FR2674989A1 - COOLING DEVICE FOR A SEMICONDUCTOR ELEMENT - Google Patents

Abstract

The cooling device for semiconductor elements (1) comprises a cooling element (2) disposed between the semiconductor elements (1) connected by a conductor (6), and having a disc-shaped insulator (9) disposed between the elements. (6, 2), and an enveloping insulator (11) located around the circumference of the cooling element (2), the cooling element (2), the connecting part of this element and a radiating element of the heat being traversed by the cooling medium (3) which is electrically conductive. Application in particular to devices for cooling semiconductor elements.

Description

The present invention relates to a cooling device for a

  semiconductor element and in particular relates to a cooling device for cooling a plurality of semiconductor elements by means of a cooling medium introduced into a cooling element.

  cooling arrangement arranged between the plurality of semi-

  drivers through a connecting conductor

  for semiconductor elements.

  Examples of conventional cooling devices

  for a semiconductor element are described in JP-A-58-37482 (1983), and are shown in FIGS.

  and 12 of the drawing of the present application.

  In the cooling device for a

  semiconductor element shown in FIG.

  metal cooling element 2 is arranged between

  respective semiconductor elements 1, a 4-ray element

  heat is coupled to the cooling element

  2 by means of insulating tubes 26, and a half

  coolant having a good evaporation capacity fills the cooling element 2 and

  element 4 radiating heat.

  In the cooling device for a

  semiconductor element shown in FIG.

  cooling element 2 is arranged between

  respective semiconductors by means of a

  6, which serves as a connection terminal, an insulating plate 5 is disposed between the connecting conductor 6 and the cooling element 2, and the latter is arranged to communicate with the element 4 radiating heat through a tube of

passage 7.

  In these cooling devices for semiconductor elements, when heat is produced

  by the semiconductor elements 1 under the effect of a

  penetrating into these elements, heat is transferred

  in the cooling medium contained in the cooling element

  cooling 2, the cooling medium evaporates to

  the interior of this element and the bubbles produced by

  The poration penetrates into the heat radiating element 4 and is cooled therein so that they become liquefied, and the liquefied cooling medium returns to the interior of the cooling element 2 to cool the cooling elements. semiconductor elements 1 In these structures, the common element 4 radiating heat does not

  bypasses the semiconductor elements

  1, since the common element 4 radiating from the

  heat is electrically isolated from the se-

  respective conductors 1 by the insulating tubes 26 or the

insulating plate 5.

  In the conventional cooling devices described above for semiconductor elements, trichloro-trifluoroethane (Freon 113) has been widely used as a cooling medium, but the chlorine contained in the cooling medium causes degradation of the ozone layer. in the stratosphere

  so that the production of such a cooling medium

  has been stopped on a large scale in the world, and that such a cooling medium has been rapidly replaced by cooling media containing no chlorine. It is envisaged that water will be one of the cooling media not containing

  chlorine, but the usually available water is

  triply conductive so that, if it is necessary to pre-treat the water to make it electrically

  insulation, the cooling device has di-

  important measures, which is not appropriate for the

  cooling system such as that used for a

  semiconductor system, which is required in particular

has small dimensions.

  Therefore, it is also envisaged to use electrically conductive water as such as a cooling medium, but when such water is used for the cooling device by semiconductor elements as shown in FIG. cooling element 2 is electrically connected to the heat-radiating element 4 via the water in the insulating tube 26, and

  the electrical elements are electrically short-circuited

  In addition, when using such water for

  positive cooling for semiconductor elements

  As shown in FIG. 12, the electrical insulation between the respective semiconductor elements 1 is maintained by the routing distance required by the insulating plate 5 arranged between a pair of conductors.

  6 and the cooling element 2 Cepen-

  according to JEM-1103 (Japanese Industrial Standard for

  electrical machinery with regard to the

  insulation rate for control devices), a distance greater than 30 mm must be provided for a circuit having a nominal voltage of 1500 V and an isolation distance of 1.5 times greater, ie greater than at

  mm, for the same circuit in a polluted environment.

