JPH0797619B2 - Deburring-free lead frame and resin molding method for the lead frame - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to resin molding during the manufacturing process of IC packages and other semiconductor packages.
The present invention relates to a lead frame in which burrs do not occur in an outer lead portion of a lead pin and deburring is unnecessary, and a method for manufacturing the lead frame.

[0002]

2. Description of the Related Art A resin mold for a semiconductor chip prevents scratches and dust from adhering to a semiconductor element and protects it from electrical, chemical, metallic, and other external influences to ensure stable performance. It is done to maintain semi-permanently.
Most of the resin molds use epoxy thermosetting resin, and after bonding the semiconductor chip to the lead frame, put it in the mold and inject the liquid mold resin to cure it. .

During molding of this resin, if the molding resin leaks to the outer lead portion, it becomes a burr and adheres firmly. The burr on the outer lead portion makes the subsequent solder (or tin) exterior treatment incomplete, resulting in a loss of electrical conductivity and a loss of the semiconductor function.

Therefore, in order to prevent the resin from leaking to the outer lead portion during resin molding, the following measures have been conventionally taken. The first is widely used for both flat type (also called quad type) and DIP type of lead frames. A dam bar (also called tie bar) that connects lead pins is integrated near the outer lead part of each lead pin. It was formed. With this dam bar, the resin leaking out of the molding die is dammed in front of the outer lead portion.

In the second method, the dam bar is removed from the lead frame, and instead a tape made of, for example, a polyimide resin (eg "Kapton" (trade name)) is attached to the front and back surfaces of that portion. This tape also intends to block the resin leaking out of the molding die just before the outer lead portion, like the dam bar.

[0006]

However, in the above-mentioned lead frame with a dam bar, it is necessary to punch and remove the dam bar later with a press die. Since the press die is made finer and more accurate to correspond to the lead frame which has been changed, the wear and deformation of the press die due to the punching of the dam bar is fast and the cost is high. Moreover, this press die needs to have a shape corresponding to each type of lead frame, which is problematic in terms of productivity.

Next, the tape to which the above-mentioned tape is attached does not need to have the dam bar cut later, and therefore, it is easy to apply it to a lead frame having a fine and multi-pin structure. However, since the tape is only attached to the front and back of the lead pin, the gap between the lead pins is not filled with tape,
When the resin is molded, the molding resin goes through a gap and
It easily leaks to the cord part, and burr tends to adhere.

Since any of the conventional burr generation preventing means is insufficient, a step of removing the burr adhering to the outer lead portion is required. For example, a chemical method of dipping in a strong acid or electrolytic treatment in a caustic soda solution is required. It was necessary to go through a deburring means such as an electrochemical method or a mechanical method of spraying the powder with a jet water stream or high pressure.

Instead of the above tape, cream
Or paste resin material onto the XY table and display
It is also conceivable to apply a thin string using a sensor (example
For example, as a technique for holding and fixing lead pins,
JP-A-63-283054 related to the invention of the applicant
reference). However, the application of this thin string-shaped resin material
The filling status between the pins and the status of the front and back surfaces of the pins are read.
It is necessary and sufficient to hold and fix the pin.
It is injured. Also, the position where the resin material is applied should be the same as the lead pin.
The position is close to the tip of the
It is within the range of being shielded. These are the above techniques
When the resin is molded, the table between the pins and the mold and pin
・ All points that mold resin leaks from the gap on the back side
Because it is not taken into consideration.

The present invention is intended to solve the problems in the conventional semiconductor package manufacturing process . The purpose of the immediate Chi present invention, unlike the conventional lead frame, the resin
Reliably prevent resin leakage during molding,
This prevents burrs from being generated at the edge and eliminates the need for deburring.
Resin frame and its lead frame.
It is to provide the rud method .

[0011]

First, a lead frame according to the present invention that does not require deburring has an outer portion near a portion 4 to be resin-molded later in the lead frame 1 having no dam bar between the lead pins 3. to, Rutoto fill 3 between the lead pins in thin cord-like perpendicular to the lead pins 2
Also, a thin resin film 19 is formed on the front and back surfaces of each lead pin 2.
So formed, it is to be calculated and form a resin dam portion 5 made ultraviolet curable resin.

