JPS58147049A - Semiconductor stack - Google Patents

Abstract

PURPOSE:To obtain uniform temperature of cooling fin and thereby to obtain small size and light weight semiconductor stack by providing a hollow portion to a bolt along the bolt axis and filling a coolant therein at the time of providing semiconductor elements in parallel with plurality of element units mounted to a cooling fin and tightening them with a through bolt. CONSTITUTION:A stad type semiconductor element 1 is fixed on a cooling film 2 and plurality of it are provided in parallel. Thereafter, they are tightened with a solid bolt 4 using a through hole 3 provided through a fin 2. A semiconductor stack is configurated as explained above. At this time, a solid bolt 4 is replaced with a hollow bolt 4. This hollow bolt 5 is provided with a hollow portion 5' formed along the bolt axis. This hollow portion is vacuumed and is filled with a coolant such as water or flon. Thereby, a temperature of fin 2 becomes constant and a temperature difference between the areas near the element 1 and that of far therefrom becomes small.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a semiconductor stack, particularly in a structure in which a plurality of stud-shaped semiconductor elements are combined with a plurality of cooling fins.
The present invention relates to a semiconductor stack suitable for uniform temperature distribution, size, and weight reduction.

[Technical Background of the Invention] Figures 1 and 2 are a plan view and a front view showing the structure of a well-known semiconductor stack, particularly when using a plurality of stud-shaped semiconductor elements in parallel. It is something. In other words, the semiconductor stack shown in Figure 111 @2 causes a confectionery unit 411 by attaching a stud-shaped semiconductor element l to a cooling fin 2, and inserting a bolt 4 through a hole 3 provided in each cooling fin 2. The cooling fins 2 are connected to each other by tightening.

By the way, in conventional semiconductor stacks, the bolts 4 for connecting the cooling fins 2 were made of solid F411 construction, that is, without hollow parts, as shown in the Confucian diagram in Figure 3. , there were problems as described below.

[Problems with background technology]

In the configuration of the semiconductor stack shown in FIGS. 1 and 2, an unbalance in the current of the stud-type semiconductor element 1 and a difference in forward voltage drop cause an unbalance in the amount of heat generated by each element. do. Therefore, the capacity of the cooling fins 2 needs to be sized to take into account the worst case of forward voltage drop and the worst case of current balance.

However, if a solid structure as shown in FIG. 3 is used as the cooling fin 2'f: connecting bolt 4 as in the past, m as shown in FIG.
This shows the K distribution. This is due to the poor thermal conductivity of the bolts 4, but if an attempt is made to even out the temperature distribution, the size of the cooling fins 2 will inevitably increase, resulting in an increase in weight. In addition, in each cooling fin 2, the temperature difference between the vicinity of the element and the far part becomes large, reducing the fin efficiency, so in order to secure the necessary performance, it is necessary to further enlarge the fin shape. there were. For this reason, an increase in the size and weight of the semiconductor stack itself is unavoidable, and some countermeasures have been required.

[Purpose of the invention]

Therefore, the object of the present invention is to overcome the drawbacks of the above-mentioned prior art,
When using multiple stud-type semiconductor devices in parallel, it is easy to equalize the temperature of the cooling fins provided for each semiconductor device and reduce the temperature difference between the near and far parts of the cooling fin. The objective is to provide a semiconductor stack that can be realized in the future.

[Summary of the invention]

In order to achieve the above object, the present invention provides a semiconductor stack having a unit group including a plurality of element units in which semiconductor elements are attached to a cooling member and a hollow part filled with a coolant, It is constructed from a tightening member that penetrates each cooling member and tightens them together.

[Embodiments of the invention]

Below, 1 of the present invention! Examples will be described with reference to the drawings.

FIG. 4 is a partial cross-sectional side view of a hollow bolt 5 used in a semiconductor stutter according to an embodiment of the present invention. 5-
is a vertical cross-sectional view of the hollow bolt 5.

