WO1979000814A1

WO1979000814A1 - Semiconductor device comprising two semiconductor elements

Info

Publication number: WO1979000814A1
Application number: PCT/DE1979/000011
Authority: WO
Inventors: H Irmler
Original assignee: Bbc Brown Boveri & Cie; H Irmler
Priority date: 1978-03-23
Filing date: 1979-01-27
Publication date: 1979-10-18
Also published as: GB2037075A; DE2812700A1; NL7902281A; EP0018363A1

Abstract

The semiconductor device comprises two circular semiconductor plates (10, 11) arranged one on the top of the other with, in between, a metal washer (12). Other me washers (13, 14) are placed respectively above t top plate (11) and below the bottom plate (10). On the metal washers (12, 13, 14), connection terminals (23, 24) are fixed said connection terminals coming out of the casing (20) on a same side. The stack of semiconductor plates (10, 11) and metal washers (12, 13, 14) is mounted, through a ceramic disc (16), on a base (26) provided with a threaded bolt (18). To ensure a good thermal conduction from the top semiconductor plate (11) to the base (26), the bottom semiconductor plate (10) has a bigger diameter. The top metal washer (13) presents a recess or an aperture allowing a control terminal (25) to come into contact with the top semiconductor plate (11).

Description

Semiconductor arrangement with two semiconductor elements

Technical field:

The invention relates to a semiconductor arrangement with two semiconductor elements in the form of tablets provided with electrodes, insulated or passivated on the edge side, without housings per se in a common housing, at least one of which is controllable and which is electrically connected in series or in parallel are, where two main connections of main electrodes of the same name and at least one control connection, one main connection between the two semiconductor elements, - in the case of a series connection, a central tap, - are led out of the housing on one side.

<& Underlying state of the art:

In known arrangements of this type, which contain controllable or non-controllable semiconductor components or both types mixed in different circuit variants, it is already known to have an electrical center tap between two semiconductor elements of a module spatially at the end of the row in a row out of the housing ¬ to arrange connections ("Power Semiconductors" from March 1974 by AEI Semiconductors (Publication 111 pp. 48/49). This arrangement has the advantage that, for example, when using two modules with two semiconductor elements each Series connection for the construction of a full-way rectifier bridge, the center taps for the connection of the alternating current connections are easily accessible.The internal structure of a module does not refer to the abovementioned literature, but it can be assumed that the individual semiconductor elements are insulated from one another are arranged on a base plate .

In such a known arrangement of two semiconductor elements next to one another in a common housing, each semiconductor element being fastened and connected in a conductive manner to a common contact layer which is firmly attached to an electrical insulating ceramic disk on a copper base plate, a module comprising two is used for the construction Semiconductor elements require two ceramic disks as insulating intermediate disks and four metal disks for the connection of the main electrodes (DE-Gm 75 12 573). However, the known semiconductor arrangement with two semiconductor elements next to one another on a copper base plate is advantageous in that it provides largely problem-free dissipation of the heat loss up to currents of approximately 200 A.

^* ^ _KtA (y OMPI

_ - ° ⁴ However, this advantage is not very significant because, as mentioned, the known, large-volume arrangement leads to high housing costs. In modern semiconductor components, the cost of a "bare" tablet is only about a third of the cost of the housing.

Disclosure of the Invention:

Based on the semiconductor arrangement mentioned at the outset, the invention is based on the object of creating a small-volume arrangement for current intensities up to approximately 150 amperes.

This object is achieved in that the tablets are stacked on top of one another in a tower-like manner on a thermally conductive base part that is set up for the mechanical assembly of the semiconductor arrangement, and in that, between and under both tablets, electrically and thermally conductive metal discs for coupling the center tap and the Main connections are provided.

With the tower-like structure of the semiconductor elements and the associated parts, only one insulating disk, preferably a ceramic disk, and only three metal blanks, preferably molybdenum blanks, are required compared to the known arrangements of two semiconductor components next to one another on a common base plate . Furthermore, none of the arrangements described at the beginning allows the advantageous possibility of producing the semiconductor arrangement without an insulating pane and thus using the base part as a main connection.

