JPH11265962A - Semiconductor device package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a semiconductor device package to be less warped, by a method wherein a chamfered part or a curved surface part is provided to the four corners of a ceramic board. SOLUTION: A ceramic board 1 and a resin board 21 are bonded together to form a composite package, and a chamfered part a or a curved surface part b is provided to the four corners of a ceramic board 1 respectively. A chamfered part or a curved part may be provided to the corners of the resin board 21. The composite package equipped with the resin board 21 which is provided with no window is less warped than the composite package equipped with the resin board 21 that is provided with a window. At this point, the chamfered part denotes a part where a corner is obliquely cut off at an angle of 45 deg.. On the other hand, the curved surface part b denotes a part where a corner is cut into a curved surface. By this setup, the composite board composed of the ceramic board 1 and the resin board 21 that are bonded together can be less warped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package for a multi-terminal, narrow-pitch semiconductor device and a method of manufacturing the same.
In particular, using a resin film, a resin substrate having a metal layer such as a wiring layer on the surface of the resin film and a high thermal conductive material layer disposed on the back surface, and bonding the resin substrate to a supporting substrate made of a high thermal conductive material The present invention relates to a combined semiconductor element package and a method of manufacturing the same.

[0002]

2. Description of the Related Art Various types of packages, such as ceramics, resins, and metals, on which semiconductor chips such as LSIs are mounted, have been increased in density due to high integration, high speed, large power consumption, and large chips of LSIs. High-speed response and high heat dissipation are required. In addition, the applications of these semiconductor chips are wide ranging from industrial applications such as workstations, personal computers, and computers to electronic devices such as portable devices, printers, copiers, cameras, televisions, and videos. The performance itself has also improved.

A package on which an LSI chip of high performance and high integration density is mounted must be able to be connected to the LSI chip with multiple terminals and a narrow pitch, have a high wiring density, have good heat radiation, and handle high-speed signals. It is required that the number of input / output terminals of the package be increased and the pitch can be reduced. Further, there is a need for a technology for manufacturing a high-performance package satisfying these conditions at a low cost with a simple configuration and high reliability.

[0004] In order to enhance the function of a semiconductor device, three pillars, namely, multi-bit, large-capacity, and high-speed, are the pillars. For example, demands for higher speeds have had a significant impact on packages. This is because the number of input / output terminals (the number of pins) to the semiconductor element is increased and data is processed in parallel to increase the speed. For this reason, multi-terminals (multi-pins) has become one proposition in packages. In addition, the miniaturization of portable devices and the miniaturization of packages for high-density mounting are also required. This demand is particularly great in the field of multimedia, amusement and communication equipment, which will greatly increase in the future.

[0005] Various packages have been developed to satisfy the two needs of increasing the number of pins and reducing the size. In order for the connection technology with the semiconductor chip to function effectively, the package side must also have a narrow-pitch, multi-terminal inner lead part, and the connection between the mounting board, such as a printed circuit board, and the package must be a multi-terminal, narrow It is necessary to make it pitch. Further, as described above, the package needs to handle high-speed signals due to the increase in the speed of the LSI, so that it is necessary to consider the electrical characteristics.

[0006] In order to satisfy the above demands for a package having multiple terminals and a narrow pitch, the package structure has been changed from a conventional pin insertion type or a surface mount type such as a QFP (Quad Flood Package). , BGA
(Ball Grid Array) There is a tendency to move to a package. In order to increase the number of terminals and reduce the pitch, the conventional surface mount type has seen limitations in terms of terminal accuracy, inductance caused by leads, strength of the leads themselves, and accuracy during mounting. is there. Also, the surface mount type has a disadvantage that the package must be increased in size as the number of terminals increases.

The BGA can reduce the inductance as compared with the conventional package and can adapt the multilayer wiring structure of the package body at a high speed, and is used for consumer products such as large computers, personal computers, and portable devices. Is spreading. The BGA has a package structure using a protrusion connection body (solder ball) made of solder as an input / output terminal of the package, and improves reflection delay of a high-speed signal due to inductance caused by pins and leads as described above. It is possible. Further, in addition to shortening the connection distance by the solder ball, it is easy to narrow the pitch and increase the number of terminals by forming the solder ball.
Promising as an I package. Furthermore, the increase in the number of terminals by the formation of solder balls reduces the package size itself, improves the mounting density on printed circuit boards, etc., improves the electrical characteristics by reducing the parasitic capacitance, inductance, and resistance of wiring, and reduces the size of the package. Can be expected to improve high frequency characteristics. On the other hand, from the viewpoint of the heat radiation of the package, the power consumption increases and the heat generation tends to increase year by year as the integration density and the speed of the LSI increase. Moreover, in the case of computers, the size of the main unit has been reduced,
The number of boards tends to increase, and the gap between the boards is gradually narrowing.