Second, the lee according to the present invention that does not require deburring.
Resin molding method of the lead frame is a rie de frame 1 without a dam bar to the lead pins between 3 and outer portions adjacent to the portion 4 which is a resin model Rudo, in thin cord-like perpendicular to the lead pins 2, between the lead pins 3 And fill each
A thin resin film 19 is formed on the front and back surfaces of the lead pin 2.
The resin dam portion 5 made ultraviolet curable resin was formed, the
After that, the lead frame 1 with the resin dam portion 5 is
In addition to the concave portion corresponding to the mold portion 18, the resin film 19
A model with a shallow groove 20 that corresponds to the position, shape, and thickness.
It is charged into the space between the molds 16 and the mold 16 is
The outer resin can be
Allows resin molding without resin leakage to the lead section 14
It is what

In the above structure, the resin material 7 is applied to the lead frame 1 in a cream or paste resin.
It is desirable to use the dispenser 8 and the XY table 9 for the material 7, and a mask may be used for printing , although not shown. In the figure, 10 is the island portion, 12 inner lead portion, 13 inner lead fixing unit, 1 7 shows a mold resin.

[0014]

The operation state of the lead frame which does not require deburring according to the present invention and the resin molding method for the lead frame is as follows. First, in the flat type lead frame 1 without a dam bar, an ultraviolet curable resin material is used so that the lead pin 2 is filled with a narrow cord that is orthogonal to the lead pins 2 in the vicinity of the outer peripheral portion of the resin molded portion 4. 7 is applied and cured to form a resin dam portion 5 (see FIG. 1). The resin dam portion 5 in this case is formed so as to surround the adjacent outer peripheral portion of the portion 4 to be resin-molded later, and is coated.
Resin material 7 flows and is thin on the front and back of each lead pin 2.
It is the lead frame 1 on which the resin film 19 is formed.
(See Figure 3).

Further, in the DIP type lead frame 1 without a dam bar, ultraviolet curing is performed so as to fill the space between the lead pins 3 in a strip shape orthogonal to the lead pins 2 at both outer positions close to the resin-molded portion 4. A mold resin material 7 is applied and cured to form a resin dam portion 5 (see FIG. 2). This resin dam portion 5 when both the are formed on both outer portion in proximity of the portion 4 which is a resin molded, the resin material was similarly coated labeled with the 7
Flow through the thin resin film 19 on the front and back surfaces of each lead pin 2.
Is formed on the lead frame 1 (see FIG. 3).
See).

Next, the lead frame with the resin dam 5 is attached.
Insert the mold 1 into the space between the molding dies 16 and mold it with resin.
However, at this time, injection into the recess corresponding to the resin mold part
A part of the filled mold resin 17 causes a gap between the lead pins 3
And tries to leak to the outer lead portion 14 side. Shi
However, the lead frame 1 is resin-molded.
Fill the space between each lead pin 3 at the outer part close to the part 4.
The resin dam 5 formed as described above tries to leak out.
That the mold resin 17, where dam to stop by leaking
It is prevented (see Fig. 3).

Further, to the concave portion corresponding to the resin mold portion.
A part of the injected and filled mold resin 17 is a lead pin.
Leaks through a slight gap between the front and back surfaces of the mold 2 and the mold 16.
Try to. However, as described above, the lead frame 1
Is a thin resin film 19 formed on the front and back surfaces of each lead pin 2.
The resin film 1 is formed on the molding die 16.
Forming a shallow groove 20 corresponding to the position, shape and thickness of 9
I am doing it. Therefore, the resin film 1 engaged with the recess 20
9 acts as a sealing material (see FIG. 5).
It also prevents the mold resin from leaking from the gap between
It has stopped.

Therefore, the lead frame according to the present invention
1 and the resin molding method therefor, the resin mold is
Mold resin 17 moves to outer lead portion 14 when rolled
It surely prevents it from leaking out, which later becomes burr
There is no sticking (see Fig. 6, Fig. 7 and Fig. 8).
See).

