JP2009065206A - Method for manufacturing plate stack, more specifically method for manufacturing cooling unit or cooling unit element made of plate stacks - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an innovative method for manufacturing a plate stack. <P>SOLUTION: In the method for manufacturing a cooling unit, a cooling unit element, or a heat sink made of at least one plate stack that has at least two plate-shaped elements 1 to 4 made of a metal, e.g., of copper, and that is provided with passages or openings 5 to 7, the stacked elements are mutually jointed by being heated up to a processing temperature with jointing means on jointing surfaces formed on the surface side of the elements, to form a stack. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for making or manufacturing a plate stack, in particular at least one plate stack comprising at least two plate-like elements made of metal, for example copper, and provided with a passage or opening. A stack of elements is heated to a processing temperature to form a stack using bonding means on a bonding surface formed on the surface of the element Are joined together.

Coolers, also known as microcoolers, are known in the art and are specifically designed to cool electronic elements or modules, especially high power elements or modules, and are thin metals that are joined together to form a stack. It consists of a (metal foil) plate, and the inner plate is configured with openings or passages so as to form cooling channels or channels for the refrigerant inside the plate stack or cooler. For surface bonding of the plates, they are provided with bonding means on the bonding surface, ie on the surface side. Then, to bond or connect the plates, the plates are stacked on top of each other and then heated to a suitable processing temperature and melted onto the bonding surface by the bonding means (bonded or hot melt layer). ) And after cooling the stack, they join together to form a plate stack.

A disadvantage of the known method is that shrinkage, undesirable hollows, or dead space is present inside the stack at the junction between the openings or passages of two adjacent plates while the tie layer or hot melt layer solidifies. This (dead space) creates undesirable turbulence in the refrigerant flowing through the cooler formed by the plate stack.

The object of the present invention is to provide a method which eliminates this drawback.

The object is a method of manufacturing a plate stack, in particular comprising at least one plate stack with at least two plate-like elements made of metal, for example copper, provided with a passage or opening. This is accomplished by a method of manufacturing a cooler or cooler element or heat sink. In this, the stacked elements are joined together by heating to the processing temperature that forms the stack, using joining means on the bonding surface formed on the surface of the elements, wherein the joining means are: It is also applied to the inner surface of the passage or opening prior to joining.

Further possible embodiments of the invention are the subject of the dependent claims. The invention will be described below on the basis of exemplary embodiments with reference to the accompanying drawings.

In the figure, 1 to 4 are plate-like elements or plates made of metal (for example, copper or copper alloy), which are bonded to each other to form a stack and cool electronic devices not shown. A cooler or heat sink, or a part of the cooler or heat sink. The plates 1-4 in the illustrated embodiment are quadrilateral materials of the same size of metal foil, for example copper foil. The plates 1 to 3 are configured to form a cooler structure or cooling channel through which liquid refrigerant can flow, for example. That is, the plate 1 is provided with a passage or opening 5 near two opposing peripheral sides and near the center of these peripheral sides. The plate 2 has one slit-like opening 6 on the corresponding opposite peripheral side, each of which (slit-like opening) extends in parallel to each peripheral side, and the plate 3 has a plurality of slit-like openings. 7, which extend parallel to each other and parallel to the other two peripheral sides of the quadrilateral material of the plates 1-4. Further, when the plates 1-4 are joined together to form a cooler, the passages or openings 5-7 have each opening 5 coincident with the opening 6, each opening 6 coincides with one end of the opening 7, and the plate 2 The opening 7 of the plate 3 away from the plate 3 is configured to be closed by the plate 4.

In this way, the opening 7 forms a plurality of parallel cooling channels, each of which is connected at one end to a distribution channel formed by one opening 6. The distribution channel formed by the opening 6 can be connected to the cooling circuit by the connection formed by the opening 5.

