JPH03224258A - circuit device - Google Patents

Abstract

PURPOSE:To improve productivity, electrical and mechanical characteristics, and, in particular, airtight properties, by forming a composition composed of Ag, Au, Pd and Pt of specified wt.%, on an oxidative metal surface containing Ni, and bonding the composition to a ceramic substrate. CONSTITUTION:In a lead frame 1, non-oxidizable composition composed of 30-99.5wt.% Ag, 0.5-70wt.% Au, 0-60wt.% Pd, and 0-35wt.% Pt is formed on the surface of Ni containing oxidative metal like kovar. By screen printing method, a glass paste layer 5 for bonding is formed on an AlN substrate 2 on which a metal layer 4 is formed. The frame 1 is sandwiched between the substrate 2 and a base body 3, and subjected to glass bonding. After the frame 1 is plated with gold, a bare chip 7 is die bonded. After Au wire bonding, an upper lid 9 of kovar is fixed by using Au-Sn solder 10, and a circuit device is formed. Since high temperature processing is enabled in the air, productivity is superior and various kinds of defects can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit device and a method for manufacturing the same.

[Prior Art] Conventionally, as an airtight container for incorporating a semiconductor integrated circuit element into a circuit device, a metal lead terminal has been used between a ceramic substrate and a ceramic substrate or a metal plate having an opening for forming a part of a cavity. , such as nickel-cobalt-iron (Ni-Co-Fe), the alloy Kovar (trademark), the Ni-Fe alloy 42 alloy (
Ceramic packages are known in which a ceramic substrate is sandwiched and bonded with low melting point glass, and a ceramic package is made in which a ceramic substrate and a ceramic top cover are bonded with low melting point glass and hermetically sealed. These low-melting point glasses are bonded in a non-oxidizing atmosphere such as nitrogen gas, nitrogen-hydrogen mixed gas, or argon gas to prevent metal members such as metal lead terminals from oxidizing.
This is done by heating to a temperature of 000°C.

However, since the above bonding is performed in such a non-oxidizing atmosphere, the organic binder contained in the low melting point glass layer is not completely removed, and the gas generated by the removal of the binder causes bubbles in the molten glass layer. It seems to be scattered as.

Such bubbles sometimes connect with each other, forming voids (bubbles) that communicate the inside and outside of the joint, which has the disadvantage of reducing airtightness.

In order to prevent the formation of voids in the glass layer, the above-mentioned joints are separated and heated in advance to degas the gas contained in the glass, and then the gas is hermetically sealed to ensure airtightness. It has been reported that it prevents the decline of
(Japanese Patent Publication No. 52-41184) is also available.

However, glass is heated to high temperatures during bonding,
Furthermore, since it is exposed to a non-oxidizing atmosphere, it may be reduced, which has the drawback of lowering its insulation properties and lowering its mechanical strength. Furthermore, in order to completely remove piping from the glass and prevent deterioration due to reduction of the glass, when glass bonding is performed in an oxidizing atmosphere, for example in air, the surface of the metal terminal becomes oxidized and becomes unusable. It becomes possible. In particular, the coefficient of thermal expansion is 50~60X 10-'°
Kovar is an alloy containing C″′ and Ni, which is similar to alumina and aluminum nitride substrates.

42 alloy and the like have the disadvantage that an oxidized corrosion layer made of Ni--Fe composite oxide is formed on the surface, which cannot be recovered even by post-treatment, such as acid-alkali cleaning.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to solve the previously unknown N
A circuit device characterized in that it has a structure in which an oxidation-resistant metal member having a composition for preventing oxidative corrosion in a high-temperature oxidizing atmosphere formed on the surface of an oxidizing metal containing i and a ceramic substrate is bonded. The manufacturing method on 9th floor
It is intended to be shared with T vision.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and the surface of the nickel-containing oxidizing metal is coated with 30 to 99.5% by weight of gold.
0.5-70 wt% palladium
0-60 wt% platinum 0-35
The present invention provides a circuit device characterized in that it has a structure in which an oxidation-resistant metal member and a ceramic substrate formed with a composition consisting of % by weight are bonded via a layer of glass or glass ceramics.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view showing the basic structure of a circuit device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the assembly process of the circuit device of the present invention shown in FIG. It is.

In FIGS. 1 and 2, 1 is a lead frame, 2 is an insulating substrate, 3 is a bonding base, 3' is an opening in the base 3, and 4
．． 4' is a metal layer, 5 is a glass paste for bonding, 6 is a glass layer formed by firing the glass paste 5, 7 is a bare IC chip, 8 is a wire 9 for wire bonding
is a top cover made of ceramics or Ni-containing metal.

