby, it is possible to prevent tip parts of the inner leads 4 from being stuck together; it is possible to prevent the inner leads from being deformed when the stuck inner leads are stripped.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a lead frame for a semiconductor device.

[Conventional technology]

Is the conventional lead frame in the 3rd Q? l As shown in (a) to (c), the island 1, the hanging bin 3 that supports the island 1 on the frame 2, and the internal leads arranged around the island 1 are provided on the same plane. A pad 5 plated with an Au layer or the like for bonding was provided at the tip of the internal lead. If the lead frames were overlapped as shown in FIG. 4, the butt portions at the tips of the internal leads would sometimes stick to each other due to the Au layer.

[Problem to be solved by the invention]

The above-mentioned conventional lead frames are formed on the same plane, so when the lead frames are overlapped, the butt parts of the tips of the internal leads stick together, and the internal leads are deformed when they are peeled off. There is.

Furthermore, a short length of the internal lead inside the mold sealing area has a disadvantage that the tensile strength is low and it is easy to come off.

[Means to solve the problem]

The lead frame of the present invention includes an island for mounting an element, and an internal lead having a pad portion disposed around the island and having a noble metal film at the tip, wherein the pad of the internal lead is It has a protrusion provided in an area other than the area.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1(a) to 1(c) are a plan view, a sectional view taken along line xx', and an enlarged view of part A, showing an embodiment of the present invention.

As shown in FIGS. 1(a) to (c), there is an island 1 for mounting elements, a hanging bin 3 that supports the island 1 on the frame 2, and a hanging bin 3 arranged around the island 1 and supported on the frame 2. The internal lead 4, the pad portion 5 provided by plating the tip of the internal lead 4 with an Au layer, etc., and a portion of the internal lead 4 outside the area where the pad portion 5 is provided and inside the sealing area 6. A lead frame is constituted by the protrusion 7 provided by press working.

FIGS. 2(a) and 2(b) are a sectional view and an enlarged view of part B showing a state in which the glued frames of the present invention are stacked.

As shown in FIGS. 2(a) and 2(b), the protrusions 7 provided on the internal leads 4 prevent the Au layers 5 from coming into contact with each other even when the lead frames are stacked, and the tips of the internal leads 4 are prevented from coming into contact with each other. The Au layer 5 prevents the parts from sticking together.

Further, the protrusion 7 has the effect of preventing the internal lead 4 from being pulled out from the sealed resin body.

〔Effect of the invention〕

As explained above, the present invention prevents the internal leads from sticking to each other when lead frames are overlapped by providing a protrusion in an area other than the noble metal layer provided at the tip of the internal lead, thereby making it possible to peel off the sticking. This has the effect of preventing deformation of the internal leads due to

Furthermore, the tensile strength of the external leads is increased, and the internal leads are less likely to come off than the sealed resin body, which has the effect of reducing contamination that enters via the internal leads.

[Brief explanation of drawings]

FIGS. 1(a) to (c) are a plan view, a sectional view taken along the line xx', and an enlarged view of part A, and FIG. 2(a) shows an embodiment of the present invention.
, (b) is a cross-sectional view and an enlarged view of part B showing the stacked lead frames of the present invention, and FIGS. 3(a) to (C) are plan views and Y-Y' showing an example of a conventional lead frame. A line sectional view and an enlarged view of part C, and FIG. 4 are partial sectional views showing a state in which conventional lead frames are stacked. 1...Island, 2...Frame, 3...Hanging bottle, 4
. . . Internal lead, 5. Pad portion, 6. Sealing region, 7. Projection portion.

Claims (1)

[Claims] In a lead frame comprising an island for mounting an element, and an internal lead having a pad portion disposed around the island and having a noble metal film at the tip thereof, the internal lead is provided in an area other than the pad portion of the internal lead. A lead frame characterized by having a protrusion.