JP2008288330A - Semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a flow of a refrigerant in a refrigerant channel near a semiconductor element where fins are arranged at large pitches becomes a laminar flow, a heat transfer rate becomes low and large cooling performance cannot be obtained in conventional semiconductor devices when an arrangement pitch in a direction orthogonal to a circulation direction of the refrigerant of fins in the refrigerant channel of a cooler is made different in accordance with a distance from the semiconductor element. <P>SOLUTION: The semiconductor device 1 is provided with the substrate 10 where an IGBT element 20 is mounted on one face side and the cooler 50 in which the refrigerant channel 51a is formed inside a cabinet 51 to which the substrate is bonded, and the fins 52 which are arranged along the refrigerant circulation direction in the refrigerant channel and divide the refrigerant channel are disposed in the direction orthogonal to the circulation direction of the refrigerant. The arrangement pitch in the direction orthogonal to the circulation direction of the refrigerant of the fin differs in accordance with the distance from the IGBT element. Projections 52a becoming turbulence generation accelerating parts accelerating turbulence generation of a flow of the refrigerant are disposed on sides of the fins arranged near the IGBT element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a coolant channel is formed in a substrate on which one or more semiconductor elements are mounted on one side, and a housing to which the substrate is joined, and a direction along the coolant flow direction in the coolant channel The present invention relates to a semiconductor device provided with a plurality of coolers in which a plurality of fins that are arranged in a section and divide the refrigerant flow path are provided in a direction substantially orthogonal to the flow direction of the refrigerant.

In a semiconductor device such as an inverter device used in a hybrid vehicle or the like, a power semiconductor element such as an IGBT through which a large current flows is provided, and the power semiconductor element generates heat when a current flows. It is practiced to cool the power semiconductor element by attaching a device.
The cooler includes a casing to which a substrate on which the power semiconductor element is mounted is joined, and a coolant channel through which a coolant flows is formed in the casing.
In the refrigerant flow path of the cooler, a plurality of fins arranged in a direction along the refrigerant flow direction and defining the refrigerant flow path are provided in a direction substantially perpendicular to the flow direction of the refrigerant. It is comprised so that it may cool efficiently.

In recent years, since the amount of heat generation tends to increase as the output of the semiconductor device increases, the cooler configured as described above is required to improve the cooling efficiency.
In order to improve the cooling efficiency, for example, it is conceivable to increase the flow velocity of the refrigerant flowing through the refrigerant flow path. However, if the flow velocity of the refrigerant is increased, the pressure loss in the refrigerant flow path increases, so the refrigerant is circulated. It is necessary to use a pump having a large maximum discharge pressure.

However, since there is a limit to the maximum discharge pressure performance of a pump that can be actually used, a cooler that can improve the cooling efficiency without using a pump having a large capacity has been devised (Patent Document 1). reference).
That is, the fins arranged in the refrigerant flow path have a large arrangement pitch in the direction substantially perpendicular to the refrigerant flow direction in the fins located near the power semiconductor element and are located far from the power semiconductor element. In the vicinity of the power semiconductor element, the flow rate of the refrigerant is increased to increase the flow rate of the refrigerant to improve the cooling efficiency. At a position far away, the flow rate is reduced to reduce the flow rate of the refrigerant to suppress the cooling efficiency.

For example, the semiconductor device 101 illustrated in FIG. 7 includes a substrate 110 on which an IGBT element 120 and a diode element 130, which are power semiconductor elements, are mounted on one side, and a coolant channel in a housing 151 to which the substrate 110 is bonded. 151 a is formed, and fins 152, 152... That are arranged in a direction along the refrigerant flow direction in the refrigerant flow path 151 a and define the refrigerant flow path 151 a are substantially orthogonal to the flow direction of the refrigerant ( A plurality of coolers 150 provided in the left and right direction in FIG. 7, and the arrangement pitch of the fins 152, 152... In a direction substantially orthogonal to the refrigerant flow direction is a distance from the IGBT element 120. Depending on the semiconductor device, the semiconductor device is different.
And the arrangement | positioning pitch of fin 152 * 152 ... arrange | positioned near the said IGBT element 120 is made into a large pitch, the flow velocity of a refrigerant | coolant is enlarged, the flow volume of a refrigerant | coolant is increased, and the cooling efficiency is improved. On the other hand, at a position far away from the IGBT element 120, the arrangement pitch of the fins 152, 152... Is set to a small pitch to reduce the flow velocity, thereby reducing the refrigerant flow rate and suppressing the cooling efficiency.

