JP2724864B2 - Package for storing semiconductor elements - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a package for accommodating a semiconductor element, particularly a semiconductor element for accommodating a semiconductor integrated circuit element.

(Prior art and its problem) Conventionally, a semiconductor element housing package for housing a semiconductor element is made of an electrically insulating material such as ceramics, and a recess for housing the semiconductor element is provided in a substantially central portion of an upper surface thereof. To electrically connect a semiconductor element to an external circuit and an insulating base having a wiring conductor made of a refractory metal powder such as tungsten (W), molybdenum (Mo), and manganese (Mn) derived from the periphery to the periphery. An external lead terminal attached to the wiring conductor via a brazing material such as silver brazing, and a lid. The semiconductor element is attached and fixed to the bottom of the concave portion of the insulating base, and each electrode of the semiconductor element is fixed. And the wiring conductor are electrically connected via bonding wires, and the lid is joined to the upper surface of the insulating base with a sealing material such as glass or resin to hermetically seal the semiconductor element inside. A semiconductor device by Rukoto.

In such a conventional package for accommodating a semiconductor element, an insulating base is usually formed of an electrically insulating material such as alumina ceramics. For example, a ceramic green sheet (green) formed by adding a suitable organic solvent and a solvent to alumina ceramics powder is mixed. A metal paste composed of a refractory metal powder such as tungsten (W), molybdenum (Mo) or manganese (Mn) is printed on the upper surface of the sheet) in a predetermined pattern by a screen printing method in a thick film.
It is manufactured by firing at a temperature of ° C.

However, in this conventional package for housing a semiconductor element, the wiring conductors are formed by a thick film forming technique such as screen printing, and it is difficult to miniaturize the wiring conductors. As a result, in the case where a high-density, high-integration semiconductor element having an increased number of electrodes has been accommodated therein in recent years, there has been a disadvantage that the shape of the package becomes extremely large.

In order to solve the above-mentioned drawbacks, it has been proposed to use a thin film forming technique capable of miniaturization instead of forming the wiring conductor formed on the upper surface of the insulating base by a thick film forming technique. .

As shown in FIG. 4, a semiconductor element housing package in which this wiring conductor is formed by a thin film forming technique is an insulating substrate 11.
(Cr), Titanium (Ti), Tantalum (T
a), tungsten (W), molybdenum (Mo), copper (C
u) or the like is deposited by a thin film forming technique such as sputtering or vapor deposition, and has a structure in which a wiring conductor 12 of a predetermined pattern is formed. While being mounted and fixed, each electrode of the semiconductor element 13 is connected to the wiring conductor 12 via the wire 14, and then the bowl-shaped lid 15 is joined to the insulating base 11 via the sealing material 16 made of glass. Thus, a semiconductor device is obtained.

Incidentally, the wiring conductor 12 adhered and formed on the upper surface of the insulating base 11.
Usually, nickel (Ni) + gold (Au), nickel (Ni) + platinum (Ni) + gold (Au) are used to effectively prevent oxidative corrosion of the wiring conductor 12 on its outer surface and to reduce the electrical resistance of the wiring conductor 12. A protective film 17 made of Pt), gold (Au), platinum (Pt), or the like is formed.

However, in this package for housing semiconductor elements, a protective film 17 made of gold (Au) or platinum (Pt) is formed on the outer surface of the wiring conductor, and the gold (Au) and platinum (Pt) are formed.
When the lid 15 is bonded to the upper surface of the insulating base 11 via the glass sealing material 16 because the wettability with glass is poor, the wiring conductor
The bonding strength between the glass sealing material 12 and the glass sealing material 16 is low. Therefore, when an external force is applied to the package, for example, when transporting the semiconductor element housing package, the external force causes peeling between the wiring conductor and the glass sealing material. As a result, the hermetic sealing inside the package is easily broken, and the semiconductor element housed inside cannot be normally and stably operated for a long period of time.

(Object of the Invention) The present invention has been devised in view of the above-mentioned drawbacks, and has as its object to completely and hermetically seal a package and to operate a semiconductor element contained therein normally and stably for a long period of time. It is an object of the present invention to provide a semiconductor element housing package having a high-density wiring conductor that can be used.