Plates 1 to 4 are bonded media or means (coating 8) applied to the surface area of the bonding surface or surface side of adjacent plates 1 to 4 in the plate stack that is not occupied by openings 5 to 7 Are joined or joined together on the surface to form a plate stack that forms a cooler, and the joining means is a soluble or meltable metal region (joined or melted) when joined by heating to the processing temperature. After cooling, the plates 1-4 are joined or bonded together to form a plate stack or cooler. The disadvantages of the prior art are that, as shown in FIG. 2, in the region of the joint between the plates 1 and 2 in the region of the openings 5 and 6, for example, the debonding of the bonding layer or the molten layer or the bonding layer during cooling or Due to shrinkage and / or insufficient coverage with soluble or meltable metal during bonding, after bonding, a dead space 9 is formed in the bonding layer at the junction between the two plates in the open area It is to be done.

These dead spaces 9 are a major drawback. That is, they cause undesirable turbulence in the refrigerant flowing in the cooler or cooling channel. In particular, these dead spaces 9 lead to undesirable corrosion, especially at the ends or edges of the openings 5 to 7 exposed for the dead space 9.

FIG. 3 shows a first possible embodiment of the invention. In this embodiment, plates 1-4 are similarly used to manufacture a plate stack or cooler 10, but before joining plates 1-4, the coating 8 as a joining means is applied to the cooler 10. Not only does it completely cover at least the binding surface or adjacent surface side of the plates 1-4, but also the sides or internal surfaces of the passages or openings 5-7 are of sufficient thickness, as indicated by positions ad in FIG. The bonding or joining means are applied so that they are covered with each other and each has an inner coating 8.1.

After joining the plates 1 to 4 to form a cooler, the dead space 9 that occurs in the prior art is removed, even considering the surface tension of the molten metal during the joining process, in particular the side surface of the opening The surface and the end of the channel of the cooler 10 formed by the cover are covered with a joining means, as the joint of the plates 1 to 4 in the region of the openings 5, 6 and 7 is shown at position e in FIG. Will be.

FIG. 4 shows yet another possible embodiment of the invention similar to FIG. In this embodiment, only the passages or openings 6 of the plate 2 are provided with a coating 8.1 made of bonding means on their inner surface, and the plates 1, 3, 4 have bonding means only on their bonding surfaces. In any case, at least the adjacent openings 5 and 7 by having a sufficiently thick coating 8.1 in the region of the openings 6, ie by having a sufficient amount of joining means volume during bonding. Are sufficiently covered with the material of the bonding or bonding layer formed by the bonding means, so that inconvenient dead space 9 is not formed and the ends or edges of the adjacent openings 5 and 7 are formed on the bonding layer. It will be coated with material.

With respect to FIG. 4 above, all the plates 1 to 4 are provided with a joining means or coating 8 at least on their joining surface, but the joining means (coating 8.1) is at least one of the plates 1 to 3. It was envisaged that the interior or side surface of the passage or opening was also applied. On the other hand, in general, only one of the two adjacent plates of the stack or cooler 10 is provided with bonding means on the surface side and the inside or side surface of the passage or opening. It is possible to have no means. For example, as a variant of the embodiment described with reference to FIG. 4, the plate 1 is provided with joining means at least on its surface side to be coupled with the plate 2 and on the inner surface of the opening 5, and the plate 3 has its two surfaces. Although the joining means is provided on the inner surface of the opening 7, the plates 2 and 4 can be provided with no joining means. The joining of all the plates to form the cooler 10 during the joining of the plates 1 to 4 is achieved by the joining means of the plates 1 and 3, and further between the individual plates in the region of the openings 5-7. Since the joint is covered, the undesired dead space 9 is eliminated.

Therefore, similarly, only the plate 2 is provided with bonding means on its two surface sides and the inner surface of the opening 6, and similarly, the plate 4 is provided with bonding means on at least the surface side coupled to the plate 3. However, the plates 1 and 3 can be provided with no joining means. During bonding, the joints between the individual plates are likewise covered with a meltable metal in the area of the openings 5-7, so that unwanted dead space 9 is eliminated.

Further, a modification of this method is conceivable, for example, in which the bonding means coating 8.1 is provided only on the inner surfaces of the openings 5 and 7, and the inner surface of the opening 6 is not provided with the bonding means.

