KR100891652B1 - Substrate for mounting a semiconductor chip on - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a semiconductor package, and more particularly, to a semiconductor chip mounting substrate in which bumps are formed on a flexible metallic body and flip chip bonding a semiconductor chip on the bumps. will be.

In the semiconductor chip mounting substrate according to the present invention, a bump pad that is processed according to a predetermined circuit shape and connected to a chip pad of a semiconductor chip that is flip chip bonded to an upper surface thereof is formed, and has a metal substrate body having flexibility in the thickness direction. ; And an insulating layer in which a solid film type or liquid dielectric material is attached or coated on the substrate body and laminated, and a through hole is formed at a position where the bump pad is formed. And a bump formed on the bump pad so as to contact the chip pad of the semiconductor chip through the through hole of the insulating layer.

Thus, the present invention provides a semiconductor chip mounting substrate that can be applied not only to fabrication of a conventional flip chip bonding type semiconductor package but also to various applications such as a smart card or a RF device having a lead frame requiring flexibility.

Description

Substrate for mounting a semiconductor chip on}

1 is a view showing an example of a semiconductor package formed by a conventional flip chip bonding method,

2 is a view illustrating in detail a portion of the semiconductor chip mounting substrate and the semiconductor chip of FIG.

3 is a view illustrating a semiconductor chip mounting substrate for flip chip bonding according to the present invention;

4 is a diagram illustrating components of the semiconductor chip mounting substrate of FIG. 3 separated from each other;

5A is a view showing a surface on which a semiconductor chip of a semiconductor chip mounting substrate for a smart card is mounted;

FIG. 5B is a view illustrating a contact pad surface of FIG. 5A;

6 illustrates a semiconductor package in which a semiconductor chip is mounted on the semiconductor chip mounting substrate of FIGS. 5A and 5B.

FIG. 7A is a diagram illustrating a semiconductor chip mounting substrate manufactured by forming an insulating layer from a solid dielectric film on a dual type lead frame.

FIG. 7B is a diagram illustrating a semiconductor chip mounting substrate fabricated by forming an insulating layer with a solid dielectric film on a quad type lead frame.

FIG. 8A is a diagram illustrating a semiconductor chip mounting substrate manufactured by applying an insulating dielectric layer to a liquid dielectric material on a dual type lead frame. FIG.

FIG. 8B is a diagram illustrating a semiconductor chip mounting substrate fabricated by applying an insulating dielectric layer to form a dielectric layer on a quad type lead frame. FIG.

FIG. 9 illustrates a semiconductor package in which a semiconductor chip is mounted on the semiconductor chip mounting substrates of FIGS. 7A, 7B, 8A, and 8B.

<Description of Symbols for Major Parts of Drawings>

2, 3, 4: board for semiconductor chip mounting 21: substrate body

22, 32, 42: insulation layers 23, 33, 43: bump

24 and 44: bump pads 35 and 45: semiconductor chips

36, 46: Filling material 31: Contact pad

41: lead frame

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a semiconductor package, and more particularly, to a semiconductor chip mounting substrate in which bumps are formed on a flexible metallic body and flip chip bonding a semiconductor chip on the bumps. will be.

As the integrated circuits become thinner and shorter, the size of semiconductor chips mounted on a substrate becomes smaller and leads of chips become smaller, thereby minimizing lead spacing. As a result, a problem arises in that a semiconductor chip cannot be directly mounted on a substrate using a conventional printed circuit board (PCB), and an application package has appeared to solve this problem. Currently, the most common type of package is a ball grid array (BGA) package, which uses a bump to connect a semiconductor chip and a mother board.

In this case, the BGA package mounts a semiconductor chip on a substrate for mounting a semiconductor chip. In the related art, an input / output terminal of the semiconductor chip is usually connected to a semiconductor chip mounting substrate by wire bonding. Connected with. However, in the case of the conventional wire bonding method, there is a limitation in applying to products requiring more finer lead spacing and high speed operation, and there is a problem in that assembly cost is high.

Therefore, in recent years, a manufacturing process is achieved by using a flip chip bonding method in which a metal bump is formed in advance on a semiconductor chip or a substrate, and the circuit part on the semiconductor chip is inverted and mounted to the semiconductor chip mounting substrate using the metal bump as a connecting member. Simplify and increase productivity.

