JP2544947B2 - Method for manufacturing semiconductor device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a bridge circuit.

[Prior Art] As is well known, a diode bridge circuit is one in which four diode elements D _{1 to} D ₄ are connected as shown in FIG. 6, and an alternating current input to input terminals 1 and 2 is converted into a direct current. And a predetermined direct current is output to the output terminals 3 and 4.

There are various structures for forming the above-mentioned diode bridge circuit, and there is, for example, one shown in FIG. 5 as a structure in which the diode chip is directly fixed to a lead frame as a conductor plate.

In the figure, the lead frame 1 has a connecting portion provided with feed holes 12 formed by a transfer machine at a constant pitch in its longitudinal direction.
A large number of 11 and a set of lead portions 13a and 14a extending from the connecting portion 11 in a substantially perpendicular direction are formed in the longitudinal direction of the lead frame 1. The lead portions 13a, 14a have base portions 13a, 14a formed in a substantially L-shape so that their tip portions embrace each other.

Four diode chips 1 are provided on the base portions 13a and 14a.
5 is fixed, and two leads 16 are fixed on the upper surface of the diode chip 15 in a strip shape across the base portions 13b and 14b so as to connect the diode chips 15 facing each other. Regarding the polarities of the diode chips 15 fixed to the base portions 13a and 14a, those on the same base portion have the same polarity. For example, the anode side of the base portion 13b is the lower side.
The diode chips 15 are arranged, and the base portion 14
Two diode chips 1 with the cathode side facing down for b
5 is placed.

After that, the lead portions 13a, 14a and the lead 16 are resin-sealed so that the ends thereof are exposed to the outside, and the lead frame
The connecting portion 11 of 10 is cut off to complete a semiconductor device having a built-in diode bridge circuit.

[Problems to be Solved by the Invention] When operating the conventional semiconductor device, the base portion 13b,
Mounting the diode chip 15 on the upper surface of 14b is done manually by using an automatic machine or a predetermined jig. In any case, all four diode chips should be mounted in the same polarity. You can't do that, and you have to make sure you have two in the opposite direction. When this work is performed manually, the worker must mount it while paying attention to its polarity, and there is a problem that the work efficiency decreases and defective products are likely to occur due to erroneous mounting.

On the other hand, when mounting the diode chips on the base part with an automatic machine, the polarities must be reversed two by two,
There is a problem that the mechanism of the automatic machine becomes complicated. That is, if the diode chip supply mechanism is a mechanism that supplies the same polarity, it is necessary to supply the diode chips of opposite polarities to one of the base portions, and therefore a polarity reversal mechanism is required, and When supplying diode chips having different polarities to the respective base parts in advance, there is a problem that a two-system supply mechanism is required and the configuration of the automatic machine becomes complicated.

[Object of the Invention] The present invention has been made in order to solve the above-described problems, and the polarity of the diode chips to be supplied / mounted on the base portion is set to be in the same direction so that the diode chips can be supplied automatically. An object of the present invention is to provide a semiconductor device manufacturing method capable of suppressing the generation of defective products due to an incorrect polarity even when the diode chips are supplied and mounted by simplifying the mechanism of the machine or manually.

[Means for Solving the Problems] In the method of manufacturing a semiconductor device of the present invention, a pair of lead portions having the same pitch are projectingly provided on two lead frames, and a base portion formed at the tip of the lead portions is provided. Supply and mount the diode chips to form the diode bridge so that they all have the same polarity, and fix them.After that, flip one lead frame so that the upper surface of each diode chip is at the tip of the other lead part. This is to obtain a semiconductor device in which a predetermined diode bridge circuit is formed by being fixed so as to face the provided protrusions.

