JPS61105393A - Micro bellows and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to 1 micro bellows and a method for producing the same.
In particular, the present invention relates to a liquid cooling micro bellows for individually and highly efficiently cooling each semiconductor chip in a semiconductor module in which a plurality of semiconductor chips are mounted on a wiring board, and a method for manufacturing the same. More specifically, the present invention relates to stretchable and thin peroses and methods of manufacturing the same.

[Background of the invention]

In the past, with the development of semiconductor technology, the amount of heat generated from a single chip element continued to increase, and forced air cooling methods were unable to sufficiently cool semiconductor chips. The upper limit has almost been reached.

For this reason, particularly for high-speed data processing devices and similar devices, an elegant cooling device using a liquid has been devised, as disclosed in Japanese Patent Publication No. 56-31473, for example.

In this type of device, in order to reduce the thermal resistance from the semiconductor chip to the cooling medium, it is necessary to connect the two with a good thermal conductor. At the same time, due to deformation of the board on which the chips are mounted or non-uniform soldering, the height or inclination of individual chips may be uneven, or there may be differences in thermal expansion coefficients. requires a movable part that can be expanded and contracted.

Regarding the structure of the above-mentioned joint part, Japanese Patent Publication No. 56-33862
A method using a thin plate or fine sand as disclosed in Japanese Patent Publication No. 56-2419, a method using an elastic body as disclosed in Japanese Patent Publication No. 56-317,
A method using a tight bellows disclosed in Japanese Patent No. 43 is known.

Among these methods, the former two methods have problems such as poor elasticity and higher thermal resistance than the bellows method, so currently the method using bellows has the highest performance and is possible to implement. This is considered to be a highly efficient cooling method.

However, in an actual high-speed data processing device, for example, 100
Approximately 100 semiconductor chips are mounted on an m+ square board, so even if at least one bellows is attached to one semiconductor chip, its outer diameter will be 10
Figure 84 shows an outline of a conventional bellows manufacturing method.

As can be seen in the figure, the thin plate rings 31 are overlapped and their outer and inner edges are heated with a welding torch 33, 36.
Weld by.

In Fig. 4, 34.35 is a power source, 37° 38 is a welding electrode, 39.40 is a shielding gas, 41.42 is an arc filter, and 32 is a section **.

However, in the conventional method of manufacturing a welded bellows as shown in FIG. 4, the torch 36 must be placed inside, making it difficult or impossible to manufacture a shed bellows.

As for small-sized bellows, a manufacturing method using an electroplating method as shown in FIG. 5 is known.

That is, the plating solution 47 is filled in the container 43, and the middle mold 44 and the N1 electrode 46 are immersed therein. and,
Said plating type 44 and N1m! When a voltage is applied between the poles 46 by the power supply 45, 1iliK of the medium 44
Electroformed bellows 48 is formed.

However, in this I11 method, one unit length is required because (1) variations occur in the wall thickness, and (2) the shape of the peaks cannot be made into an acute angle or a small radius of curvature (due to the need to secure the supply of plating solution). (3) If the wall is made thin, pinholes are likely to occur and the reliability of airtightness is poor. It was difficult to use this method in high-speed data processing equipment that requires high performance.

[Purpose of the invention]

The object of the present invention is to provide a cooling device that can be used for cooling devices for semiconductor modules in high-speed data processing equipment, etc., is small, has a large amount of deformation, is airtight, and has high reliability over a long period of time. To provide a micro bellows having a.

[The tf# characteristic of the present invention is l! IK, IKROPERO The manufacturing method involves assembling the product.

With this manufacturing method, even if the bellows is small and has a complex shape, it is possible to form a film with a fine shape using thin film formation technology, so the alignment of the laminated layers can be performed with high precision. 5-inch and K-shaped bellows, minute and precise bellows can be easily manufactured.

The second feature of the present invention is its unique structure in which the inner and outer edges of thin metal rings stacked to form a micro bellows are bonded every other inch with a bonding film. .

Because of this flexible structure, the microbellows according to the present invention has a large number of ridges per unit length.

Therefore, compared to conventional electroformed bellows, stress can be reduced when the same amount of deformation is applied.

Furthermore, by selecting a low-intensity gold film as the material for the bellows, it is possible to use a material that is difficult to fusion weld or plate by FM.