[0008] For these reasons, the package itself is required to be thin and have a structure excellent in heat dissipation and a material having high thermal conductivity. In order to cope with the thinness and the narrow pitch, a resin substrate on which a wiring layer pattern or the like can be formed by using a photolithography technique is effective. The resin substrate is formed by bonding copper foil on both sides of a resin film such as a liquid crystal polymer, and enables narrow pitch wiring to the copper foil by using a photolithography technique. However, such a resin substrate has a problem in coplanarity (surface flatness) when the thickness is 150 μm or less. On the other hand, due to the nature of the resin film, the heat radiating surface does not allow heat to escape, and has a heat-retaining structure. As described above, the power consumption that can be applied by the resin substrate alone is low, and in order to increase the power consumption, it is necessary to use a heat sink or a radiation fin. In addition, when a large semiconductor element is mounted due to the difference in thermal expansion coefficient from the semiconductor element, uneasy factors such as chip breakage have been common. When mounting a high power consumption semiconductor element with a large semiconductor element, a package made of a high heat conductive material such as ceramics or metal is often used. For example, alumina ceramics generally use a copper-tungsten (Cu-W) alloy for a heat sink. In order to efficiently remove the heat generated by the semiconductor element, regardless of the resin substrate single package or the alumina / Cu-W package, a cavity down structure as shown in FIG. It was necessary to directly remove the heat through the radiation fins 13.

Recent advances in the function of semiconductor devices have increased not only the power consumption but also the number of input / output pins. The chip size of semiconductor devices is also increasing to follow such movements, but the increase in chip size of semiconductor devices leads to a reduction in the number of pellets taken from a wafer, leading to an increase in the cost of semiconductor devices. I will. Flip chip mounting technology has been developed to avoid this and to reduce the number of steps for mounting semiconductor elements, and its practical use has been progressing in recent years. Due to such efforts, an increase in the chip size of the semiconductor device is avoided despite an increase in the number of input / output pins.

However, despite the trend on the device side, if a cavity-down structure as shown in FIG. 9 is employed to efficiently remove heat from the semiconductor device, input / output pins are arranged in an area immediately below the semiconductor device. For the package, an increase in the number of input / output pins means an increase in the package size. This is contrary to the market trend of systems that have been symbolized as light, light and small over the years, and has not been a useful package.

In order to respond to such circumstances, proposals have been made regarding the manufacture of a semiconductor package using highly thermally conductive ceramics, and a package has been developed which has a reduced package size and can sufficiently cope with the heat generated by the semiconductor element. However, since all of them use expensive high-thermal-conductivity ceramics, the package cost is high, and the fact is that they have not yet spread widely. In general, a high thermal conductive ceramics package is fired at an extremely high temperature, so that the metals that can be used as conductors are limited to tungsten and molybdenum. For this reason, the wiring of the ceramic package has a high wiring resistance, and is not suitable for high-speed signal processing. In addition, control of dimensional shrinkage during firing has become much more strict in flip chip compatible than in wire bonding type mounting packages. As described above, a package that avoids an increase in power consumption, an increase in chip size, and an increase in package size is desired. Further, it is necessary to solve the problems of suppressing the cost of the package and lowering the wiring resistance. A flip-chip mounting type package as shown in FIG. 10 has been proposed as a package that employs a cavity-up structure that does not require an increase in the package size of such a high heat generation semiconductor element and can be supplied at low cost.

The package shown in FIG.
Pad portions (lands) 77, 78, etc., for connecting with the metal bumps 6 and the electric signal wiring layer are formed of copper foil, and the resin substrate 21 is sandwiched between upper and lower copper foils. This is a composite package supported by. In the resin package constituting the composite package of FIG. 10, the flip-chip mounting portion and the lead-out wiring portion 77 and the like form a wiring conductor made of copper or the like formed on the resin film 21 by using an etching technique that can be used in photolithography. Fine and high-precision products can be manufactured. Therefore, it is suitable as a flip-chip compatible substrate.
In addition, since the dielectric constant is lower than that of ceramics, the transmission characteristics of electric signals are improved. Furthermore, since surface wiring can be routed by fine wiring, the cost is low. On the other hand, the ceramic substrate 1 is useful for supporting a soft and easily deformable resin substrate. The difference in the coefficient of thermal expansion between the semiconductor element and the resin has a considerable difference, but since ceramics are close to the semiconductor element, they serve as a thermal expansion relaxation layer and reduce damage to the semiconductor element. Basically, the ceramics have a single-layer structure, and connection through the through holes 7 can be performed at a wide pitch. Therefore, the ceramics can be easily manufactured and the number of steps is small, so that the ceramics can be manufactured at low cost.