As described above, a semiconductor chip mounting substrate and a method of manufacturing the same, which are used in a semiconductor package in which metal bumps are formed on a substrate in advance and flip-chip bonded, are disclosed in Japanese Patent Laid-Open No. 2001-0001600.

1 and 2 are views illustrating in detail an example of a semiconductor package formed by a conventional flip chip bonding method and a part of a semiconductor chip mounting substrate and a semiconductor chip used therein.

The semiconductor package 1 includes a semiconductor chip 11, a substrate 12, a bump 13, and a filler 14. In this case, an external connection terminal 15 is formed on the lower surface of the substrate 12 to connect the semiconductor chip 11 to an external circuit (not shown), and the bump 13 is connected to the semiconductor chip 11. Interposed between the substrate 12 to connect the chip pad 16 of the semiconductor chip to the substrate 12, the filler 14 fills between the semiconductor chip 11 and the substrate 12. . In addition, the substrate 12 is formed by forming a circuit pattern 122 on the surface of the substrate body 121 and plating a cover coat 123 to protect the circuit pattern 122.

In this case, the semiconductor package 1 forms the bump 13 in a region where the chip pad 16 formed on the semiconductor chip of the substrate 12 is located, and the semiconductor chip ( The semiconductor chip 11 is mounted upside down so that the chip pad 16 on the 11 is attached thereto.

In recent years, semiconductor chips have been used as semiconductor package types in various fields. They are not only mounted on a conventional printed circuit board but also require a high precision and flexibility, such as a liquid crystal display (LCD), a smart card, or a radio frequency (RF). It is widely used for equipment. Therefore, even in the case of a semiconductor chip mounting substrate has a thinner and simpler structure can be produced at a high speed, it needs a flexibility that can be applied to various environments.

 The present invention is to solve such problems,

A bump is formed on a flexible metallic substrate main body to be applied not only to fabrication of a conventional flip chip bonding type semiconductor package but also to be applied in various ways to a smart card or a RF device having a lead frame requiring flexibility. An object of the present invention is to provide a semiconductor chip mounting substrate for flip chip bonding a semiconductor chip onto a bump.

In order to achieve the above object, the semiconductor chip mounting substrate according to the present invention,

A metal substrate main body which is processed according to a predetermined circuit shape and has bump pads connected to chip pads of a semiconductor chip flip-bonded on an upper surface thereof, and having flexibility in a thickness direction; Wow

An insulating layer in which a solid film type or a liquid dielectric material is attached or coated on the substrate body and laminated, wherein a through hole is formed at a position where the bump pad is formed; And

And bumps formed through the through-holes of the insulating layer on the bump pads to contact the chip pads of the semiconductor chip.

In this case, the substrate body may be configured as a contact pad type or a lead frame.

In addition, the thickness of the insulating layer is characterized in that it is formed thinner than the thickness of the substrate body.

In addition, the bumps may be formed by solder ball insertion or screen printing.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view illustrating a semiconductor chip mounting substrate for flip chip bonding according to the present invention, and FIG. 4 is a diagram illustrating components of the semiconductor chip mounting substrate of FIG. 3.

Referring to the drawings, the semiconductor chip mounting substrate 2 includes a substrate body 21, an insulating layer 22, and a bump 23. In this case, the bump pad 24 is formed at a position connected to the chip pad of the semiconductor chip (not shown) on the substrate main body 21, and the through hole is formed at the position at which the bump pad 24 is formed. An insulating layer 22 is stacked on the substrate main body 21, and the bump 23 penetrates the through hole 221 of the insulating layer 22 on the bump pad 24 so as to form the insulating layer 22. It is formed to protrude upward. The semiconductor chip is mounted on the semiconductor chip mounting substrate 2 such that a part of the bump 23 protruding over the insulating layer 22 is connected to the chip pad of the semiconductor chip.

Typically, the semiconductor chip includes a predetermined electric element, a circuit connecting the electric elements, and a chip pad serving as a terminal for connecting the circuit with an external circuit through the semiconductor chip mounting substrate 2. . The semiconductor chip is mounted on the semiconductor chip mounting substrate 2 by flipping the chip pad to be connected to the bump 23 toward the lower surface by a flip chip bonding method. However, the semiconductor chip mounting substrate 2 according to the present invention may not be limited and used only in the case of the semiconductor chip mounting by the flip chip bonding.