  When incorporating an insulating plate that satisfies the condition mentioned above, the size of the cooling device using the electrically conductive cooling medium becomes greater than that of the

  conventional cooling device that uses half

  electrically insulating cooling place.

  An object of the present invention is to provide a small cooling device for

  a semiconductor element using a cooling medium

electrically conductive

  To achieve the goal stated above,

  according to a first embodiment of the invention,

  vention, a cooling device for a se-

  miconductor, in which a cooling element is

  disposed between a plurality of semiconductor elements

  united by a connecting conductor, a radiating element

  heat is connected to the connecting portion of the cooling element, and a cooling medium is introduced into the cooling element, the connecting part and the radiating element of the heat, characterized in that the medium is used

  cooling an electric cooling medium-

  conduct, that the part of that element of

  cooling, turned towards said connecting conductor-

  It comprises an insulator having good thermal conductivity or the outer circumference of said cooling element situated between a pair of said conductors.

  connection is covered by an insulator.

  According to a second embodiment of the invention,

  a cooling device is provided for a

  semiconductor system, in which a cooling element

  ment is arranged between a plurality of semiconductor elements

  connected by a connecting conductor, an element

  radiating heat is connected to the connecting part

  of the cooling element, and a cooling medium

  cooling is introduced into the cooling element

  in the connecting part and in the radiating element of the heat, characterized in that

  as a cooling medium a cooling medium

  electrically conductive device and that the said

  cooling is an insulation with a

good thermal conductivity.

  In a cooling device for a semiconductor element according to the first embodiment of the invention, an insulator is provided on the facing portions of the connecting conductor and the cooling element and on

  the outer surface of the cooling element

  between a couple of the connecting conductors, the electrical insulation between the front part of the conductor

  connection and the cooling element is not de-

  ended by the distance of travel as in the dis-

  conventional positives, but by the thickness, that is to say the

  dielectric strength at breakdown, insulation, which

  covers the corresponding part of the cooling element

  in order to obtain a cooling device

  In addition, the semiconductor elements are electrically insulated with respect to the cooling element, using the same insulator, so as to prevent an electrical short-circuit between the terminals of the semiconductor elements even if one uses for

  the cooling device a cooling medium

  electrically conductive system including water, which is

  available and does not pose any risk of degradation

of the environment.

  In a cooling device for a semiconductor element according to the second mode of

  embodiment of the present invention, the element of

  cooling is made of an insulating material, no

  circuit shorting the terminals of the semicon-

  ductors through the cooling element

  is not formed even when the entire cooling device is made with small dimensions.

  Moreover, thanks to the implementation of this

  a cooling medium can be used.

  tri-conductor, such as water, which is readily available and carries no risk of degradation of

the environment.

  Other features and advantages of the pre-

  invention will emerge from the description given below.

  after making reference to the appended drawing, on the-

what:

  FIG. 1 represents a cross-sectional view of

  of one embodiment of a cooling device for a semiconductor element according to the present invention; Figure 2 shows a cross section

  another embodiment of the cooling device

  dissement for a semiconductor element according to the present invention;

  FIG. 3 is a vertical cross-section

  of another embodiment of the

  cooling for a semiconductor element according to the present invention;

  FIG. 4 is a vertical cross-section

  of another embodiment of a cooling device for a semiconductor element according to the present invention;

  FIG. 5 is an expanded perspective view.

  part of the embodiment of the present invention.

  shown in Figure 1; FIG. 6 is an enlarged cross-section of a main part of another form of

  realization of cooling device for a

  semiconductor device according to the invention; Fig. 7 shows an enlarged cross-section of a main portion of another embodiment of a cooling device.

  for a semiconductor element according to the present invention.

  vention; FIG. 8 is an enlarged cross-section of a main part of another form of

  realization of cooling device for a

  semiconductor device according to the present invention; Figure 9 is an enlarged cross-section of a main portion of another form of

  realization of cooling device for a

  semiconductor device according to the present invention; FIG. 10 is an enlarged cross-section of a main portion of another form of

  realization of the cooling device for a

  semiconductor device according to the present invention; Figure 11, which has already been mentioned,

  is a perspective view of a cooling device

  conventional for a semiconductor element; and Figure 12, which has already been mentioned, is a vertical cross section of another device

  conventional cooling system for a semiconductor element

tor.

