JPH01321665A - Manufacture of resin sealed semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the development of lattice burrs by causing a dam part crossing lead terminals and a lead frame between sealing resin layers to be in a continuous state, thereby performing a half punching process of a lead frame part which is surrounded by leads, the dam part, and the sealing resin layers. CONSTITUTION:A dam 2 is installed to leads 1 which are formed at a metallic frame body in such a way that the dam extends by intersecting in the longitudinal direction of the leads and end parts of sealed resin layers which are sealed in cavities have a continuous state. Then, places 6 which are defined by an end face 4 of sealing resin layer 3, the dam part 2 facing the above end face, and extension lines of side faces 5 and 5 of the leads 1 and 1 which are adjacent each other are treated by a half punching process. Subsequently, a prescribed semiconductor integrated circuit element is mounted at a bed part and a resin sealing process is performed with a thermo- compression bonding process as well as a transfer molding method and the sealing resin layers 3 are formed. Further, a half punching process is performed. A its process prevents a molten resin layer from flowing into the dam part 2 when the resin sealing process is carried out, outer leads 1 which are free from burrs are introduced from the sealing resin layers 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a technique for preventing paris generated in a resin encapsulation process including a semiconductor element mounted on a lead frame.

(Prior Art) In the assembly process of semiconductor elements in which circuits and devices are built into a semiconductor substrate, a lead frame is usually used to assemble the semiconductor element, and the semiconductor element is further protected from the external atmosphere by a resin sealing process. By the way, among the etching process and pressing process, which are known as manufacturing methods for lead frames of DIP, SIP, and a combination of both, the latter is currently exclusively used, and is used for manufacturing highly integrated multi-bins such as integrated circuits. In reality, the pitch between outer leads of structural elements has to be reduced.

An overview of DIP and mixed type lead frames, which are mainly used to mount semiconductor devices with a large degree of integration, is that a plurality of unit bodies each having a frame made of gold steel are successively formed. Depending on the number, they are classified as long or short. On the other hand, a lead starting from this point is formed in the gold GT frame toward the center of the unit, and a bed is connected between a pair of leads near the center to form a semiconductor element. Make it possible to manage the board.

The lead end near the semiconductor substrate is left in a free state, and a through hole is formed in each unit in the frame made of gold R to facilitate transportation and make it compatible with automation.

In this way, the lead frame equipped with the bed portion and lead terminals is formed with connecting strips or dams that increase the mechanical strength of both components and function as banks in the resin sealing process.
The position thereof is formed so as to extend in a direction intersecting the lead relatively close to the frame.

Then, a thermocompression bonding process using thin metal wires for electrical connection between electrodes and leads formed on the semiconductor element and a resin sealing process are followed by a cut-to-bend process to cut the dam area and separate the mount part from the rest.

As a result, an integrated circuit is formed in which leads, that is, outer leads formed in a predetermined shape are led out from the thickness direction, that is, from the sides, of the sealing resin layer formed in the shape of a rectangular parallelepiped. Note that the name of the leads formed on the lead frame is changed from inner leads to outer leads depending on before and after the thermocompression bonding process between the electrodes formed on the semiconductor element and the lead terminals.

By the way, in the resin sealing process using the transfer molding method, a lead frame is placed between a pair of molds placed in a special machine, and molten resin is introduced into the cavity through the cull and runner formed in the mold. Then, an aging treatment is performed at a predetermined temperature to complete the process. As a result, a semiconductor device is manufactured in which the outer leads are led out from the side portion of the sealing resin M, which is formed into a substantially rectangular parallelepiped shape as described above.

Since this semiconductor device is inserted into a kit for electronic equipment to form an electric circuit or used in the testing process of semiconductor elements, it is necessary to form it according to specifications to prevent poor connections and socket clogging. .

By the way, so-called pars often occur on the outer leads of products molded by the transfer molding method and equipped with a sealing resin layer, and many proposals have been announced as countermeasures and efforts have been made to eliminate them. .

As mentioned above, the pair of molds used in the resin sealing process are manufactured through precision machining, but the existence of microscopic gaps cannot be denied, and it is inevitable that the sealing resin will flow out during the resin sealing process. be.

A method for preventing the occurrence of paris due to the sealing resin will be described with reference to FIG. 3. As described above, a runner section is provided that branches from a cull formed along the surfaces of a pair of rectangular parallelepiped metal members and extends toward the ends of the metal members,
Further, a plurality of cavities connected to the gate portion are provided at the terminal portion.

As shown in FIG. 3, lead terminals 21 installed in a metal frame (not shown) are provided with dam portions 22 that intersect in the axial direction. The void 24 formed in the dam portion 22 is also filled with the sealing resin layer 23.

(Problem to be Solved by the Invention) Even if the sealing resin layer filled in the void 24 is removed, a portion remains and so-called lattice cracks occur.

For this reason, it is used for semiconductor devices with a large lead pitch.
- In the de-frame, a, how to take the trouble to set up the pieces,
b. A method of forming a convex part on the mold corresponding to this part,
Furthermore, a method is known in which the C0 frame is installed using a chemical etching process. However, in methods a and b, it is unavoidable that a gap of about 50 μm is formed between the leads 21, and in method C, a gap of about the thickness of the lead frame is formed, so the sealing resin layer is It flows into the gaps and forms a grid. On the other hand, in a lead frame with a small lead pitch, it is difficult to take measures to prevent the formation of such frames.

