JPH11163229A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a semiconductor device in heat dissipating properties and to protect a sealing body against warpages. SOLUTION: A semiconductor device consists of a tab 2a which supports a semiconductor chip 1, an inner lead 2b where a bump mount 2c mounted with a bump 3 extending toward the periphery of the tab 2a is provided, an outer thin insulating sheet 4 which is bonded to the underside 2d of the inner lead 2b to support the inner leads 2b and to insulate an adjacent bump 3, a heat sink 6 which is bonded to an inner thin insulating sheet 5 and equipped with an exposed part 61, a bonding wire 7 which electrically connects the semiconductor chip 1 to the inner leads 2b, and a encapsulating body 8 which encapsulates the semiconductor chip 1 and the bonding wires 7 with resin. The inner leads 2b are insulated from the heat sink 6 by an inner thin insulating sheet 5, and heat is transferred from the inner leads 5 to the heat sink 6 through the insulating sheet 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a technique for manufacturing the same, and more particularly to a semiconductor device having external terminals provided with bumps and manufactured using a lead frame and a method for manufacturing the same.

[0002]

2. Description of the Related Art The technology described below studies the present invention,
Upon completion, they were examined by the inventor, and the outline is as follows.

In the field of electronics, there is a demand for downsizing or higher performance of electronic devices and the entire device including the same, and in order to cope with such demands, higher speed and higher integration of semiconductor devices are being attempted.

As a result, the number of pins and the fine pitch of semiconductor devices have been rapidly advanced, and dimensions per function have been greatly reduced.

[0005] As an example of a package technology corresponding to the above demand, a BGA (Ball Grid) using bumps for external terminals has been proposed.
Semiconductor devices called Arrays are drawing attention.

The BGA includes TAB (Tape Automat).
ed Bonding) or lead frame (LF)
(Hereinafter referred to as LF-BGA) have been devised and developed.

Among them, in the case of an LF-BGA manufactured using a lead frame, an outer thin-film insulating sheet is disposed on the lower surface of the inner lead (the surface on the bump mounting side) and the upper surface (the surface on the chip mounting side). ) Has a structure in which a sealing main body formed by resin sealing is arranged.

The BGA is described in, for example, Nikkei BP, issued May 31, 1993, Susumu Kayama and Kunihiko Naruse (monitoring), “Practical Course VLSI Packaging Technology (Lower)”, pp. 173 to 178. Are listed.

[0009]

However, in the LF-BGA of the above-described technique, an outer thin film insulating sheet is provided on the lower surface of the inner lead, and a sealing body portion made of a sealing resin is provided on the upper surface. Therefore, heat dissipation (thermal conductivity)
The problem is that semiconductor chips with high power consumption cannot be mounted.

Further, since the coefficient of thermal expansion is significantly different between the metal inner lead and the sealing body of the sealing resin, there is a problem that the package body, that is, the sealing body, is warped.

An object of the present invention is to provide a semiconductor device for improving heat dissipation and preventing warpage of a sealing body, and a method of manufacturing the same.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0013]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

That is, a semiconductor device according to the present invention comprises a plurality of thin tabs provided with a thin tab supporting a semiconductor chip and a bump mounting portion extending outwardly around the tab and mounting a bump. An inner lead, an outer thin-film insulating sheet joined to a surface of the inner lead on a bump mounting side to support a plurality of the inner leads and insulate adjacent bumps, and joined to a surface of the inner lead on a chip mounting side; An inner thin film insulating sheet to be provided, a heat dissipating member provided with an exposed portion that is provided to be joined to the inner thin film insulating sheet and that is exposed to the outside, and a conductive member that electrically connects the semiconductor chip and the inner lead. A sealing body formed by resin-sealing the semiconductor chip and the conductive member, wherein the inner lead and the heat radiating member are formed by the inner thin film insulating sheet. In which the insulating and heat transfer between the takes place.

Thus, heat generated from the semiconductor chip is transferred to the tab, the sealing resin, the outer thin-film insulating sheet, the inner lead,
It can be released to the outside via the inner thin film insulating sheet and the heat radiating member.