[0013]

The composite package as shown in FIG. 10 is manufactured by laminating ceramic substrates and resin substrates having different coefficients of thermal expansion. For this reason, there is a problem that a large warp occurs in the package after bonding due to a change in the ambient temperature or the like. If the package is significantly warped, the package may fall from the suction jig during transport. In particular, in the case of a BGA package, a problem such as a displacement of the ball occurs when the ball is mounted. In particular, in the portion near the corner of the package, the amount of warpage per unit length is larger than the amount of warpage in the center of the package, so that the ball is likely to be displaced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor device package in which warpage is reduced.

[0015]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies for the purpose of reducing the warpage generated in the package, and as a result, when the corners of the ceramic substrate have been chamfered. Found that the amount of warpage of the package was suppressed, and completed the present invention.

That is, according to the present invention, a chamfered portion a or a curved portion b is provided at four corners of a ceramic substrate 1 in a composite package formed by bonding a ceramic substrate 1 and a resin substrate 21 as shown in FIG. It is another object of the present invention to provide a semiconductor device package characterized by the above. Hereinafter, the present invention will be described in detail.

The simplest way to prevent such a composite package from warping is to simply increase the thickness of the ceramic substrate 1 as shown in FIG. In addition, if the ceramic substrate 1 having high thermal conductivity is thick, it is effective for heat dissipation.
However, in recent years, the thickness of the package has been demanded to be thinner and thinner, and the thickness of the ceramic substrate 1 is going against it. In addition, thick ceramics are not desirable because they have the disadvantage of low board mounting reliability.

On the other hand, when bonding members having different coefficients of thermal expansion, it is generally known that a so-called sandwich structure can suppress the warpage of those members. Therefore, in the composite package as well, it is possible to suppress the warpage of the composite package by bonding the resin substrate 21 to the front surface and the back surface of the ceramic substrate 1 via the adhesive 2 as shown in FIG. However, bonding the resin substrate to the back surface of the ceramic substrate 1 not only increases the heat resistance component, lowers the power consumption that can be used by the semiconductor element, but also increases the cost of the package itself. .

FIG. 5 is a plan view of a conventional composite package. As shown in FIG. 5, the four corners of the ceramic substrate 1 are not dropped. The present inventors have focused on the four corners of the ceramic substrate 1 and made intensive studies. As a result, as shown in FIG. 1, if a chamfered portion a or a curved portion b is formed at the corner of the ceramic substrate 1, the package is formed. That the amount of warpage can be reduced. Since the warpage of the package increases as it goes diagonally from the center of the package, the amount of warpage of the entire package can be reduced by reducing the corners of the four corners of the package. Although the chamfered portion a or the curved portion b is provided only at the corner of the ceramic substrate 1 in FIG. 1, it may be provided at the corner of the resin substrate.

Further, the present inventors have found that a resin substrate 21 as shown in FIG. 1 having no window (generally, a flip-chip mounting type package) has a resin substrate 21 as shown in FIG. It was also confirmed that the reduction in the amount of warpage was greater than when there was a window (generally, a wire bonding mounting type).

Here, the chamfered portion and the curved surface portion are as follows.
It is defined as: FIGS. 6A and 6B are diagrams for explaining the chamfered portion and the curved portion, where FIG. 6A illustrates the chamfered portion and FIG. 6B illustrates the curved portion. As shown in FIG. 5A, the chamfered portion indicates a portion obtained by diagonally cutting off a corner, and the angle is 45 degrees. The dimensions of the chamfer are determined by the length of C in the figure. On the other hand, as shown in FIG. 5B, the curved surface portion refers to a portion where a corner is cut off to a curved surface, and its size is determined by the length of R in the drawing.

The ceramic substrate is preferably a ceramic made of alumina, aluminum nitride, silicon nitride, silicon carbide, or diamond, or may be a composite substrate made of two or more of these. Further, the ceramic substrate may be provided with a metal wiring layer.

According to the experimental results of the present inventors, the present invention shows that a ceramic substrate having a thickness of
It has been confirmed that the present invention is particularly effective for a composite package in which a resin substrate having a thickness of not more than mm is bonded. Further, since the warpage of the package is greatly affected by the heat history at the time of bonding the ceramic substrate and the resin substrate, the present invention is particularly effective for a system bonded at a high temperature. Therefore, it is effective when bonding using an adhesive having a glass transition point of 70 ° C. or higher.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited by these.

First, as a measurement sample, 35 × 35 m
m, prepare an aluminum nitride substrate with a thickness of 0.6 mm,
Chamfers are provided at the four corners of the board, and the dimension C is 1 mm, 5 mm
And those having curved surface portions provided at the four corners of the substrate and having dimensions R of 1 mm and 5 mm, respectively. Also,
As a comparative example, one having neither a chamfered portion nor a curved surface portion was prepared. Each of the ceramic substrates has 34.5
A resin substrate having a size of 34.5 × 34.5 mm and a thickness of 0.1 mm was bonded using an adhesive film having a size of 34.5 mm and a thickness of 60 μm. As the resin substrate, a substrate without a window as shown in FIG. 1 and a substrate with a window as shown in FIG. 2 (window diameter 15 mm square) were prepared.

