KR820002403B1 - Passivated and ecapsulated semiconductors and method of making same - Google Patents

Abstract

The invention is concerned with semiconductor which is shielded by plastic capsule and fabrication. This provides an excellent thermal cycling resistance device. The device contains a electric conductive metal contact member and electrode terminal. Semiconductor is connected the end of the contact member by a connecting member, (30) is a stability film. The composition of this film is Zinc and boron. In general the coefficient of expansion of the plastic capsule (40) is disregarded. The size of (40) is selected by the existing facilities.

Description

Preparation of surface stabilized coated and encapsulated semiconductors

1 is a side view of a semiconductor device before the surface stabilization coating and the capsule are coated.

FIG. 2 is a side view showing a cross section of the semiconductor device of FIG. 1 after coating a glass surface stabilizing coating. FIG.

FIG. 3 is a side view showing a cross section of the device of the semiconductor of FIG. 2 coated on a surface stabilizing film as a plastic capsule. FIG.

The present invention relates to a semiconductor coated with a surface stabilizing film and a capsule and a method of manufacturing the same. In particular, it relates to a glass surface stabilizing coating, a semiconductor coated with a plastic capsule, and its manufacture. It is a known fact that semiconductor devices are more practical and can be used for a long time if they are coated to stabilize and protect their surfaces.

Many materials have been used for such coatings, which have been used in alkaline glass to include the alkali tree zinc borosilicate glass of US Pat. No. 3,752,701.

Such glass surface stabilizing coatings and capsule coatings provide stability to semiconductor bonding, machining and sealing.

However, there are the following disadvantages.

(1) Lack of reproducibility in external size due to technical problems and the nature of the material.

(2) It is elliptical and difficult to handle.

(3) the light passes well,

(4) Difficult to write.

The prior art is to add various plastics or resins to glass, which is a stabilizing coating and a capsule coating material.

In such devices varnish materials stabilize around semiconductor junctions. Such junction stabilizing material is melted and coated with epoxy or silicone liquid. However, the plastic coating of the prior art has the following disadvantages.

(1) Varnish (or junction stabilizing materials such as varnish or silast) can completely protect the semiconductor from moisture.

(2) The plastic material which stabilizes and coats a junction part degrades the operation characteristic at high temperature.

(3) Plastic, which is a coating material, has a lower permeability than glass. Thus, the device coated with the plastic stabilizing film and the capsule fails the pressure test under 15 p s, i.

(4) Plastic sheath is not fireproof.

Despite these shortcomings, semiconductors coated with plastics with surface-stabilized coatings and capsules have been manufactured ahead of semiconductors coated with glass-stabilized coatings and capsules with glass, and manufacturers and user organizations have tested, marked and taped reel packed. It has been produced and consumed in large quantities by setting the size standard to enable automatic machine operation for inserting elements into a print engine.

All of the disadvantages of devices coated with plastics with surface stabilized coatings and capsules are overcome in devices coated with glass with surface stabilized coatings and capsules, but the size and shape of the glass sections vary from device to device. This variety has many problems in automatic machine operation.

For example, since automatic machine operation that lowers the unit price cannot be used, there is a problem that manual assembly is inevitable to achieve excellent characteristics. Thus, despite the various disadvantages of semiconductors coated with plastics and surface stabilized coatings and capsules, they are still widely used for their automation advantages.

A semiconductor device in which plastic and glass are composited and coated with a surface stabilizing film and a capsule has been used in the prior art, but such a device has not been improved satisfactorily. Such semiconductor devices (published in u.s.p 3,237,272 u.s.p. 3,149,396) have the following disadvantages.

(1) It cannot be used for the axial electrode semiconductor.

(2) Use a glass with a low melting point that does not provide the advantages of the glass coating described above.

(3) Use microscopic surface stabilization coatings of silicate glass that result in surface stabilization only at low voltage levels.

Accordingly, an object of the present invention is to provide a semiconductor device in which a glass surface stabilized film and a plastic capsule are coated with the advantages of the glass surface stabilized film and the plastic capsule.

It is a further object to provide an assembly having an appearance suitable for an automatic mechanism for the fabrication of a device coated with a plastic surface stabilizer film and a capsule.