10 is solder for joining.

The lead frame 1 is made of an oxidation-resistant metal member in which a composition that imparts oxidation resistance to the surface of an oxidizable metal containing Ni (Ni-containing metal) is formed. This Ni-containing metal is used for boat fishing, with a small coefficient of thermal expansion (such as oxidizing Kovar, 42 alloy, Ni-copper (Cu) alloy, etc.), which contains Ni and has a melting point of 800°C or higher. The material is not limited to metals.These alloys have thermal expansion coefficients close to those of ceramics, and are therefore used as metal members such as lead pins and seal rings of ceramic semiconductor packages.

The following composition is suitable for imparting oxidation resistance to this Ni-containing metal. % means weight % unless otherwise stated.

Silver (Ag) 30-99.5% Gold (Au)
0.5-70% palladium (Pd)
0-60% Platinum (Pt) 0-3
5% Ag in the composition is strongly related to oxidation resistance.

Ag is an essential component that provides oxidation resistance, and has a rating of 99.
Oxidation resistance can be imparted even at a very high content of 5%.

When Ag is less than 30%, Ni in the base metal diffuses from the Ni-containing metal (hereinafter also referred to as base metal) to the alloy surface according to the present invention in a temperature range of 400°C or higher, forming an oxidized layer of Ni. Therefore, it is not appropriate.

A desirable range is 30 to 95%, more preferably 40 to 90%. Particularly preferably 50 to 80
%.

Au, Pd, and Pt are components that provide stability to the bonding of Ag with the base material, and play a role in strengthening the adhesive force of the Ag film with the base material and preventing evaporation of Ag at high temperatures. .

Au is an essential component, and if it exceeds 70%, Ni in the base material
It is not suitable because it tends to diffuse into the surface and the oxidation resistance decreases. If Au is less than 0.5%, adhesion with Ni-containing metals will be poor.

A desirable range is 5-70%. More preferably, it is 10 to 60%, and a particularly desirable range is 20 to 5%.
It is 0%.

Although Pd is not an essential component, it has the effect of improving the adhesion of Ag to the Ni-containing metal and also has the effect of preventing evaporation of Ag at high temperatures. If it exceeds 60%, Ni in the base material tends to diffuse to the surface and oxidation resistance decreases, which is not suitable.

A desirable range is 0.5-40%. More preferably, it is 1 to 20%, particularly preferably 2 to 10%.
It is.

Although pt is not an essential component, it has the effect of improving the adhesion of Ag to the Ni-containing metal and also has the effect of preventing evaporation of Ag at high temperatures. If it exceeds 35%, PtAg
It is not suitable because it forms an intermetallic compound with a and the adhesive strength with the base material decreases.

A desirable range is 0.5% to 20%. More preferably, the range is 1 to 10%, and a particularly desirable range is 2 to 10%.
It is 6%.

Furthermore, the composition according to the present invention can be formed by sequentially forming compositions of different compositions on the surface of a base material, which fall within the scope of the composition according to the present invention (such as forming a plurality of layers or laminating them). You can also do it.

Further, the method of forming the composition according to the present invention on the surface of the base material is not particularly limited, but it can be formed by a general coating method such as plating or dipping.

Furthermore, although the formed thickness of these compositions according to the present invention is not particularly limited, in general, if the formed thickness is about 0.5 to 5 μm, it will have oxidation-resistant properties up to about 1000° C., which is the heat-resistant temperature of the base material, in an oxidizing atmosphere. can be held.

Even if the surface of the oxidation-resistant metal member of the present invention is plated with Au or the like in consideration of aesthetic appearance and workability, the functions and effects of the present invention will not be impaired.

Since the insulating substrate 2 helps dissipate heat from the bare chip 7, ceramics such as aluminum nitride (AIN) having excellent thermal conductivity are usually used.

The base body 3 is used to attach the top cover 9 to the recovery device of the present invention, and is made of ceramics such as alumina and AIN, and metals such as Kovar and 42 alloy, which have good thermal conductivity among ceramics. AIN is preferred. still,
When the above-mentioned metal is used as the material of the substrate 3, it is preferable to form the composition according to the present invention on the surface of the substrate.

The metal layer 4 can be made of gold (Au), silver (Ag), Ni, or an alloy containing at least one of these, but it is preferable to use Au, which has excellent bonding properties with both the bare chip and the ceramic substrate 2. The substance is not limited to this as long as it has excellent properties. As the bonding glass paste 5, various types of bonding glasses having low melting points are usually used. Further, instead of the bonding glass, glass-containing glass ceramics with excellent bonding properties can be used.

When ceramic is used as the material of the base 3 and metal is used for the top cover 9, after forming the metal layer 4° on the base 3, the top cover 9 is further bonded thereon using solder 10. is preferred. The metal layer 4' is made of Au, which has excellent bonding properties with ceramics.

Ag, Ni, or an alloy containing a small amount of one of these is usually used, and as the solder 10, Pb-3n solder, Au-5i solder, etc. are usually used, but Au-3n solder, which has excellent airtightness, is used. Desirable.Kovar is used for the base 3.

If a metal such as 41 alloy is used, the metal layer 4° is not necessary.

Next, FIG. 3 is a sectional view showing the basic configuration of a recovery device according to an embodiment of the present invention, which is different from that shown in FIG. 1, and FIG. 4 is an assembly of the recovery device of the present invention shown in FIG. It is a sectional view showing a process. 3. In Fig. 4, 21 is a lead frame, 22 is an insulating substrate, 23 is a metal layer such as Au, 24 is a glass layer for bonding, 25 is a bare IC chip, 26 is a wire for wire bonding, 27 is an upper lid made of ceramics, Ni-containing metal, or the like.

Note that the circuit device of the present invention is not limited to the structure shown in FIGS. 1 and 3.

[Function] In the circuit device of the present invention having a structure in which an oxidation-resistant metal member and a ceramic substrate are bonded, the metal portion is not oxidized even when heated in an oxidizing atmosphere, so that the oxidation-resistant metal member and the ceramic substrate are bonded together. It becomes possible to thermally bond ceramic substrates through a glass layer in an oxidizing atmosphere such as air. Therefore, the organic binder in the glass layer can be easily depyrined, and no bubbles are generated in the glass layer.
It has the effect of not reducing airtightness, and
Since the bonding is carried out by heating in an oxidizing atmosphere, the glass is not reduced. In other words, it is thought that the effect is that there is no decrease in insulation resistance or decrease in mechanical strength due to the reduction of the glass.

[Example] (Example 1) Thickness: 0.1 mm, external size: 27.5 x 27.5 mm
Kovar (29Ni-16Co-55Fe) lead frame (32 bins, 25 mil pitch),
Thickness 0.5 mm used as base, external size 9 x 9 m
58% Ag, 42% Au by electrolytic plating on the surface of the Kovar seal ring (opening 8 x 8 mm)
A composition consisting of the following was formed to a thickness of 1.5 μm.

The electrolytic plating conditions were as follows: Au, Ag as the plating liquid.
using a mixture of cyanide solutions with a current enrichment of 0.3 A/
dm2 using a Ti/Pt alloy as an anode and Kovar as a cathode.

Apart from this, commercially available AIN board (9X9X1mm)
(AGN-2 manufactured by Asahi Glass. Thermal conductivity '200 W/m
An Au paste was formed by printing with a thermal expansion coefficient of 45×10 −7° C.−1) and fired in air at 900° C. for 1 hour to form a metal layer on the AIN substrate.

Next, commercially available low melting point glass frit (A1203-5iO
To impart printability to 80% of □-B203 series), 20% of an organic vehicle consisting of ethyl cellulose resin and α-terpineol solvent was added, mixed for 1 hour in an alumina porcelain mortar, and then dispersed with three rolls. Then, a glass paste for bonding was prepared.

Next, as shown in FIG. 2, a glass paste for bonding was formed on the AIN substrate on which the metal layer was formed by screen printing. A glass paste for bonding was also formed on the lower surface of the base by screen printing. The lead frame was sandwiched between the AIN substrate on which the glass paste layer for bonding was formed and the base, and
By heating at 0° C. for 2 hours, the lead frame was sandwiched between the base and the AIN substrate to perform glass bonding. In addition, in order to facilitate wire bonding using Au wire, a 1μ Au plating layer was applied to the surface of the lead frame.
m was formed to produce a circuit device package.

Next, as shown in Figure 1, four bare chips are placed on the metal layer.
Die bonding was performed at 30° C., and wire bonding was performed using Au wire. Then, the top cover made of Kovar was made of Au-5.
This was sealed by heating at 320° C. for 10 minutes using n-solder to obtain 100 semiconductor circuit devices.