  Hereafter, we will explain some forms of

  of the present invention with reference to the drawing.

  Fig. 1 shows a vertical cross section showing a cooling device embodiment for a semiconductor element according to the present invention, and in which a plurality

  of semiconductor elements 1 comprise, to their two former

  trenches, respectively connecting conductors 6, and, between them, a cooling element 2,

  whose interior is filled with a cooling medium

  electrically conductive The outer surface of

  the cooling element 2 is covered by an insulation

  lant 8 having good thermal conductivity, except

  with regard to part 2a of connection to a

  In addition, the cooling element 2 is connected with

  The insulating material 8 is bonded to a heat radiating element 4 via the passage 7. For example, boron nitride, aluminum nitride, alumina, beryllium oxide and the like can be used. of

silicon carbide.

  In this structure, electrical insulation

  The gap between the connecting conductor 6 and the cooling element 2 is maintained by the dielectric strength at breakdown of the insulator 8 so that the cooling device according to the present embodiment has small dimensions compared to the conventional device. cooling such

  shown in FIG. 12 and whose dielectric rigidity

  depends on the tracking distance of the plate

insulating 5.

  We will now explain a specific structure

  insulation 8 covering the cooling element

  2 with reference to FIG. 5, which is a view in FIG.

  developed perspective of a main part of the cooling device for a semiconductor element according to

the present embodiment.

  The cooling element 2 has a configuration

  cylindrical girding having a short axial length

  in the parallel stacking direction of the semi-

  conductors, the two axial ends of the cylindrical body

  are closed and, at the upper part of the cooling element 2, a part is provided

  cylindrical connecting piece 2 a which extends in a direction

  radial arrangement and is adapted to be connected to the passage 7, as shown in Figure 1 The insulator 8 is formed of insulators 9 in the form of discs, arranged on both axial ends of the cooling element 2 and having a diameter slightly greater than that of

  the cylindrical cooling element 2, an insulator

  9 covering the outer circumference of the cooling element 2 between two insulators 9 in the form of facing disks, and another wraparound insulator 10 covering the connecting portion 2a The disc-shaped insulators 9 and the wraparound insulation 11 are joined by an insulating adhesive

  12, and when necessary, the other insulation

  loppant 10 and the wrapping insulation 11 may also be

  are joined together by an insulating adhesive.

  The disc-shaped insulator 9 is made of a material having good thermal conductivity, such as, for example, boron nitride, aluminum nitride, alumina, beryllium oxide and silicon carbide. as explained above, but the enveloping insulators 10 and 11 are not necessary in the case of such good conductivity, since the heat produced by the semiconductor elements is transferred to the cooling medium 3 via the connecting conductor 6, of

  disc-shaped insulation 9 and the cooling element

  Therefore, it may be

  In this case, the enveloping insulators 11 and 11 may be made in one piece or after placement of a cylindrical wraparound insulation 11, which

  is hollowed out in the part corresponding to the part of

  2a and has a slightly long axial length

  greater than that of the cooling element 2, and placing a cylindrical insulating wrapper 10 surrounding the connecting portion 2a, the two insulators being able to

  be made in one piece while being adjusted

  In addition, the axial ends of the wrapping insulation 11 are preferably cut off after the contraction operation in such a way that the cooling element 2 is shrunk by the application of heat.

  to align them with the end faces of the

  chilling 2 to bring them together with the insulation in the form of

disc 9.

  Since almost all of the outer surface of the cooling element 2 is covered by the insulator 8, the dielectric strength between the metal cooling element 2 and the conductor

  6 is determined by the dielectric strength

  to the breakdown of insulation 8, which makes it possible to obtain

  a cooling device having small di-

sions.