The saving of a Kramik disc and a molybdenum disk in the solution according to the invention compared to the known arrangements simplifies in the case of integral transitions between the ceramic plate and the base part and the molybdenum the corresponding soldering and the semiconductor bodies or the ceramic disk. However, if there is a need to electrically insulate the base part from the semiconductor conductors, then a single electrically insulated, thermally conductive washer is preferably used between the base part and the lower metal disc.

Pressure contacting is also possible. The stacking and pressure contacting of semiconductor components is known as such (DE-Gm 77 11 450 and BBC publication "Thyristor CS 550" from 1973 (order no. D GHS 30382 D)). In the known cases, however, finished disc cells, i.e. With . a semiconductor device provided, stacked un pressure-contacted.

The dimensions of the lower tablet are preferably larger in the slice plane than the upper tablet. Without this measure, a higher heating of the upper tablet would result with the same load. If the lower tablet is made somewhat larger, the thermal resistance for the upper tablet given by the bottom part h is smaller. This means that a higher surge current is possible on the one hand, and on the other hand the upper temperature limit for the highest permissible, periodic peak reverse voltage shifts upward in the forward direction (blocking voltage). The somewhat increased costs for the lower tablet can be accepted because of the savings in housing costs achieved by the tower-like structure. Overall, this results in a cost saving of approximately 33% for the tower structure.

The dimensions of the electrically insulating pane or the ceramic pane are expediently larger than the lower tablet in the plane of the pane. With this measure, there is advantageously a large creepage distance and a corresponding insulation against voltage flashovers. Preferably ^"circular areas serve as bases for the insulating glazing, the metal discs and the tablets, and it is aimed at a conical overall structure of insulating glazing, metal blanks and tablets. This has two advantages:

On the one hand, a smaller overall volume is achieved because of the circular areas, on the other hand, the already mentioned soldering in the soldering furnace is simplified, i.e. the overall conical arrangement can simply be introduced upside down into a corresponding conical soldering shape in the soldering furnace.

As in the known arrangements mentioned at the outset, the tablets are expediently embedded in casting resin. According to the invention, a plastic pipe serves as a lost mold for the casting resin, i.e. the plastic tube, which is preferably also circular in cross-section, surrounds the tower structure of the disk, metal blanks and tablets and the cast resin as the casing shell. The bottom part expediently has a recess or a depression for receiving the lower edge of the plastic tube or casing shell. On the one hand, this advantageously results in good mechanical fixation. on the other hand, it is advantageous to improve the insulation because the space in the recess below the ceramic disc is also filled with casting resin.

The base part is expediently designed in a manner known per se as a screw base (BBC publication "Thyristor CS 16" from 1972 (order no. G HS 1474 a D)). This design is characterized by an advantageous mechanical connection option.

Alternatively, the bottom part can be designed as a connecting plate with mounting holes. In this embodiment, the position of the semiconductor arrangement during assembly by means of screws guided through the connection bores and thus also

the position of the electrical Anschlösse on the other side precisely fixed, while using a simple ^<• screw base the final position of ports in Ein¬ turn of the thread is not fixed. However, the screw base can also be provided with markings or a stop for limiting the rotary movement.

When using controllable semiconductor elements, the metal round blanks located above the tablets each have openings for the control connections which are made in isolation and come into contact with the control electrodes.

As an alternative to this solution for controllable semiconductor components, the upper tablet can also be placed eccentrically to the geometric central axis of the lower tablet, which is perpendicular to the wafer plane. In this case, the control zone with control electrode and connection of the lower semiconductor element is located in the area of the lower tablet, which is not covered by the upper tablet. In addition, the metal disk lying on a tray can advantageously be formed as a circular section. The control zones of both tablets remain freely accessible.

