JPH09116045A - Resin-sealed semiconductor device of bga type using lead frame and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent warp of a package and package cracks caused by moisture absorption by reason of close contact defect of sealing resin with a simple structure. SOLUTION: A semiconductor device 100 is provided with an inner lead 122, an external terminal connected thereto integrally for electrical connection with an external circuit and a semiconductor element mounting die pad 121 in a plane and a lead frame wherein an external terminal is arranged two- dimensionally is used. A semiconductor element is mounted on a die pad in one surface side of a lead frame, a terminal 111 of a semiconductor element and an inner lead tip are electrically connected by a wire 150 and an external electrode 160 integrally connected to an external terminal arranged two- dimensionally is provided in the other surface. A surface side whereon a semiconductor element of a lead frame is mounted is sealed with sealing resin and the other surface side is sealed with another insulation resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a BGA type resin-sealed semiconductor device using a lead frame.

[0002]

2. Description of the Related Art In recent years, with the trend toward higher performance of electronic devices and lighter, thinner and smaller electronic devices, LSIs, as typified by ASICs, have been increasingly integrated and functionalized. Along with this, the switching noise inside the package cannot be ignored for high-speed signal processing. In particular, the simultaneous switching noise of the IC has a large effect on the effective inductance of the wiring inside the package. We have responded to this by increasing the number of power supplies and grounds. As a result, higher integration and higher functionality of the semiconductor device have led to an increase in the total number of external terminals (pins), and a demand for a multi-terminal semiconductor device has been required. Multi-terminal I
C, particularly ASIC represented by gate array or standard cell, microcomputer, DSP (Digital)
Plastic QFP (Quad) using a lead frame as a package for providing a user with a high cost performance such as a Signal Processor
Flat Package) has become mainstream, and currently 3
It has been put to practical use up to more than 00 pins.

The QFP uses the single-layer lead frame 520 shown in FIG. 5B. As shown in FIG. 5A, the semiconductor element 510 is mounted on the die pad 521.
Inner leads 522 with surface treatment such as silver plating
The tip portion and the terminal 511 of the semiconductor element 510 are connected to the wire 53.
No. 0 is connected, and sealing is performed with a sealing resin 540. After that, the dam bar portion 524 is cut and the outer lead 52
3 is formed into a gull wing shape. As described above, the QFP has been developed as a structure having outer leads 523 for electrically connecting to an external circuit in four directions of the package and capable of supporting multiple terminals. The single layer lead frame 520 used here is typically 42
As shown in FIG. 5B, a metal material having a high electric conductivity and a high mechanical strength, such as an alloy (42% nickel-iron alloy) or a copper alloy, is used as a raw material by a photo etching method or a stamping method. It was made into a shape.

However, speeding up of signal processing of semiconductor devices,
Higher functionality has required more terminals. In QFP, the external terminal pitch has been narrowed to accommodate multiple terminals without increasing the package size. However, as the external terminal pitch becomes narrower, the width of the external terminal itself becomes narrower and the strength of the external terminal decreases. Therefore, it is difficult to cope with skew of outer leads and to maintain planarity (flatness) in a post-process such as forming, and it is difficult to maintain package mounting accuracy in mounting.

To cope with such a problem in mounting the QFP, a BGA (Ball Grid Array) is used.
A plastic package called a has been developed.
In this BGA, usually, a semiconductor element is mounted on one surface of a double-sided substrate, and spherical solder balls are two-dimensionally arranged on the other surface as external terminals of a package. ), And is a package that is compatible with mountability. B
The GA has the advantage that the external terminal interval (pitch) can be increased even with the same number of external terminals as compared with the QFP in which external terminals are provided on four sides of the package. Was able to respond. BGA is
Generally, the structure is as shown in FIG. FIG. 4B shows FIG.
FIG. 4C is a view seen from the back surface (substrate) side of (a), and FIG. This BGA is a die pad 405 and a semiconductor element 40 for mounting the semiconductor element 401 on one surface of a base material 402 of a flat plate (resin plate) having heat resistance represented by BT resin (bismaleimide resin).
1 to 1 have bonding pads 410 electrically connected by bonding wires 408, and on the other surface, solder balls arranged in a grid pattern or a zigzag pattern for electrically and physically connecting an external circuit and a semiconductor device. And an external connection terminal 406 formed by
6 and the bonding pad 410 are electrically connected by a wiring 404, a through hole 450, and a wiring 404A. However, in this BGA, a circuit for connecting a semiconductor element to be mounted and a wire is provided, and external terminals (solder balls) for mounting on a printed circuit board after being made into a semiconductor device are provided on both surfaces of the board 402, and these are through holes. This is a complicated structure that is electrically connected via 450, and the circuit length through which the signal passes becomes long, and the circuit design is also complicated. In addition, the process of manufacturing a substrate for a conventional plastic BGA composed of a heat-resistant and insulating resin base material is based on conventional printed circuit boards such as punching holes in a resin base material, conducting plating of front and back circuits, and solder resist printing. A similar process is required, and it is inevitably a long process as a whole. In addition, there are many restrictions on a circuit process for realizing high density, and it is difficult to manufacture at low cost. Further, the through hole 450 may be broken due to the influence of the thermal expansion of the resin, and there are many problems in terms of reliability.
In addition, the package warps due to the difference in thermal expansion coefficient between the base material 402 such as BT resin and the sealing resin, or the adhesive force (adhesion force) between the base material 402 and the sealing resin is weak. This is a problem because package cracks may occur due to moisture absorption due to poor adhesion.