  However, the connecting conductor 6 pos-

  sede the shape of a plate that has a predetermined width

  relatively small as shown in Figure 5,

  ferent circular end faces of

  the cooling element 2 and spring in a direction

  perpendicular to the exit direction of the connecting portion 2a of the cooling element 2 or,

  in another embodiment, it is clear from the

  opposite to the exit direction of the

  Therefore, when considering the electrical insulation between the connecting conductor 6 and the cooling element 2, the electrical insulation

  along the outbound direction of the connecting conductor

  It is important that the connecting conductor

  6 forms a terminal which protrudes beyond the surfaces, facing each other, of the cooling element 2 and the disc-shaped insulator 9, which has the effect that at the level of this part outgoing, there is the problem regarding insulation, as mentioned with reference to the

figure 12.

  That is why, strictly speaking, it is

  satisfying that the insulation 8 surrounding the re-king element

  2 is applied so as to cover a part of the cooling element 2 at least close to the outgoing portion of the connecting conductor 6. In such a case, an insulator having a good thermal conductivity, for example the insulator, is provided. shaped

  disc 9, on the parts, facing each other, of the conductive

  6 and the cooling element 2 and, with regard to the outer circumference of the cooling element 2, which is situated between the

  disc-shaped insulators 9, it is satisfactory to

  see an enveloping insulation that covers at least the part

  out of the connecting conductor 6.

  Figure 6 is a larger-scale cross-section of a main part of another form of

  realization of the cooling device for a

  semiconductor circuit according to the present invention.

  In the present embodiment, the direction of exit

  Connection conductor 6 is chosen in such a way

  extend in the opposite direction to that of the connecting part

  Similarly, in the present embodiment, a similar advantage is obtained by providing a wrapping insulation 11 around the outer circumference of the cooling element 2, which is located between the

  two connecting conductors 6, but the stiffness of

  between the two connecting conductors 6 is maintained mainly by the tracking distance of

  the enveloping insulation 11, and therefore the insulation

  loppant 11 is provided with an un-joined outer surface of

  to increase its dielectric strength.

  FIG. 7 represents a larger-scale cross-section of a main part of another embodiment of the cooling device for the semiconductor element according to the present invention, in which the insulator 8 is arranged between the connecting conductor. 6 and the cooling element 2 consists of a pair of insulators of the type in the form of

  boxes 22 and 23 having good thermal conductivity

  If two insulators of the box-like type 22 and 23

  are assembled in such a way as to constitute a part in overlap

  24 at the part corresponding to the outgoing part of the connecting conductor 6

  this embodiment, the distance of

  is increased by the overlapping part 24 of

insulation 8.

  Figure 8 shows a variation of the embodiment shown in Figure 7, in which the portion, which requires a high dielectric strength, i.e., the overlap portion 24 of the pair of box-shaped insulators 22 and 23 which cover the cooling element 2 located between the connecting conductors 6, is formed by a plurality of elements

  overlap in order to further increase the

tracking.

  Fig. 9 shows an enlarged cross-section of a main portion of another embodiment of a cooling device

  for a semiconductor element according to the present invention.

  The basic structure of this form of

  is substantially identical to that shown in Figure 6, but in addition, the cooling element 2

  and the insulation 8, and the insulation 8 and the connecting conductor

  6 are joined by force, for example by a member

  sif possessing good thermal conductivity Therefore, the thermal contact resistances between these

  elements are reduced so that the semiconductor element

  1 is effectively cooled by the medium of

cooling 3.

  FIG. 2 represents a vertical cross-section of another embodiment of the cooling device for a semiconductor element according to FIG.

the present invention.