As a result, it is possible to improve the heat radiation of the sealing body of the LF-BGA.

Accordingly, the thermal resistance in the sealing main body can be reduced, and the thermal resistance can be reduced.

Further, a method of manufacturing a semiconductor device according to the present invention
A tab supporting the semiconductor chip and a plurality of inner leads extending outwardly around the tab, and bonding an outer thin-film insulating sheet to a surface on the bump mounting side of the inner lead; A step of preparing a lead frame to which the inner thin film insulating sheet is bonded; a step of mounting the semiconductor chip on the tab; a step of electrically connecting the semiconductor chip and the inner lead by a conductive member; Attaching a heat radiating member provided with the inner thin film insulating sheet, and forming a sealing body by resin sealing the semiconductor chip and the conductive member;
A step of separating the sealing main body from the lead frame; and a step of forming the bump on a bump mounting portion of the inner lead of the sealing main body.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a semiconductor device (LF-B) according to the present invention.
FIG. 2 is a cross-sectional view showing an example of the embodiment of the structure of FIG. 1, FIG. 2 is an enlarged partial plan view showing an example of the structure of a lead frame used in the semiconductor device shown in FIG. 1, and FIG. It is a perspective view which shows an example of the structure of the heat radiation member used, and the injection | pouring direction of a sealing resin.

The semiconductor device according to the present embodiment is provided with bumps 3 as external terminals and is an LF-BGA manufactured using the lead frame 2 shown in FIG. , But its use is not particularly limited.

The LF-BGA is composed of a thin tab 2a for supporting a semiconductor chip 1 on which a semiconductor integrated circuit is formed, and a bump mounting portion extending outside the periphery of the tab 2a and mounting the bump 3. A plurality of thin inner leads 2b provided with the inner leads 2c and an outer thin film joined to the lower surface 2d (the surface on the bump mounting side) of the inner leads 2b to support the plurality of inner leads 2b and insulate the adjacent bumps 3 An insulating sheet 4, an inner thin-film insulating sheet 5 joined to the upper surface 2e (the surface on the chip mounting side) of the inner lead 2b, and an exposed portion 6a provided to be joined to the inner thin-film insulating sheet 5 and exposed to the outside. Bonding wire 7 (conductive member) for electrically connecting the heat radiating plate 6 (heat radiating member) to the connection terminal 1a of the semiconductor chip 1 and the corresponding inner lead 2b.
And a sealing body 8 formed by resin-sealing the semiconductor chip 1 and the bonding wires 7. The inner thin-film insulating sheet 5 performs insulation and heat transfer between the inner lead 2 b and the heat sink 6. Things.

Heat sink 6 provided on the LF-BGA
(See FIG. 3) is, for example, a material having high thermal conductivity such as aluminum or copper and having high rigidity as a solid (here, a polyimide film used for an inner thin-film insulating sheet 5 and an outer thin-film insulating sheet 4 described later). And a notch 6b (flow path opening) serving as a flow path of the sealing resin 9 at the time of resin sealing is provided on each of the four sides.

Further, the radiator plate 6 in the LF-BGA of the present embodiment is formed in a frame shape.

That is, as shown in FIG. 3, the heat radiating plate 6 has a rectangular frame shape, and a cutout 6b serving as a flow path at the time of resin sealing of the sealing resin 9 is provided on each side thereof. .

Thus, resin sealing can be performed by transfer molding using the notch 6b as a flow path.

The location, number and shape of the cutouts 6b are not limited to those in the present embodiment, and can be variously changed.

In the LF-BGA of the present embodiment, the heat radiating plate 6 is attached to the inner thin film insulating sheet 5 attached to the inner lead 2b.

The inner thin-film insulating sheet 5 has an adhesive layer on both front and back surfaces, and a heat sink 6 is attached to this adhesive layer.

Here, the structure of the lead frame 2 (see FIG. 2) used for the LF-BGA of the present embodiment will be described.

The lead frame 2 shown in FIG.
This is an enlarged view of only one F-BGA area, and an actual lead frame 2 is a multiple frame having a plurality of areas shown in FIG.