11! The hollow bolt 5 shown in Figures 4 and 5 is basically applied to a semiconductor stack having the structure shown in Figures 1 and 2, but the difference from the solid bolt 4 is that The structure is such that a hollow portion 5' provided along the bolt axis is evacuated and then a refrigerant such as water flon is sealed therein.

In addition, Fig. 8 is a summary of Fig. 1, and Fig. 4 is for the configuration of the second cause.
After applying the hollow bolt 5 as shown in Fig. 5,
This is a cross-sectional view taken at -A@, and in this case, in order to improve the thermal conductivity between the cooling fins 2 and the hollow bolts 5, the gap between the cooling fins 2 and the hollow bolts 5 is filled with thermally conductive putty 6.

In this configuration, when there is a temperature difference between each cooling fin 2, the hollow bolt 5 acts as a heat pipe and transports heat in a direction that reduces the temperature difference. Even inside, if there is a temperature difference, the hollow bolt 5 transports heat in a direction that reduces the temperature difference.

As a result, it is possible to obtain a temperature distribution at each position on the semiconductor stack, as shown in Figure 7, with less temperature difference depending on the position compared to the temperature distribution shown in Figures 1 and 6. In this way, with the hollow bolts 5 penetrating the cooling fins 2, the temperature difference between the respective cooling fins 2 is almost eliminated by the action of the refrigerant that repeats evaporation, vapor movement, and condensation inside the hollow bolts 5.

As a result, the size of the cooling fins 2 is determined by the size of the semiconductor element 1) I
IE! 5! Since there is less weight to account for imbalance, the shape is smaller and it is also effective in reducing weight. Furthermore, since the temperature distribution within one cooling fin 2 is improved, the fin efficiency is increased and the cooling fin 2 can be made smaller.

Note that a wick may be inserted inside depending on how the hollow bolt 5 is attached. Furthermore, if a double threaded stud 7 as shown in the partial cross-sectional side view of FIG. 9 is used instead of the hollow bolt 5, the stack itself can be made smaller and lighter.

In addition, when the hollow bolt 5 or the double-threaded stud 7 having a hollow part for a heat pipe is manufactured, a thin tube can be connected in advance to the plug 5A of the hollow part 5' to form a structure in which the heat pipe is embedded. , through which evacuation or refrigerant injection may be carried out, and finally the thin tube may be sealed.◎ [Effects of the Invention] As described above, according to the present invention, a cooling fin to which a stand-type semiconductor element is attached is provided. f: By making the bolts or studs that connect multiple bolts or studs hollow and filling them with refrigerant, we have achieved a uniform gjA degree distribution, and as a result, we have created a semiconductor stack that can be made smaller and more sophisticated. You can get it.

[Brief explanation of drawings]

1 and 2 are a front view and a plan view showing the structure of a well-known semiconductor stack. FIG. 3 is a bolt 40F1iX-1 used in a conventional semiconductor stack. A partial cross-sectional side view of a hollow bolt applied to a semiconductor stack according to an example, FIG. 5 is 1!4
The vertical cross-sectional view of the hollow bolt shown in the figure, @6 is an explanatory diagram of the temperature distribution in a conventional semiconductor stack. #! Fig. 7 is an explanatory diagram of the temperature distribution of the semiconductor stack according to the embodiment of the present invention, and Figs. FIG. 9 is a partially sectional side view of a double threaded stud having a hollow structure. 1--Stud type semiconductor element, 2--Cooling fin, 4-
・・Solid bolt, 5.-Hollow bolt. Applicant's agent Kiyoshi Inomata

Claims (1)

[Scope of Claims] 1. A unit group consisting of a plurality of element units each having a semiconductor attached to a cooling member arranged side by side, and a hollow portion filled with cold #&T, and penetrating through each cooling member to connect these. A semiconductor stack consisting of a clamping member that clamps each other together costs $4.11. 2. The semiconductor stack according to claim H, wherein the fastening member comprises a hollow bolt provided through a hole drilled in the cooling member. 3. The semiconductor stack according to claim 2, wherein the hole in the cooling member is in contact with the hollow bolt through a thermally conductive putty.