The measurement was performed by evaluating the amount of warpage of the ceramic substrate before bonding the resin substrate (initial state) and the amount of warpage of the ceramic substrate after bonding the resin substrate.

Here, the measurement conditions are summarized below.

(Condition 1): A resin substrate without a window is bonded to a ceramic substrate having a chamfered portion at each of the four corners of the substrate and having a dimension C = 1 mm.

(Condition 2): A ceramic substrate having chamfered portions at the four corners of the substrate and having a dimension C = 5 mm, or a resin substrate without a window bonded thereto.

(Condition 3): Curved portions are provided at the four corners of the substrate,
A resin substrate having a window bonded to a ceramic substrate having the dimension R = 1 mm.

(Condition 4): Curved portions are provided at the four corners of the substrate,
A resin substrate having a window bonded to a ceramic substrate having the dimension R = 5 mm.

(Comparative Example 1): A resin substrate having no window is bonded to a ceramic substrate having neither a chamfered portion nor a curved portion at the four corners of the substrate.

(Comparative Example 2): A resin substrate having a window adhered to a ceramic substrate having neither a chamfered portion nor a curved portion at the four corners of the substrate.

Table 1 shows the evaluation results. The amount of warpage shown in Table 1 indicates the difference between the minimum amount of warpage and the maximum amount of warpage in the substrate.

[0035]

[Table 1] From Table 1, the warpage after bonding is as follows for the ceramic substrate of the present invention example in which chamfered portions or curved surface portions are provided at the four corners of the substrate.
It can be seen that the number is reduced as compared with the comparative example in which the chamfered portion and the curved portion are not provided at the four corners of the substrate. In addition, when the resin substrate has no window, the amount of warpage after bonding is reduced.
Therefore, it can be said that the effect of the present invention is greater when the resin substrate has no window.

FIG. 7 shows the result of measuring the warpage of the ceramic substrate of Comparative Example 1 from the center of the substrate toward the outside of the substrate in a diagonal direction. As shown in FIG. 7, the difference between the maximum amount of warpage (the amount of warpage at the center of the substrate) and the minimum amount of warpage (the amount of warpage at the corners of the substrate) is about 80 μm as shown in Table 1.
m. By applying the present invention to such a ceramic substrate, the warpage is reduced because the difference between the maximum warpage amount and the minimum warpage amount is provided by providing chamfers and curved surfaces at the four corners of the substrate having a large warpage. This is because the warp applied to the entire substrate is substantially reduced.

According to the experiments by the present inventors, when the ceramic substrate is 35 × 35 mm, when the dimension C of the chamfered portion and the dimension R of the curved portion are 1.0 mm or more, about 10 μm is obtained.
It has been found that the warpage of m can be reduced.

The present invention is applicable to a cavity-up structure as shown in FIG. 8A and a cavity-down structure as shown in FIG.

[0039]

As described above, according to the present invention, the warpage of the composite substrate in which the ceramic substrate and the resin substrate are bonded is reduced by a simple method of providing chamfered portions and curved portions at the four corners of the ceramic substrate. It becomes possible.

Therefore, it is possible to provide a composite package which is thin and has less warpage without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a plan view showing a package for a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a semiconductor device package according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional semiconductor device package.

FIG. 4 is a cross-sectional view showing another conventional semiconductor device package.

FIG. 5 is a plan view illustrating the semiconductor device package of FIG. 3;

FIG. 6 is a diagram for explaining a chamfered portion and a curved portion.

FIG. 7 shows the result of measuring the warpage of a conventional ceramic substrate from the center of the substrate toward the outside of the substrate in a diagonal direction.

FIG. 8 is a diagram showing an example of a package form to which the present invention is applied.

FIG. 9 is a cross-sectional view showing a conventional semiconductor device package.

FIG. 10 is a cross-sectional view showing another conventional semiconductor element package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nitride ceramic substrate 3 Adhesive 4 Semiconductor chip 6 Metal bump 7 Through-hole metal 8, 18 Projection bump 11 Heat sink 12 Bonding wire 13 Heat radiation fin 14 Window 21 Resin film 72, 77, 78 Connection pad part

Claims (2)

[Claims] 1. A package for a semiconductor device, comprising: a composite package comprising a ceramic substrate and a resin substrate bonded to each other, wherein chamfered portions or curved portions are provided at four corners of the ceramic substrate. 2. The semiconductor device package according to claim 1, wherein the ceramic substrate is any one of alumina, aluminum nitride, silicon nitride, silicon carbide, and diamond.