The lead frame 2 is provided with a tab 2a for mounting and supporting the semiconductor chip 1, a tab suspension lead 2f for supporting the tab 2a from four directions, and a bump mounting portion 2c for mounting the bump 3. And a frame member 2g supporting the inner leads 2b and the tab suspension leads 2f, and is made of, for example, an alloy of iron and nickel, copper, or the like.

Further, in the lead frame 2, the lower surface 2d of the inner lead 2b (the surface on the bump mounting side)
The outer thin film insulating sheet 4 is joined to the inner lead 2b, and the inner thin film insulating sheet 5 is joined to the upper surface 2e (the surface on the chip mounting side) of the inner lead 2b.

The outer thin-film insulating sheet 4 is made of LF-B having the area of the inner lead 2b and the area of the tab 2a.
It has a size corresponding to the area of one GA, and a plurality of through holes 4a (see FIG. 1) for disposing the bumps 3 are provided according to the bump mounting portions 2c of the inner leads 2b.

The bump mounting portions 2c provided on each of the inner leads 2b and the tab suspension leads 2f are entirely arranged in a lattice pattern, whereby a plurality of bump mounting portions 2c provided on the outer thin film insulating sheet 4 are provided. Are also arranged in a lattice pattern corresponding to the bump mounting portions 2c.

The inner thin-film insulating sheet 5 is formed in a frame shape according to the shape of the frame-shaped heat radiating plate 6.

As a result, the outer thin-film insulating sheet 4 and the inner thin-film insulating sheet 5 having the desired sizes are respectively formed by LF-
Each BGA is attached to the lead frame 2.

The outer thin-film insulating sheet 4 and the inner thin-film insulating sheet 5 have a thickness of, for example, 100 μm or less, preferably about 50 to 75 μm, and the base material is formed of an insulating material such as a polyimide film. I have.

Further, the outer thin film insulating sheet 4 and the inner thin film insulating sheet 5 have an adhesive layer on both front and back surfaces of the base material. However, the adhesive layer does not necessarily need to be formed on both the front and back surfaces, and may be formed on any one of the surfaces, and may not be formed on both the front and back surfaces.

The adhesive layer includes, for example, a thermosetting adhesive and a thermoplastic adhesive. In the present embodiment, the case where the thermosetting adhesive layer is formed will be described. .

The sealing resin 9 is, for example, a thermosetting epoxy resin, and the bonding wire 7 is a thin wire made of gold or the like.

Further, the semiconductor chip 1 is made of silver paste 1
0 is fixed to the tab 2a.

The bumps 3 are ball-shaped external terminals formed of solder, and are arranged in a lattice pattern on the back surface of the sealing body 8.

The semiconductor device according to the present embodiment (LF-B
GA) will be described.

The method for manufacturing the semiconductor device is described in FIG.
5 is a method for manufacturing an LF-BGA (see FIG. 1) using the lead frame 2 shown in FIG.

First, the lead frame 2 shown in FIG. 2 is prepared.

That is, a tab 2a for supporting the semiconductor chip 1 and a plurality of inner leads 2 extending around the tab 2a.
b, and the position of the lower surface 2d (the surface on the bump mounting side) of the inner lead 2b (the position of the bump mounting portion 2c of the inner lead 2b and the corresponding through hole 4a of the outer thin film insulating sheet 4). A lead frame in which the outer thin-film insulating sheet 4 is joined to the jointed portion), and the frame-shaped inner thin-film insulating sheet 5 is joined to a predetermined portion (where the heat radiating plate 6 is attached) on the upper surface 2e (the surface on the chip mounting side). Prepare 2

Subsequently, a silver paste 10 as a die bonding material is applied to the tab 2a of the lead frame 2, and the semiconductor chip 1 is mounted thereon to perform die bonding.

Thus, the semiconductor chip 1 is mounted on the tab 2a.

Further, wire bonding for electrically connecting the connection terminals 1a of the semiconductor chip 1 and the corresponding inner leads 2b with bonding wires 7 (conductive members) is performed.

Thereafter, a frame-shaped heat radiating plate 6 (heat radiating member) having an exposed portion 6a is attached to the inner thin-film insulating sheet 5.