[Operation] In the semiconductor device manufacturing method of the present invention, since all diode chips are supplied and mounted on the lead portion of the lead frame with the same polarity, defective products caused by erroneous mounting by manual work In addition to the drastic reduction in the generation rate, the use of an automatic machine requires only one system for supplying and mounting the mechanism, which simplifies the mechanism and enables low-cost manufacturing. Moreover, one lead frame is reversed. The diode bridge circuit can be formed all at once by only fixing them, and the manufacturing process can be simplified and the number of parts can be reduced.

[Embodiment] An embodiment of the present invention will be described below.

First, referring to FIG. 1 and FIG.
A lead frame is shown.

FIG. 1 shows the structure of the first lead frame 20. The lead frame 20 has a connecting portion 21 in which feed holes 22 are formed at predetermined intervals in the longitudinal direction thereof, and a pair of lead portions 23a, 23b are formed in a substantially perpendicular direction from the connecting portion 21 to form a lead frame 20.
Are provided at predetermined intervals W ₁ in the longitudinal direction.

Base portions 24a, 24b, which are bent in an L shape so as to continuously face the lead portions 23a, 23b, are formed to have a size of L ₁ from the center of the feed hole 22, and the base portions 24a, 24b
24b has a tip portion 25a, 25b in a dimension of L ₂ from the center of the base portion 24a, 24b, and a predetermined distance W _{2 in the} longitudinal direction.
It is formed with.

The tip portions 25a, 25b are, as shown in FIG. 1 (b),
A step portion 26 is formed, and a projecting portion 27 formed by pressing is provided on the tip end portions 25a and 25b.

FIG. 2 shows the structure of the second lead frame 30, the first lead frame 30.
Lead portions 33a, 33b are provided at a predetermined distance W ₁₁ from the connecting portion 31 having the same structure as that of the lead frame 20 in a direction perpendicular to the connecting portion 31. And the distal portion 34 bends inward in succession one lead portion 33a is formed, projections 35 by press working to the front end portion is provided at a predetermined interval W _21. A base portion 36 that is also bent inward is formed at the connecting portion 31 at the tip of the other lead portion 33b.

The dimensional relationship between the base portion 36 and the tip portion 34 is as shown in the figure, the base portion 36 is formed with a dimension of L ₁₁ from the center of the feed hole 32 formed in the connecting portion 31, and the position of the tip portion 34 is the base. It is formed at the dimension L ₂₁ from the center of the portion 36.

On the base portions 24a, 24b and 36 of the first lead frame 20 and the second lead frame 30, a total of four diode chips 37 are mounted and fixed in the shaded portions, but their polarities are different. All are aligned in the same direction.

Further, the dimensions of the first lead frame 20 and the second lead frame 30 are set to be the same.
That is, L ₁ = L ₁₁ , W ₂ = W ₂₁ , and L ₂ = L ₂₁ .

Thus, due to the above dimensional relationship, both lead frames 2
When 0 and 30 are overlapped, the diode chips 37 and the protrusions 27 and 37 provided on the tip portions 25a, 25b and 34 overlap each other at the same position.

Next, the first and second lead frames 20, 3 having the above structure
A method of manufacturing a semiconductor device using 0 will be described.

First, the first and second lead frames 20 and 30 are set on a semiconductor chip mounting machine (not shown). Since the lead holes 20, 32 have the same pitch of the feed holes 22, 32, even if the first and second lead frames 20, 30 are mixedly supplied to the semiconductor chip mounting machine. good. That is, the lead holes 20, 30 of the lead frame 20,
Since two diode chips 37 are mounted in the same size position from 32, respectively, even if the first and second lead frames 20 and 30 are mixedly supplied, the semiconductor chip mounting machine can be mounted. The diode chip is mounted at a predetermined position by the operation of the provided semiconductor chip supply arm under the same conditions.

Regarding the polarity of the diode chip, the first and second lead frames 20 and 30 are mounted so that the cathode side faces downward and the anode side faces upward.