(Means for Solving the Problems) The present invention relates to a semiconductor device housing comprising an insulating frame or an insulating cover attached to an insulating substrate having a wiring conductor formed on the upper surface by a thin film forming technique via glass. In the package, the wiring conductor on the upper surface of the insulating base is provided with a coating film made of at least one of chromium, titanium, and tantalum on an outer surface in contact with the glass.

(Examples) Next, the present invention will be described in detail based on examples shown in the accompanying drawings.

FIGS. 1 and 2 show an embodiment of a package for housing a semiconductor element according to the present invention, wherein 1 is an insulating base made of an electrically insulating material such as ceramics, and 2 is a lid made of the same electrically insulating material. The insulating base 1 and the lid 2 constitute an insulating container for housing a semiconductor element.

The insulating base 1 has a mounting portion for mounting and fixing a semiconductor element at a substantially central portion of the upper surface, and the semiconductor element 3 is attached and fixed to the mounting portion via an adhesive.

The insulating substrate 1 is made of alumina (Al ₂ O ₃ ), silica (Si
A ceramic material powder such as O ₂ ) is mixed with an appropriate organic solvent and solvent to form a slurry, which is formed into a sheet by employing a conventionally known doctor blade method, and is formed at a high temperature (about 1600 ° C.). It is manufactured by firing.

On the upper surface of the insulating substrate 1, a wiring conductor 4 having a predetermined pattern is formed by a thin film forming technique. The wiring conductor 4 functions to connect a semiconductor element housed in the package to an external circuit.

The wiring conductor 4 has, for example, a three-layer structure as shown in FIG. 2, the first layer 4a is made of at least one of titanium (Ti) and tantalum (Ta), and the second layer 4b Is made of tungsten (W), a kind of molybdenum (Mo), or an alloy of tungsten (W), molybdenum (Mo), titanium (Ti), and tantalum (Ta), and the third layer 4c is made of copper (Cu). ing.

The first layer 4a constituting the wiring conductor 4 acts as an adhesion layer for strengthening the adhesion between the insulating base 1 and the wiring conductor 4, and has a thickness of 0.01 to 5.0 μm, preferably 0.1 to 5.0 μm. ~
A range of 2.0 μm is good. The second layer 4b acts as a bonding layer for firmly bonding the first layer 4a and the third layer 4c, and has a thickness of 0.1 to 3 μm, preferably 0.2 to 2.0 μm.
The range of μm is good. Further, the third layer 4c acts to reduce the electric resistance of the wiring conductor 4, and has a thickness of 0.1 to 10.0 μm.
m, preferably in the range of 0.5 to 5.0 μm.

The respective layers 4a, 4b, 4c constituting the wiring conductor 4 are sequentially formed on the upper surface of the insulating base 1 by a conventionally known thin film forming technique such as sputtering or vapor deposition.

The wiring conductor 4 can be miniaturized since each of the layers 4a, 4b, and 4c constituting the wiring conductor 4 is formed by a thin film forming technique, and can be formed at a very high density on the upper surface of the insulating base 1. .

The third layer 4c, which is the uppermost layer of the wiring conductor 4, is formed of copper (Cu). The copper (Cu) is easily oxidized, or the oxidation of copper (Cu) is effectively prevented. Nickel (Ni), gold (Au), platinum (P)
A protective film 5 made of a metal having excellent corrosion resistance such as t) is formed. This protective film 5 has a thickness of 0.5 to 10.0 μm.
m, preferably in the range of 1.0 to 5.0 μm.

The wiring conductor 4 is provided with titanium (T) at a portion of the outer surface where a lid 2 described later is joined via a sealing material made of glass.
i), a coating film 6 made of at least one of chromium (Cr) and tantalum (Ta) is formed thereon, and the coating film 6 is formed on the wiring conductor 4 by a method such as vapor deposition. .

The coating film 6 is composed of titanium (Ti), chromium (Cr), and tantalum (Ta) that adhere to both the wiring conductor 4 (actually, the protective film 5) and the glass sealing material (wettability). When the lid 2 is bonded to the insulating base 1 via the glass sealing material 7, the wiring conductor 4 and the glass sealing material 7 are bonded together with a large adhesive strength, and are applied by applying an external force. It does not come off.