Brief description of the invention:

Show it:

1 shows a semiconductor arrangement with two semiconductor elements which are opposed to a base part by a

Ceramic disc are electrically insulated;

FIG. 2 shows the electrical circuit diagram of the arrangement according to FIG. 1 when the semiconductor elements are connected in series;

-BUREAU

OMPI, τ> o Fig. 3 shows the electrical diagram of the arrangement

1 with parallel connection of the semiconductor elements;

4 is a plan view of a connection panel for the:

1 with two variants of the bottom part thereof;

FIG. 5 shows a blocking voltage-temperature characteristic for a semiconductor element according to FIG. 1;

FIG. 6 shows a structure with two semiconductor arrangements according to FIG. 1 side by side on a connection board;

Fig. 7 is an electrical circuit diagram for arrangement according to

Fig. 6;

8 shows an example of a pressure-contacted arrangement;

Fig. 9a variants for the supply of control connections to 11b and a plan view of the corresponding metal blank.

Best way of carrying out the invention: According to FIG. -1, a lower and an upper silicon tablet 10 or 11 are electrically connected to one another by a metal blank 12, preferably made of molybdenum, that is to say that their metallizations (not shown) or the corresponding main electrodes of the same name are electrically connected to one another. The upper main electrode of the upper tablet 11 and the lower main electrode of the lower tablet 10 are each also contacted with a metal blank 13 or 14, preferably as molybdenum. The lowermost metal blank 14 is preferably a surface layer metallized in some areas via a solder layer 15 with an insulating disk 16 Ceramic disc, mechanically and thermally connected. The ceramic disk 16 is in turn connected mechanically and thermally via a further plumb bob 17, preferably on the basis of lead and silver with a peak at about 320 ° C., to a base part 18. The cut bottom part 18 is formed in this embodiment as a screw base and has a recess or recess 19 for receiving the lower edge of a plastic tube 20, which serves as a lost form for receiving epoxy resin and as a casing.

To the lower circular metal blank 14, a first outer Haupt¬ is terminal 22 soldered to the upper circular metal blank 13, a second main terminal 23 and to the central metal blank ^"1, a terminal 24, the te with series connection of Halbleiterele 10 and 11 serves as a center tap. In Parallelschaltun the upper tablet 11 is turned over, a control connection 25 is also indicated in broken lines for the upper tablet te 11. Designs with controllable semiconductor elements are described in more detail below.

From Fig. 1 it can also be seen that the overall structure of the arrangement of tablets 10 and 11, metal blanks 12 to 14 and ceramic disk 16 is essentially conical with a taper towards the connection side. The connection side is the upper side in the illustration. However, the semiconductor arrangement can be used in any position.

The ceramic disk 16 protrudes somewhat, i.e. it is circular in its extensions in the disk plane

Design in diameter, larger than the metal blank 14 above it and the lower silicon tablet 10. It is also larger than a central base part 26 of the lower base part 18. With this design, there is also the outstanding areas of the ceramic pane 16 epoxy resin 21. As already described, this results in a large creepage distance, and the semiconductor arrangement can be isolated up to voltages of e__a 3000 V.

FIG. 2 shows the circuit diagram of the series connection of the two silicon tablets 10 and 11 realized in FIG. 1 with their connections. In the case of a parallel connection according to FIG. 3 with the upper tablet 11 turned over, the lower metal blank 14 must be connected to the upper metal blank 13.

The outer connection 23 then forms the connection to the main electrodes of the same name, the outer connection 24, which is connected to the central metal ring 14, then forms the outer main connection for the two other main electrodes of the same name. It is understood that the polarity of the individual elements 10 and 11 shown can be reversed in both arrangements.

In the same way, an anti-parallel connection of two thyristors is also possible, which can then be used as a module for the construction of reversing converters.

Fig. 4 shows a mounting plate 27 on which a screw base 18 is mounted. The screw base 18 with the semiconductor arrangement, not shown, is screwed in according to a marking 28 or a stop. As an alternative to the screw base 18, a connecting plate 29 with bores 30 can be provided as the base part. As already described at the outset, in this case the position of the connections 22 to 25 is determined by the through bores or threaded bores in the mounting plate 27 corresponding to the bores 30.