FIG. 5 shows a plate that is joined to form a plate stack or cooler 10a, similar to FIG. This embodiment uses a total of 5 plates, namely plates 1 to 4 and an additional plate 2 between plates 3 and 4, where the plate of the illustrated embodiment is a metal foil, for example four sides of the same size of copper foil Formed in the same way from shaped material. Surface bonding or joining of the plates 1-4 to form a plate stack or cooler 10a is similarly performed by using joining means and heating to the processing temperature. In the cooler 10a, the passages or openings 6 of the two plates 2 form a distribution channel having an enlarged diameter, and the passages or openings 7 of the plate 3 are a plurality of cooling channels extending between these distribution channels. Are similarly formed. The cooler 10a is closed on both sides by the plates 1 and 4, so that the opening 5 likewise forms an external connection connecting to the distribution channel formed by the opening 6, for this purpose for example shown. No tubular connecting element is provided.

In this method, the joining means are not only applied to the surfaces of the plates 1 to 4 or the joining surfaces to be joined together, but at least some of the plates are also on the inner surfaces of the passages or openings provided in these plates. Coated. This example is reproduced in FIGS.

In the embodiment shown in FIG. 6, prior to joining the plates 1 to 4 to form the cooler 10a, the joining means are provided on the surface of only every other plate and on the inner surface of the opening. That is, as shown at positions a, c, e, plates 1, 3, 4 with coatings 8 and 8.1 are provided. During bonding or bonding, soluble or meltable metal made using bonding means covers all adjacent plate 1-4 joints in the region of openings 5, 6, 7 and is therefore inconvenient. The dead space 9 is removed, and the edge of the opening and the inner surface of the opening are covered with the metal of the bonding layer at the joint between the plates 1 to 4.

The same result can also be achieved with the embodiment shown in FIG. 7 in which only two plates 2 are provided with a joining means (coating 8) on the surface side and a joining means (coating 8.1) in the opening 6. it can. In this embodiment, the metal that can be melted during bonding covers all the junctions between the plates 1 to 4 in the region of the openings 5 to 7 and also the inner surface of these openings, so undesirable dead space 9 Is removed.

The joining means can be applied by various means depending on, for example, the kind of joining means and therefore the kind of joining means. For example, if a direct bonding process is used, for example, if plates 1-4 are made from copper and a direct copper bonding process is used, the bonding means is a reactive gas bonding between the metals of each plate. In a plate made of copper, the bonding means is CuO and / or Cu ₂ O, and the bonding or bonding is performed in the inert gas atmosphere containing a low concentration of oxygen by connecting the plates 1 to 4 configured in a stack. This is done by heating to a processing temperature of 1065 ° C. to 1082 ° C. and then cooling to ambient temperature.

Next, the application of the joining means is performed by an appropriate chemical treatment of the plates 1 to 4 or the foil material, for example. The plates with joining means to the inner surface of the opening, joining means layer, i.e., for example, the chemical process to form the CuO and / or Cu 2 _O coating does not take place until the construction or making an opening.

Various metals or metal alloys are suitable as bonding means, and in particular, the metal and the solder of the plates 1 to 4 are formed at the processing temperature, and the melting temperature thereof (solder) is higher than the melting temperature of the metals of the plates 1 to 4. A fairly low metal or metal alloy is suitable as a joining means.

A suitable joining means is, for example, a Ni-P alloy having a phosphorus content of 1 to 20% by weight. The joining or joining of the stacked plates 1 to 4 is then performed by heating the plate stack to a processing temperature of 850 ° C. to 1082 ° C. and then cooling to ambient temperature, whereby the joining means is at the processing temperature. The copper of the adjacent plates 1 to 4 and solder that can be melted are formed.

Silver is a joining means particularly suitable for plates 1 to 4 made of copper, and the joining is performed by heating to a processing temperature of 780 ° C to 1080 ° C.

For example, tin or a tin alloy is a suitable joining means. Bonding or joining of the stacked plates 1 to 4 is performed by heating the plate stack to a processing temperature of about 170 ° C to 280 ° C.

Application of the joining means is accomplished chemically, for example, by electroplating or dipping.

If the thickness of the plate is 0.1-2 mm, the thickness of the sufficient bonding means coating 8.1 on the inner surface of the opening is about 0.5-1.5 μm.

