KR20050102941A - Pakage for semiconductor device - Google Patents

Abstract

The present invention is to provide a semiconductor device package that can reduce the open failure of the semiconductor chip is flip chip bonded in the package, the elastic chip between the flip chip bonded semiconductor chip in the package body and the lead bonded to the package body An open defect is eliminated by interposing a bumper made of an insulating material having a semiconductor material, bringing the semiconductor chip into close contact with the solder ball and the package body.

Description

Semiconductor device package {Pakage for Semiconductor device}

The present invention relates to a package of a semiconductor device, and more particularly, to a semiconductor device package capable of reducing open defects of a semiconductor chip flip-chip bonded inside the package.

In general, a semiconductor package is a semiconductor chip mounted on a substrate such as a ceramic, a lead frame, a printed circuit board, a circuit tape or a circuit film, and the semiconductor chip and the substrate are electrically connected to each other. I / O member is formed so that it can be connected to.

The purpose of such a semiconductor package is to protect the semiconductor chip from external environment such as moisture, dust, temperature and mechanical shock, and also to make the semiconductor chip have a certain external shape and reliably connected to the external device, and to heat the semiconductor chip externally. To release efficiently.

The packaging of semiconductor chips has a great influence on the cost, reliability, and performance of semiconductor devices, and these semiconductor device packages have been used in the assembly process of mounting semiconductor packages on printed circuit boards in accordance with the trend of miniaturization and multifunctionality of electronic / communication devices. In addition to being fast and accurate, research and development is aimed at minimizing the overall required area and space.

The type of semiconductor package is classified according to the type of material used and the type to be mounted on the printed circuit board. As a package material, two types of plastic and ceramic are generally used. In this case, the plastic material is inexpensive while the reliability is low, and the ceramic has a high price, but the reliability is good.

1 is a side cross-sectional view showing an example of a semiconductor device package, a cavity having a predetermined size is formed therein so that the semiconductor chip can be accommodated, and a ceramic having a conductive pattern for electrical connection to the outside on the upper surface of the cavity A semiconductor chip 12 having a package body 11 made of a material, an integrated circuit flip-chip bonded by a solder ball 13 on an inner top surface of the package body 11, and a junction on an upper portion of the package body 11. It consists of a lead (LID) 13 to seal the cavity of the package body.

As a semiconductor element using the package of the above structure, a surface acoustic wave filter, a temperature compensation crystal oscillator (TCXO), a crystal oscillator, FBAR, etc. are mentioned, for example.

In this case, the die or the chip 12 mounted on the cavity must maintain a predetermined degree of vacuum in the cavity in order to operate normally while being protected from the external environment.

The package body 11 may be generally formed by sequentially stacking a plurality of rectangular ceramic sheets and a plurality of square ring-shaped ceramic sheets and compressing them, and a space for accommodating a semiconductor chip, that is, a cavity is formed therein. do. The package body 11 further includes a configuration for electrically connecting the semiconductor chip 12 mounted therein to the outside (for example, a printed circuit board). In addition, the package body 11 is generated from the semiconductor chip 12. It may further include a structure for dissipating heat.

In this package structure, when the semiconductor chip 12 is mounted on the package body 11, after forming a solder bump ball (hereinafter referred to as solder ball) 13 on the input and output electrodes of the semiconductor chip 12, The inner body of the package body 11 is pasted upside down and bonded. At this time, the solder ball 13 formed on the semiconductor chip 12 is bonded to the conductive pattern formed on the inner upper surface of the package body 11, thereby making an electrical connection with the outside.

Therefore, when the solder balls 13 are not uniform, the force is concentrated in some solder balls, and the other solder balls may be attached without even bonding. Due to the poor contact of the solder ball 13, an open defect occurs in which the electrical path of the semiconductor chip 12 is short-circuited.

The present invention has been proposed to solve the above-mentioned conventional problems, and an object thereof is to provide a semiconductor device package capable of reducing open defects of a semiconductor chip flip-chip bonded inside the package.

As a constituent means for achieving the above object of the present invention, the semiconductor device package of the present invention, the package body of the ceramic material is formed with a stepped portion is formed so as to form a predetermined conductive pattern and the inner cavity; A semiconductor chip flip-chip bonded to the upper surface of the cavity of the package body through solder balls; A lid bonded to an upper surface of a stepped portion of the package body to seal a cavity formed in the package; And a bumper made of an insulating material having elasticity, interposed between the semiconductor chip and the lead, and contacting the semiconductor chip to the upper surface of the package body by elastic force.