Insulation resistance value between lead terminals of this circuit device.

A He leak test was conducted to evaluate the bonding strength of the lead terminals as well as the airtightness. the result,
All of the above 100 circuit devices have an insulation resistance value of 3X 10
”Ω, lead terminal bond strength 10 kg/mm2 or more,
It exhibited excellent electrical and mechanical properties with a He leak rate LX of 10-8 stdcc/sec or less, and also exhibited excellent airtightness, and was satisfactory in terms of performance.

(Example 2) As shown in Fig. 1, the thickness is 0.1 mm and the outer diameter is 52X.
52 mm Kovar alloy (29Ni-16co-
55Fe) node frame (180 bins +'20
mil pitch) on the surface of 58% Ag as in Example 1.
, a composition consisting of 42% Au was formed to a thickness of 1.5 μm.

Apart from this, a commercially available AIN board (AGN-2 manufactured by Asahi Glass)
．． Thermal conductivity 200 W/mK, thermal expansion coefficient 45X
10-”C bow) board (dimensions: 34X 34X 1
A substrate (dimensions = 34 x 34 x 1 mm) having an opening (14 x 14 mm) and an opening (14 x 14 mm) was prepared, and the AI
An Au metal layer was formed on the N substrate in the same manner as in Example 1.

In a similar manner, a metal layer of Au was also formed on the substrate (as shown in FIG. 2).

Next, the same bonding glass paste used in Example 1 was formed on the AIN base and the AIN substrate in the same manner as in Example 1.

The AIN board and A on which the glass paste for bonding was formed
The lead frame is sandwiched between the IN substrate and the
Glass bonding was performed by heating at 50° C. for 2 hours.

In order to facilitate Au wire bonding, a 1 μm thick Au plating layer was formed on the surface of the lead frame to fabricate a package for the circuit device.

Next, as shown in FIG. 1, the bare chip 17 was bonded onto the Au metal layer at 430° C., and wire bonding was performed using an Au wire. Then, the top lid made of Kovar was sealed by heating it at 320°C for IO minutes using Au-Sn solder, and the semiconductor circuit device was heated to l 00 (
[ii1 obtained.

A He leak test was conducted on 100 of these semiconductor circuit devices in order to evaluate the insulation resistance between the lead terminals, the bonding strength of the lead terminals, and the airtightness.

As a result, all 100 of these circuit devices had an insulation resistance value of 3.
X 10'4Ω, lead terminal bonding strength 10kg/mm
2 or more, He leak rate IX 1O-8std cc
It exhibited excellent electrical and mechanical properties of less than /sec, as well as excellent airtightness, and was satisfactory in terms of performance.

(Example 3) As shown in Figure 4, the thickness is 0.1 mm and the external size is 35 x 35.
mm Kovar (29Ni-16co-55Fe)
Manufactured frame (48 pins, 25 mil pitch)
As in Example 1, 62% Ag, 38% Au
% was formed to a thickness of 1.5 μm.

Apart from this, a commercially available AIN board (GN-2 manufactured by Asahi Glass)
, thermal conductivity 200 W/mK, thermal expansion coefficient 45X 1
0-'℃ phase) substrate 22 (dimensions: 34X 34X 1
mm) was prepared, and a metal layer of Au was formed in the same manner as in Example 1.

Next, the same bonding glass paste used in Example 1 was formed on the AIN substrate, the lead frame was placed on top, and the lead frame and the AIN substrate were heated in air at 850° C. for 2 hours. were joined. In order to facilitate Au wire bonding, a 1 μm thick Au plating layer was formed on the surface of the lead frame to produce a package for a circuit device.

Next, as shown in FIG. 3, a bare chip was bonded onto the Au metal layer at 430° C., and wire bonding was performed using an Au wire. Then, the upper lid made of AIN was used as the bonding glass and the sealing glass (T-made by Iwaki Glass) was used as the bonding glass.
1918F (trade name)) for 10 minutes at 415° C. to obtain 100 semiconductor circuit devices.

A He leak test was conducted to evaluate the insulation resistance between the 100 lead terminals of this semiconductor circuit device and the bonding strength of the lead terminals, as well as to evaluate the airtightness.

As a result, all 100 pieces had an insulation resistance of 3XlO'4Ω
, lead terminal bonding strength 10 kg/mm2He leak rate IX 10-' 5td-cc/sec or less, showing excellent electrical and mechanical properties as well as excellent airtightness, and was satisfactory in terms of performance. .