It is an object of the present invention to provide an element that is strong in waterproofness and does not fail a sealing test. Another object is to provide a device having excellent operating characteristics at room temperature and high temperature and exhibiting excellent thermal cycling resistance.

In addition, it is an object of the present invention to provide a simple and economical process for producing a semiconductor device coated with such a surface stabilizing film and a capsule.

The above objects of the present invention are realized in a semiconductor device coated with a surface stabilizing film and a capsule and such a manufacturing method. The device includes a semiconductor body, a plurality of electrically conductive metal contact members, and a plurality of electrically conductive electrode terminal portions. A first connecting portion (connecting member) for connecting the semiconductor to the distal end of each contact portion and a second connection portion for connecting the other end of each contact portion to the distal end of each electrode terminal.

The uniform surface stabilization coating area of the molten particles of the nonconductive non-alkali glass covers the exposed portion, the first connection portion, and the contact portion of the semiconductor body. Glass having a coefficient of thermal expansion, such as that of the connecting portion and the semiconductor body, is used. The capsule region of the non-conductive plastic coats the stabilizing coating region, the exposed surface, the contact portion, and the connected head portion of the second connection portion and the electrode terminal portion. Moreover, the semiconductor device has an axial electrode terminal with an unconnected end of the electrode terminal portion extending out of the plastic capsule region.

In a preferred embodiment, the stabilizing coating region is uniform in construction and has a radius thickness of at least 0.13 mm (preferably 0.13-0.25 mm) in the semiconductor plane. Have a bead shape. And the capsule part is cylindrical shape suitable for the above-mentioned automation machine. The contact is a refractory metal, the glass is a non-alkali zinc boron silicate glass, and the plastic is an epoxy or silicone plastic.

In order to coat the stabilized film on the semiconductor element, a slurry of non-conductive non-alkali glass having a thermal expansion coefficient such as a thermal expansion coefficient of the semiconductor and the contact portion is coated. The glass particles are heated to a temperature where they melt to form a uniform stabilizing coating. In order to coat the capsule on the semiconductor device coated with the stabilization film, the non-conductive plastic is melted and coated on the stabilized area, the exposed surface, the contact portion and the head of the electrode terminal connected thereto. In the process, the slurry has a slurry solution of ionized water or non-ionic organic compound. After use, the slurry is heated to remove the slurry solution. The remaining glass is then heated to 68.0-750 ° C. for 4-20 minutes to melt to form a homogeneous stabilizing coating.

The semiconductor coated with the stabilizing film and the capsule of the present invention combines the reliability of the glass stabilizing film with the appearance of an automated plastic capsule.

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

1 shows a semiconductor device disclosed in US Pat. No. 463,678, indicated by numeral 10. In FIG. The element 10 is a type of axial electrode semiconductor. However, the principles of the present invention can be applied to other forms of semiconductor devices. The device 10 is substantially made of silicon, but in some places it contains a semiconductor 12 containing a small amount of impurities such as phosphorous and boron. In order to facilitate understanding of the principles of the present invention, the semiconductor 12 is shown to be connected to only two axial electrodes attached thereto, but in addition to transistors, N-type P-type coupled or junction transistors, and field effect transistors. Can be used.

The principle of the present invention is generally as follows, wherein the semiconductor of the present invention is formed into a thin wafer-like diode (shown) or a long thread connected as a few chips in series, or Depending on the pico, suitable materials (eg aluminum) are used together, with each device having a number of electrode terminals extending there.

At each end of the silicon chip 12, thin layers 14 and 14 ', which are conductive contact materials, are deposited.

However, the present invention may be substituted with other materials besides aluminum, and for example, silver solder, aluminum, silicon alloys, or the like may be used. The portions 14, 14 'can be deposited on the silicon chip 12 by conventional resonant semiconductor technology, which is already known.

The contacts 16, 16 ', which spread outwardly from each of the parts 14, 14', are electrically conductive metals, such as molybdenum, tungsten, titanium or alloys thereof. Metals with the same properties are preferred.

Alloys of the above-described metals may be used, or alloys mixed with metals according to the above metals may be used.