In addition, in the semiconductor device package according to the present invention, the bumper may be implemented as an insulating film having a thickness substantially equal to a gap between the lead and the semiconductor chip.

In addition, in the semiconductor device package according to the present invention, it is preferable that the bumper is formed in a plate shape that can cover all of the upper surface of the semiconductor chip, and be implemented as a plurality of balls symmetrically formed on the upper portion of the semiconductor chip. Can also be.

In addition, in the semiconductor device package according to the present invention, the bumper is preferably implemented by a material that does not melt at high temperatures of 300 ° C. or higher, and is preferably implemented by a material having high thermal stability.

Hereinafter, with reference to the accompanying drawings will be described the configuration and operation of the semiconductor device package according to the present invention.

2 is a side cross-sectional view showing a structure of a semiconductor device package according to the present invention, wherein the semiconductor device 20 includes a package body 11 made of a ceramic material having a step formed such that a predetermined conductive pattern is formed and an internal cavity is formed. The semiconductor chip 12 is flip-chip bonded to the upper surface of the cavity in the cavity of the package body 12 by solder balls 13 and the upper surface of the stepped portion of the package body 11 to seal the cavity formed inside the package. The lead 14 is made of an insulating material having elasticity, and is interposed between the semiconductor chip 12 and the lead 14, and the solder ball 13 of the semiconductor chip 12 is elastically applied to the package body 11. It includes a bumper (15) in close contact with the).

In the above structure, the package body 11 is made of a rectangular shape having a stepped portion as in the prior art, the inner upper surface is formed with a conductive pattern for electrical connection with the outside. In addition, the top surface shape of the package body 11 has a rectangular ring shape.

In addition, the lead 14 includes a lead that serves to protect the semiconductor and seal the cavity, and may be implemented by various methods.

For example, a cold rolled steel sheet called KORVA material is prepared, and the cold rolled steel sheet is bruised into a predetermined shape, and then the upper and lower surfaces thereof are subjected to nickel or nickel-phosphorus plating as an electrolytic plating layer or an electroless plating layer, respectively. Afterwards, Ag-Cu plating may be further performed on the lower nickel plating layer to form an AgCu layer. In addition to this, a method of plating Au on a KOVAR material and attaching AuSn solder to the KOVAR base may include Ni on the KOVAR base. It can also be implemented using the method of plating and attaching SnPb solder, plating Ni on the KOVAR base, and using it as a lead.

The lead 14 implemented in this manner is joined to the upper surface of the stepped portion of the package body 11 by ventilating, fusion, or welding, thereby sealing the inside of the package body 11, that is, the cavity in a vacuum state. . This protects the semiconductor chip 12 mounted in the cavity from the external environment.

The semiconductor chip 12 is a solder ball 13 is formed is flip chip bonding. Here, flip chip bonding refers to a connection method in which a protrusion (i.e., solder ball 13) is formed on a connection pad of a chip and directly connected to a substrate, which does not require a wire connection process, and is the thinnest among the connection methods. Not only is it simple, but also has excellent integration degree and performance, it is used for many semiconductor devices requiring miniaturization. As described above, during the flip chip bonding, since the height of the solder balls 13 is not uniformly formed, the low height solder balls 13 may not be completely connected. At this time, if only the semiconductor chip 12 can be pressed from above, it is possible to significantly reduce the connection failure rate without repairing the device.

Accordingly, in the present invention, a force is applied to the bumper 15 by the bonded lead 14 through a bumper 15 made of an elastic material between the semiconductor chip 12 and the lead 14. The semiconductor chip 12 is pressed toward the package body 11 by the elastic force of the bumper 15. As a result, open defects for the solder balls 13 that are not completely connected may be reduced.

The bumper 15 is first bonded to the lower surface of the lead 14, and then formed between the lead 14 and the semiconductor chip 12 by a bonding process of the lead 14 and the package body 11. Can be. On the contrary, the bumper 15 is fixed between the lead 14 and the semiconductor chip 12 by joining the lead 14 and the package body 11 while the bumper 15 is placed on the semiconductor chip 12. It can also be formed. Here, the bonding process of the lead 14 and the semiconductor chip 12 may be performed by seam sealing, heat fusion, welding, or the like. In this case, the lead 14 and the semiconductor chip 12 are fixed by using a clamp or the like. In the state, fusion or welding may be performed to prevent the positional change by the bumper 15.

