JP2002319640A - Package for semiconductor integrated circuit, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce weight and to improve heat radiating property in a package for a semiconductor integrated circuit, for which the semiconductor integrated circuit is fixed, in a base member (10) whose upper part is opened and a metal lid plate (22) mounted on the opening of the base member is seam-jointed to the base member and sealed airtightly. SOLUTION: The base member (10) is provided with a body part (12) made of aluminum, whose upper part is opened, and the metal seal frame (14) of high electrical resistance, jointed to the opening edge of the body part and the metal lid plate (22) is seam-jointed to the seal frame (14). The seam frame (14), having high electrical resistance, is made of kovar (R), and it is preferable that the lid plate (22) be made of the kovar as well. It is preferable that gold plating or nickel plating be applied to the kovar. The metal seal frame (14) is jointed by a discharge plasma sintering process and the metal lid plate (22) is seam-jointed to the seal frame (14).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal package for hermetically sealing a semiconductor integrated circuit.

[0002]

2. Description of the Related Art Various materials and shapes are known as packages used for semiconductor integrated circuits such as hybrid ICs, but those having a highly reliable specification are those that can be hermetically sealed. It is customary to do so.

[0003] As a method of hermetic sealing, a brazing method using solder and a resistance seam welding method are generally used. The brazing method is used to hermetically seal a metal or ceramic package (with a seal frame) using a metal lid. The heating temperature is relatively low and the thermal effect on the integrated circuit is small. The airtightness after stopping is good, and it has features such as relatively easy resealing. However, during the sealing process, fine particles of solder penetrate into the package,
There are problems that the circuit may be short-circuited, that the joint has low heat resistance, and that it is easily deteriorated in a high-temperature environment.

In the resistance seam joining method, a conical roller electrode is used, and an intermittent current flows between the lower electrode also serving as a work table under a constant pressing force and a moving speed to seam weld the entire periphery of the package. Things. A micro parallel seam joining method is also known as an improvement of the resistance seam joining. This method presses a pair of tapered roller electrodes rotating along a base member and a metal lid plate placed thereon along opposing ends of the lid plate under a constant pressure condition. In this state, pulsation is conducted, and airtight sealing is performed by a roll-spot type joint forming method by Joule heat generated in the joint.

[0005] In such a resistance seam joining method or a micro parallel seam joining method, it is difficult to perform a seam joining again by opening a lid and performing repairs and the like, and special equipment for seam welding is required. Although it has problems such as the following, it is widely used because of its high hermetic sealing reliability and excellent environmental resistance. In these methods, both the base member and the lid plate are preferably made of a material having relatively high electrical resistance. For example, a material obtained by plating gold or nickel on Kovar is used. Here, Kovar is an Fe-Ni-Co alloy and is known to have a thermal expansion coefficient comparable to that of a ceramic substrate.

[0006]

In recent years, the demand for large-scale hybrid ICs has been increasing due to multi-chip modules and the like. The weight of the package has increased, and the increase in the weight cannot be ignored. Also, since the heat generation increases due to the higher density of the integrated circuit, it is required to improve the heat dissipation of the package.However, the thermal conductivity of Kovar is poor, and when this is used for the base member, The heat dissipation becomes worse.

The present invention has been made in view of such circumstances, and has as its first object to provide a package of a semiconductor integrated circuit capable of reducing weight and improving heat dissipation. It is a second object to provide a method for manufacturing this package.

[0008]

According to the present invention, it is an object of the present invention to fix a semiconductor integrated circuit in a base member having an open top, and to seam-join a metal lid placed on an opening of the base member to the base member. In the hermetically sealed package for a semiconductor integrated circuit, the base member includes an aluminum main body having an open upper part, and a high electric resistance metal seal frame joined to an opening edge of the main body, This is achieved by a semiconductor integrated circuit package, wherein the metal lid plate is seam-bonded to the seal frame.

Here, the seal frame having high electric resistance is preferably made of Kovar, and the lid plate is preferably made of Kovar. Kovar has poor corrosion resistance to salt etc.
Kovar is preferably plated with gold or nickel.

A second object is to fix a semiconductor integrated circuit in a base member having an open top, and seam-join a metal lid placed on an opening of the base member to the base member.
(1) A method of manufacturing a hermetically sealed package for a semiconductor integrated circuit, comprising the steps of: (1) bonding a metal seal frame having a high electrical resistance to an opening edge of an aluminum body having an open upper portion by a discharge plasma sintering method; 2) A method of manufacturing a package for a semiconductor integrated circuit, wherein a metal lid plate is seam-bonded to the seal frame.