[0006]

As described above, since the resin-sealed BGA semiconductor device is manufactured by using a base material such as BT resin, its structure is complicated and reliability is low. In addition to many problems, there is also a problem of package cracks due to moisture absorption due to warpage of the package due to the material used and poor adhesion of the sealing resin, and there has been a demand for countermeasures. The present invention is to cope with this, and has a relatively simple structure and does not have a complicated structure like the conventional resin-encapsulated BGA semiconductor device shown in FIG. A resin-encapsulated BG using a lead frame that does not cause a package crack problem caused by moisture absorption due to package warpage or poor adhesion of a sealing resin.
A semiconductor device, and at the same time, a manufacturing method thereof.

[0007]

A BGA type resin-encapsulated semiconductor device using a lead frame of the present invention includes at least an inner lead for electrically connecting to a terminal of a semiconductor element, and the inner lead. An external terminal for integrally connecting with an external circuit for electrical connection with an external circuit, and a die pad for mounting a semiconductor element are provided in a plane.
A BGA type resin-sealed semiconductor device using a lead frame in which external terminals are two-dimensionally arranged, wherein a semiconductor element is mounted on a die pad on one surface side of the lead frame, The terminals (pads) of the semiconductor element and the tips of the inner leads are electrically connected by wires, and external electrodes integrally connected to external terminals arranged two-dimensionally are exposed to the outside on the other surface. And the one surface side on which the semiconductor element of the lead frame is mounted is a sealing resin, and the other surface side is a liquid resin different from the sealing resin. It is characterized in that it is entirely sealed so as to be sealed with an insulating resin which is in close contact with the resin for use and the lead frame and cured. Further, in the above, the surface of the die pad on the semiconductor element mounting side of the lead frame, the surface of the tip of the inner lead, and the surface of the external terminal connected to the external electrode are plated. Further, in the above, the insulating resin is made of a thermosetting solder resist. still,
Besides, as the insulating resin, thermosetting polyimide, thermosetting epoxy, photosensitive polyimide resin or epoxy resin, thermoplastic polyimide resin, or the like can be used.

A method of manufacturing a BGA type resin-encapsulated semiconductor device using the lead frame of the present invention is a method of manufacturing a BGA type resin-encapsulated semiconductor device using the lead frame, which is at least in order. , (A) A support film is provided on one surface side of the lead frame as a frame for supporting the lead frame at least in a range larger than the resin sealing region and for sealing the resin when the resin is sealed. The step of attaching, and (B) mounting the semiconductor element on the die pad of the lead frame, not on the side where the support film is attached, and electrically connecting the terminal (pad) of the semiconductor element and the tip of the inner lead with a wire. And (C) a step of sealing the side of the lead frame on which the semiconductor element is mounted with a sealing resin, and (D) removing and removing the support film to form a support film. A liquid resin different from the sealing resin is closely adhered to the sealing resin and the lead frame in a region corresponding to the substantially resin sealing region on the separated and removed side, and then the liquid resin is formed. In the step of forming an opening through which the external terminal region of the lead frame is exposed to the outside and hardening the insulating resin, (E) through the opening of the insulating resin,
And a step of integrally connecting to an external terminal of the lead frame and forming an external electrode made of solder exposed to the outside. And in the above,
The insulating resin is characterized by comprising a thermosetting solder resist.

Here, the term "planar" means that the die pad, the inner lead, and the external terminal are on the same plane and substantially on the same plane, and also includes the case where the die pad is down-set.