In this way, instead of uniformly increasing the cooling capacity of the entire refrigerant flow path, by increasing the cooling capacity near the power semiconductor element that needs cooling, the location where the pressure loss increases is close to the power semiconductor element. As a result, the cooling efficiency is improved while reducing the pressure loss of the entire refrigerant flow path.
JP 2006-80211 A

When cooling is performed with the refrigerant flowing in the refrigerant flow path, one index indicating the cooling performance is a heat transfer coefficient, and the heat transfer coefficient is the magnitude of the Reynolds number of the refrigerant flowing in the refrigerant flow path. Determined by.
Specifically, the Reynolds number is determined by the flow rate of the refrigerant flowing in the refrigerant flow path formed in a general tube shape, the width of the refrigerant flow path partitioned by the fins, etc., and the Reynolds number is small. In the region, the refrigerant flow becomes a laminar flow and exhibits a low heat transfer coefficient, and in the region where the Reynolds number is large, the refrigerant flow becomes a turbulent flow and exhibits a high heat transfer coefficient.

  However, as described above, when the arrangement pitch in the direction substantially orthogonal to the flow direction of the refrigerant of the fins arranged in the refrigerant flow path is made different according to the distance from the power semiconductor element, The refrigerant flow in the refrigerant flow path near the power semiconductor element where the fins are arranged at a large pitch may become a laminar flow depending on the flow speed of the refrigerant, the refrigerant flow path width, etc., and only a low heat transfer coefficient can be obtained. Large cooling performance may not be obtained.

  Therefore, in the present invention, the refrigerant flow is changed to a turbulent flow even in a small Reynolds number region where the refrigerant flow in the refrigerant flow channel formed in a general tube shape becomes a laminar flow. It is an object of the present invention to provide a semiconductor device provided with a cooler capable of obtaining high thermal conductivity and improving cooling performance.

A semiconductor device that solves the above problems has the following characteristics.
That is, as described in claim 1, a coolant channel is formed in a substrate on which one or more semiconductor elements are mounted on one surface, and a housing to which the substrate is joined, and the coolant in the coolant channel A fin arranged in a direction along the flow direction and defining the refrigerant flow path includes a plurality of coolers provided in a direction substantially orthogonal to the flow direction of the refrigerant, and the fin is substantially orthogonal to the flow direction of the refrigerant. Disturbances that promote the generation of turbulent flow of the refrigerant on the side surfaces of the fins that are arranged in different directions depending on the distance from the semiconductor element and that are arranged in the vicinity of the semiconductor element. A flow generation promoting unit is provided.

  According to a second aspect of the present invention, the turbulent flow generation promoting portion includes a plurality of protrusions that protrude from the side surface of the fin and gradually increase from the upstream side to the downstream side in the refrigerant flow direction.

  According to a third aspect of the present invention, the turbulent flow generation promoting portion includes a plurality of holes penetrating the side surfaces of the fins.

  According to a fourth aspect of the present invention, the turbulent flow generation promoting portion includes a plurality of slits formed in a direction substantially orthogonal to the refrigerant flow direction on the side surface of the fin.

  With the configuration as described above, the width dimension of the refrigerant flow path disposed in the vicinity of the semiconductor element and the flow rate of the refrigerant are such that the flow of the refrigerant flowing through the refrigerant flow path becomes a laminar flow. Even if there is, the flow of the refrigerant flowing through the refrigerant flow path is turbulent by the turbulent flow generation promoting part, and has a high heat transfer coefficient, so that the cooling efficiency in the vicinity of the semiconductor element is increased. It becomes possible to raise.

