JPH1154650A - Composite package and manufacturing method thereof - Google Patents

Abstract

(57) [Problem] To provide a composite package for a semiconductor element having good adhesive properties and excellent heat conduction. SOLUTION: A thin oxide layer 12 is formed on a surface of a non-oxide ceramic substrate 11, and a resin substrate 10 and the non-oxide ceramic substrate 11 are bonded with an adhesive 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-terminal, narrow-pitch semiconductor element package, and more particularly to a semiconductor element composite package in which a ceramic substrate and a resin substrate or a film are bonded and bonded, 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. There is a trend toward higher speeds and higher heat dissipation. In addition, the applications of these semiconductor chips are wide ranging from industrial applications such as workstations, personal computers, and business computers to electronic devices such as portable devices, printers, copiers, cameras, televisions, and videos. The performance itself has also improved. Packages that mount high-performance, high-integration-density LSI chips must be able to connect to the LSI chip with multiple terminals and a narrow pitch, have high wiring density, have good heat dissipation, and can handle high-speed signals. It is required that the number of input / output terminals of a package can be increased and the pitch can be reduced. Further, there is a need for a technique for manufacturing a high-performance package satisfying these conditions at a low cost with a simple process and high reliability.

[0003] In order to enhance the function of a semiconductor element, three pillars of increasing the number of bits, increasing the capacity, and increasing the speed are the pillars. Among them, the demand for high speed has had a great influence on the package. This is because the number of pins for input / output to the semiconductor element is increased and data is processed in parallel to achieve higher 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. Various packages have been developed to meet these two needs of multi-pin and miniaturization. In order for the above-mentioned connection technology to function effectively, the package side must also have a narrow-pitch, multi-terminal inner lead part, and the connection between the package and the mounting board, such as a printed circuit board, must be a multi-terminal, narrow-pitch. It is necessary to do. 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.

[0004] In order to satisfy the above demands for a package having multiple terminals and a narrow pitch, the package structure is a conventional pin insertion type or a surface mounting type such as a QFP (Quad Flood Package). From BGA
(Ball Grid Array) package. This is because limits to the number of terminals and the narrow pitch in a surface mount type package are becoming apparent in terms of terminal accuracy, inductance due to leads, strength of leads themselves, mounting accuracy, and the like. Another reason is that the surface mount type package has a disadvantage that the outer dimensions must be increased with the increase in the number of terminals.

The BGA can reduce the inductance compared to 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. BGA is a protruding connector (solder ball) made of solder as the input / output terminal of the package
It is possible to improve the reflection delay of a high-speed signal and the like due to the inductance caused by the pins and leads as described above. Further, in addition to shortening of the connection distance by the solder ball, narrow pitch and multiple terminals can be easily achieved by forming the solder ball.
Promising as an SI package. Furthermore, the narrow pitch and multiple terminals due to the formation of the solder balls reduce the package size itself, improve the mounting density on printed circuit boards, etc., improve the electrical characteristics by reducing the parasitic capacitance, inductance, and resistance of wiring, and improve the package. Improvement of high frequency characteristics and the like can be expected by downsizing.

On the other hand, when viewed from the heat radiation side of the package, L
As the integration density and the speed of the SI increase, the power consumption increases, and the amount of heat generated tends to increase year by year. Moreover, in the computer, while the size of the main body has been reduced, the number of boards has been increasing, and the gap between the boards has been gradually narrowed. For this reason, a structure and a material which are thin and have excellent heat dissipation properties are also required. Ceramic packages are mainly used for high heat dissipation packages. Ceramics include aluminum nitride (AlN) and silicon nitride (Si ₃ N).
₄ ), alumina (Al ₂ O ₃ ), glass ceramics, etc., which are properly used depending on the specifications such as the calorific value and high frequency characteristics. In particular, non-oxide ceramics such as AlN and Si ₃ N ₄ have characteristics of good thermal conductivity. However, even when ceramics having good heat dissipation properties are used, there is a limit in terms of heat dissipation. That is, it is difficult to have a thick structure such as a radiation fin or a heat pipe due to the restriction of the gap between the boards, and the air cooling efficiency of the fan is also reduced.

Further, in a ceramic package,
When mounted on a printed circuit board, the difference in thermal expansion coefficient between the package and the printed circuit board is large, so that there is a problem in that the connection reliability (mounting reliability) of the solder ball portion as the connection portion is low. The difference in the coefficient of thermal expansion is caused by a thermal history in a reflow soldering process when mounting a BGA package on a printed circuit board, and by a change in environmental temperature during normal use.
In any case, since the difference in thermal expansion coefficient between the ceramics and the printed circuit board is large, thermal stress concentrates on the solder ball portion with low mechanical strength, causing cracks in the solder ball and further breaking the solder ball. Therefore, there has been a problem that the reliability of the connection part is reduced. Al ₂ O ₃ (alumina), a typical oxide ceramic, has been widely used as a ceramic for a conventional package. However, since the difference in thermal expansion coefficient from the silicon end crystal is large, the size of the silicon chip is increased and the density is increased. It has also been shown to hinder implementation.