The third feature of the present invention is that a metal ring having the same shape as the joint surface is interposed between the thin metal rings forming the micro bellows.

With this upstream configuration, the gap between the beads is wide.
Crevice corrosion is reduced when cooling water is placed inside the bellows.

A fourth feature of the present invention is that the inner surface of the page is coated with an inorganic film by vapor phase or physical vapor deposition. With this configuration, the corrosion resistance of the bellows can be greatly improved.

Example of CAljl] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1(a) is a cross-sectional view showing the method for manufacturing microbellows according to the present invention.

First, the multiple thin nickel rings that make up the bellows
and 4 are alternately stacked in the required number inside a heater lO provided in the furnace.

At that time, the thin plate ring 1 (excluding the topmost one)! On piece w (upper g in the illustrated example) of 4, NIB f)ta and IEa+6 are formed in advance on the inner and outer peripheries of the edges by sputtering or the like with a mask applied beforehand, and then the remaining film is On the surface, prevent bonding of Sl and N4 wX2
, 5 are formed.

As mentioned above, when stacking the thin plates 1-14 alternately, a cylindrical graphite jig 8 and a round bar are placed in the center so that each thin plate ring is arranged coaxially. A 2Ic graphite jig 9 is used to position each tII plate ring.

After the thin rings 1.4 have been sectioned, pressurized oil A7 is applied to these thin rings l from above.

Each retaining plate ring 1 and 4 are joined by applying pressure to 4 and heating the inside of the furnace to about 1100° C. using a heater 10 in the air.

Figure 1(b) shows the wR of the bellows manufactured by this method.
It shows the Ifil II structure.

According to the manufacturing method of this example, even if a small bellows with an outer diameter of 105 m or less and a wall thickness of several tens to hundreds of pm is used,
Regardless of the number of threads, in other words, it is possible to easily assemble and manufacture products with any number of threads with high FF dimensions.

In addition, the amount of expansion and contraction of the bellows per unit length can be several times larger than that of electroformed bellows because the shape of the ridges can be made acute and the number of ridges on the unit length teeth can be increased. In this example, the bonding film and the bonding prevention film were formed only on one side of each thin plate ring, but as shown in FIG. 6(a), six films were formed on both sides of each thin plate ring 1.4. This allows for even more reliable bonding.

In addition, as shown in FIG. 4B, none of the six films is formed on the thin plate ring 1, but a bonding film 3.6 is formed on the inner periphery of one side of the thin plate ring 40 and the outer periphery of the opposite side. It is clear that a similar 1-cycloperose can also be produced by forming adhesion prevention mz + s in the remaining portions of each.

To summarize the above, what is required in the present invention is that bonding films are alternately interposed between the adjacent thin plate rings on the inner and outer edges thereof, and a bonding prevention film is provided in the portions where no bonding film is interposed. At least one of the bonding M and the bonding prevention film is formed in advance on at least one surface of the adjacent thin plate rings in the step 9 where the bonding M and the bonding prevention film are interposed.

Note that the above-mentioned bonding prevention film may be omitted in some cases.
Alternatively, it may be removed after manufacturing.

Regarding the material of the thin plate ring 1.4, Nl is used in the above embodiment, but stainless steel, various types of Nl, F
Even if a thin plate ring such as @gold alloy or A4 and k1 alloy is used, the low melting point alloy film as the bonding film 3.6 can be used as N1-
N such as Otsu 0Cr-5, 0Fe-4, 58i-5, OB
By changing to an alloy such as L-based alloy or AI'-8t, it can be easily assembled into a bellows in the same manner as in this embodiment.

FIG. 2 is a sectional view showing another embodiment of the four-piece construction in which the corrosion resistance of the inner surface of the bellows is improved.

As is clear from the figure, in this embodiment, outer and inner connecting rings 14 and 16 in the shape of mating surfaces are inserted between the thin plates 12 constituting the bellows. In this case, the bonding film (not shown) may be formed on at least one of the thin plate ring 12 and the bonding ring 14.16.

Then, after assembling it into a bellows using the same hot pressure welding method as described above, AICIH and CO,
Flowing a mixed gas of H1 and H1, the entire body is heated after 100cs, and while the bellows is expanded and contracted in this state, AI, O, and O are deposited on the inner surface to a thickness of about 1 μm. nizro,
.