  According to the present invention, the flow of the refrigerant flowing through the refrigerant flow path disposed in the vicinity of the semiconductor element is turbulent by the turbulent flow generation promoting unit, and has a high heat transfer coefficient. It becomes possible to increase the cooling efficiency in the vicinity of the semiconductor element.

  Next, modes for carrying out the present invention will be described with reference to the accompanying drawings.

  A semiconductor device 1 shown in FIG. 1 includes a substrate 10 on which an IGBT element 20 and a diode element 30 that are semiconductor elements are mounted on one surface side, and a refrigerant flow path 51a serving as a space in which a refrigerant flows inside a housing 51. The other surface side of the substrate 10 is bonded to the upper surface of the cooler 50 via the solder 40.

  Fins 52, 52,... Are arranged in the refrigerant flow path 51a of the cooler 50 in a direction along the refrigerant flow direction in the refrigerant flow path 51a (the depth direction in the drawing in FIG. 1) to define the refrigerant flow path 51a. Are provided in a direction substantially perpendicular to the flow direction of the refrigerant (left and right direction in FIG. 1).

  In the present example, the plurality of fins 52, 52,... Are integrally configured by a member formed into a bellows shape by bending a thin plate member into an uneven shape, and the thin plate member formed into a bellows shape. Is enclosed in the casing 51, whereby the refrigerant flow path 51a is divided into a plurality of sections.

In each refrigerant flow path 51a partitioned by a plurality of fins 52, 52,..., Three surrounding surfaces (left and right surfaces and upper surface, or left and right surfaces and lower surface) are surrounded by the fins 52, 52, and 52. The other surface is surrounded by the inner peripheral surface of the casing 51.
In this way, in each refrigerant flow path 51a defined by the fins 52, 52..., The refrigerant flows from the front side of the sheet in FIG.

  Further, the arrangement pitch of the fins 52, 52,... Arranged on the left and right of each partitioned refrigerant flow path 51a differs depending on the arrangement position of the fins 52, 52,. The arrangement pitch of the fins 52, 52,... Located near the IGBT 20 having a large is relatively larger than the arrangement pitch of the other parts, and the arrangement pitch of the fins 52, 52,. It is set smaller than the arrangement pitch of the fins 52, 52,.

  In FIG. 1, the range where the fins 52, 52... Are arranged at the substantially right and left central portions close to the mounting position of the IGBT 20 is the large pitch region Ra, and the left and right regions of the large pitch region Ra are the small pitch regions. The width of the refrigerant flow path 51a defined by Rb and defined by the fins 52, 52,... In the large pitch region Ra is defined by the fins 52, 52,. It is configured to be larger than the width dimension of the refrigerant flow path 51a.

As shown in FIG. 2, a plurality of protrusions 52a, 52a,... Are formed on the side surfaces of the fins 52, 52,.
The protrusion 52a protrudes from the side surface of the fin 52 toward the refrigerant flow path 51a, and the amount of protrusion gradually increases from the upstream side (the front side in the drawing in FIG. 1) to the downstream side (the back side in the drawing in FIG. 1). It is formed in an increasing shape.
The protrusion 52a is formed on the side surface of the fin 52 that contacts the coolant channel 51a.

As described above, in the refrigerant flow path 51a surrounded by the fins 52, 52,... Of the large pitch region Ra in which the protrusions 52a, 52a,. ..., the turbulent flow of the circulating refrigerant is promoted.
That is, by actively disturbing the flow of the refrigerant flowing through the refrigerant flow path 51a by the protrusions 52a, 52a,..., For example, protrusions 52a, 52a,. However, when the side surface is flat, the laminar refrigerant flow is turbulent.

Here, generally, whether the fluid flowing in the pipe is laminar or turbulent is determined according to the Reynolds number of the fluid, and the heat transfer coefficient of the fluid is It is determined according to the Reynolds number.
That is, FIG. 3 shows the relationship between the thermal conductivity of a fluid flowing in a general pipe line and the Reynolds number, but a region where the Reynolds number is substantially smaller than Re with a certain Reynolds number Re as a boundary. In, the fluid flow is laminar, and the fluid flow is turbulent in a region generally larger than Re, and the region where the Reynolds number is near Re is the transition region from laminar to turbulent flow. .

