JPS62171148A - Manufacture of chip carrier type ic - Google Patents

Abstract

PURPOSE:To prevent a bending from a section, where a lead is brought into contact with a package, by bringing excellent molds into contact with the inside and outside of the lead, conducting secondary preworking and performing secondary bending. CONSTITUTION:A projecting mold 7 is arranged inside leads 2 and recessed molds 8 outside the lead 2, and a support base 6 is slid downward by pushing both molds from an upper section, and the nose sections of the leads are bent at approximately 90 deg.. A mold package 1 is placed on a support base 9, recessed molds 10 using SKD thermally treated to HRC 58 deg.-60 deg. as a blank are brought into contact with the outsides of the leads 2, the mold package is pushed by a projecting mold 11 of the same quality from an upper section, and secondary pre-bending is conducted up to approximately 45 deg.. Rollers 14 are brought into contact with the outsides of the leads by pushing a projecting mold 13, the leads are bent gradually up to a vertical position, and circular arcs on the insides of the leads 2 can be formed in desired bendings R.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a chip carrier type IC, and particularly to a method for bending a leaped chip carrier type IC.

(Prior Art) In recent years, with the increase in the degree of integration of semiconductor IC devices, the number of lead pins of IC/cage has rapidly increased.

For this reason, flat wire was used, but it had the disadvantage that the leads were easily bent when mounted on a printed circuit board. Therefore, in recent years, PLCC (Plastic Leaped Chip Carrier), which does not need to be worried about lead bending, has become mainstream. P
In an LCC, a large number of leads drawn out from a mold are plated for half a day (approximately 10 μm) in order to be mounted on a wiring board. - It is bent at a nearly right angle at a position extremely close to the side surface of the mother package, and the tip of the lead is formed into a semicircular arc shape, recessed into the back surface of the socket.

Conventionally, the process for manufacturing such a PLCC is to simultaneously bend the lead tip and the periphery of the lead using convex and concave molds, then remove the mold and bend -J? from the side of the lead. The PLCC was completed by bending the lead bend around the 7 kaso to 90 degrees, applying force from above, making the lead tip into a semi-circular arc shape, and sinking it into the cage.

However, in the above method, since the tip of the reed and the surrounding area of the reed are bent at the same time, the entire inside of the reed is crushed, the thickness of the reed itself becomes thinner, and the number of pins increases. There was a problem that it was difficult to process. For this reason, a technique has been developed in recent years in which the tip of the lead and the area around the cage are bent in separate processes.

First, a primary bending process is performed, which is a preliminary process of forming the tips of a plurality of leads pulled out from a mold/package containing a semiconductor chip into a semicircular arc shape. As a result, the tip of the IJ-do is bent at a substantially right angle. Next, as a second bending process, force is applied from the outside of the lead that has been subjected to the first bending process, and the lead is bent to 90 degrees. Finally, as a tertiary bending process, add an upward bend and fold it into the package so that it is on a semicircular arc with the lead tip, as shown in Figure 3 (
, ) is completed.

However, when the secondary bending process is performed using the above method, the lead 2 is bent from the part where it contacts the package 1, as shown in FIG. The part of the inside of the shoe cage that is not solder-plated is pulled out and the copper material 3 is exposed, and the part where the lead 2 is in contact with the pack horn is several tens of μm thick.
There was a problem that a gap occurred.

To solve these problems, package 0.
A 7-shaped or concave notch is made on the inside of the lead at a distance of 2 to 0.3, and in the second bending process, the lead becomes i4.
This prevents bending from the part in contact with the package.

(Problems to be Solved by the Invention) However, in the above method, as shown in FIG. 5(b), since the notch 4 is provided on the lead surface and the bending process is performed, it is true that the lead 2 is bent into the /J package 1. However, since the inside of the lead bending part in the second bending process has no roundness, that is, there is no bending radius, the lead outside the bending part near package 1 will not bend. The elongation rate of the material was low and cracks appeared on the surface, causing quality problems.

(Means to solve the problem) In order to solve the above problem, the present invention applies a good mold to the inside and outside of the lead, performs a second preliminary process, and then performs a second bending process. .

(Function) Since the present invention uses the above-mentioned method, by carrying out the secondary preliminary processing, a crush is formed only in the inner bending part, and due to the collapse, the bending center in the secondary bending process is This has the effect of making it different from the bending center during the next preliminary machining.

(Example) An example of the present invention will be described with reference to FIG. 1 (4) to υ).

In FIG. 1A), a mold containing a semiconductor chip
A first bending process, which is a preliminary process, is performed to form the tip of the rod 2 pulled out from the cage 1 into a semicircular arc shape. This first bending process is performed by placing the mold and the cage 1 on the support stand 6, placing the convex mold 7 inside the lead 2 and the concave mold 8 outside the lead 2, and placing the convex mold 7 on the outside of the lead 2. By pushing from above, the support stand 6 slides downward, and the tip of the lead becomes rounded as shown in the figure. FQ (1°V bend/, - In Fig. 1 (B), mold guccano 1 is placed on support stand 9, and T (RC58°~6
A concave mold 10 made of SKD (dice steel) that has been heat-treated so as to have an angle of 0° is in contact. Press the gutter 1 from above with a convex mold 11 of the same quality, and perform a secondary preliminary bending process to approximately 45°, which is within the bending area of the lead 2, using the point where the convex mold 11 hits as the origin. I do.