(Example 4) The composition for forming a circuit device having the same structure as in Examples 1 and 2.3 on the surface of a lead frame was as shown in Table 1.
Without changing any other conditions, 28 pieces of 100× each were produced, for a total of 2800 pieces of 3×.

When all of these circuit devices were tested in exactly the same manner as in Examples 1 to 3, the results were exactly the same as in Examples 1 to 3, and the performance was satisfactory.

Furthermore, in order to evaluate the oxidation resistance properties of 2800 lead frames with the same structure as in Example 1, 90
100 hours (hr) at 0°C, 1000 hr.

After heating for 10,000 hr, conductivity on the surface 1 Adhesion of the composition layer 1 The presence or absence of oxide scale generation on the surface was investigated, and the results are summarized in [Table 1].

[Characteristics Evaluation Method] 1) Visual inspection using a 10x optical microscope for the presence or absence of oxide scale 2) Conductivity Characteristics The presence or absence of conductivity was evaluated using a digital multimeter manufactured by Y, H, and P.

3) Adhesion After performing a 90° bending test three times, the presence or absence of cracks and peeling was evaluated using a 10x optical microscope. (Mi
1, STD, 883CMethod 2004) (Comparative Example 1) A glass paste for bonding was used that had exactly the same structure as Examples 1 to 3, but did not form the composition according to the present invention on the surface of the lead frame. The lead frame was bonded to the AIN substrate by firing. Firing is 850
C. for 2 hours under nitrogen. Other conditions are Example 1
- 10 semiconductor circuit devices each in exactly the same way as in 3.
0 pieces, a total of 300 pieces were produced.

For a total of 300 circuit devices of these three types of semiconductors, a He leak test was conducted to evaluate the insulation resistance between the lead terminals and the bonding strength of the lead terminals, as well as to evaluate the airtightness.

As a result, the insulation resistance value was approximately 1×10 8 Ω, and the bonding strength of the lead terminal was approximately 2.8 kg/mm 2 , which were extremely low (unsatisfactory) compared to products heated in air.

Furthermore, the He leak rate indicating airtightness is 2X 10-'5
The airtightness was as low as td-cc/sec, and it became clear that the airtightness was insufficient.

When the cross section of this semiconductor circuit device was observed, it was found that a large number of bubbles were present in the bonded glass portion, and some of the bubbles formed continuous bubbles. This is considered to be the reason why the airtightness and the bonding strength of the lead terminals deteriorated.

Furthermore, Because some of the glass was returned, Absolutely wire resistance value.

It is thought that the mechanical strength has decreased. It will be done.

[Continuation of Table 1]Continuation of [Table-1]EContinuation of Table-1]Continuation of [Table-1] [Effects of the Invention] The circuit device of the present invention is made of Ni-containing metals such as Kovar. Since the composition according to the present invention has oxidation resistance on the surface, bonding with the ceramic substrate through the glass layer can be carried out in an oxidizing atmosphere, for example, at high temperature in air for good productivity. This also has the effect of preventing metal members from being oxidized and corroded (or losing continuity).

Further, since the heating for bonding is performed in an oxidizing atmosphere, the glass layer is not reduced and the electrical and mechanical properties are not deteriorated, so it has the effect of exhibiting high electrical and mechanical properties.

Furthermore, since the organic vehicle in the glass is easily degassed, there is no reduction in airtightness due to air bubbles, and the glass has the effect of exhibiting high airtightness.

As described above, the present invention has unprecedented productivity, excellent electrical and mechanical properties, and excellent airtightness.
It has the effect of being able to provide a circuit device, and its industrial value is great.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the basic configuration of a recovery device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the assembly process of the circuit device shown in FIG. 1, and FIG. 3 is different from FIG. 1. FIG. 4 is a sectional view showing the assembly process of the recovery device shown in FIG. 3. FIG. l: Lead frame 2: Insulating substrate 3: Base for bonding

Claims (2)

[Claims] (1) A composition consisting of 30 to 99.5% by weight of silver, 0.5 to 70% by weight of gold, 0 to 60% by weight of palladium, and 0 to 35% by weight of platinum was formed on the surface of an oxidizing metal containing nickel. A circuit device characterized by having a structure in which an oxidation-resistant metal member and a ceramic substrate are bonded via a layer of glass or glass ceramics. (2) A method for manufacturing a circuit device, which comprises firing and bonding the oxidation-resistant metal member described in item 1 and a ceramic substrate in an oxidizing atmosphere using glass ceramics or glass paste.