  In the previous embodiment, the cooling element 2 was made of a metal and

  insulation 8 was arranged between the connecting conductor

  6 and the cooling element 2 to achieve the insulation between these elements, but in the present form

  of embodiment, the cooling element 2 is constituted

  killed by an insulating material with good conductivity

  As a result, the insulation 8 covering the cooling element 2 is removed and furthermore

  even when electrically conductive water is used

  as a cooling medium 3, the limits of the

  semiconductors are never short-circuited so that a cooling device is obtained without the risk of environmental degradation in the structure

  of the present embodiment, as in that

  shown in FIG. 6, the cooling element 2 has an unconfined surface at its circumference

  located between the two connecting conductors

  6, which increases the dielectric strength of

  In addition, as shown in FIG. 10, the connection conductor 6 and the cooling element 2 made of an insulating material having a good thermal conductivity are connected to the cooling element 2 between the two connecting conductors 6.

  joined by an adhesive having good conductivity

  temperature, the thermal contact resistance between these elements is reduced and the semiconductor element 1 is

  effectively cooled by the cooling medium 3.

  Figure 3 shows a cross section

  vertical showing another embodiment of

  positive cooling for a semiconductor element,

  according to the present invention The structure of the present invention

  this embodiment in connection with the re-

  2 and other elements associated therewith

  is the same as that of the embodiment

  shown in Figure 2, the same reference figures are

  assigned to the same elements, and none will be given

  plication We will explain below only the elements

  which differ from those of the embodiment

shown in Figure 2.

  An inlet tube 16 used as an inlet for the cooling medium 3 and an outlet tube 17 used

  as output for the cooling means 3 are connected with

  respectively connected to the connecting portion 2a of the cooling element 2 The other end of the outlet tube 17 is connected to the radiating element 4 and the other end of the inlet tube 16 is connected to corded to the element 4 radiating heat through a pump 14 Therefore, the medium

  3 located in the cooling element

  heated by the heat supplied by the se-

  1 is sent to the radiating element 4 of the

  heat through the outlet pipe 17, and the middle

  heated cooling place is cooled there and the cooled cooling medium is returned to the cooling element 2 via the tube

  input 16 so as to cool the semiconductor elements

1.

  When the circulation circuit is

  using the pump 14 for the cooling medium.

  the freedom of design is increased, particularly as regards the position of the radiating element 4 of

  In fact, in cooling devices

  as shown in Figures 1 and 2, which

  read the evaporation of the cooling medium 3, the location of the radiating element 4 of the heat is limited to a circulation range of the cooling medium.

  determined by the difference in temperature between these elements and, on the other hand, in the case of

  forced, the location of the radiating element 4 of the

  is determined by the capacity of the pump

  14 In addition, the structure in connection with the element of

  2 and the elements associated therewith of the present embodiment may be replaced by those shown in FIG. 1 and FIGS. 6 to 10,

  substantially with the same benefits.

  Fig. 4 is a vertical cross-sectional view showing another embodiment of a cooling device for a semiconductor element according to the present invention. The structure of the present embodiment in connection with the cooling element 2 and other elements which are associated with it is the same as

  that of the embodiments represented on the

  FIGS. 2 and 3, the same reference numerals denote the same elements and no explanation will be given. Only the elements which differ from those of the embodiments shown in the figures will be explained below.

2 and 3.

  Heat-receiving portions 18a of the respective heat-conveying tubes 18 are inserted into and connected to the respective cooling elements 2, and heat radiating portions 18b of these cooling elements, which are equipped with fins of thermal radiation 19, protrude

outside of these elements.

  According to the present embodiment, since the respective tubes 18 conveying the

  heat are isolated from the semiconductor elements

  1 and to the connecting conductor 6 via the cooling element 2 made of an insulating material having good thermal conductivity, no short circuit appears between the terminals of the semiconductor elements 1, even when the fins

  of heat radiation 19 of the tubes 18 conveying heat

  In addition, the 18-gauge tubes are in contact with each other.

  heaters can be connected to ground after each of their reciprocal connections and, in a

  such case, any electric shock is prevented even if a person

  The heat-transmitting tubes 18 are furthermore in contact with the cooling element 2 and the elements associated with them in the present form.

  may also be replaced by the one

  shown in Figure 1 and Figures 6 to 10, and this

  with the same advantages.