Such an alloy should, of course, be selected from alloys having a coefficient of expansion such as thermal expansion of the semiconductor body 12, and other parts other than the contact 16 also have a coefficient of thermal expansion such as that of the semiconductor body 12. Must have

The braze alloy spreading out from each of the contact portions 16 and 16 'has a shape of 18 and 18' whose outer shape is flat. Such alloys consist of about 80-89% copper, about 5-15% silver and about 4-6% phosphorus, using 80/15/5 silver solder sold as a general merchandise or The high temperature brazing alloys (SILFOS) sold by Ingrehard Ind. Street Division of Inghad Mind Chemical Corporation are used. Such hard solder alloys generally have freezing point. It is 640 ° C, has a melting point of about 705 ° C, and does not require oxidation or reduction during soldering.

The axial electrode terminals, such as the heads of nails, denoted by numerals 20 and 20 ', have heads whose ends are joined to the contacts 16 and 16' by hard solder alloys 18 and 18 '. 22) and (22 '), and the ends 24 and 24' are connected to other circuit elements. The electrode terminals 20, 20 'are made of copper or alloys thereof, and the alloy of these metals is alone or with other metal alloys, together with the hard solder alloys of the preforms 18, 18'. Bonded but preferably composed of copper, silver, or alloys thereof, as described above, cores and sleeves are sometimes used together with electrode terminals to reduce the heat of the semiconductor body 12, which is used for electrode terminals. It is added for the purpose of reducing the production cost or electrical insulation for the electrode terminal. The portion 14, 14 'and the junction terminals 16, 16' used to connect the semiconductor body 12 to the junction terminals 16 and 16 'are connected to the electrode terminal head 22, Portions 18, 18 'connecting to 22' are not features of the present invention, and other connections proposed by other skilled persons may be used instead. The aluminum connection of (14) and (14 ') is a hard connection between silicon and aluminum, and is melted at about 575 ° C. to bond the silicon body 12 to the refractory metals of the body parts 16 and 16'. Let it be.

In this way, the connection molded bodies 18 and 18 'of copper / silver / phosphorus have a particularly preferable effect in high temperature bonding. As such, the assemblies are brazed at higher temperatures than soft solder joints and are therefore stronger because they reduce the porosity produced by butt joints, and at such high temperatures and humidity conditions (eg 85 ° C and 85% relative humidity). As can withstand high electrical and thermal resistance. And because the strength is further increased by brazing, it is possible to form the assembly 10 without any side despite the following process.

In FIG. 2, a surface stabilizer coating is coated to prevent decontamination of the exposed semiconductor body 12 which has been corroded to remove contamination. The stabilization film 30 is coated on the exposed surface of the semiconductor body 12 and the aluminum electrode portions 14, 14 ′ and at least the entire contact portions 16, 16 ′. It is preferable that the stabilization film 30 is not connected to the hard brazing alloys 18 and 18 '.

This stabilizing film 30 is inherently homogeneous and is a melt of nonconductive high melting glass having a thermal expansion coefficient such as the semiconductor body 12 and the contact portions 16 and 16 '.

The stabilization coating layer 30 forms a bead having a radius thickness of 0.13 mm or more in the plane of the semiconductor body 12, preferably 0.13-0.25 mm, which withstands high voltage levels.

Such glass, which is used as the stabilizing coating 30, is a non-alkaline zinc-boron silicate glass, which is also mentioned in US Pat. No. 9,752,701, which is 55-85% zinc oxide, 22-27 by weight ratio. % Boron trioxide, 0-13% silicon dioxide, 2-4% lead monoxide, and 2-4% alumina, and 0.5 2.0% antimony trioxide if necessary. Another type of glass is 1-alkaline lead-borosilicate glass, consisting of 45-51% lead monoxide, 36-44% silicon dioxide, 8-13% boron trioxide, and 2-5% alumina. The trade names "Inotek 740" and the like are used.

However, such non-conductive, non-contaminating glasses have thermal expansion rates such as contacts 16 and 16 ', which can be coated on the semiconductor object 12. Typical silicon semiconductors have thermal expansions of approximately 23-2.5 × 10 ^-6 cm / cm- ° C, and representative molybdenum contacts have a coefficient of thermal expansion of approximately 4.5-5.0 × 10 ^-6 cm / cm- ° C and zinc The stabilized coating of boron silicate glass has a coefficient of thermal expansion of 4.2-4.4 x 10 ^-6 cm / cm-° C within a temperature of about 0 ° -300 ° C.

This method of thermal expansion is the minimum value at which the stabilizing coating 30 of the glass is broken, or the contacts 16, 16 'are broken or the semiconductor body 12 is destroyed. From the joints 16, 16 'is the minimum that comes off. In general, thermal expansion coefficients of this magnitude are satisfactory.

The thermal expansion coefficients of the connection areas 14 and 14 'are generally negligible because their thickness is very thin. The material of the capsule 40 is a plastic material of epoxy or silicon type. They can also make the opacity or mark easier to display, as well as increase or decrease the thermal directivity, depending on the application. The expansion coefficient of the plastic capsule layer 40 is generally ignored because the degree of hardening of the plastic is not large.

The plastic capsule 40 may be molded into a cylindrical shape by using a plastic stabilizer and an automatic machine used to coat the capsule to obtain the reliability of the glass surface stabilizer coating and the economics of the plastic capsule.

In the semiconductor body 10 of FIG. 1, the surface of the semiconductor body 12 is coated with a stabilized film, and then the slurry is finely purified from the glass coated with capsules. It is made by covering a part of (16) and (16 ').

This can be easily done by pouring the slurry onto the semiconductor body while rotating the assembly to form a bead by the rotational force and the surface tension of the slurry.

Non-conductive water or nonionic organic solvents are used as additives for the slurry (for example, drying in hot air at 100-400 ° C. for 5-30 minutes). It is possible to form a coating layer in a state of revolving on the surface of the semiconductor body 10 only with such additives and glass applied.

The fine particles of the glass are heated to a temperature at which the glass particles are sufficiently melted to form a bead-shaped stabilizing film. The temperature and heating time should be varied depending on the shape of the glass, but generally 4-20 minutes, heating to 680-750 ° C is sufficient for the molten glass to form a homogeneous stabilizing film. After the stabilization film 30 is formed, it is gradually cooled and the capsule material of the non-conductive plastic is melt-coated on the surface of the stabilization film 30. At this time, a suitable method such as a melt inflow method or an injection method is used. 16), (16 ') or the heads 22, 22' of the electrode terminal components are also coated. The size or shape of the capsule 40 formed of plastic can be easily selected by the existing apparatus, and the other assembly can be easily reproduced in one assembly.

Surface stabilization and coating and capsule coated devices according to the invention are superior in all respects to glass stabilized coated semiconductor devices. In other words,

(1) The corresponding lifetime is very long (both reverse bias and AC operation).

(2) Long service life even at elevated temperatures or under DC blocking (high voltage) conditions.

(3) No defects even when sealed (checked by moisture circulation and pressure test).

(4) There are no critical defects even under the conditions of soldering and thermal cycling.

(5) High physical strength (does not interfere with bending test due to the strength of the lead wire or the lead wire itself). Moreover, the coating of the stabilizing film and the capsule on the semiconductor is similar in appearance to the plastic electrode combination generally made, so it is not only made by the automatic production method but also can be branded or packaged as a tape. In addition, when forming the shape, it can also be made by a general standard plastic axial electrode semiconductor element and a manufacturing tool. This improved result is due to the high temperature hard brazing (about 600 ° C.) of the junction of the semiconductor composite, due to the high temperature glass seal by the glass stabilizing film on the silicon chip, and the cylindrical shape of the plastic capsule. will be.

In addition, the embodiment of the present invention described herein may be modified in various ways, and such a melting technique has conventionally existed.

Therefore, the spirit and scope of the present invention should be limited only by the claims and not by the foregoing specification.

Claims (1)

A junction portion comprising a semiconductor body, a plurality of conductive electrode terminal portions, a plurality of conductive metal junction portions, a first connection portion for firmly connecting the semiconductor to the distal end of the junction, and a second connection portion firmly connecting the other distal end of the junction to the distal end of the electrode. And a non-conductive homogeneous glass having the same thermal expansion coefficient as that of a semiconductor, coated with a bead-shaped surface stabilizing coating, wherein the cylindrical capsule made of plastic is coated on the head of the stabilizing coating, the second connection part and the electrode terminal. Manufacturing method of semiconductor.

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