A micro parallel seam joint is suitable for the seal joint. In this invention, the main body of the base member is made of aluminum, and a seal frame such as Kovar is joined to the opening edge of the base member. For this joining, a discharge plasma sintering method is used. In this case, if both surfaces are roughened or a powdery metal inclusion is interposed, the bonding can be performed more favorably.
Roughening is performed by cutting the joint surface to a maximum roughness of 3 μm or more.
Preferably, it is about 0.3 mm. Further, as the metal inclusion, a powder (average particle diameter of about 10 μm to 0.3 mm) such as a metal (eg, aluminum) having a melting point equal to or lower than that of the main body (aluminum) or a lid plate (such as Kovar) is suitable.

[0012]

FIG. 1 shows a package according to the present invention.
FIG. 2A is a plan view showing a base member before the lid plate is joined, and FIGS. 2B and 2C are a right side view and a front view showing a package in which the lid plate is joined with a partial cross section. is there. 2 is a view showing a spark plasma sintering method, FIG. 3 is a sectional view of a test piece sintered by a plasma sintering method, and FIG. 4 is a view showing a micro parallel seam joining method.

In these figures, reference numeral 10 denotes a base member. The base member 10 comprises a substantially box-shaped main body 12 having an open top and a seal frame 14 joined to an opening edge of the main body 12. Is done. A number of small holes are formed in the vertical wall of the main body 12, and leads 16 are inserted through these small holes to be insulated and sealed.

The main body 12 is made of an aluminum alloy.
The seal frame 14 is made of Kovar. Aluminum and Kovar are joined by a spark plasma sintering method.

In the spark plasma sintering method, as shown in FIG. 2, a plasma heat is generated by using a spark discharge (transient arc discharge) generated when a pulse voltage is applied to a small gap between bonding surfaces. It is to be sintered. In FIG. 2, reference numeral 18 denotes a DC pulse power supply. The DC pulse output from the power supply 18 is supplied to the main body 12 and the seal frame 14 which are pressurized at a predetermined pressure, and sinters the joint between the two by discharge. Let it.

FIG. 3 is a sectional view of a test piece sintered by a plasma sintering method. FIG. 2A shows that a test piece of an aluminum alloy body 12 and a Kovar seal frame 14 is used to perform a roughening treatment 13 by cutting at least one of these joint surfaces. Discharge. FIG. 3B shows the case where metal powder 13A is interposed together with or instead of the surface roughening treatment.
It is desirable that the melting point of the metal powder 13A is substantially the same as or lower than that of the metal to be joined. For example, aluminum powder or aluminum alloy powder is suitable. If an activating material having an action of reducing the oxide film on the bonding surface is used for the metal powder 13A, the oxide film covering the bonding surface is reduced and the bonding surface is activated to facilitate bonding.

In order to evaluate the joining of the aluminum alloy main body 12 and the Kovar sealing frame 14 produced by spark plasma sintering, tests of airtightness and joining strength were carried out. This test was performed on a test piece made of aluminum and Kovar as shown in FIG.

The airtightness test is performed on the bonding interface and the base gas.
Measuring permeability with a helium leak detector
Was performed. As a result, the helium gas permeation amount is 1 ×
10 ^-TenPam^Three/ S or less. Joining
In the strength test, pull until the material breaks with a tensile tester
Power gradually increased. As a result, the destruction mode is aluminum
It is known that it will destroy the mother body, and it should not be a joint interface failure
Was confirmed. That is, the airtightness of the joint is sufficiently high,
The joint strength was found to be sufficiently large.

As described above, the seal frame 1 is attached to the main body 12.
A semiconductor integrated circuit (not shown) is adhesively fixed in the base member 10 to which the base member 4 is bonded, and is connected to the lead 18 by a bonding wire (not shown) or the like. Then, the base member 10 having the integrated circuit mounted thereon is fixed to a work table 20 shown in FIG. The work table 20 can be rotated and / or translated in accordance with the shape of the base member 10. Then, a lid plate supply means (not shown) carries the lid plate 22 to the seal frame 14 of the base member 10. The lid plate 22 is formed by applying gold plating or nickel plating on both sides of the flat surface of Kovar.

In FIG. 4, reference numerals 24 and 24 denote tapered roller electrodes which are held by supporting arms (not shown) so as to be rotatable on a common horizontal axis. This support arm can move up and down. As the seam joining power source, a power source for a single-phase AC resistance spot welding machine can be used. That is, the single-phase alternating current is phase-controlled by the thyristor bridge 26 and supplied to the primary side of the welding transformer 28, and the induced voltage on the secondary side of the transformer 28 is guided to the respective roller electrodes 24. Reference numeral 30 denotes a controller that controls the firing phase angle of each thyristor of the thyristor stack 26 based on the phase of the single-phase AC power supply. The controller 30 controls the energization time and the cooling time so as to enable seam joining by pulsation energization.