When the coating film 6 has a thickness of 0.01 μm or less, the adhesive strength between the wiring conductor 4 and the glass sealing material 7 tends to decrease. When the body 2 is bonded via the glass sealing material 7, stress is generated between the wiring conductor 4 and the coating film 6, and the stress tends to cause peeling between the two. Is preferably in the range of 0.01 to 5.0 μm.

Thus, the semiconductor element 3 is located substantially at the center of the upper surface of the insulating base 1.
Then, the electrodes of the semiconductor element 3 are connected to the wiring conductor 4 via the bonding wires 8 and the bowl-shaped lid 2 is attached to the insulating base 1 via the glass sealing material 7. A semiconductor device is obtained by bonding the semiconductor element 3 on the upper side and hermetically sealing the semiconductor element 3 inside.

As glass sealant 7 for bonding the lid 2 on the upper surface of the insulating substrate 1 is the melting point of the _{PbO-B 2 O 3 -SiO 2} -ZnO system 400
A low-melting glass having a temperature of about 450 ° C. is used, and if it is welded to the bottom surface of the lid 2 in advance, the handling becomes easy.

The present invention is not limited to the above-described embodiment. For example, as shown in FIG. 3, an insulating frame 9 made of an electrically insulating material is formed on an insulating base 1 having a wiring conductor 4 on an upper surface by a glass material 10. It is also possible to apply the technology of the present invention to a portion where the insulating base 1 and the insulating frame 9 are joined to each other in a semiconductor element housing package having a structure attached via the same.

(Experimental Example) Next, the operation and effect of the present invention will be described based on an experimental example described below.

First, the insulating base and the lid having the structure shown in FIG.
Prepare individually.

A plate made of alumina ceramic (Al ₂ O ₃ ) is used as the insulating substrate, and a metal film having a thickness and a material shown in Table 1 is applied to the entire upper surface thereof as a wiring conductor by a thin film forming technique.

Incidentally, gold (Au) is used as a protective film on the surface of the metal film.
A thickness of 2.0 μm was applied, and at least one of titanium, chromium, and tantalum as a coating film was applied to a part of the upper surface of the protective film by plating to a thickness shown in Table 1.

A bowl made of alumina ceramic (Al ₂ O ₃ ) is used as the lid, and PbO-B ₂ O ₃ -SiO ₂ -Zn
O-based glass is welded.

Next, a lid is placed on the coating film of the insulating substrate, and the glass welded to the bottom surface of the lid is heated and melted to join the lid to the insulating substrate.

Then, while fixing the insulating base and applying a rotational force to the lid, peeling occurs between the wiring conductor and the glass,
The rotational force when the lid was peeled from the insulating substrate was measured with a torque strength meter, and the value was evaluated as the bonding strength between the wiring conductor and the glass.

Sample numbers 30 and 31 are comparative samples for comparison with the present invention, and are conventional products in which a coating film is not provided on the surface of the wiring conductor.

 The results are shown in Table 1.

(Effect of the Invention) As can be seen from the above experimental results, when a coating film made of at least one of titanium, chromium, and tantalum is formed on the wiring conductor, the lid is joined to the insulating substrate via the glass sealing material. In this case, the bonding strength between the wiring conductor provided on the insulating base and the glass sealing material is increased, and no peeling occurs even when an external force is applied between the two. Therefore, it is possible to keep the inside of the package airtight at all times, and to operate the semiconductor element contained therein normally and stably for a long period of time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a package for accommodating a semiconductor device of the present invention, FIG. 2 is an enlarged cross-sectional view of a circle portion of FIG. 1, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention. FIG. 4 is a sectional view of a conventional package for housing a semiconductor element. 1: Insulating substrate, 2: Lid 4: Wiring substrate, 5: Protective film 6: Coating film, 7: Glass sealing material

Claims (1)

(57) [Claims] 1. A package for housing a semiconductor element, comprising an insulating frame or an insulating lid attached via glass to an insulating substrate having a wiring conductor formed on the upper surface thereof by a thin film forming technique. Wherein the wiring conductor is provided with a coating film made of at least one of chromium, titanium, and tantalum on an outer surface in contact with the glass.