Here, detailed explanation of the processing in FIG. 1(B) will be given using FIG. 2 which is an enlarged view of the peripheral area of the shoe cage.

The convex part of the convex mold 11 has an angle of about 40 degrees from the vertical direction, and the tip has a rounded shape with a radius AA'. The concave part of the concave mold 10 is tapered at about 45 degrees from the horizontal direction, and the corner part on the outside of the lead bending part near the package 1 is rounded with a radius BB'. The support stand 9 is molded by the convex mold 11.
It has a mechanism that slides downward when Motsukeno 1 is pressed.

From above, the convex mold 1 weighs approximately 3 tons (in the case of 18 bottles)
When the supporting table 9 and the mold pa and cage 1 placed on the concave mold 10 are pushed with a force of 1, the supporting table 9 slides downward by about 3 degrees, and the lead curve as shown in the figure is obtained. At this time, since the convex portion of the convex mold 11 is more acute than 50° (50°
If the lead is bent, it will come into close contact with the concave mold).Crush the inner bent part of the lead by about 20μ. Due to this dipping, the bending center of the lead was previously at B, but due to the crushed shape by the convex mold, the bending center of the lead moves to A (relative to the inner bending R1 before crushing, that is, CB). , the inner bending R1 after crushing, that is, A A' is about 1.5 times). Therefore, no bending stress is applied to the package 2 during the second bending process.

In FIG. 1(C), the molding hole and package 1 which have been subjected to the secondary bending process are placed on the support stand 12, and the support stand 12 is moved by pressing the convex mold 13 upward. Slide downward. At the same time, the roller 14 hits the outside of the lead and gradually bends it until it becomes vertical. As this process progresses, the inner arc of the lead 2 gradually becomes smaller, allowing a desired bending radius to be formed.

In FIG.
(This mold has the shape shown in the figure in order to process the tip of the IJ-de, which is bent at 90 degrees, into a semicircular arc shape.) PLCC as shown in FIG. 3 is completed.

(Effects of the Invention) As described above in detail, according to the present invention, in the secondary bending process, which is a pretreatment for the secondary bending process, the mold as described in the embodiment is used. By performing crushing at the same time as preliminary bending, the position of the bending center of the lead is changed. As a result, no bending stress is applied to the joint between the package and the lead, so no gap is created between the package and the lead. Moreover, since the method performs the secondary bending process without notching, a bending radius is formed inside the bending part, so that the elongation rate of the lead material at the outer corner part does not become very large. In other words, the PL is highly reliable because no cracks or cracks occur.
CC can be provided.

[Brief explanation of drawings]

FIGS. 1(g) to 1) are cross-sectional views of the steps of the present invention. FIG. 2 is an enlarged view of the surrounding area of the pan cage during the second preliminary processing. FIG. 3 is a perspective view of a PLCC completed according to the present invention. Figures 4 and 5 show PLCs completed using conventional processing methods.
A perspective view of C. 1... A cage, 2... Lead, 3... Copper, 4...
... Notsuchi, 5... Crack, 6... Support stand, 7.
...Convex mold, 8...Concave mold, 9...Support stand, 1
0...Concave mold, 11...Convex mold, 12...Support stand, 13...Convex mold, 14...Roller, 15
...Support stand, 16...Convex mold. Patent applicant: Oki Electric Industry Co., Ltd. 2 pieces, + 1 knife, 1 scoop, 1 nail, 1 nail, 2 pieces, Figure 2 (A)! / Yup processing 2nd meeting Processing (B)] -2: Missing + 1% 61 P1〃Work (D) Volume 5 Charcoal bending i゛ Machining Invention process maze diagram Figure 1 λ, Invention Fig. 3. Conventional processing method. Fig. 4.
Figure 5 Procedural Amendment (issued) 1. Indication of the case 1985 Patent Application No. 010976 2. Name of the invention Method for manufacturing a chip carrier type IC 3. Person making the amendment Relationship with the case Patent Application Person Place (
105) 1-7-12-4, Toranomon, Minato-ku, Tokyo.
Agent address (105) 1-7 Ko, Toranomon, Minato-ku, Tokyo
5. Subject of amendment Column c4 of "Invention I Ar\" in the specification
1206, Contents of amendment (1) The text "Fig. 3 (a)" on page 3, line 13 of the specification is corrected to "Fig. 3." (2) On the 16th line of the same page of the same book, the text "Figure 4 (a)" is amended to read "Figure 4." (3) On page 4, line 9 of the same book, the text "Figure 5 (b)" is amended to read "Figure 5." (4) On page 7 of the same book, line 3: “Approximately 3 slides.”
I corrected it to "slide for about 3 minutes." (5) In the 5th line of the same page of the same book, the statement ``The convex part is...concave'' is corrected to ``The convex part is at an angle more acute than 45 degrees (・If it is 15 degrees, it is concave.''). (6) Ibid. From the 12th line to the 13th line of the same page, the text ``・gunokage 2'' is corrected to ``Anokeno 1''.

Claims (1)

[Claims] a step of bending the tips of a plurality of leads pulled out from a molded package at a substantially right angle; and a step of pre-bending the remaining portions of the leads by a predetermined angle while pressing the lead portions near the package. A method for manufacturing a chip carrier type IC having the following.