At this time, preheating is performed to such an extent that the thermosetting adhesive layer of the frame-shaped inner thin-film insulating sheet 5 becomes soft, and the frame-shaped radiating plate 6 is positioned according to the frame shape of the inner thin-film insulating sheet 5. And temporarily fix it.

Thereafter, the lead frame 2 including the inner thin-film insulating sheet 5 is heated to a predetermined temperature to cure the thermosetting adhesive layer of the inner thin-film insulating sheet 5, whereby the heat radiating plate 6 is moved to the inner thin-film insulating sheet. Attach to sheet 5.

Subsequently, the semiconductor chip 1 and the bonding wires 7 are resin-sealed to form a sealing body 8 as a package body.

At this time, the sealing resin 9 is passed through the notch 6b (flow path opening) of the heat sink 6 and resin-sealed by transfer molding.

That is, as shown in FIG. 3, the notch 6 b provided in the heat sink 6 is used as a flow path of the sealing resin 9.
The sealing resin 9 is injected from the direction of the arrow through the notch 6b, and the resin is sealed by transfer molding.

Since the radiator plate 6 of the LF-BGA of this embodiment is formed in a frame shape, the flow of the sealing resin 9 at the time of resin sealing can be further smoothed.

In this embodiment, when resin sealing is performed by transfer molding, resin sealing is performed so that the exposed portion 6a of the heat sink 6 is exposed.

That is, the surface (exposed portion 6a) of the heat sink 6
By performing resin sealing so that the sealing resin 9 does not flow around, the exposed portion 6a can be exposed to form the sealing body portion 8.

Thereafter, the package body, that is, the sealing body 8 is separated from the lead frame 2.

That is, the frame portion 2g is cut at a predetermined location on the outer periphery of the sealing main body portion 8, thereby separating the sealing main body portion 8 from the lead frame 2.

Subsequently, in the outer thin film insulating sheet 4 exposed on the back surface of the sealing body 8, the through holes 4 arranged in a lattice and exposing the bump mounting portions 2c of the inner leads 2b are exposed.
Supply solder balls to a.

Thereafter, the inner leads 2b of the sealing body 8 are
The bump 3 is formed on the bump mounting portion 2c.

That is, the solder balls are melted through the sealing main body portion 8 in a reflow furnace (not shown), thereby forming the bumps 3 on the bump mounting portion 2c.

As a result, an LF-BGA (semiconductor device) using the lead frame 2 shown in FIG. 2 can be manufactured.

According to the semiconductor device of this embodiment and the method of manufacturing the same, the following operation and effect can be obtained.

That is, the heat radiating plate 6 is joined to the upper surface 2 e of the inner lead 2 b via the inner thin film insulating sheet 5, and the sealing body 8 has the heat radiating plate 6 having higher thermal conductivity than the inner thin film insulating sheet 5. Thereby, heat generated from the semiconductor chip 1 can be released to the outside via the tab 2a, the sealing resin 9, the outer thin film insulating sheet 4, the inner lead 2b, the inner thin film insulating sheet 5, and the heat radiating plate 6.

As a result, the thermal resistance in the sealing body 8 can be reduced, and therefore the thermal resistance can be reduced.

As a result, it is possible to improve the heat radiation of the sealing body 8 of the LF-BGA.

The rigidity of the sealing body 8 can be increased by providing the sealing body 8 with the heat radiating plate 6.

Thus, it is possible to prevent the sealing body 8 from warping due to the rigidity of the heat radiating plate 6.

As a result, when the bump 3 is formed as an external terminal in the LF-BGA, the flatness of the bump 3, that is, the solder ball surface can be improved.

Furthermore, since the heat dissipation of the LF-BGA can be improved and the sealing body 8 can be prevented from warping, the semiconductor chip 1 with high power consumption can be mounted.

As a result, a LF-BGA with high power consumption can be realized.

Further, the notch 6b (flow path opening) serving as a flow path of the sealing resin 9 at the time of resin sealing is provided on the heat sink 6, so that the sealing resin 9 at the time of resin sealing is formed. Since a flow path can be secured, LF-BGA can be manufactured by transfer molding.