[0010]

The BGA type resin-encapsulated semiconductor device using the lead frame of the present invention is configured as described above, so that the quality is better than that of the conventional BGA type resin-encapsulated semiconductor device shown in FIG. It is possible to provide a BGA type resin-encapsulated semiconductor device with less problems in manufacturing and manufacturing cost. Specifically, at least an inner lead for electrically connecting with a terminal of a semiconductor element, an external terminal for integrally connecting with the inner lead to electrically connect with an external circuit, and mounting a semiconductor element. A lead pad in which the external pad and the external terminals are two-dimensionally arranged, and the external electrodes integrally connected to the two-dimensionally arranged external terminals are exposed to the outside. As a result, the BGA type semiconductor device is realized with a simple structure as compared with the conventional BGA type resin-sealed semiconductor device shown in FIG.
Further, the one surface side on which the semiconductor element of the lead frame is mounted is a sealing resin, and the other surface side is a liquid resin different from the sealing resin on the sealing resin and the lead frame. Since the whole is sealed by sealing with the insulating resin that is closely adhered and cured, the adhesiveness between the sealing resin and the thermosetting insulating resin is shown in FIG. B
It is possible to improve the adhesiveness between the encapsulating resin and the base material (BT resin) in the GA type resin-encapsulated semiconductor device, and as a result, the package cracks are reduced. Specifically, by using an insulating resin as a thermosetting solder resist, it is in a state of good adhesion with the sealing resin, and in an area corresponding to the external terminal area of the insulating resin lead frame, It is possible to make an opening for an external electrode by a method of plate making by a lithography technique. In addition, the surface of the die pad on the side of the semiconductor element mounting of the lead frame, the surface of the tip of the inner lead, and the surface of the external terminal connected to the external electrode are plated, so that the mounting of the conductive element, the wire bonding, the external The formation of electrodes is ensured. The method for manufacturing a BGA type resin-encapsulated semiconductor device using the lead frame of the present invention is configured as described above, so that the BGA using the lead frame of the present invention is configured.
It enables the manufacture of semiconductor devices of the type. In particular, by using a thermosetting solder resist as the insulating resin, it is not necessary to create an opening using a gas such as a carbon dioxide gas laser or an excimer laser.

[0011]

EXAMPLE An example of a BGA type resin-sealed semiconductor device using the lead frame of the present invention will be described with reference to the drawings. FIG. 1 is a BGA using the lead frame of the embodiment.
2 is a cross-sectional view of a resin-sealed semiconductor device of a type shown in FIG.
FIG. 2A shows a lead frame used for the semiconductor device of the embodiment after the outer shape processing, and FIG.
It is an enlarged view of about 1/4 part of (a). FIG. 2 (a)
In FIG. 2, the fixing tape shown in FIG. 2B is omitted for clarity. Further, in FIG. 2A, the number of inner leads, the number of external terminal portions, and the like are shown smaller than those in FIG. 2B in order to make the whole easier to understand. 1 and 2, 100 is a semiconductor device, 1
Reference numeral 10 is a semiconductor element, 120 is a lead frame, 121 is a die pad, 121A is a suspension lead, 122 is an inner lead, 122A inner lead tips, 122B is a connecting portion, 123 is an external terminal, 123B is a connecting portion, 124 dam bars, and 126 is fixed. Tape, 130 is insulating resin, 1
40 is a sealing resin, 150 is a wire, and 160 is an external electrode.

BGA using the lead frame of this embodiment
The resin-sealed semiconductor device 100 of the type is an inner lead 122 for electrically connecting to a terminal of a semiconductor element shown in FIG. 2, and an inner lead 122 integrally connected to the inner lead 122 to electrically connect to an external circuit. External terminal 123 for performing
And a lead frame 120 in which a die pad 121 for mounting a semiconductor element is provided in a substantially planar shape, and external terminals 123 are two-dimensionally arranged, and one surface side of the lead frame 120 is provided. The semiconductor element 110 is mounted on the die pad 121, and the terminal (pad) 111 of the semiconductor element 110 and the inner lead tip 122A are electrically connected by the wire 150, and the other surface is arranged two-dimensionally. The external electrode 160 integrally connected to the external terminal 123 is provided so as to be exposed to the outside. And
A BGA type resin-sealed semiconductor device 100 using the lead frame of the present embodiment is mounted with the semiconductor element 110 of the lead frame 120. One surface side is the sealing resin 140 and the other surface side is The whole is sealed so as to be sealed with the thermosetting insulating resin 130. The insulating resin 130 is a liquid resin different from the sealing resin 140 that is adhered to the sealing resin 140 and the lead frame 120 and cured.