  As explained above, in a first embodiment of the invention, an insulator is provided on the parts, facing each other, of the connecting conductor and of the cooling element and on the circumference of the the cooling element located between the two connecting conductors, an insulating material having good thermal conductivity is used for the insulator at the parts, which are made

  face of the connecting conductor and the

  cooling, and an electric cooling medium-

  conductor fills the cooling element, which has the effect that the large dimensioning of the device

  is reduced, that the short circuit

  between the terminals of the semiconductor elements, for example by the cooling medium and the

  cooling is prevented and that a device is

  safe cooling time for a semiconductor element

  poses no environmental problem In addition, in accordance with

  In accordance with a second embodiment of the invention, the cooling element is made of an insulating material having a good thermal conductivity, the connecting conductor is electrically isolated from the cooling element without requiring a particular insulating tube. , and furthermore an electrically conductive cooling medium is used, which allows

  to obtain a simple cooling device and to

  size for a semiconductor element, without any

wan of environment.

Claims (8)

  1 Cooling device for an element   semiconductor (1), wherein a cooling element   ment (2) is disposed between a plurality of semi-   conductors joined by a connecting conductor (6), a heat-radiating element (4) is connected to the connecting portion of the cooling element, and a cooling medium (3) is introduced into   the cooling element in the connecting part   in the radiating element (4) of the heat,   characterized in that an electrically conductive cooling medium is used as the cooling medium (3), whereby the portion of said cooling element (2) is   towards said connecting conductor, or the circumference   outside of said cooling element (2) situated between a pair of said connecting conductors (6) is covered by an insulator (9, 11) and that at least the insulation   (9) located on the part of said cooling element   which is directed towards the said connecting conductor   is an insulator with good thermal conductivity.   2 cooling device for a semiconductor element according to claim 1, characterized in that said insulator is constituted by an insulation in   plate form (9) disposed between said connecting conductor   cord (6) and said cooling element (2) and   by an enveloping insulation (11), which covers the circumference   outer portion of said cooling element.   3 Cooling device according to the claim   2, characterized in that another isolation is provided   wrapping liner (10), which covers the connecting part   said cooling element.   Cooling device for a semiconductor element according to claim 2, characterized in that said enveloping insulator (11) and said plate-shaped insulator (9) are joined by an insulating adhesive (12) to   level of their parts facing each other.   Cooling device for a semiconductor element according to claim 4, characterized in that said plate-shaped insulator (9) has a size substantially identical to that of the part of said cooling element, which is located opposite the   insulation, and is set up with this part.   6 Cooling device for an element   semiconductor (1), wherein a cooling element   ment (2) is disposed between a plurality of semi-   conductors joined by a connecting conductor (6), a radiating element of the heat is connected to the   connection of the cooling element, and a half   cooling zone (3) is introduced into the cooling element, the connecting part and the radiating element of the heat, characterized in that an electrically conductive cooling medium (3) is used as the cooling medium. and that said cooling element (2) is constituted by a solenoid (22,23)   possessing good thermal conductivity.   7 Cooling device for an element   semiconductor according to any one of claims 1   at 6, characterized in that said insulator (9,22,23), which has a good thermal conductivity, is constituted by at least one of the following components boron nitride, aluminum nitride, alumina and beryllium oxide and silicon carbide.   8 Cooling device for an element   semiconductor according to any one of claims 1   at 7, characterized in that water is used as the medium   electrically conductive cooling system (3).   9 Cooling device for an element   semiconductor according to any one of claims 1   to 8, characterized in that a pump (14) is provided between the connecting portion of said cooling element   (2) and said radiating element (4) of heat to form   sea a passage to forced circulation.   Cooling device for an element   semiconductor according to any one of claims 1   at 8, characterized in that the heat receiving portion (18 a) of a heat carrying tube (18) is connected to said cooling member (2), and the heat radiating portion (18 b) of said tube conveying heat   constitutes said element (4) radiating heat.