The substrate main body 21 is processed into a shape capable of forming a circuit capable of connecting the semiconductor chip with an external circuit of a thin plate-like metallic material. As the substrate main body 21, it is preferable to use a metallic material such as copper (Cu) or alloy (Alloy) having conductivity so as to be connected to the internal circuit of the semiconductor chip, the thickness is necessary electrical properties, strength, and flexibility It is preferable to be 75 ~ 125㎛ to have. At this time, it is preferable that the thickness of the substrate main body 21 is made thicker than the thickness of the insulating layer 22 to configure the semiconductor chip mounting substrate 2.

In the conventional case, a relatively thick plate of BT resin (Bismaleimide-Triazine resin), etc., is prepared at the bottom of the substrate body, a thin copper plate is bonded thereon, and then a circuit is manufactured by etching or the like. The substrate is manufactured by plating nickel (Ni) or gold (Au) or the like, but in the present invention, the substrate main body 21 is processed into a relatively thick plate with a metal layer corresponding to a circuit pattern, and the substrate main body 21 thereon. The insulating layer 22 is formed by attaching a dielectric material thinner than) to fabricate the semiconductor chip mounting substrate 2.

In addition, the bump pad 24 is formed on the substrate main body 21 at a position connected to the chip pad of the semiconductor chip when the semiconductor chip is mounted. The bump pad 24 may be formed by plating a metal such as gold (Au), silver (Ag), or palladium (Pd) at a required position on the substrate main body 21 processed into a required shape. Therefore, it can be formed by spot plating. In this case, the bump pad 24 serves as a terminal of the substrate body 21 connected to the semiconductor chip.

In addition, the substrate main body 21 may be a contact pad type or a lead frame type for use in a smart card or an RF (radio frequency) device, or the like. Applicable to production.

The insulating layer 22 is interposed between the semiconductor chip and the substrate main body 21, and is formed on opposite surfaces of the substrate main body 21 and the insulating layer 22 to be formed by the bump 23. Parts other than the input / output terminals electrically connected to each other are insulated from each other, and the substrate main body 21 is processed and maintained in a required shape. In this case, the chip pad of the surface of the semiconductor chip facing the substrate main body 21 and the bump pad 24 of the surface of the semiconductor body facing the semiconductor chip 21 constitute the input / output terminals.

In addition, the insulating layer 22 may be provided on the substrate body 21 by making a dielectric material into a solid film type. In addition, through-holes 221 are formed in the insulating layer 22 so that the bumps 23 connecting the chip pads and the bump pads 24 may be formed therethrough.

The insulating layer 22 prepares a film of dielectric material in a required size and shape, and processes the through-hole 221 in the film, such as laminating on the prepared substrate body 21. It is formed by attaching in a method. In this case, the insulating layer 22 may be replaced with the above-described method, to prepare a film of the prepared dielectric material, and then attach the through-hole 221 on the substrate body 21 by laminating or the like. It may be formed by processing.

In this case, the through hole 221 may be formed by mechanical processing such as a mold or laser drilling, or may be formed by chemical processing such as etching. In addition, the through hole 221 may be formed in consideration of the size of the chip pad and the bump pad 24 and the size of the bump 23 are connected to each other, the diameter of 50 ~ 1000㎛ It is desirable to have.

In addition, the insulating layer 22 is formed on the substrate main body 21 so as to have a thickness thinner than the substrate main body 21 processed into a relatively thick plate shape, the thickness is preferably 10 ~ 75㎛. . In this case, depending on the method of forming the bump 23, the height of the bump 23 may be adjusted by adjusting the thickness of the insulating layer 22.

In the present embodiment, the insulating layer 22 is formed by attaching a solid film of dielectric material on the substrate main body 21. However, in another embodiment, the liquid dielectric It may be formed by applying a material to the substrate body 21.

The bump 23 penetrates the through hole 221 formed in the insulating layer 22 on the bump pad 24 formed on the substrate main body 21, and an end portion thereof protrudes from the top surface of the insulating layer 22. It is formed to be. At this time, the end portion of the bump 23 is brought into contact with the chip pad of the semiconductor chip and then bonded to each other to mount the semiconductor chip on the semiconductor chip mounting substrate 2.

In this case, the bump 23 may be formed in various ways, such as a solder ball insertion method, a screen printing method, or an electroplating method. In this case, in the case of the solder ball inserting method, the bump pad 24 on the substrate body 21 and the through hole 221 formed in the insulating layer 22 attached to the substrate body 21. After inserting the solder ball into the space created by the reflow, the bump is formed by reflow in a furnace. At this time, the height of the bump 23 may be adjusted by adjusting the size of the inserted solder ball.