Next, the step of fixing the diode chips 37 mounted on the first and second lead frames 20, 30 is performed. In carrying out this fixing step, the first and second lead frames
Apply solder cream on the base parts 23a, 24b and 36 of 20, 30 or diode chips.
Preliminary solder is attached to 37 itself.

Then, as shown in FIGS. 3 and 4, the surfaces of the first and second lead frames 20, 30 on which the diode chips 37 are mounted are stacked so as to face each other. That is, the positional relationship when they are stacked is such that the upper surface of the diode chip 37 on the first lead frame 20 is the second surface.
It overlaps with the protrusion 35 provided at the tip of the lead frame 30 of
The upper surface of the diode chip 37 of the second lead frame 30 is the protrusion 2 provided on the tip portions 25a and 25b of the first lead frame 20.
It is in a positional relationship that overlaps with 7.

Note that a jig or the like for stacking the lead frames 20 and 30 is not shown.

Next, as described above, the lead frames 20 and 30 are stacked and heated by a heating means such as a hot plate to melt the solder and fix them.

After this fixing step, the portion indicated by the alternate long and short dash line 1 _n is resin-sealed, and finally, the connecting portions 21 and 31 of the lead frames 20 and 30 are connected to the respective lead portions 23a, 23b, 33a and 33b, and the connection is made. A finished product is obtained by cutting along the portion indicated by the chain double-dashed line 1 _m in FIG. 3 so as to cross the portions 20 and 30.

[Effects of the Invention] As described above, according to the present invention, all the polarities of the diode chips can be mounted on the lead frame, so that in the case of manual work, a defective product is generated due to an incorrect polarity of the mounted diode chips. Can be prevented. Further, even when supplying the diode chip by using an automatic machine, the polarity reversing mechanism is not necessary, so that the mechanism becomes simple and the device becomes inexpensive, so that the semiconductor device as a finished product can be provided at a low price. It has an excellent effect of.

[Brief description of drawings]

FIG. 1 shows the structure of a first lead frame used in the present invention. FIG. 1 (a) is its plan view and FIG. 1 (b) is
The side view and FIG. 2 show the structure of the second lead frame, FIG. 2 (a) is a plan view thereof, FIG. 2 (b) is a side view thereof, and FIG. FIG. 4 is a plan view showing the structure of a developing semiconductor device, FIG. 4 is a side view showing the structure of a semi-manufacturing semiconductor device according to the present invention, and FIG. 5 is a semiconductor device of this type manufactured by a conventional manufacturing method. And FIG. 6 is a circuit diagram of a semiconductor device manufactured by the conventional manufacturing method and the manufacturing method of the present invention. 20 …… First lead frame 30 …… Second lead frame 21,31 …… Coupling 23a, 23b, 33a, 33b …… Lead 24a, 24b, 36 …… Base 25a, 25b, 34 …… Tip 27,35 …… Projection, 37 …… Diode chip

Claims (1)

(57) [Claims] 1. A first lead frame and a second lead frame in which at least one pair of opposingly arranged lead portions projecting from a connecting portion in a direction substantially perpendicular to each other are formed, and the lead portions have a common pitch. And a lead frame, and a first diode chip fixing step in which one diode chip is fixed to each of the lead parts of the pair of opposingly arranged lead parts of the first lead frame with their polarities aligned. And a pair of opposingly arranged lead portions of the second lead frame, on one of the lead portions, corresponding to the two diode chips fixed to the lead portions on the first lead frame. A second diode chip fixing step in which two diode chips are fixed with the same polarity, and a first lead frame to which the diode chips are fixed and one lead portion Second lead frames to which two die chips are fixed are superposed so that the upper surfaces of the diode chips face each other, and a protrusion formed on each of the tips of the lead portions of the first lead frame. Of the lead portions of the second lead frame, the diode chip is formed by stacking and fixing the diode chip and the protrusion formed at the tip of one of the lead portions facing each other so as to face each other. A method of manufacturing a semiconductor device, comprising: