US2667722A - Mold for use in the manufacture of dry rectifiers - Google Patents

Mold for use in the manufacture of dry rectifiers Download PDF

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Publication number
US2667722A
US2667722A US236972A US23697251A US2667722A US 2667722 A US2667722 A US 2667722A US 236972 A US236972 A US 236972A US 23697251 A US23697251 A US 23697251A US 2667722 A US2667722 A US 2667722A
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US
United States
Prior art keywords
manufacture
semi
mould
plug
conductor
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US236972A
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English (en)
Inventor
Jenkins Alexander
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens Mobility Ltd
Original Assignee
Westinghouse Brake and Signal Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Westinghouse Brake and Signal Co Ltd filed Critical Westinghouse Brake and Signal Co Ltd
Application granted granted Critical
Publication of US2667722A publication Critical patent/US2667722A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor

Definitions

  • This invention relatesv to the manufacture of dry rectiers of the kind comprising a body of semi-conducting material carried by a metal support or holder and is particularly applicable to the manufacture of small rectifier elements of this kind of such a size, for example, as are used in alternating current measuring instruments.
  • Such small rectier elements are troublesome to handle, this disadvantage being particularly apparent in the manufacture of so-called crystal rectifiers, such as germanium or silicon rectiers, when securing the semi-conductor to the metal support or holder.
  • the manufacture of these crystal rectiers usually involves the step of cutting wafers of the desired size from a larger rod or ingot of the semi-conductor material, which is an operation of some intricacy due to the small size of the wafers.
  • a mould for the manufacture of dry rectiers of the above kind includes means for casting a body of semi-conductor material in the form of a number of projections each of a suitable size and shape to t its metal support or holder and connected by a thin web.
  • the body is divided up into individual elements by cutting or fracturing the web between the projections, preferably after securing to the supports or holders.
  • Certain semi-conductor materials for example, germanium, when in the molten state, have a high surface tension which makes it impossible to cast elements of the small size contemplated by the present invention by the normal method of straight forward pouring of the molten material into a suitable mould and this difficulty is overcome according to the invention by subjecting the semi-conductor material and the mould to a vacuum, melting the semi-conductor material, and then forcing the molten material into the mould by destroying the vacuum.
  • Figure 2 is a cross-sectional view taken along the line II-II of Figure l;
  • FIG. 3 is a view of the other end of the mould
  • Figure 4 is a cross-sectional View taken along the line IV-IV of Figure 2;
  • Figure 5 is a perspective view of the two parts of the mould with the centre plug removed.
  • Figure 6 illustrates the cast body when removed from the mould.
  • the body of semi-conductor material is cast in a mould, comprising a block I of carbon or other suitable material such as silica, provided with a tapered bore 2 of circular cross section into which ts a similarly tapered plug 3 of such a length that, when it is fully inserted into the bore, it does not extend the full length of the bore so that the end of the plug forms the base of a receptacle or crucible 4 of which the portion of the bore extending beyond the end of the plug forms the sides.
  • a mould comprising a block I of carbon or other suitable material such as silica, provided with a tapered bore 2 of circular cross section into which ts a similarly tapered plug 3 of such a length that, when it is fully inserted into the bore, it does not extend the full length of the bore so that the end of the plug forms the base of a receptacle or crucible 4 of which the portion of the bore extending beyond the end of the plug forms the sides.
  • each of the flats recesses 'l Radially along the length of each of the flats recesses 'l are formed. These recesses are conical or of such other shape and size as corresponds with the shape and size of the metal holders which are to receive the semi-conductor in the finished rectifier element. 'I'he end of the plug forming the base of the crucible is provided with a conical recess 8, co-axial with the plug, communicating at its apex through a bore 9 and passages l with the chambers 6.
  • the tapered plug 3 is inserted into the bore and the mould is supported so that the two are substantially vertical with the crucible 4 formed at the end of the bore uppermost.
  • a quantity of the semi-conductor material is inserted in the crucible and the atmosphere evacuated to a few millimetres of mercury.
  • the mould is then heated, by high frequency induction for example, until the semi-conductor is molten, whereupon the vacuum is suddenly destroyed. This results in the forcing of the molten material from the crucible 4 through the passage I0 into the chambers 6 and recesses 1.
  • the vacuum should be destroyed by the introduction of a suitable gas.
  • a suitable gas for example, when germanium is the semi-conductor an inert gas such as argon, hydrogen or nitrogen may be used.
  • theicharacteristics of some semi-conductors are improved by the addition of certain impurities and this may be accomplished by the use of a suitable gas to destroy the vacuum.
  • the mould isstatedto beofY carbon or silica, it will be understood by thoseskiiled in the art that the choice of material will be governed by a consideration of Atheeffect that certain materials have upon the semi-conductor material being used.
  • the plug After cooling, which may be controlled, if desired, to produce a favourable crystalline structure of the material, the plug is loosened by tapping the propjecting end Il and is withdrawn from the block and the semi-conductor is removed in the form of a number of projections l2, each-of a suitable size and shape to lit their metal. holders, connected-by.aethin-web I3, somewhat in the form of a comb (see-Fig. 6),
  • the semi-conductor is then supported inia jig which maybe in the-form of a perforated sheet while a metal coating-is deposited, in any suitable manner, upon thefsides vof the projections which are then solderedintotheir metal holders and the individualelementsseparated bybreaking the connecting web.
  • a mould comprising, in combination, a block having a tapered bore extending therethrough; -a plug correspondingly tapered Afor ttin'gsaidPbore and .havingrecesses formed in a cutaway portion of the tapered surface thereof; and a Crucible formed by one end of said plug -and the wall of said bore extending beyond said endfa passage extending between said Crucible Vand said cutaway portion.
  • 'a'mould comprising, in combinan tion, a'blockfhaving a tapered circular bore extending therethrough; a cylindrical plug correspondingly tapered for tting into said bore and having at least one longitudinally extending flat formed 'onthetapered surface thereof with a number of radial recesses formed therein; and a cr-u'ciblefformed by one end of said plug and the Wall of said bore extending beyond said end, a passage ,eXtending-'betvveensaid crucible'and a ⁇ chamber formed-between said ⁇ nat and ⁇ the fbore.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Ceramic Engineering (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Rectifiers (AREA)
US236972A 1950-09-18 1951-07-16 Mold for use in the manufacture of dry rectifiers Expired - Lifetime US2667722A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB22843/50A GB690240A (en) 1950-09-18 1950-09-18 Improvements relating to the manufacture of dry rectifiers

Publications (1)

Publication Number Publication Date
US2667722A true US2667722A (en) 1954-02-02

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ID=10185941

Family Applications (1)

Application Number Title Priority Date Filing Date
US236972A Expired - Lifetime US2667722A (en) 1950-09-18 1951-07-16 Mold for use in the manufacture of dry rectifiers

Country Status (5)

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US (1) US2667722A (US06265458-20010724-C00056.png)
BE (1) BE505850A (US06265458-20010724-C00056.png)
FR (1) FR1039807A (US06265458-20010724-C00056.png)
GB (1) GB690240A (US06265458-20010724-C00056.png)
NL (1) NL81435C (US06265458-20010724-C00056.png)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2778162A (en) * 1954-04-12 1957-01-22 Corning Glass Works Centrifugal casting of glass articles
US2825549A (en) * 1954-12-28 1958-03-04 Itt Mold for semi-conductor ingots
US2864139A (en) * 1953-05-19 1958-12-16 Texas Instruments Inc Method and apparatus for producing intermediate semi-conductor product
US2875556A (en) * 1953-07-31 1959-03-03 Vig Corp Apparatus for molding refractory materials
US3002320A (en) * 1951-11-16 1961-10-03 Bell Telephone Labor Inc Preparation of silicon material
US3156549A (en) * 1958-04-04 1964-11-10 Du Pont Method of melting silicon

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1536821A (en) * 1924-09-27 1925-05-05 Gen Electric Apparatus for and method of making vitreous silica
US1581829A (en) * 1921-03-29 1926-04-20 Gen Electric Quartz working
US1601123A (en) * 1926-05-20 1926-09-28 Joseph L King Holder for automobile license plates
US1908086A (en) * 1927-12-10 1933-05-09 Leonard H Mattingly Method of making a universal joint
US1966615A (en) * 1929-11-21 1934-07-17 Croning Johannes Metal casting process
US2048319A (en) * 1933-02-25 1936-07-21 Carborundum Co Method of producing cast refractory and similar articles
US2277014A (en) * 1940-07-06 1942-03-17 Electric Railway Improvement Co Rail bonding apparatus
US2276823A (en) * 1940-12-13 1942-03-17 Electric Railway Improvement Co Rail bonding apparatus
US2296575A (en) * 1940-10-24 1942-09-22 Union Switch & Signal Co Manufacture of alternating current rectifiers
US2379919A (en) * 1943-05-01 1945-07-10 Fed Telephone & Radio Corp Manufacture of selenium elements

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1581829A (en) * 1921-03-29 1926-04-20 Gen Electric Quartz working
US1536821A (en) * 1924-09-27 1925-05-05 Gen Electric Apparatus for and method of making vitreous silica
US1601123A (en) * 1926-05-20 1926-09-28 Joseph L King Holder for automobile license plates
US1908086A (en) * 1927-12-10 1933-05-09 Leonard H Mattingly Method of making a universal joint
US1966615A (en) * 1929-11-21 1934-07-17 Croning Johannes Metal casting process
US2048319A (en) * 1933-02-25 1936-07-21 Carborundum Co Method of producing cast refractory and similar articles
US2277014A (en) * 1940-07-06 1942-03-17 Electric Railway Improvement Co Rail bonding apparatus
US2296575A (en) * 1940-10-24 1942-09-22 Union Switch & Signal Co Manufacture of alternating current rectifiers
US2276823A (en) * 1940-12-13 1942-03-17 Electric Railway Improvement Co Rail bonding apparatus
US2379919A (en) * 1943-05-01 1945-07-10 Fed Telephone & Radio Corp Manufacture of selenium elements

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3002320A (en) * 1951-11-16 1961-10-03 Bell Telephone Labor Inc Preparation of silicon material
US2864139A (en) * 1953-05-19 1958-12-16 Texas Instruments Inc Method and apparatus for producing intermediate semi-conductor product
US2875556A (en) * 1953-07-31 1959-03-03 Vig Corp Apparatus for molding refractory materials
US2778162A (en) * 1954-04-12 1957-01-22 Corning Glass Works Centrifugal casting of glass articles
US2825549A (en) * 1954-12-28 1958-03-04 Itt Mold for semi-conductor ingots
US3156549A (en) * 1958-04-04 1964-11-10 Du Pont Method of melting silicon

Also Published As

Publication number Publication date
NL81435C (US06265458-20010724-C00056.png)
BE505850A (US06265458-20010724-C00056.png)
GB690240A (en) 1953-04-15
FR1039807A (fr) 1953-10-09

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