In addition, in the screen printing method, a screen plate having a hole formed at a position corresponding to a position at which the bump 23 is formed on the substrate main body 21 is placed on the insulating layer 22, and then The liquid solder paste is pushed into the through hole 221 with a blade so as to fill the liquid solder paste through the holes of the screen plate, and after removing the screen plate, the solder paste is reflowed in a furnace. The bumps 23 are formed by performing reflow. At this time, the height of the bump 23 may be adjusted by adjusting the thickness of the screen plate.

At this time, in order to allow the semiconductor chip to be stably mounted on the semiconductor chip mounting substrate 2, the height of the bump 23 is 3/4 times to the thickness of the insulating layer 22 to 7 /. It is preferable to make it four times.                     

5A, 5B, and 6 are diagrams illustrating a semiconductor chip mounting substrate for a smart card as another embodiment. More specifically, FIG. 5A is a view showing a surface on which a semiconductor chip of a smart chip semiconductor chip mounting substrate is mounted, FIG. 5B is a view showing a contact pad surface of FIG. 5A, and FIG. 6. 5A and 5B illustrate a semiconductor package in which a semiconductor chip is mounted on the semiconductor chip mounting substrate of FIGS. 5A and 5B.

Referring to the drawings, the semiconductor chip mounting substrate 3 includes a contact pad 31, an insulating layer 32, and a bump 33. In this case, when the semiconductor package is mounted on a thin plate, such as a smart card, it is preferable to apply the contact pad 31 so as to be in direct contact instead of forming a solder ball terminal under the substrate body as in a normal case. .

In addition, the insulating layer 32 having a through hole formed at a position connected to the chip pad of the semiconductor chip 35 on the contact pad 31 is stacked on the contact pad 31, and the bump 33 Is formed to protrude above the insulating layer 32 through the through hole of the insulating layer 32 on the contact pad 33. At this time, the portion where the bump 33 is formed on the metallic thin pad of the contact pad 31 is preferably plated with nickel / gold (Ni / Au) or nickel / palladium (Ni / Pd).

In addition, the semiconductor chip 35 is mounted on the semiconductor chip mounting substrate 3 such that a part of the bump 33 protruding over the insulating layer 32 is connected to the chip pad of the semiconductor chip. In addition, the filler 36 is coated on the semiconductor chip 35 on the semiconductor chip mounting substrate 3 on which the bumps 33 are exposed and around the semiconductor chip 35 with the filler 36. It is possible to prevent the exposed bump 33 and the outside of the semiconductor chip 35 from being oxidized and corroded.

In this case, the filler 36 may include an encapsulant type and an underfill type that fills between the semiconductor chip 35 and the semiconductor chip mounting substrate 3, as shown in FIG. 6. Can be. However, in the latter case, the opposite side of the surface on which the chip pad (not shown) of the semiconductor chip 35 is formed is exposed to the outside, thereby effectively dissipating heat generated during the circuit operation of the semiconductor chip 35. There is also. In this case, an epoxy resin or the like may be used as the filler.

In the present embodiment, detailed descriptions of the same matters as in the previous embodiment will be omitted, and the present invention may be similarly applied.

7A, 7B, 8A, 8B, and 9 are diagrams illustrating a semiconductor chip mounting substrate having a lead frame as a substrate body as still another embodiment. More specifically, FIGS. 7A and 7B illustrate a semiconductor chip mounting substrate fabricated by forming an insulating layer of a solid dielectric film on a dual type and quad type lead frame, respectively. 8A and 8B illustrate a semiconductor chip mounting substrate fabricated by coating an insulating layer by coating a liquid dielectric material on a dual type and quad type lead frame. 9 is a diagram illustrating a semiconductor package in which a semiconductor chip is mounted on the semiconductor chip mounting substrates of FIGS. 7A, 7B, 8A, and 8B.