In any case, removing the lattice particles requires an expensive deburring machine, or takes a lot of time, but the process is not complete. For this reason, there are drawbacks such as difficulty in insertion during the inspection process, etc., and damage to the precision mold for the press process in the subsequent cut-and-bend process.

The present invention provides a novel method for manufacturing a resin-sealed semiconductor device that eliminates the above-mentioned drawbacks, and particularly aims to suppress the occurrence of lattice flashes.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve this object, the present invention uses a lead frame between a dam part and a sealing resin layer, which is installed to intersect with a lead terminal extending from a metal frame. A method is adopted in which the lead frame portion surrounded by the lead, the dam portion, and the sealing resin layer is half punched in a continuous state.

(Function) As described above, in the lead frame used in the method for manufacturing a resin-sealed semiconductor device according to the present invention, approximately half of the continuous lead frame portion is cut by a half punch, and the remaining half is continuous. Since it is in a flat state, the gap between the dam part and the sealing resin is prevented from being filled, and the occurrence of paris is suppressed.

This half-punch is a process that uses a punch with a diagonal cutting surface, which cuts about half the thickness of the lead frame, leaving the remaining part that the punch does not touch as it was before the pressing process. . This process leaves the lead frame in a dangling state, but the overall shape is flat like a continuous lead frame. However, if the cut part comes loose and is not flat, it is restored to a flat state before moving on to the cutting process. .

That is, a thermocompression bonding process using thin metal wires following this pressing process,
After finishing the resin sealing process, etc., the dam part is cut by a cutting process, that is, a cut-to-bend process, and a semiconductor device with an outer lead with almost no paris is obtained, which may clog the socket or damage the precision mold for the press process. This problem can be avoided.

(Example) The present invention will be described in detail with reference to FIGS. 1a and 1b and FIG. 2, and parts that overlap with those in the prior art are given the same numbers. FIG. 1a is a perspective view showing the shape of a lead frame to which the method of the present invention is applied, FIG. 1 is a top view thereof, and FIG.
The figure is a top view of a semiconductor device completed by this method.

The lead frame used in the present invention as shown in FIGS. 1a and b is a narrow pitch DI for multi-bin integrated circuit devices.
This is for P, and its structure is similar to that of the prior art, so a detailed explanation will be omitted. That is, in a metal frame (not shown), a dam 2 extending across the longitudinal direction of the metal frame (not shown) is installed, and a sealing resin layer 3 sealed in the cavity is installed. The end portions shall be continuous as shown in the figure. In other words, it is made into a plate with the same thickness as Dam 2.

And the planned end face 4 of the sealing resin layer 3. A half-punching process is performed on the dam 2 portion facing this, and on the extension line of the side surfaces 5, 5 of the adjacent leads 1, 1, and on a location 6 divided by the dam 2 portion.

This half-punching process was explained in the action column, but to briefly touch on it, as shown in the figure, a punch (not shown) with a diagonal cut surface is used to press the divided area 6 and place adjacent to the dam 2 part. Cut about half of the paper, including the remaining part, and leave the remaining part in a continuous state, that is, in the state before cutting. The part where this half-punch process was performed will be in a dangling state, and if it is not flat, it will be corrected using a press machine.

Next, a predetermined semiconductor integrated circuit element is mounted on a bed portion (not shown) formed on this lead frame by a conventional method, and a thermocompression bonding process and a resin sealing process are performed using a transfer molding method to form a sealing resin layer 3. 1a.

Proceed as in b.

Next, a resin-sealed semiconductor device as shown in FIG. 2 is fabricated through a known destabilizing process, cut-and-bend process, and packaging process. In such a manufacturing method, the molten resin layer is not flowed out to the dam 2 portion during the resin sealing process, so that an outer lead with almost no 5 holes is drawn out from the sealing resin layer.

Therefore, it can be smoothly inserted into the socket, and there is no risk of damaging the precision mold during the pressing process.

〔Effect of the invention〕

As described above, in the method of the present invention, since no lattice chips remain, the deburring process that had to be performed in the past is simplified, and troubles caused by the remaining lattice chips are eliminated, leading to improved productivity. It will be done.

[Brief explanation of the drawing]

FIG. 1a is a top view showing the shape of a lead frame to which the method of the present invention is applied, FIG. 1b is a cross-sectional view thereof,
FIG. 2 is a perspective view of a resin-sealed semiconductor device completed using the method of the present invention, and FIG. 3 is a top view showing the shape of a lead frame to which the conventional method is applied. Agent Patent Attorney Norio Ogo Figure 1 2111

Claims (1)

[Claims] A process of preparing a metal frame body, a process of forming a lead from this frame towards the center, a process of installing a dam part that intersects this lead, and a process of forming a bed between the leads located near the center. a process of forming a semiconductor element in the bed part, a process of covering the semiconductor element to be installed in the bed part with a sealing resin layer, and a process of forming a continuous state of the lead frame between the dam part and the sealing resin layer; 1. A method for manufacturing a resin-sealed semiconductor device, comprising the step of half-punching a lead frame portion surrounded by layers.