The bumper 15 is preferably in the form of a plate and is preferably applied evenly to the entire solder ball 12. Therefore, it is preferable to use an insulating film. By the way, when it is not possible to make a plate shape, it can implement | achieve many ball-shaped bumpers symmetrically arrange | positioned according to the shape of the semiconductor chip 12. FIG. For example, when the shape of the semiconductor chip 12 is rectangular, one ball-shaped bumper may be placed at each corner side and one at the center to form a uniform force.

3 is a side cross-sectional view illustrating the relationship between device size and bumper 15 size in the semiconductor device package according to the present invention. In FIG. 3, L1 represents the height of the cavity formed in the package body 11. L2 represents the height of the solder ball 13, L3 represents the thickness of the semiconductor chip 12, and L4 represents the distance between the lead 14 and the semiconductor chip 12.

Referring to the above, in the semiconductor device, the space between the semiconductor chip 12 and the lead 14 is a value obtained by subtracting the height of the solder ball height L2 + the thickness of the semiconductor chip L3 from the cavity height L1 of the package body 11, and the bumper 15. ) Should be approximately the same as L4 or slightly thicker than L4. The thickness of the bumper 15 may vary depending on the elasticity of the material used as the bumper.

For example, the height L1 of the cavity in the package body 11 is 0.5 mm, the thickness L3 of the semiconductor chip 12 is 0.35 mm, and the height L2 of the solder ball 13 is approximately 0.03 mm (at least 0.02 mm and at most 0.04 mm). When the bumper 15 is about 0.13 ~ 0.11mm in thickness. That is, the height of the bumper 15 is within 22% to 26% of the height of the cavity in the package body 11.

In addition, the semiconductor device flip-bonds the semiconductor chip 12 to the package body 11, and then the lead 14 and the package body 11 are bonded by a heat fusion process, which is about 240 ° C. The melting point of AuSn, which is a material of the lead 14, is about 280 ° C., so that the bumper 15 should be able to withstand up to 300 ° C., and there should be no characteristic change (especially elastic force, etc.) at high temperature. No harmful gas may be generated that may affect the characteristics of the semiconductor chip 12.

Therefore, the bumper 15 may be made of a material that can withstand high heat, is thermally stable, and has no elasticity and generates no harmful gas. In addition, it is more preferable if it is a material excellent in workability and easy to handle.

As the material of the bumper 15 which satisfies these conditions, for example, polyamide, epoxy resin series, urethane, teflon, carbon series metal mesh, kaol fiber, metal plate sponge, silicone rubber, porous insulating film, and the like can be used. .

According to the above, the semiconductor device package of the present invention can press the semiconductor chip by applying a predetermined physical force without deformation of the flip chip bonded semiconductor chip, thereby reducing the open defect of the solder ball has an excellent effect. .

1 is a side sectional view showing a structure of a general semiconductor device package.

2 is a side sectional view showing a semiconductor device package structure according to the present invention.

3 is a schematic diagram illustrating a bumper size in a semiconductor device package structure according to the present invention.

Explanation of symbols on the main parts of the drawings

10, 20: semiconductor element

11: package body

12: semiconductor chip

13: solder ball

14: Lead (LID)

15 bumper

Claims (6)

A package body made of a ceramic material having a stepped shape such that a predetermined conductive pattern is formed and an inner cavity is provided; A semiconductor chip flip-chip bonded to the upper surface of the cavity of the package body through solder balls; A lid bonded to an upper surface of a stepped portion of the package body to seal a cavity formed in the package; And A bumper made of an insulating material having elasticity and interposed between the semiconductor chip and the lead to closely adhere the semiconductor chip to the top surface of the package body by elastic force. A semiconductor device package comprising a. The method of claim 1, The bumper is a semiconductor device package, characterized in that formed with an insulating film having a thickness almost equal to the gap between the lead and the semiconductor chip. The method of claim 1, The bumper is a semiconductor device package, characterized in that the plate-shaped. The method of claim 1, The bumper is a semiconductor device package, characterized in that implemented as a plurality of balls are formed symmetrically on top of the semiconductor chip. The method of claim 1, The bumper is a semiconductor device package, characterized in that implemented in a material that does not melt at high temperatures of 300 ℃ or more. The method of claim 1, The bumper is a semiconductor device package, characterized in that implemented with a material having high thermal stability.