The essentially conical tower structure according to FIG. 1 allows the upper silicon tablet 11 to be thermally relieved. The lower silicon tablet 10 is made 20 to 50% larger than the upper one. This results in a small heat resistance to the bottom part. Without this measure, the upper temperature limit for the maximum permissible, periodic peak reverse voltage in the forward direction U- would be shown in FIG. _RM at about 125 ° C (shown in dashed lines), with thermal relief it is about 150 ° C, in each case based on thyristors. To increase the strength against surge currents, the central base zone of the tablet 1 can also be enlarged, ie a larger volume is offered. In the case of a thyristor for 1200 V peak reverse voltage, which normally has a thickness of the base zone of 180 μm, this is increased, for example. 250 μm. A larger neutral zone is thus created when subjected to stress both in the blocking direction and in the blocking direction (= forward direction). An upper temperature limit of 150 ° C. for diodes and 180 ° C. for diodes can also be reached. A somewhat larger forward voltage drop is accepted; but this is insignificant because of the possible significantly larger surge currents.

When combining a diode with a thyristor, the tablet for the diode is preferably arranged at the top because it can tolerate a higher temperature.

To improve the electrical behavior, podiuming or a corresponding distancing of the lower pn junction of the lower silicon tablet 10 is also possible in a manner known per se (DE-OS 24 00 863). The tablets 10 and 11 can also be bevelled negatively and / or positively in a manner known per se in order to increase the blocking capacity (AU-PS 244 374, DE-AS 12 81 584). The edge is also preferably glass-passive. J-REACT

OMPI

«_Ä _ £ ' FIG. 6 shows the assembly of two semiconductor arrangements according to FIG. 1 with the help of connecting plates 29 on a common one. Mounting plate 27. according to Fig. 4. Ceramic disks are missing in this case. The mounting plate 27 forms a main connection for both semiconductor arrangements. When the main connections 23 are connected, a fully controlled full-wave rectifier is thus created with the two AC connections 24 and 24 * and the external connection polarity shown in FIG. The control connections are omitted in the illustration according to FIG. 6. In Fig. 7 it is indicated by dashed lines that the arrangement can also be constructed from diodes or can be supplemented by diodes 31 and 32.

8 shows that the semiconductor arrangement can be contacted in a simple manner by pressure. For this purpose, the plastic tube 20 has an inwardly facing edge 33, an outwardly facing edge 34 below, which engages behind an inwardly facing Ra d 35 of the bottom part 18. A clamping device (not shown) (indicated by arrow 36) exerts the corresponding contact pressure on the semiconductor device via a yoke 37 enclosed by the upper edge of the plastic tube 20. In this case, a molybdenum disc 12 ', a copper disk 38 and a molybdenum disc 12''can be located between the two tablets 10 and 11. In the yoke 37 and in the round plates 13 and 12 ″ and in the copper disk 38, bushings for the connections to the external connections (not shown) are indicated by dashed lines. For the control connections, reference is made, for example, to FIG. 9. The center tap 24 can be separately isolated and led out upwards (Flg. 9a). The Keramik¬ disc 16, which can be in all the described embodiments of alumina _(A1? 0_) or Beylliumoxid (Be_0_) be¬ can ngsbeispiel of FIG even when the Execute. Be removed. 8 When the ceramic disk 16 is removed, the screw base 18 forms a main connection. 9a and 9b shows the attachment of control connections 25 and 36 to the semiconductor tablets 11 and 10. The housing with the base part is omitted in this illustration. The same reference numerals are used for the parts already explained. The upper main connection 2 is shown in dashed lines because there is also the possibility of pressure contact. The upper molybdenum blank 13 is a bushing 37 (Fig. 9b). Through this implementation 37, the control connection 25 connected to a corresponding metallization 38 of a control zone of the upper silicon tablet 11 is carried out in isolation. Such implementation of a control connection is known with simultaneous pressure contacting of the adjacent main connection to si (DE-AS 16 39 402). The control connections 26 and 36 can also be pressure-contacted in a manner known per se via springs with the corresponding metallizations 38, 39 on the corresponding control zones of the tablets 10 and 11 (DE-AS 24 05 930). - In the embodiment shown in FIG. The control connection 36 for the lower silicon tab 10 with a corresponding metallization 39 _' on one

Control zone in the silicon tablet 10 soldered. It is is guided by mutually perpendicular bores 40 and 41 of the copper disk 38.

10a shows that the upper silicon tablet 11 can also be placed eccentrically with respect to the central axis 42 of the lower, larger silicon tablet 10. The lower silicon tablet 10 has a lateral, elongated (Fig. 1 control zone 43. The molybdenum blank 12 need not have an isolated feedthrough in this case.

11a, the silicon tablets 10, 11 and the molybdenum discs 13, 12, 12 'are stacked centrally to the central axis. The molybdenum blanks 12 and 13 are formed as circular sections, which is shown in FIG. 11b for the round blank 13 is shown. The control connections 25 and 26 are led to speaking side control zones 44 and 43 with metallizations 38 and 39, respectively. The supply of the control connections 25 and 36 can be varied in any way. It goes without saying that, in a modification of the exemplary embodiments, the contacting of a central gate is also possible.

Commercial usability:

Semiconductor arrangements of this type can be used as modules for the construction of converter circuits.

-BVJ E-UΓ

OMP1

Claims

Expectations

1. Semiconductor arrangement with two semiconductor elements in the form of electrodes provided with edge-insulated or passivated tablets which are housingless per se in a common housing, at least one of which is controllable and which are electrically connected in series or in parallel, with two main connections of main electrodes of the same name troden and at least one control connection, a main connection between the two semiconductor elements, - in series connection additionally as a center tap, - are led out of the housing on one side, characterized in that the tablets (10, 11) on a for the mechanical assembly of the semiconductor arrangement, thermally conductive bottom part (26) are stacked like a tower, and that on, between and under both tablets (10, 11) electrically and thermally conductive metal rings (12, 13, 14) for the coupling the center tap (24, 24 *) and the main connections (22, 23) are seen.

2. Semiconductor arrangement according to claim 1, characterized in that between the bottom part (26) and lower metal ring (14) there is a thermally conductive, electrically insulating plate (16).

3. Semiconductor arrangement according to claim 1 or 2, characterized in that the lower tablet (10) laterally projects above the upper tab (11).

4. Semiconductor arrangement according to claim 1, 2 or 3, characterized in that the electrically insulating disc (16) projects beyond the lower tablet (10) on all sides,

5. Semiconductor arrangement according to at least one of claims 1 to 4, characterized in that the base surfaces of the tablets (10, 11), the metal discs (12, 13, 14) and the insulating disk (16) are circular and in that the tower-like stack of insulating disk (16), metal disc (12, 13, 14) and tablets (10, and 11) is conical.

6. Semiconductor arrangement according to at least one of claims 1 to 5, characterized in that the tablets are embedded in casting resin and that a plastic tube (20) surrounds the casting resin as a lost form.

7. Semiconductor arrangement according to at least one of claims 1 to 6, characterized in that the bottom part (26) has a recess (19) for receiving the lower edge of the housing shell (20).

8. Semiconductor arrangement according to at least one of claims 1 to 7, characterized in that the bottom part (26) has a screw base (18).

- 9. Semiconductor arrangement according to at least one of claims 1 to 7, characterized in that the base part is designed as a connecting plate (29) with fastening bores (30).

10. Semiconductor arrangement according to at least one of claims 1 to 9, characterized by metal blanks (12, 12 ', 12' ', 13, 14) made of molybdenum and an insulating disk (16) made of ceramic.

12. Semiconductor arrangement according to at least one of claims 3 to 10, characterized in that the metal blanks (12, - 13) located above a tablet (10, 11) are formed as circular sections.

13. Semiconductor arrangement according to at least one of claims 1 to 10, characterized in that the upper tablet (11) is eccentrically placed on the lower, larger tablet (10).

14. Semiconductor arrangement according to at least one of claims 1 to 10, 12, 13, characterized in that in the area which is not covered by the upper tablet (11) or by one of the metal blanks (12, 13), control zone (43, 44) and control connection (25, 36) of the tablets (10, 11).

- REA L

_ OMPI CHANGED CLAIMS

(Received at the International Office on June 8, 1979 (June 8, 1979))

1. Semiconductor arrangement with two semiconductor elements in the form of electrodes provided with edge-insulated or passivated tablets (10, 11) without housing, of which at least one (11) can be controlled, the tablets (10, 11) being interposed electrically and thermally conductive metal blanks (12, 13, 14) are stacked on top of one another in a tower-like manner on a thermally conductive base part (26) set up for mounting the semiconductor arrangement, and two main connections (22, 23) of non-identical main electrodes and at least one a control connection (25) is led out of the housing (20; 33), characterized in that only a single metal blank (12) is arranged between the two tablets (10, 11), that directly on this metal blank (12) Main connection (24) is attached as a center tap, which is also led out of the housing (20, 33), and that the lower (10) of the two tablets have a larger base area sits as the top (11).

2. Semiconductor arrangement according to claim 1, characterized ge indicates that between the bottom part (26) and lower Me¬ tallronde (14) is a thermally conductive, electrically insulating disc (16).

3. Semiconductor arrangement according to claim 1 or 2, characterized in that the components (10,11,12,13,14,16) of the tower-like stack are soldered.

4. Semiconductor arrangement according to claim 1, 2 or 3, da¬ characterized in that the two main connections (22,23) the main electrodes of the same name are attached directly to corresponding metal blanks (13, 14).

5. Semiconductor arrangement according to at least one of claims 1 to 4, characterized in that the base area of the tablets (10, 11), the metal blanks (12, 13, 14) and the insulating disk (16) is circular and that the tower like stack of insulating disc (16), metal blanks (12,13,14) and tablets (10,11) is conical.

6. Semiconductor arrangement according to at least one of claims 1 to 5, characterized in that each stack is embedded in casting resin, and that a plastic tube (20) surrounds the casting resin as a lost mold.

7. Semiconductor arrangement according to at least one of claims 1 to 6. characterized in that the bottom part (26) has a recess (19) for receiving the lower edge of the housing shell (20).

9. Semiconductor arrangement according to at least one of claims 1 to 7, characterized in that the bottom part is formed as a connecting plate (29) with fastening bores (30).

11. Semiconductor arrangement according to at least one of claims 1 to 10, characterized in that the respective Metal trays (12 '*, 13) located above a tablet (10, 11) have bushings (37, 40) for the control connections (25, 36) which are carried out in an insulated manner.

12. Semiconductor arrangement according to at least one of claims 1 to 10, characterized in that the metal blanks (12, 13) located above a tablet (-10, 11) are formed as circular sections.

13. Semiconductor arrangement according to at least one of claims 1 to 12, characterized in that the upper tablet (11) is placed eccentrically on the lower, larger tablet (10).

1-4. Semiconductor arrangement according to at least one of Claims 1 to 13, characterized in that all main and control connections (22, 23, 24, 24 ', 25) are led out of the housing (20, 33) on one side.

15. Use of semiconductor devices according to claims 1 to 14, characterized in that a rectifier bridge circuit is constructed from two tower-like stacks mounted on a common mounting plate (27).

'BΛJREAZT

________ INARTICLE 19 CERTIFICATE

The changes in the new patent claim 1 are due to the fact that US Pat. No. 3,532,941 is the closest prior art to the subject of the application.

The new claims 2, 5, 6, 7, 8, 9, 10, 12, 13 correspond to the original claims.

The new claims 3 and 4 are based on the figure description.

The new claim 14 is supported in the preamble of the original claim 1.

The new claim 15 relates to the use of a semiconductor arrangement according to claims 1 to 14. It is also based on the description of the figures.

The new claims no longer include the embodiments of FIGS. 8, 9a and 9b.