Regarding the problem of the difference in thermal expansion coefficient, in recent years, reliability has been improved by forming a composite package in which a printed circuit board and a resin substrate having a similar thermal expansion coefficient are bonded to a ceramic substrate with an adhesive or the like. I have. This composite package uses a composite package in which a non-oxide ceramic substrate with high thermal conductivity and a resin substrate that forms the wiring layer are bonded and electrically and mechanically bonded, thereby taking advantage of the advantages of both. Things. In other words, the advantages of high reliability due to the thermal expansion coefficients of the resin substrate and printed circuit board being substantially equal, the ease of fine wiring by lithography on the resin substrate, and the advantage of low cost of the resin substrate and the non-oxidation The structure makes good use of the advantages of the high thermal conductivity of the ceramic substrate.

[0009]

However, in the above-described composite package, it is desired to improve the reliability of the bonding between the non-oxide ceramic substrate such as AlN or Si ₃ N ₄ and the resin substrate, which is characterized by high thermal conductivity. It is rare. In other words, the problem is that the surface of the non-oxide ceramic substrate lacks wettability with the adhesive for bonding the resin substrate and the adhesive is easily peeled off.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and has as its object to provide a semiconductor package having excellent bonding reliability when a non-oxide ceramic substrate and a resin substrate are bonded together. I do.

[0011]

The poor wettability between the surface of the non-oxide ceramic substrate and the adhesive is due to the OH or COOH group, which is a functional group of the adhesive, and the surface of the non-oxide ceramic. This is because of low affinity.

The inventors of the present invention have conducted intensive studies on the problem of the affinity of the interface. As a result, if an oxide layer is formed on the surface of the non-oxide ceramic, the oxide layer is adsorbed on the oxide layer when the adhesive is applied. The affinity between the adhesive and the non-oxide ceramic surface is improved through the OH group and COOH group of the adhesive,
It has been experimentally demonstrated that adhesion between a resin substrate and a non-oxide ceramic substrate can be promoted, and a highly reliable composite package has been realized.

That is, the composite package of the present invention comprises a non-oxide ceramic substrate, an oxide layer formed on the surface of the non-oxide ceramic substrate, an adhesive layer formed on the surface of the oxide layer, A first feature is that it is a package for a semiconductor element having a resin substrate formed on a layer. Here, the “resin substrate” means a resin substrate or a resin film composed of a multilayer or a single layer having a wiring layer.

In the first aspect of the present invention, the non-oxide ceramic is preferably AlN. This is because it has a high thermal conductivity, is excellent in heat radiation characteristics, and has a thermal expansion coefficient closer to that of silicon than oxide ceramics such as Al ₂ O ₃ and beryllia (BeO). Also, the hardness is lower than that of Al ₂ O ₃ of oxide ceramics, so that processing is easy.

An organic resin adhesive for bonding a non-oxide ceramic substrate and a resin substrate generally depends on hydrogen bonding via a polar group in a molecule. In particular, when an epoxy resin or an isocyanate resin is used, if a surface of a substance to be bonded has a hydroxyl group, strong bonding is provided by hydrogen bonding or direct primary bonding force.

In the case of oxide ceramics, O ²⁻ ions having high polarizability protrude to the space side from the metal ions M ^{n + in} terms of structure. Multiple O instead of O ² -ion
When the H ^- ion surrounds the M ^{n +} ion, the charge becomes neutral from above, so that the symmetry of the-charge centered on the + charge is improved, and the distortion of the neutralization of the electrostatic charge is reduced. For this reason, in the case of oxide ceramics, hydroxylation is likely to occur when water in the atmosphere comes into contact, and the surface is thereby stabilized. If the hydroxyl groups cover the surface, hydrogen bonds (or direct primary bonds) occur between the hydroxyl groups and the adhesive molecules,
Adhere strongly.

However, non-oxide ceramics, especially A
In the case of nitride ceramics such as 1N and Si ₃ N ₄ , since the surface of the powder is active, it reacts with moisture in the air to generate ammonia. In such a case, it is considered that hydroxyl groups are generated on the surface of the powder ceramics. However, adhesion may be hindered by the presence of ammonia. On the other hand, the surface of the nitride ceramic substrate that has become a dense sintered body does not easily react with moisture in the air at room temperature, and thus it is difficult to cause hydroxylation. Therefore, even if the organic resin adhesive is directly applied to the surface of the non-oxide ceramic substrate, peeling often occurs. Especially,
In the case of a thermosetting resin, when the internal cohesive force of the adhesive is increased by curing, the adhesive is easily peeled.