5t3N, +StC+ZrC, Tic, etc. can be used, and generally any material with good corrosion resistance may be used.

According to the embodiment shown in FIG. 2, the gap between the thin plates 77 can be widened by inserting the joining ring between the thin plate rings of the bellows. Ninth, it is possible to uniformly coat the entire inner surface of the bellows with a corrosion-resistant film.

As a result, even when low-purity water flows into the bellows, the lifespan against corrosion can be significantly improved.

FIG. 3 shows a sectional view of an application example in which the micro bellows according to the present invention is applied to a cooling device for a multi-chip module of a semiconductor device.

In this figure, the semiconductor chip 20 has a metal oxide film 2
1 on the multilayer wiring board 19 by solder 22.

On the semiconductor chip 20, an SIC ceramic 23 having good thermal conductivity and strong electrical insulation is placed.
A micro bellows 17 hermetically sealed is separately provided to a module sealing cap 18 whose lower end is hermetically sealed and whose upper end is formed with a water supply and drainage duct (29, 30) inside.

Note that the micro bellows 17 made of metal and the SIC ceramic 23 are designed to relieve stress caused by a difference in thermal expansion.
They are joined via a buffer material 26.

On the other hand, the semiconductor chip and the S1C ceramic are connected by solder via a metallized film.

Further, the micro bellows 17 and the sealing cap 18 can be bonded together using a low melting point alloy film at the same time when the micro bellows 17 is bonded and assembled.

Here, Nl is used for the micro bellows 17, Canofnicopal (iron-nickel-cobalt alloy) is used for sealing, and N1-
4XB, Nl -7X Cr -3XFo -4,5X for the low melting point alloy film for joining the bellows and the sealing cap
In the figure, the inside of the micro bellows 17 is designed to efficiently supply cooling water from the water supply duct 29 to the surface of the SIC ceramic 230. , a freezing pipe 27 is provided.

According to the configuration example shown in FIG.
0 are metallically bonded to each other, the thermal resistance between the two becomes low and the cooling efficiency becomes extremely high.

Moreover, since the external force applied to the semiconductor chip 20 can be reduced, the fatigue life of the solder connection part of the semiconductor chip 20 to the substrate 19 can be improved, and the reliability of the module can be improved1. As a result, the reliability of the cooling device can also be greatly improved.

[1110 Effect] As detailed above, according to the present invention, the present invention provides a compact, highly flexible, long-term airtight and corrosion-resistant product that can be used as a cooling device for semiconductor modules in high-speed data processing equipment, etc. This results in a highly reliable micro bellows.

[Brief explanation of drawings]

FIG. 1(a) is a cross-sectional view for explaining the method of manufacturing micro bellows by Kinei 1jlK, FIG. 1(b) is a partial cross-sectional view of the micro bellows manufactured by the method, and FIG. FIG. 3 is a sectional view of another embodiment of the present invention in which the corrosion resistance of the bellows is improved.
A four-sided view showing an example of application of the micro bellows of the present invention, FIG. 4 is a cross-sectional view for explaining a conventional method of manufacturing a bellows, and FIG. 5 is a conventional method of manufacturing an electroformed bellows. FIG. 6 is a sectional view of a main part of another embodiment 2 of the micro bellows of the present invention and a method of manufacturing the same. 1.4... Nickel thin plate ring, 2.5... Bonding prevention film, 3.6... Bonding film, 7... Pressure jig, 8, 9
...Graphite jig, 10... Heater, 12... Thin plate ring, 13... Bonding prevention film, 14.16... Bonding ring, 15... Coating film, 17... Micropair a -Z, 18...Sealing camp, 19...Multiple birch substrate, 20...Semiconductor chip, 21...Metallized film, 22...Hand 9, 23...SiC ceramic , 26...Buffer material, 27...Pipe, 28...
・Cooling water, 29... Water supply duct, 30... Drainage duct Patent attorney Michihito Hiraki Figure 2 Figure 3 Figure 4 Figure 6

Claims (11)