Since the resin dam portion 5 thereafter can be easily removed by performing an electrolytic treatment with a chemical solution such as an alkaline solution, a press die corresponding to each type of lead frame such as press punching of a dam bar. There is no need to arrange . Further, since the removal of the resin dam portion 5 with a chemical solution may be performed instead of the conventional chemical deburring step or as a pretreatment step for the next solder exterior treatment, it is also necessary to add a special device. Absent.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the lead frame 1 has been made finer and has more pins in recent years, the number of lead pins 2 is reduced in order to facilitate understanding of the contents of the present invention in FIGS. 1 to 8 showing an embodiment. It is displayed.

First, the flat type or DIP type lead frame 1 without a dam bar may be formed by known means such as press working or photo etching. The resin dam portion 5 may be formed on the lead frame 1 after the partial plating 6 for bonding is applied to a predetermined portion of the lead frame 1.
You may go before applying.

The position and shape of the resin dam 5 are as follows.
In the flat type lead frame 1, as shown in FIG.
In the vicinity of the outer periphery of the resin-molded portion 4,
A thin cord that is orthogonal to each lead pin 2 and has a space 3 between each lead pin.
Apply UV-curable resin material 7 to fill it, and
Is cured to form the resin dam portion 5.

Also, with the DIP type lead frame 1,
Is the proximity of the resin-molded portion 4 as shown in FIG.
On both outer sides, in the shape of a thin string orthogonal to each lead pin 2.
An ultraviolet curable resin material that fills the space 3 between the lead pins.
Coating material 7 and curing it to form resin dam part 5
I am doing it.

The resin material 7 forming the resin dam portion 5 is
As long as it is a paste-like or cream-like UV-curing type, for example, an acrylic resin, an epoxy resin, a polybutadiene resin, a silicone resin, or the like may be used, but a high temperature of about 200 degrees Celsius during resin molding may be used. It must also have heat resistance to withstand. Generally, an acrylic resin to which an ultraviolet curing type curing agent is added may be used.

A means for applying the resin material 7 is shown in FIG.
As shown in, it is preferable to use the dispenser 8 and the XY table 9, but the present invention is not limited to this, and printing using a mask may be used. Further, as a curing means for the resin material 7, in the case of a photo-curing type, ultraviolet light or other light may be irradiated.

Dam portion 5 formed on the lead frame 1
Is an outer part close to the part 4 to be resin-molded later
In addition, as shown in FIG. 4, a thin string shape orthogonal to each lead pin 2
Fill the space between each lead pin 3 with each lead pin 2
A thin resin film 19 is formed on the front and back surfaces of
deep.

After that, the lead frame with the dam part
The mold 1 is resin-molded, and the molding die 16 at that time
In addition to the concave portion corresponding to the resin mold portion 18, in FIG.
As is apparent, the position, shape, and thickness of the resin film 19 should be matched.
The one having the corresponding shallow groove portion 20 is used.

In this state, the mold resin material is placed between the molds 16.
The material may be filled, cured and resin-molded (Fig. 5).
reference). As a result, the resin mold as shown in FIG.
Lead frame 1 is formed, but FIG. 7 is flat
FIG. 8 is a plan view of a type, and FIG. 8 shows its perspective view.
It

[0029] As the agent for dissolving and removing the dam portion 5 made of resin, for example, alkaline NaOH100g / l
The solution may be used for electrolytic treatment. The inner lead fixing portion 13 may be a conventional tape to which a tape is attached, or JP-A-63-283054 disclosed by the same applicant as the present application.
A resin may be applied as described in the publication. In the figure, 11 is an island suspension pin, 15 is an outer lead fixing pin (also referred to as a section bar), and 21 is a lead frame receiving plate.

[0030]

As is apparent from the above, the lead frame which does not require deburring and the resin molding method for the lead frame according to the present invention are different from the conventional lead frame in that the resin leaks to the outer lead portion at the time of resin molding. To
Can be reliably prevented, Ru can be dispensed with the deburring process to prevent the occurrence of burrs.

That is, in the conventional lead frame with a dam bar, it is necessary to punch the dam bar later with a press die even if the occurrence of burrs is suppressed, and a press die corresponding to each type of lead frame is required. both when there is a problem in sexual terms, fine and precision the press die is worn,
Deformation was fast and the cost was high. Moreover, those subjected pasting conventional tape lead pin table-back side, lead pins
For gap is formed between, leaked into the mold resin there Utarido section during resin molding, burrs are attached not easily
However, there was a problem in productivity and economy.