The lead frame 120 is shown in FIG.
The outer shape was processed by etching as shown in (a),
A 0.1 mm thick copper alloy was used. The material of the lead frame may be 42 alloy (42% nickel-iron alloy) other than copper alloy. In the lead frame after the outer shape processing, as shown in FIG.
As shown in (a), the external terminal 123 is in a state of being integrally connected to the dam bar 124 provided on the outer peripheral portion of the lead frame 120 and serving as a dam at the time of resin sealing via the connecting portion 123B. The unnecessary portion including the dam bar 124 is cut and removed during the manufacturing process described later. Further, the inner lead tip 122A is subjected to outer shape processing in a state where the tips are connected. However, as shown in FIGS. 2C and 2A, after fixing tape 126 is fixed and fixed at a predetermined position, as shown in FIG. As shown in (c) and (b), the unnecessary connecting portion 12
Used by cutting off 2B. As shown in FIG. 2 (c) (a), the inner lead tip 122A is externally machined by connecting only the tip with the connecting portion 122B.
In some cases, the outer shape is processed so as to be connected to the die pad. The semiconductor chip 110, the wire 150, and the external electrode 160 are connected to the semiconductor chip mounting side surface of the die pad 121 of the lead frame 120, the wire bonding surface of the tip of the inner lead 122, and the external electrode 160 side surface of the external terminal 123, respectively. Plating is done,
The plating step is performed before taping the fixing tape 126 shown in FIGS. Lead frame 10
Generally, the thickness of 0 is finer as the lead frame material is thinner, that is, the inner lead tip 122.
Although it is possible to narrow the pitch of A, it becomes difficult to secure the strength of the entire lead frame as the thickness becomes thinner. Both narrowing of the lead pitch and securing of the strength of the outer lead may be achieved.

As the insulating resin 130, the sealing resin 1 is used.
Since it adheres to 40 without any gap, a liquid material is cured. In this example, a thermosetting solder resist (manufactured by Taiyo Ink Mfg. Co., model number PSR) was used.
-4000) was used.

The external electrode 160 is made of solder balls so as to be integrally connected to the external terminals 123 arranged two-dimensionally, and is formed so as to be exposed to the outside.

Next, an embodiment of a method for manufacturing a BGA type resin-sealed semiconductor device using the lead frame of the present invention will be described with reference to FIG. First, with respect to the lead frame 120 shown in FIG.
The fixing tape 126 is attached at a predetermined position, as shown in FIG.
As shown in (b), after the unnecessary connecting portion 122B is cut and removed (FIG. 3A), the film 180 having an adhesive on one surface is attached to the entire surface through the adhesive, and then the film The unnecessary portion was cut and removed while the lead frame was supported by 180. (FIG. 3 (b)) As the film 180, a CISV type adhesive film with a polyimide base manufactured by Nikkan Corporation was used, but the film 180 is not necessarily limited to this. For example, epoxy resin, acrylic resin or the like may be used. However, it is necessary to withstand the heat treatment in the process and be able to easily peel off so as not to affect the quality. Next, the semiconductor element 110 is mounted on the die pad 121 on the side of the lead frame 120 on which the film 180 is not attached by die bonding, and then the semiconductor element 1 is connected by the wire 150.
10 terminals (pads) 111 and inner lead tips 12
2A was electrically connected. (FIG. 3C) Next, a predetermined area of the semiconductor element 110, the wire 150, the lead frame 120, etc. was sealed with the sealing resin 140 from the side of the lead frame 120 on which the semiconductor element 110 was mounted. (FIG. 3D) Next, the film 180 was peeled off. (FIG. 3 (e)) Peeling could be easily done by applying heat at 180 ° C. Then, a liquid photosensitive solder resist (manufactured by Taiyo Ink Mfg. Co., model number PSR-4000) is applied to a region corresponding to the resin region for sealing on the side of the lead frame 120 from which the film 180 is peeled off. , Dried to a thickness of about 0.0
After forming a film of 3 mm, only a predetermined area is exposed through a predetermined pattern plate and developed with a sodium hydroxide solution to form an external terminal 12 in an area corresponding to the external terminal 123.
The opening 131 was formed so that 3 was exposed to the outside. (FIG. 3F) Next, after baking (drying) the solder resist, the external electrodes 160 made of solder were formed in the openings 320. (FIG. 3 (g)) The external electrodes (terminals) 160 made of solder balls are formed by melting the solder balls into the openings 131 of the insulating resin 130 where the external terminals 123 of the lead frame 120 are exposed.