[Claims] (1) A plurality of thin plate rings arranged on top of each other substantially coaxially, and a bonding film that is interposed between adjacent thin plate rings and alternately connects the outer peripheral edge and the inner peripheral edge of the adjacent thin plate rings; A micro bellows that is characterized by (2) a plurality of thin plate rings arranged on top of each other substantially coaxially; and a bonding film interposed between adjacent thin plate rings and alternately connecting outer and inner circumferential edges of the adjacent thin plate rings; A micro bellows comprising: a bonding prevention film formed on a surface of at least one of the adjacent thin plate rings where no bonding film is present. (3) a plurality of thin plate rings arranged substantially coaxially one on top of the other, and a joining ring interposed between adjacent thin plate rings and alternately connecting outer and inner circumferential edges of the adjacent thin plate rings; A micro bellows that is characterized by (4) The micro bellows according to claim 3, wherein the material of the joining ring is the same as that of the thin film ring. (5) a plurality of thin plate rings arranged substantially coaxially and stacked one on top of the other, and a joining ring interposed between adjacent thin plate rings and alternately connecting outer peripheral edges and inner peripheral edges of the adjacent thin plate rings; , a corrosion-preventing coating film formed on the inner surfaces of the joining ring and the thin plate ring. (6) (a) A plurality of thin film rings are stacked and arranged substantially coaxially, and (b) at that time, bonding films are interposed alternately on the inner and outer peripheral edges between the adjacent thin film rings. , and the bonding prevention film is interposed in the part where the bonding film is not interposed.
At least one of the bonding film and the bonding prevention film is formed in advance on at least one surface of the adjacent thin plate rings, and (c) the plurality of thin plate rings stacked as described above are heated to a temperature higher than the melting point of the bonding film. At the same time, pressure is applied, and (iv) thereby, each inner peripheral edge and outer peripheral edge of the adjacent thin plate rings are alternately bonded and fixed by the bonding film. (7) There are two types of thin plate rings, which are stacked alternately, and a bonding film is formed on the inner peripheral edge of the top surface of the first type thin plate ring, and a bonding film is formed on the top surface of the second type thin plate ring. 7. The method of manufacturing micro bellows according to claim 6, wherein a bond is formed on the outer peripheral edge of the micro bellows. (8) There are two types of thin plate rings, and these are laminated alternately, and a bonding film is formed on the inner peripheral edge on one side of the first type thin plate ring, and on the outer peripheral edge on the opposite side. 7. The method of manufacturing microbellows according to claim 6, wherein a bonding film is formed. (9) (a) A plurality of thin plate rings and bonding rings are arranged in a substantially coaxial manner so that the bonding rings are alternately located on the inner circumferential edge and the outer circumferential edge of the thin plate ring, and (b) At this time, a bonding film is formed in advance on the opposing surfaces of at least one of the bonding ring and the thin plate ring so that the bonding film is interposed between the bonding ring and the thin plate ring, and the bonding film of the bonding ring and the thin plate ring are formed in advance. a bonding prevention film is formed on at least one opposing surface of the adjacent thin rings so that the bonding film is interposed between the surfaces of each thin plate ring that face the adjacent thin plate rings without facing each other; (c) Heat the plurality of thin plate rings and bonding rings stacked as described above to a temperature higher than the melting point of the bonding film, and apply pressure; (d) As a result, the bonding rings and the thin plate rings are bonded and fixed by the bonding film. A method for manufacturing micro bellows characterized by the following. (10) The micro bellows manufacturing method according to claim 9, wherein the material of the joining ring is the same as that of the thin plate ring. (11) (a) A plurality of thin plate rings and bonding rings are arranged in layers substantially coaxially so that the bonding rings are alternately located on the inner peripheral edge and the outer peripheral edge of the thin plate ring, and (b) At this time, rather than interposing a bonding film between the bonding ring and the thin plate ring, a bonding film is formed in advance on the opposing surfaces of at least one of the bonding ring and the thin plate ring, and one of the bonding rings and the thin plate ring is formed in advance. a bonding prevention film is formed on at least one opposing surface of the adjacent thin rings so that the bonding film is interposed between the surfaces of each thin plate ring that face the adjacent thin plate rings without facing each other; (c) The plurality of thin plate rings and bonding rings stacked as described above are heated to a temperature higher than the melting point of the bonding film, and pressure is applied, (d) thereby, the bonding rings and the thin plate rings are bonded and fixed by the bonding film. (e) A method for manufacturing micro bellows, which comprises forming a coating film for corrosion prevention on the inner surfaces of the joining ring and the thin plate ring.