On the other hand, in the present invention, a lead frame without a dam bar is provided on the outer side of the resin molded portion close to the lead frame with a string-like shape orthogonal to the lead pins and filling the space between the lead pins. der to form a
It Therefore, the space between the lead pins was filled during resin molding .
By this resin dam portion, from which can reliably prevent the leakage of the molding resin to the outer lead portions, no burrs adhering to the outer lead portions, thus the deburring unnecessary.

Further, in the present invention, the above resin dam
The thin resin film is formed on the front and back surfaces of each lead pin.
It is designed to And this lead frame is made of resin
Position and shape of the resin film on the molding die
.Using a shallow groove that corresponds to the thickness
It Therefore, there is a slight gap between the front and back surfaces of the lead pin and the mold.
Even the part of the mold resin that is about to leak through the gap is
The resin film that engages with the ridges does not function as a sealing material.
The mold resin that tries to leak from the gap.
Can be reliably prevented.

Therefore, the lead frame according to the present invention
According to the resin molding method therefor, the resin molding
Mold resin leaks to the outer leads when
Can be reliably prevented and the subsequent deburring process becomes unnecessary.
You can

Since the resin dam portion according to the present invention can be easily and completely removed without leaving a residue afterwards with the chemical liquid, the next solder coating process can be performed completely. Further, since the dam portion removing step may be performed as a substitute for the conventional chemical deburring step or as a pretreatment step for the next solder exterior treatment, the present invention can be implemented without adding a special device. it can.

[Brief description of drawings]

FIG. 1 is a partially enlarged plan view when the present invention is applied to a flat type lead frame.

FIG. 2 is a partially enlarged plan view when the present invention is applied to a DIP type lead frame.

FIG. 3 is a partially enlarged vertical cross section in the case of applying a resin material according to the present invention with a dispenser and an XY table.

FIG. 4 is a partially enlarged perspective view of a lead pin in which a resin dam portion is formed according to the present invention.

FIG. 5 is a partially enlarged vertical sectional view of the lead frame of the present invention when resin-molded.

FIG. 6 is a partially enlarged vertical sectional view of the lead frame of the present invention after resin molding.

FIG. 7 is a partially enlarged plan view of the flat type lead frame of the present invention after resin molding.

FIG. 8 is a partially enlarged perspective view of a flat type lead frame of the present invention after resin molding.

[Explanation of symbols]

1-Lead Frame 2-Lead Pin 3-Between Lead Pins 4-Resin Molded Part 5-Resin Dam Part 6-Partial Plating for Bonding 7-Resin Material 8-Dispenser 9-XY Table 10-Island Part 12-Inner Lead Part 13-Inner lead fixing part 14-Outer lead part 16-Molding die 17-Molding resin 18-Resin molding part 19-Thin film part 20-Recessed line part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 23/28 C 8617-4M 23/29 23/31

Claims (2)

[Claims] A lead frame (1) having no dam bars between lead pins (3) is provided at an outer portion near a portion (4) to be resin-molded later.
Each lead pin 2 perpendicular to thin cord-like in filling <br/> the lead pins between 3 Rutotomoni, thin tree in front and rear surface of the lead pins 2
A lead frame that does not require deburring , characterized in that a resin dam portion 5 made of an ultraviolet curable resin is formed so that the oil film 19 is formed . In wherein rie de frame 1 of the dam bar without the lead pins between 3 and outer portions adjacent to the portion 4 which is a resin model Rudo, in thin cord-like perpendicular to the lead pins 2, between the lead pins 3
And also thin on the front and back of each lead pin 2.
Resin-made resin made of UV-curable resin on which the resin film 19 is formed
To form the lead frame 1 with the resin dam portion 5,
In addition to the concave portion corresponding to the resin molded portion 18, the resin film 1
9 has a shallow groove 20 corresponding to the position, shape and thickness of
It is charged into the space between the mold dies 16 and, in this state, the mold resin 16 is filled with the mold resin material.
By filling and curing it, it is possible to prevent resin leakage into the outer lead portion 14.
Resin molding method for lead frame, characterized by
Law.