Thus, a region near the Reynolds number Re becomes a transition region between laminar flow and turbulent flow, a region smaller than the Reynolds number Re becomes a laminar flow region, and a region larger than the Reynolds number Re becomes a turbulent flow region. The characteristics are the same in the case of the flow of the refrigerant in the refrigerant flow path 51a surrounded by the fins 52, 52,... Where the protrusions 52a, 52a,.
In other words, the Reynolds number determined by the width of the refrigerant flow paths 51a, 51a,. The flow becomes a laminar flow and exhibits a low heat transfer coefficient, and in a region where the Reynolds number is large, the refrigerant flow becomes a turbulent flow and exhibits a high heat transfer coefficient.

  Therefore, for example, the size of the Reynolds number in the refrigerant flow path 51a surrounded by the fins 52, 52... Of the large pitch region Ra in the cooler 50 and the fins 52, 52. When the Reynolds number in the enclosed refrigerant flow path 51a is within the region A in the region smaller than the transition region near the Reynolds number Re in FIG. 3, the fins 52, 52. If the protrusions 52a, 52a,... Are not formed, the refrigerant flowing through the refrigerant flow path 51a becomes a laminar flow, and high thermal conductivity cannot be obtained.

  On the other hand, when the protrusions 52a, 52a,... Are formed on the fins 52, 52,..., The refrigerant flow is disturbed by the protrusions 52a, 52a, so that turbulence is promoted. As a result, as shown in FIG. 4, the transition region between the laminar flow and the turbulent flow in the relationship between the Reynolds number and the thermal conductivity is larger than the region A from the Reynolds number Rex smaller than the region A. It exists over the range up to the Reynolds number Rey.

  That is, in the refrigerant flow path 51a in which the protrusions 52a, 52a,... Are formed, even if the Reynolds number of the refrigerant flow path 51a is within the range of the region A, the refrigerant flow path Since the flow of the refrigerant flowing in 51a is disturbed by the protrusions 52a, 52a,..., The thermal conductivity of the refrigerant flowing in the refrigerant flow path 51a whose Reynolds number is in the range of the region A is As shown by a dotted line indicating the transition region in FIG. 4, a high value is indicated.

  As described above, in the cooler 50 of the semiconductor device 1, the width of the refrigerant flow path 51a in the area near the IGBT element 20 that needs to be cooled is configured to be large, and the refrigerant flow path in the area that does not require much cooling other than that. Concerning a cooler in which the width of 51a is configured to be small so that the pressure loss increases only in the vicinity of the IGBT element 20, and the refrigerant flow path 51a in the cooler 50 as a whole reduces pressure loss and improves cooling efficiency. , Protrusions 52a, 52a,... Are formed on the side surfaces of the fins 52, 52,... That define the refrigerant flow path 51a in the large pitch region Ra, which is a region in the vicinity of the IGBT element 20, and in the large pitch region Ra. It is configured to promote turbulent flow of the refrigerant flowing through the refrigerant flow path 51a.

  That is, in the cooler 50 of the semiconductor device 1, turbulent flow of the refrigerant flowing in the refrigerant flow path 51 a is generated on the side surfaces of the fins 52, 52... Defining the refrigerant flow path 51 a in the large pitch region Ra. , Which function as a turbulent flow generation promoting portion that promotes turbulence.

  When the protrusion 52a, 52a ... is not formed in the refrigerant flow path 51a in the large pitch region Ra due to the width dimension of the refrigerant flow channel 51a in the large pitch region Ra or the flow rate of the refrigerant, Even when the flow of the refrigerant flowing through the flow path 51a is a laminar flow, the flow of the refrigerant flowing through the refrigerant flow path 51a in the large pitch region Ra is the protrusions 52a, 52a,. It becomes turbulent and has a high heat transfer coefficient, and it is possible to further increase the cooling efficiency in the large pitch region Ra.