When the lid plate 22 is placed on the seal frame 14, the roller electrodes 24, 24 descend and press the lid plate 22 at a predetermined pressure. In this state, the work table 20 moves and temporarily attaches a plurality of locations. Thereafter, while the roller electrodes 24, 24 are being rotated by the movement of the work table 20, the welding current is made to flow in a pulse shape to continuously perform seam joining. Thus, the entire periphery of the lid plate 22 is joined to the seal frame 14.

The current flowing from one of the roller electrodes 24 to the other during the seam joining mainly flows to the lid plate 22, but a part of the current is diverted to the seal ram 14. However, since the seal frame 14 is made of Kovar having a large electric resistance, the current shunted here is small. Therefore, most of the current flows to the lid 22 and the lid 2
2 generates heat. Since the current density of the current flowing through the lid plate 22 is greatest at the contact portion with the roller electrode 24, the amount of heat generated at this contact portion is the largest. As a result, the temperature of the contact portion (the contact portion between the roller electrode 24 and the lid plate 22) increases, and heat is transferred from the contact portion to the lid plate 22 and the seal frame 14.
Propagate to Thus, seam joining starts at the contact portion, and seam joining is continuously performed by movement of the contact portion accompanying movement of the work table 20.

[0023]

According to the first to third aspects of the present invention, as described above, a metal seal frame having high electrical resistance is joined to the opening edge of the aluminum main body, so that the joining current is mainly applied to the lid plate. The current that flows and escapes to the seal frame is reduced. For this reason, the calorific value of the lid plate, especially the calorific value near the contact portion with the roller electrode increases, and the seam joining is reliably performed. That is, the reliability of the seal is improved. Further, since the main body is made of aluminum, it has good heat conductivity. For this reason, the heat of the integrated circuit housed in the package can be quickly transmitted to the outside, and heat dissipation is improved.

According to the present invention, a manufacturing apparatus used for manufacturing a package can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a package according to an embodiment of the present invention;

FIG. 2 is a view showing a spark plasma sintering method.

FIG. 3 is a cross-sectional view of a test piece sintered by a plasma sintering method.

FIG. 4 is a diagram showing a micro parallel seam joining method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Base member 12 Main part 13 Roughening treatment 13A Metal inclusion (aluminum powder) 14 Seal frame 20 Work table 22 Lid plate 24 Roller electrode

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuichi Kawakami 4--20 Komukai Nishimachi, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd. (72) Inventor Masao Saito 3--20 Nishishinbashi, Minato-ku, Tokyo No. 1 Inside Nippon Avionics Co., Ltd. (72) Inventor Masao Suzuki 3-20-1, Nishishinbashi, Minato-ku, Tokyo F-term within Nippon Avionics Co., Ltd. 4J040 AA011 HA061 MA02 NA20 PA17 PA32

Claims (7)

[Claims] 1. A semiconductor integrated circuit package in which a semiconductor integrated circuit is fixed in a base member having an open top, and a metal lid placed on an opening of the base member is seam-bonded to the base member and hermetically sealed. In the above, the base member includes an aluminum main body having an open upper part, and a high electric resistance metal seal frame joined to an opening edge of the main body, and the metal lid plate is provided with the seal frame. A semiconductor integrated circuit package characterized by being seam-bonded to a semiconductor integrated circuit. 2. The package for a semiconductor integrated circuit according to claim 1, wherein both the seal frame and the lid plate are made of Kovar. 3. The package for a semiconductor integrated circuit according to claim 1, wherein the lid plate is made of a Kovar lid material plated with gold or nickel. 4. A semiconductor integrated circuit for a semiconductor integrated circuit, wherein a semiconductor integrated circuit is fixed in a base member having an open top, and a metal lid placed on an opening of the base member is seam-bonded to the base member. In the method of manufacturing a package, (1) a metal seal frame having a high electric resistance is joined to an opening edge of an aluminum main body having an open upper portion by a discharge plasma sintering method; A method of manufacturing a package for a semiconductor integrated circuit, which is seam bonded to a seal frame. 5. The method of manufacturing a package for a semiconductor integrated circuit according to claim 4, wherein in step (2), the lid plate is joined by a micro parallel seam joining method. 6. The seal frame is made of Kovar, and at least one of the joining surfaces of the seal frame and the aluminum main body is subjected to a roughening process and then subjected to discharge plasma sintering. Manufacturing method of a semiconductor integrated circuit package. 7. A semiconductor integrated circuit according to claim 4, wherein a powdery metal inclusion is interposed between the joining surfaces of the seal frame and the aluminum main body, and the joining is performed by a discharge plasma sintering method. Package manufacturing method.