[0017]

As described above, the BGA type resin-encapsulated semiconductor device using the lead frame of the present invention has a complex structure using the base material made of the conventional BT resin shown in FIG. By forming the circuit using the lead frame as the core material, the structure is simplified, the problem of deterioration in reliability due to manufacturing is eliminated, and the base material and resin in the conventional one shown in FIG. It is assumed that there is no occurrence of warpage due to the difference in the coefficient of thermal expansion and no package cracking due to moisture absorption due to poor adhesion of the sealing resin. Further, as described above, the method for manufacturing a BGA type resin-sealed semiconductor device using the lead frame of the present invention can manufacture the BGA type resin-sealed semiconductor device using the lead frame of the present invention. In particular, since a thermosetting solder resist is used as the insulating resin, its manufacture is simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a BGA type resin-sealed semiconductor device using a lead frame according to an embodiment.

FIG. 2 is a schematic view of a lead frame used in a BGA type resin-sealed semiconductor device using the lead frame lead frame of the embodiment.

FIG. 3 is a process diagram of a method for manufacturing a BGA type resin-encapsulated semiconductor device using the lead frame of the example.

FIG. 4 is a diagram for explaining a conventional BGA.

FIG. 5 is a diagram for explaining a conventional resin-sealed semiconductor device and a single-layer lead frame.

[Explanation of symbols]

 100 semiconductor device 110 semiconductor element 120 lead frame 121 die pad 121A suspension lead 122 inner lead 122A inner lead tip 122B, 123B connecting part 123 external terminal 124 dambar 126 fixing tape 130 insulating resin 131 opening 140 sealing resin 150 wire 160 external Electrode 180 Film 401 Semiconductor element 402 Base material 403 Mold resin 404, 404A Wiring 405 Die pad 406 External connection terminal 408 Bonding wire 410 Bonding pad 418 Plating part 450 Through hole 451 Thermal conductive via 500 Semiconductor device 510 Semiconductor device 511 Electrode part (pad) 520 (single layer) lead frame 521 die pad 522 inner lead 522A inner lead End 523 outer lead 524 a dam bar 525 frames (frame) unit 530 wire 540 sealing resin

Claims (5)

[Claims] 1. At least an inner lead for electrically connecting to a terminal of a semiconductor element, an external terminal for integrally connecting with the inner lead to electrically connect to an external circuit, and a semiconductor element. A BGA type resin-encapsulated semiconductor device using a lead frame in which a die pad for mounting a semiconductor device is provided in a plane, and external terminals are two-dimensionally arranged. The semiconductor element is mounted on the die pad on the surface side, and the terminal (pad) of the semiconductor element and the tip of the inner lead are electrically connected by a wire, and the other surface is a two-dimensionally arranged external terminal. The external electrode integrally connected to the lead frame is exposed to the outside, and the one surface side of the lead frame on which the semiconductor element is mounted is the sealing resin, and the other surface side is the sealing resin. Resin A lead frame is characterized in that a liquid resin different from the above is closely sealed to the sealing resin and the lead frame and is sealed with an insulating resin that has been hardened. BGA type resin-encapsulated semiconductor device. 2. The plating according to claim 1, wherein the surface of the die pad on the semiconductor element mounting side of the lead frame, the surface of the tip of the inner lead, and the surface of the external terminal connected to the external electrode are plated. BGA type resin-encapsulated semiconductor device using a lead frame. 3. A BGA type resin-encapsulated semiconductor device using a lead frame according to claim 1, wherein the insulating resin is a thermosetting solder resist. 4. A method of manufacturing a BGA type resin-encapsulated semiconductor device using the lead frame according to claim 1, wherein (A) at least one surface of the lead frame has at least one surface side. , A step of attaching a support film as a frame for supporting the lead frame and encapsulating the resin in the resin encapsulation in a range larger than the resin encapsulation area, and (B) attaching the support film Side, the step of mounting the semiconductor element on the die pad of the lead frame and electrically connecting the terminal (pad) of the semiconductor element and the tip of the inner lead with a wire, and (C) mounting the semiconductor element of the lead frame The step of sealing the formed side with a sealing resin, and (D) the supporting film is peeled off and removed, and the sealing resin is placed on a region corresponding to the substantially resin sealing region on the side where the supporting film is peeled off. A liquid resin different from the above is adhered to the sealing resin and the lead frame to form a coating film, and then the liquid resin is provided with an opening through which the external terminal region of the lead frame is exposed to the outside. And a step of forming the resin by curing, and a step (E) of forming an external electrode made of solder that is exposed to the outside and integrally connected to an external terminal of the lead frame through the opening of the insulating resin. A method for manufacturing a BGA type resin-encapsulated semiconductor device using a lead frame. 5. The method for manufacturing a BGA type resin-encapsulated semiconductor device using a lead frame according to claim 4, wherein the insulating resin is a thermosetting solder resist.