In order to avoid such peeling, effective hydroxylation may be caused on the substrate surface as in the first aspect of the present invention. In the case of non-oxide ceramics, it is effective to form a complete oxide layer on the surface. This is because due to the properties of ceramics, various grains and crystal grains having various diameters are included, and the surface is not uniformly oxidized. An incomplete oxide layer has a high possibility of causing peeling due to cracking or insufficient strength between the oxide film itself and the nitride substrate. Particularly, in the case of a nitride, when ammonia is generated, the adhesive strength may be deteriorated. The thickness of the oxide layer may be such that hydroxylation is possible, that is, it is desirable that the oxide layer be thin. Although it depends on the state of the grain interface constituting the non-oxide ceramic and the grain size of the crystal grains, it is preferably 30 μm or less, preferably 5 μm or less, and more preferably 3 μm or less. As long as the oxide layer has a thickness of about several tens of nm as long as it is a dense non-oxide ceramic having a small particle size, the effect is obtained.

A second feature of the present invention is a step of oxidizing the surface of the non-oxide ceramic substrate to form an oxide layer on the surface of the non-oxide ceramic substrate; A method of manufacturing a composite package including at least a step of bonding a ceramic substrate and a resin substrate to each other. That is, the oxide layer of the present invention may be formed by heating the surface of the non-oxide ceramics at a high temperature in a nitrogen atmosphere containing enzymes and a hydrogen gas atmosphere containing water vapor (steam). The oxide formed by the method of directly oxidizing the surface of the non-oxide ceramic is preferable because the adhesion between the oxide and the ceramic is good. As is well known, ceramics have structural features of crystal grains (bulk), crystal bonding interfaces (grain boundaries), spaces and crystal interfaces (surfaces), and pores (spaces). And then oxidize much faster. In some cases, it may be formed by a CVD method, a sputtering method, or a vacuum evaporation method, or may be used in combination with the CVD or the like after the oxidation.

According to the second feature of the present invention, when an oxide layer is formed on the surface, a hydroxyl group can be formed on the surface of the non-oxide ceramic substrate, so that it can be easily bonded to a resin substrate using an organic resin adhesive. In addition, a highly reliable semiconductor element composite package in which a resin wiring substrate is joined to a high thermal conductive non-oxide ceramic substrate can be manufactured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a composite package for a semiconductor according to an embodiment of the present invention. FIG.
As shown in FIG. 1, in the composite package for a semiconductor according to the embodiment of the present invention, an oxide layer 12 is formed on a non-oxide ceramic substrate 11.
Are bonded via an adhesive 13. The resin substrate 11 includes silver bumps 22 inside and copper foils 31 and 3 on both sides.
It is sandwiched between 4,35. The copper foil is patterned so as to form a surface wiring 35 such as an input / output pad and a land 34, and plating layers 41 and 44 are formed on the surface thereof. The semiconductor chip 1 is mounted on the cutout of the resin substrate in contact with the oxide layer 12. The solder ball 3 is formed on the land 34.

Next, a method of manufacturing a composite package for a semiconductor according to an embodiment of the present invention will be described with reference to FIGS.

(A) First, as shown in FIG.
A 100 μm projection (silver bump) 22 is formed on a copper foil 21 having a thickness of m by using a silver epoxy conductive paste or the like at a portion corresponding to an input / output pad of a semiconductor chip and a portion corresponding to a land of a package body.

(B) Next, a crystal polymer 23 having a thickness of 50 μm is applied so that the tips of the protrusions can easily break through, and the copper foils 21 and 24 are overlaid on both sides as shown in FIG. Laminate by applying temperature and pressure. Then, FIG.
As shown in (c), a window for mounting the semiconductor chip is punched out with a press.

(C) Thereafter, as shown in FIG. 2D, the copper foil is etched to form a wiring layer 35 on the surface,
A land 34 for a solder ball is formed around the periphery. afterwards,
A solder resist is formed on the surface layer by screen printing.

(D) Subsequently, nickel (Ni) and gold (Au) plating are performed as shown in FIG.
/ Au) The plating layers 41 and 44 are formed, and the resin substrate 10 is manufactured.

