JPH0648868Y2 - Semiconductor device cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] Regarding a cooling structure in which a large number of semiconductor chips are mounted on a ceramic circuit board and forced liquid cooling is performed, a matrix is formed on a wiring board (5) for the purpose of efficiently cooling the semiconductor chips. A plurality of semiconductor chips (6) mounted in a shape are provided with a coolant inlet (7) and a coolant outlet (8) in a lid (9) of a package, and the semiconductor chips are arranged. In a structure that circulates a cooling medium in a certain direction with respect to (6) to cool, a saw-toothed protrusion is provided on a ceiling part of a lid part (9) that is close to a semiconductor chip (6) and faces through a flow path. A cooling structure for a semiconductor device is configured by providing (10).

[Industrial application field]

The present invention relates to a semiconductor device cooling structure for cooling a large number of semiconductor chips by forcibly circulating a coolant.

In order to further increase the processing capability of the information processing device, the semiconductor device has a large capacity and the packaging density is also improved.

That is, a semiconductor chip configured by integrating a large number of unit elements has been downsized and the number of elements has been increased.
LSI and VLSI are in practical use.

Also, with the progress of passivation technology, the mounting method has been improved, and at the beginning, the hermetically sealed package type outer packaging method was adopted.However, semiconductor chips such as flip chip type are closely arranged on the ceramic multilayer circuit board. LSI modules have come to be adopted.

In this way, as the integration of semiconductor chips and high-density mounting progress, the amount of heat generated by the LSI module becomes enormous, requiring forced liquid cooling instead of conventional forced air cooling.

[Conventional technology]

The amount of heat generated during the use of conventional LSI chips was about 4 watts (W), but it has reached about 10 W in VLSIs with increased integration.

Therefore, LSIs in which such semiconductor chips are arranged
In the module, it was necessary to circulate the refrigerant and to forcibly cool it.

Here, the refrigerant is non-corrosive, non-dissociative and has a boiling point of LSI.
A module with a maximum operating temperature of 85 ° C or lower, such as C ₅ F _{12 with} a boiling point of 30 ° C and C ₆ F _{14 with} a boiling point of 56 ° C, is suitable.

Now, the conventional cooling structure has a package structure in which a large number of semiconductor chips arranged in a matrix are divided into multiple rows by partition walls, the refrigerant is flowed in a certain direction, and the discharged refrigerant is cooled through a pump and a heat exchanger. It had a structure that allows it to circulate while allowing it to move.

The reason why the partition wall is required is that the cooling efficiency for each semiconductor chip is made uniform by forming a flow path of the coolant and rectifying the flow path.

Since this cooling system has a structure in which the coolant is forcedly circulated, the temperature of the coolant in contact with the conventional semiconductor chip is raised by the heat generated by the conventional semiconductor chip, whereby natural convection is caused or the chip is convected by the boiling of the coolant. The cooling capacity is far superior to the cooling method.

However, as the integration of semiconductor chips is increasing,
It is necessary to develop a cooling structure that maximizes the cooling effect by liquid cooling.

[Problems to be solved by the device]

The semiconductor chips arranged in a matrix are divided by the partition walls provided in the package to form a plurality of flow paths,
When cooling the semiconductor chip by circulating the cooling medium, the boundary layer of the cooling medium is removed in order to improve the cooling efficiency.

FIG. 2 is a schematic sectional view explaining the existence of a boundary layer,
When the fluid flows in the pipe 1, the flow velocity 2 is highest at the center as shown by the arrow, and becomes slower as it approaches the pipe wall, and the flow velocity at the pipe wall 3 becomes almost zero.

The reason for this is the friction of the viscous fluid with the tube wall.

Therefore, how to reduce the influence of the boundary layer of the refrigerant is a problem that needs to be solved.

[Means for Solving the Problems]

The above problem is that a package for storing a plurality of semiconductor chips mounted in a matrix on a wiring board is provided with a coolant inlet and a coolant outlet, and the coolant is directed in a fixed direction with respect to the arranged semiconductor chips. This can be solved by adopting a cooling structure of a semiconductor device in which a saw-toothed protrusion is provided on each ceiling portion of a package which is close to the semiconductor chip and faces through a flow path .