Since the heat radiating plate 6 is formed in a frame shape, the flow of the sealing resin 9 at the time of resin sealing can be made smoother, and as a result, the sealing property in the LF-BGA can be improved. It can be further improved.

Further, since the heat radiating plate 6 has the exposed portion 6a exposed to the outside, the heat radiating property of the LF-BGA can be further improved.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the embodiments of the present invention, and does not depart from the gist of the invention. It is needless to say that various changes can be made.

For example, in the above embodiment, the case where the base material of the outer thin film insulating sheet 4 and the inner thin film insulating sheet 5 is a polyimide film has been described, but the thin film insulating sheet is not limited to a polyimide film. Instead, a thin film sheet member formed of an epoxy resin or the like may be used as long as it is an insulating thin film sheet member.

Further, the material of the heat radiating plate 6 is not limited to copper or aluminum, and any other metal material having a relatively high thermal conductivity and a high rigidity as a solid can be used. And so on.

Further, in the above-described embodiment, the case where the heat radiating plate 6 has a frame shape has been described. However, the shape of the heat radiating plate 6 is not limited to the frame shape. It may have a covered shape as in the other embodiments shown.

That is, by forming the heat radiating plate 6 with a roof, the area of the exposed portion 6a can be increased, and the heat radiation of the semiconductor device (LF-BGA) can be further improved.

When the heat radiating plate 6 is formed with a roof, a notch 6b (flow path opening) is preferably provided as shown in FIG. 5, and the sealing resin 9 is inserted through the notch 6b from the direction of the arrow. By injecting (see FIG. 4), the flow of the sealing resin 9 at the time of resin sealing can be made smooth.

In the above-described embodiment, the case where the heat radiating plate 6 is adhered to the inner thin film insulating sheet 5 by using the adhesive layer provided on the inner thin film insulating sheet 5 when attaching the heat radiating plate 6 to the inner thin film insulating sheet 5 has been described. However, when the adhesive layer is not provided on the inner thin-film insulating sheet 5, the radiator plate 6 is attached to the inner thin-film insulating sheet 5 by using, for example, an epoxy-based adhesive.
May be adhered to.

Further, as another fixing method of the heat radiating plate 6 when the inner thin film insulating sheet 5 is not provided with an adhesive layer, a method of fixing the heat radiating plate 6 simultaneously with resin sealing may be used.

That is, when performing resin sealing, the heat sink 6
(A heat dissipation member) is arranged in contact with the inner thin film insulating sheet 5, and in this state, the semiconductor chip 1 and the bonding wires 7
(Conductive member) is sealed with a resin to form a sealing body portion 8. A heat radiating plate 6 is arranged in a cavity of a molding die at the time of resin sealing, and the sealing resin is sealed simultaneously with the resin sealing. 9, the heat radiating plate 6 is fixed.

[0087]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). A heat radiating member is joined to the upper surface of the inner lead via an inner thin film insulating sheet, and the sealing body has a heat radiating member having a higher thermal conductivity than the inner thin film insulating sheet, thereby lowering the thermal resistance in the sealing body. Therefore, a low thermal resistance can be achieved.
As a result, it is possible to improve the heat dissipation of the sealing body of the LF-BGA.

(2). Since the sealing body has the heat radiation member, the rigidity of the sealing body can be increased. Thereby, it is possible to prevent the sealing body from warping due to the rigidity of the heat radiating member. As a result, LF-BG
The flatness of the bump, that is, the solder ball surface when the bump is formed in A can be improved.

(3). Since the heat dissipation of the LF-BGA can be improved and the warpage of the sealing body can be prevented, a semiconductor chip with high power consumption can be mounted. As a result, LF-BGA with high power consumption can be realized.

(4). By providing the heat dissipation member with a flow path port that becomes a flow path of the sealing resin at the time of resin sealing,
Since the flow path of the sealing resin at the time of resin sealing can be secured, LF-
BGA can be manufactured by transfer molding.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment of a structure of a semiconductor device (LF-BGA) according to the present invention.

FIG. 2 is an enlarged partial plan view showing an example of a structure of a lead frame used in the semiconductor device shown in FIG.