In particular, in the above method in which the joining means are applied by chemical or electrochemical treatment of the respective plates 1 to 4, the joining means are not only deposited in the respective open areas as coatings 8.1, It is inevitable to deposit as a coating 8 on the surfaces on both sides of the plate. If the latter is not desired, i.e., if only one of the two surfaces of a plate must be provided with a joining means, each plate is applied after application of the joining means and before joining. Further processing is performed as shown in FIG. The position a shows, for example, the plate 1, the coating 8 made from the joining means is provided on both sides, and the coating 8.1 made from the joining means is provided in the region of the opening 6. Then, by further processing steps, for example mechanical or chemical treatment, the joining means is removed from one surface, so that the plate will comprise the joining means only in the region of the other surface and the opening 5.

The general advantage of the present invention is that in all the embodiments described above, the disadvantageous prior art dead space of the joint between the plates or plates 1-4 is eliminated in the passages or open areas, and thus in particular Undesirable turbulence in the refrigerant is prevented. Furthermore, completely covering the joints between the plates 1 to 4 in the passages or openings during melting with a meltable metal also means that the same material is present on all surfaces in the finished stack, so that the liquid refrigerant Contact corrosion due to contact between (eg water) and other materials is avoided.

In particular, the embodiment described with respect to FIGS. 5 and 7 has the advantage that manufacturing and processing costs are reduced because the joining means is applied to only some of the plates 1-4 before joining. Surprisingly, in these embodiments, the junctions between the individual plates in their passages or open areas are completely covered by the meltable metal formed by the joining means, which is an undesirable dead of the prior art. Not only is the space 9 removed, but at least in the open region, the surface of the channel through which the refrigerant flows is formed from the same material, so that cold corrosion is at least maximally avoided.

The invention has been described above on the basis of exemplary embodiments. Needless to say, various modifications and changes can be made without giving up the basic concept of the present invention on which the present invention is based.

It is a development top view which simplifies and shows three metal layers or plates of a heat sink or a cooler for cooling an electronic element or module which is not illustrated. FIG. 2 is a simplified partial view of a cooler known in the prior art manufactured by surface bonding or joining the plates depicted in FIG. 1. FIG. 2 shows the individual plates of the cooler according to the invention before connection or joining, each in section at positions a to d, and the section of the cooler at position e. FIG. 4 is a view similar to FIG. 3 but showing yet another possible embodiment. FIG. 5 is a drawing depicting five layers or plates similar to FIG. 1 for producing a cooler of yet another possible embodiment. It is a figure which shows the plate of FIG. 5 before joining and forming a micro cooler in the position of a-e in a partial cross section, and shows the partial cross section of the cooler formed by a plate in the position of f. It is the figure drawn similarly to FIG. FIG. 4 shows two process steps of yet another possible embodiment of the invention at positions a and b.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plate or plate-like element 2 Plate or plate-like element 3 Plate or plate-like element 4 Plate or plate-like element 5 Passage or opening 6 Passage or opening 7 Passage or opening 8 Coating means coating or coating on the surface side 8.1 Bonding means coating or coating to opening 9 Dead space 10 Cooler 10a Cooler

Claims (4)

  Cooler or cooler element or heat sink consisting of at least one plate stack, comprising at least two plate-like elements (1-4) made of metal and provided with passages or openings (5, 7) The stacked elements (1-4) are heated to the processing temperature by applying bonding means on the bonding surfaces of the elements and on the inner surfaces of the passages or openings (5, 7). To form a stack by bonding to each other, wherein tin or at least a tin alloy is used as a bonding means, and the bonding is performed at a processing temperature of about 170 ° C. to 280 ° C.   Tin or at least a tin alloy is applied as a joining means to the bonding surface of the element (1-4) and the inner surface of the opening, then the elements (1-4) are stacked and bonded together at a processing temperature of 170 ° C. to 280 ° C. The method of claim 1, wherein: Prior to joining, all elements (1-4) should be provided with joining means (8, 8.1) on at least their joining surfaces and any passages or openings (5-7) present. The method according to claim 1, wherein the method is characterized in that Cooler or cooler element or heat sink consisting of at least one plate stack, comprising at least two plate-like elements (1-4) made of metal and provided with passages or openings (5, 7) Wherein the stacked elements (1-4) are coated with joining means (8, 8.1) on the surface of said elements and on the inner surface of the passages or openings (5-7) A method according to any one of claims 1 and 2, characterized in that it comprises an element to be applied and an element to be uncoated.

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