(E) On the other hand, in order to oxidize the surface of the aluminum nitride substrate 11 having a thermal conductivity of 170 W / mK and a thickness of 0.635 mm, the temperature is about 1 hour at 1080 ° C. in a nitrogen gas atmosphere containing oxygen. By heating, an oxide layer 12 having a thickness of about 3 μm was formed as shown in FIG. The oxidation may be performed in a hydrogen atmosphere containing steam (steam) or a high-pressure oxygen atmosphere. In some cases, monosilane (S
iH ₄ ), disilane (Si ₂ H ₆ ) or the like and N ₂ O gas or the like may be used for the CVD method. CVD is photo-excited CV
It is preferable to use D or plasma CVD.

(F) Next, the epoxy resin 13 is placed in the state shown in FIG.
Is applied to the surface on which the aluminum nitride oxide layer 12 is formed as shown in FIG. Then, as shown in FIG. 3C, if the resin substrate 10 is pressed and adhered from above the epoxy resin 13, the composite package for semiconductor device according to the embodiment of the present invention is completed. Note that an adhesive sheet may be laid between the oxide layer 12 and the resin substrate 10 and bonded by applying heat and pressure.

After the bonding, the resin substrate was pulled from the end and the peel strength was measured. The result was 1500 g / cm on average.

As a comparative example, an epoxy resin was applied to a similar aluminum nitride substrate not subjected to oxidation treatment, and the resin substrate was pressed and bonded. Holding the edge of the resin substrate and measuring the peel strength in the same manner, the average was 800 g /
cm.

As described above, the present invention has been described by the above embodiments. However, it should not be understood that the description and drawings constituting a part of the present disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operation techniques will be apparent to those skilled in the art. For example, the present invention is naturally applicable to a cavity-up structure as shown in FIG. In FIG. 4, a via hole (through hole) is provided in a ceramic substrate 11 having an oxide layer 12 formed on the surface, a via hole metal 15 is buried in the via hole, and lands 36 and 37 are provided at both ends thereof. I have. The surfaces of the lands 36 and 37 on the ceramic substrate side are also coated with Ni / Au plating layers 46 and 47. Then, Ni on the surface of the land 31 on the resin substrate 10 side is used.
The / Au plating layer 41 and the Ni / Au plating layer 46 on the surface of the land 36 on the ceramic substrate 11 side are in contact with each other via bumps of Ag or Au, so that the resin substrate 1
0 and the ceramic substrate 11 are in electrical contact.
Even in the cavity-up structure as shown in FIG. 4, a composite package having high bonding strength between the ceramic substrate and the resin substrate and excellent heat radiation characteristics can be provided. In FIGS. 1 and 4, the window (cavity) is provided in the resin substrate and the semiconductor chip is mounted on the oxide layer. However, the semiconductor chip may be mounted on the resin substrate without providing the window. Of course. Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the matters specifying the invention described in the claims that are reasonable from this disclosure.

[0032]

As described above, by forming an oxide layer on the surface of a non-oxide ceramic substrate, it is possible to increase the bonding effect of the adhesive and improve the bonding reliability of the composite package.

Further, according to the present invention, a composite package having good heat radiation characteristics can be easily manufactured with a high yield.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a composite package for a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a process cross-sectional view for explaining a method of manufacturing a composite package for a semiconductor device according to an embodiment of the present invention (part 1).

FIG. 3 is a process sectional view explaining the method for manufacturing the composite package for semiconductor device according to the embodiment of the present invention (part 2).

FIG. 4 is a schematic sectional view of a composite package for a semiconductor device according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 semiconductor chip 3 solder ball 10 resin substrate 11 non-oxide ceramic substrate 12 oxide layer 13 adhesive 15 via hole metal 21, 24 copper foil 22 silver bump 23 liquid crystal polymer 31, 34, 36, 37 land 35 surface wiring Output pad) 41,44,46,47 Plating layer

 ──────────────────────────────────────────────────の Continued from the front page (72) Noritaka Nakayama, Inventor 2-4, Suehirocho, Tsurumi-ku, Yokohama, Kanagawa Prefecture

Claims (5)

[Claims] 1. A non-oxide ceramic substrate, an oxide layer formed on a surface of the non-oxide substrate, an adhesive layer formed on a surface of the oxide layer, and formed on the adhesive layer A composite package comprising: a resin substrate; 2. The composite package according to claim 1, wherein said non-oxide ceramic is made of one of aluminum nitride and silicon nitride. 3. The composite package according to claim 1, wherein said oxide layer is an oxide layer obtained by directly oxidizing a surface of said non-oxide substrate. 4. The composite package according to claim 1, wherein said oxide layer has a thickness of 30 μm or less. 5. A method comprising: oxidizing the surface of a non-oxide ceramic substrate to form an oxide layer; and bonding the oxide layer and a resin substrate to each other via an adhesive. Method for manufacturing a composite package.