[Action]

The cooling structure according to the present invention creates a turbulent flow in the forcedly circulated refrigerant, thereby stripping the boundary layer of the refrigerant.

FIG. 1 is a principle diagram of a cooling structure according to the present invention, in which there is a wiring board 5 having a large number of input / output lead pins 4,
A flip chip type semiconductor chip 6 is mounted thereon, and a package lid 9 having a coolant inlet 7 and a coolant outlet 8 is provided so as to cover the wiring board 5.

Here, conventionally, a pump (not shown) was used to pressurize a low-boiling-point refrigerant from the inlet port 7 and suck it from the outlet port 8 to circulate it. A saw-toothed protrusion 10 is provided on the ceiling of the end 9 of the package that faces the chip 6.

As a method of removing the boundary layer of the refrigerant, the inventors have boiled the refrigerant to remove it.

Remove the turbulent flow in the refrigerant.

There are two methods, but the combined use of both methods improves the cooling efficiency.

That is, the method using boiling has generated air bubbles at the boundary between the semiconductor chip 6 and the coolant, thereby breaking the boundary layer, and the method using turbulence has used the method using turbulent flow. The vortex is generated by spreading through a narrow gap between the semiconductor chip 6 and the semiconductor chip 6, and the vortex strips the boundary layer of the refrigerant.

For this purpose, it is a necessary condition that the gap between the saw-toothed protrusion 10 and the semiconductor chip 6 is narrow.

The present invention realizes the improvement of cooling efficiency by utilizing the fact that when the semiconductor chip 6 is energized, the refrigerant boils due to heat generation and that the boundary layer of the refrigerant is broken by the turbulent flow of the refrigerant.

〔Example〕

FIG. 3 is a sectional view (A) of the cooling structure according to the present invention and a plan view (B) of the inside of the lid.

A large number of input / output lead pins 6 are provided on the lower side of the wiring board 12 made of alumina ceramic with multi-layered wiring, and 4 × 4 flip-chip type semiconductor chips are provided on the wiring board 12. 6 is attached, and a lid portion 14 provided with a projection 10 having a saw-tooth cross section, a partition wall 13, and an inlet 7 and an outlet 8 for the coolant is brought into contact with and integrated with each other to form a package.

Here, the height and pitch of the serrated protrusions 10 are 2 mm each.
The distance between the saw-toothed protrusion 10 and the surface of the semiconductor chip 6 is 0.5 mm.

Then, the outflow port 8 and the inflow port (7) are connected to a heat exchanger (not shown) and a pump, and carbon fluoride (C ₆ F ₁₄ ) is supplied at a flow rate of 1 m / s.
And forced circulation.

Next, when power is applied to the semiconductor chip (6), the boundary film of the coolant is stripped off due to the boiling of the coolant and the turbulent flow caused by the saw-toothed protrusions 10, so that the cooling efficiency per chip may be the same as that of the conventional structure. 110W while it was 60W / cm ²
It was possible to improve to about / cm ² .

[Effect of device]

According to the practice of the present invention, the cooling capacity can be improved in response to the increase in the capacity of the semiconductor chip, which makes it possible to reduce the size of the semiconductor package.

[Brief description of drawings]

FIG. 1 is a principle diagram illustrating a cooling structure according to the present invention, FIG. 2 is a schematic diagram illustrating a boundary layer, and FIG. 3 is a cross-sectional view (A) of the cooling structure according to the present invention and a plane inside a lid portion. Figure (B). In the figure, 5 and 12 are wiring boards, 6 is a semiconductor chip, 7 is an inflow port, 8 is an outflow port, 9,14 is a lid, 10 is a saw-toothed protrusion, and 13 is a partition.

Claims (1)

[Scope of utility model registration request] 1. A refrigerant inlet port (7) and a refrigerant outlet port (8) in a lid portion (9) of a package for storing a plurality of semiconductor chips (6) mounted in a matrix on a wiring board (5). In a structure in which a cooling medium is circulated in a certain direction to the arranged semiconductor chips (6) and is cooled, a lid that is close to the semiconductor chips (6) and faces through a flow path. A cooling structure for a semiconductor device, characterized in that a saw-toothed protrusion (10) is provided on a ceiling portion of the portion (9).