FIG. 3 is a perspective view showing an example of a structure of a heat radiation member used in the semiconductor device shown in FIG. 1 and an injection direction of a sealing resin.

FIG. 4 shows a semiconductor device (L) according to another embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the structure of (F-BGA).

5 is a perspective view showing an example of a structure of a heat radiation member used in the semiconductor device shown in FIG. 4 and an injection direction of a sealing resin.

[Explanation of symbols]

 Reference Signs List 1 semiconductor chip 1a connection terminal 2 lead frame 2a tab 2b inner lead 2c bump mounting portion 2d lower surface (bump mounting side surface) 2e upper surface (chip mounting side surface) 2f tab suspension lead 2g frame portion 3 bump 4 outer thin film insulating sheet Reference Signs List 4a Through hole 5 Inner thin film insulating sheet 6 Heat radiating plate (heat radiating member) 6a Exposed portion 6b Notch (flow path port) 7 Bonding wire (conductive member) 8 Sealing body 9 Sealing resin 10 Silver paste

Claims (7)

[Claims] 1. A semiconductor device provided with a bump as an external terminal, comprising: a thin tab supporting a semiconductor chip; and a bump mounting portion extending outwardly around the tab and mounting the bump. A plurality of thin inner leads provided with; an outer thin-film insulating sheet joined to a surface of the inner lead on the bump mounting side to support the plurality of inner leads and insulate adjacent bumps; An inner thin-film insulating sheet joined to the chip mounting surface of the inner lead; a heat dissipating member provided to be joined to the inner thin-film insulating sheet and having an exposed portion exposed to the outside; the semiconductor chip and the inner A conductive member for electrically connecting the lead; and a sealing body formed by resin-sealing the semiconductor chip and the conductive member. The semiconductor device, wherein an insulating and heat transfer between the heat radiating member and the inner leads is carried out. 2. The semiconductor device according to claim 1, wherein the heat radiating member is provided with a flow path opening serving as a flow path of a sealing resin at the time of resin sealing. 3. The semiconductor device according to claim 1, wherein said heat radiating member is formed in a frame shape. 4. A method of manufacturing a semiconductor device using bumps as external terminals, comprising: a tab for supporting a semiconductor chip; and a plurality of inner leads extending outwardly around the tab. Bonding the outer thin film insulating sheet to the surface on the bump mounting side, and preparing a lead frame in which the inner thin film insulating sheet is bonded to the chip mounting side surface, and mounting the semiconductor chip on the tab, A step of electrically connecting the semiconductor chip and the inner lead by a conductive member; a step of attaching a heat radiating member having an exposed portion to the inner thin film insulating sheet; and a resin sealing of the semiconductor chip and the conductive member Forming the sealing body portion by separating the sealing body portion from the lead frame; and forming the sealing body portion from the lead frame. The method of manufacturing a semiconductor device characterized by a step of forming the bumps on the lamp mounting unit. 5. A method of manufacturing a semiconductor device using a bump as an external terminal, comprising: a tab for supporting a semiconductor chip; and a plurality of inner leads extending outwardly around the tab. Bonding the outer thin film insulating sheet to the surface on the bump mounting side, and preparing a lead frame in which the inner thin film insulating sheet is bonded to the chip mounting side surface, and mounting the semiconductor chip on the tab, Electrically connecting the semiconductor chip and the inner lead with a conductive member; and disposing a heat radiating member having an exposed portion in contact with the inner thin film insulating sheet, and in this state, the semiconductor chip and the conductive member. Forming a sealing body by resin sealing the resin body; separating the sealing body from the lead frame; and forming the inner part of the sealing body. Forming the bump on the bump mounting portion of the lead. 6. The method of manufacturing a semiconductor device according to claim 4, wherein, when the resin sealing is performed, the sealing resin is passed through a flow path opening provided in the heat dissipation member, and the resin is sealed by transfer molding. A method of manufacturing a semiconductor device. 7. The method for manufacturing a semiconductor device according to claim 4, wherein the resin sealing is performed such that the exposed portion of the heat dissipation member is exposed when the resin sealing is performed. A method for manufacturing a semiconductor device.