Further, as the turbulent flow generation promoting portion formed on the side surface of the fin 52, in addition to the above-described protrusions 52a, 52a, etc., the following can be used.
For example, as shown in FIG. 5, a plurality of holes 52 b, 52 b... Penetrating the side surfaces of the fin 52 can be formed in the fin 52.

Also in this case, the flow of the refrigerant flowing through the refrigerant flow path 51a surrounded by the fins 52 in which the holes 52b, 52b,... Are formed is disturbed by the holes 52b, 52b,. Turbulence is promoted, and the heat transfer rate of the refrigerant flowing through the refrigerant flow path 51a in the large pitch region Ra can be increased to further increase the cooling efficiency.
As described above, the plurality of holes 52b, 52b,... Formed in the fin 52 can be used as a turbulent flow generation promoting portion that promotes the turbulent flow generation of the refrigerant flow.

Further, as the turbulent flow generation promoting portion formed on the side surface of the fin 52, the following can be used.
For example, as shown in FIG. 6, a plurality of slits 52c, 52c,... Can be formed on the side surface of the fin 52 in a direction substantially orthogonal to the flow direction of the refrigerant flowing through the refrigerant flow path 51a.

Also in this case, the flow of the refrigerant flowing through the refrigerant flow path 51a surrounded by the fins 52 formed with the slits 52c, 52c,... Is disturbed by the slits 52c, 52c,. Turbulence is promoted, and the heat transfer rate of the refrigerant flowing through the refrigerant flow path 51a in the large pitch region Ra can be increased to further increase the cooling efficiency.
As described above, the plurality of slits 52c, 52c,... Formed in the fin 52 can be used as a turbulent flow generation promoting unit that promotes the turbulent flow generation of the refrigerant flow.

It is side surface sectional drawing which shows a semiconductor device. It is a perspective view which shows the fin in which the projection part was formed as a turbulent flow generation promotion part. It is a figure which shows the relationship between the Reynolds number of the fluid which flows through a general pipe line (pipeline in which the turbulent flow generation promotion part is not formed in the side surface), and thermal conductivity. It is a figure which shows the relationship between the Reynolds number of the refrigerant | coolant which flows through the inside of the refrigerant | coolant flow path enclosed by the fin in which the turbulent flow generation promotion part was formed, and thermal conductivity. It is a perspective view which shows the fin in which the hole was formed as a turbulent flow generation promotion part. It is a perspective view which shows the fin in which the slit was formed as a turbulent flow generation promotion part. It is side surface sectional drawing which shows the conventional semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 10 Board | substrate 20 IGBT element 30 Diode element 50 Cooler 51 Case 51a Refrigerant flow path 52 Fin 52a Protrusion part

Claims (4)

A substrate on which one or more semiconductor elements are mounted on one side;
A refrigerant flow path is formed inside the casing to which the substrate is joined, and fins that are arranged in a direction along the refrigerant flow direction in the refrigerant flow path and define the refrigerant flow path are defined as the flow direction of the refrigerant. A plurality of coolers provided in a substantially orthogonal direction,
An arrangement pitch of the fins in a direction substantially perpendicular to the refrigerant flow direction is a semiconductor device that differs according to the distance from the semiconductor element,
Provided on the side surface of the fin disposed in the vicinity of the semiconductor element is a turbulent flow generation promoting portion that promotes turbulent flow generation of the refrigerant flow.
A semiconductor device. The turbulent flow generation promotion part protrudes from the fin side surface, and the protrusion amount is composed of a plurality of protrusions that gradually increase from the upstream side to the downstream side in the refrigerant flow direction.
The semiconductor device according to claim 1. The turbulent flow generation promoting portion is composed of a plurality of holes penetrating the side surface of the fin.
The semiconductor device according to claim 1. The turbulent flow generation promoting unit is composed of a plurality of slits formed in a direction substantially orthogonal to the refrigerant flow direction on the side surface of the fin.
The semiconductor device according to claim 1.

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