Referring to the drawings, the semiconductor chip mounting substrate 4 includes a lead frame 41, an insulating layer 42, and a bump 43. In this case, the bump pad 44 is formed at a position connected to the chip pad of the semiconductor chip 45 on the lead frame 41, and the insulation is formed at the position where the bump pad 44 is formed. A layer 42 is laminated on the lead frame 41, and the bumps 43 are formed to protrude above the insulating layer 42 through the through holes of the insulating layer 42 on the bump pad 44. do. The semiconductor chip is mounted on the semiconductor chip mounting substrate 4 such that a part of the bump 43 protruding over the insulating layer 42 is connected to the chip pad of the semiconductor chip.

In this case, when the insulating layer 42 is formed by attaching a solid dielectric film on the lead frame 41, as shown in FIGS. 7A and 7B, a series of adjacent layers of the insulating layer 42 are adjacent to each other. The lead frames 41 are connected to each other, a through hole is formed at a position where the semiconductor chip 45 and the lead frame 41 of the insulating layer 42 are connected, and the bumps are formed in the through holes. 43 is formed, and the said semiconductor chip mounting substrate 4 is formed.

Accordingly, in the case of the dual type lead frame, the insulating layer 42 is formed by connecting two strips of two rows of lead frames that face each other in plan view, and are separated into two strip shapes. In addition, in the case of a quad type lead frame, the insulating layer 42 is formed in a shape in which four insulating layers having a planar strip shape are interconnected to form respective sides of a quadrangle.

In addition, when the insulating layer 42 is coated with a liquid dielectric material on the lead frame 41 to form an insulating layer, as shown in FIGS. 8A and 8B, each of every one of the lead frames Insulating layers are formed to be separated from each other, and a through hole is formed at a position where the semiconductor chip 45 and the lead frame 41 of the insulating layer 42 are connected, and the bumps are formed in the through holes. 43 is formed to form the semiconductor chip mounting substrate 4.

In addition, a filler 46 may be applied to a region in which the semiconductor chip 45 is mounted on the semiconductor chip mounting substrate 4 on which the bumps 43 are exposed and around the semiconductor chip 45. Similarly, the filler 46 may include an encapsulant type and an underfill type that fills between the semiconductor chip 5 and the semiconductor chip mounting substrate 3.

In the present embodiment, detailed descriptions of the same matters as in the previous embodiment will be omitted, and the present invention may be similarly applied.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The present invention provides a semiconductor chip mounting substrate which forms a bump on a flexible metallic body and flip-bonds a semiconductor chip on the bump, so that the semiconductor mounting substrate can have a thinner and simpler structure. It was.                     

In addition, since the bump is exposed on the semiconductor chip mounting substrate by the insulating layer of the dielectric material, there is no distortion during assembly and dimensional stability can be obtained.

In addition, the size and height of the bump may be adjusted according to the thickness of the insulating layer and the size of the through hole.

In addition, due to the flexibility of the material, it can be produced in a sheet type (sheet type), but can be manufactured in a reel type (reel to reel type) substrate for semiconductor chip mounting is excellent in mass productivity.

In addition, it is not only applied to the fabrication of a conventional flip chip bonding semiconductor package, but also to be applied in various ways to RF equipment having a smart card or a lead frame that requires flexibility.

Claims (10)

A metal substrate body processed according to a circuit shape and having a bump pad connected to a chip pad of a semiconductor chip flip-bonded on one surface thereof and having flexibility in a thickness direction; An insulating layer stacked on the substrate body and having a through hole formed at a position at which the bump pad is formed; And And a bump formed on the bump pad so as to contact the chip pad of the semiconductor chip through the through hole of the insulating layer. The method of claim 1, A substrate for mounting a semiconductor chip, wherein the substrate main body is of a contact pad type. The method of claim 1, A substrate for semiconductor chip mounting, wherein the substrate main body is a lead frame. The method of claim 1, A substrate for semiconductor chip mounting, wherein the insulating layer is a film type. The method of claim 1, The substrate for semiconductor chip mounting, characterized in that the insulating layer is made by applying a liquid dielectric material. The method of claim 1, The semiconductor mounting substrate, characterized in that the diameter of the through-hole formed in the insulating layer is 50 ~ 1000㎛. The method of claim 1, The height of the bump is 3/4 to 7/4 times the thickness of the insulating layer, the semiconductor mounting substrate. The method of claim 1, And a thickness of the substrate body is greater than a thickness of the insulating layer. The method of claim 1, The substrate body has a thickness of 75 ~ 125㎛, the insulating layer is a semiconductor mounting substrate, characterized in that 10 ~ 75㎛. The method of claim 1, And the bump pad is dot-plated with a conductive metal.

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