DE1301378B - Process for the production of multilayer electrical circuit elements on a ceramic basis - Google Patents

Description

There are single-layer circuit elements known which, for. B. provided with a printed circuit are. Such single-layer circuit elements can be stacked in blocks, which results in multi-layered circuit elements Circuit elements. In the case of such multi-layered circuit elements,

connections between the individual circuit levels io known processes,
required, which must therefore enforce the slats. However, according to the principles of the well-known

Such multi-layered circuit elements can be th method according to the inventive method build up an organic insulating material base. These drive the capillary system to be provided very easily Insulating materials, however, are not so well manufactured in-house. A corresponding further training shafts such as ceramics as an insulating material. This is particularly beneficial for the method according to the invention if ceramics are particularly small, it indicates that the ceramics block is being made, Circuit elements preferred because they have a substantial- in green ceramic lamellae, according to the lent higher heat capacity than organic insulating capillary system, perforated and in the through materials Has. This, in turn, makes it possible to use a metallic Heat build-up see the circuit element more closely 30 to have a voluminous additive that can be expelled build. Also is the resistance to pointing paste which is then to be coated mechanical and chemical effects in ceramics stacked in a block and expelled the additives very high. heated and then sintered. To

Known circuit elements on ceramic this development is the capillary system in the However, the basis is large because there are still 35 individual layers simply by applying paste The process is known to produce a multilayered elec- tric layer, while the lamellae penetrate Irish circuit diagram in a confined space in a connection through breakthroughs who prepared ceramic block bring in. The object of the invention, and about the size of the spirit later it, a method of the type mentioned so desired capillaries. These breakthroughs are great to design that circuits on the tightest 30 easy to accomplish because they are only through Allow space to be accommodated. extend the thickness of the lamellas, i.e. proportionally

The invention is characterized in that they are moderately short. The expulsible voluminous additive a ceramic block with a metal-lined paste primarily escapes when heated deten capillary system according to the desired through the capillary system, but also through the Pipe system is established and that then the 35 green ceramic lamellas.

Capillary system filled with molten metal The metallic lining of the capillaries can

will. A capillary system par excellence in connection with the aforementioned training Ceramic block cannot easily be made with Me- by adding to the production of the metallitall to fill. Experience has shown that the metal does not see the lining lining the paste, as is the case with the bean all places, there remain gaps, and by means of these 40 known methods, a metallic one If there are gaps, the pipeline system becomes unusable. It contains a proportion that can occur during budding and sintering even fine lines not immediately, every process assumes a metal state or with all not using known processes in the ceramic container. However, this metallic component then forms block during sintering, because these metals do not have the complete line connections, but rather the high sintering temperatures only decompose the desired metallic lining, or driven out, so that the conduit is then deposited on the capillary walls system is destroyed at least in some places or a porous structure within the capillaries or has electrical interruptions that it forms. One selects metallic parts that makes useless. A metallic lining survives the sintering process or when sintered Capillary systems can, however, be achieved and their purely metallic state be maintained capillary system lined with metal like this can take. Examples of this are given below fill in with molten metal as the give. If here and in the following from metallic Experience has shown. So that it allows the lining to be spoken about, not only is it supposed to Invention, understood the line system on the basis of a wall lining of the capillaries a capillary system in the ceramic, 55 but also a lining through the resulting in extremely small dimensions mentioned porous structure. In both cases the leads. Effect with regard to the subsequent completion with

It is known to print the same with multilayered liquid metal, namely the one that by Ceramic based circuits connect this lining with the pouring of the capillaries the conductor tracks of the various levels through 60 metal is made possible or favored. The metal fragments To provide and see proportions in the ceramic material can be powdered, refractory media to be filled in with a metallic paste. The tall be or compounds of those metals that are in Paste has a removable, voluminous additive that can be reducible so that it can be followed by heat on, which after the stacking of the ceramic plates to the sintering process in their purely metallic form a block is expelled by heating, 65 are present.

whereupon the stack is then sintered. These may be needed for production

The resulting line connections consist of the chemical additives of the metallic lining, Metal parts of the paste, which can be added to the paste with ceramic particles, z. B. reducing

Additions. The heating, that is to say the heating for expelling the pasty additives, is expedient and / or the heating during the sintering process, in a reducing atmosphere, thus either the already pure metallic components cannot oxidize or, on the other hand, metal compounds can be reduced to their purely metallic state.

The metal spout of the capillary system can either be melted by immersion in a bath Metal or by applying metal to the externally accessible parts of the capillary system which is melted and then flows into the capillary system. In both In some cases, the gas must escape within the capillary system, and to aid this, recommends make the filling in a negative pressure atmosphere.

The invention will now be explained in more detail with reference to the drawing. In this shows

F i g. 1 shows the individual process steps in a block diagram of the method according to the invention,

F i g. 2 shows an exploded view of a circuit element which is produced by the method according to the invention is,

2a shows the cross sections according to arrows 2A-2A from FIG. 2,

F i g. 3 shows the illustration from FIG. 2 a, after the individual lamellas have been packaged,

Fig. 4 shows the arrangement of Fig. 3 after the pasty portion of the paste was expelled and the capillaries are lined with metal, and

F i g. 5 shows the arrangement from FIG. 4 after the capillary system has been filled with metal.

According to FIG. 1, the manufacturing method according to the invention according to Box 1 begins with the fact that green ceramic lamellas are shaped so that they can then be metallized. Under Green ceramic lamellas are here and in the following ceramic lamellas made from unfired ceramic understood, that is, from a plastic ceramic base with additions of chemical or of organic nature and / or binder additives exist. In connection with the invention are various green ceramic lamellas can be used; but they have to meet certain criteria. With a preferred Embodiment of the invention, the green ceramic lamellae in a reducing Sintered atmosphere. As a result, the oxide components of the green ceramic lamellae must not become too be easily reducible. If z. B. the ceramic material contains lead oxides and titanium oxides, then is it is less suitable in connection with the invention, because these oxides easily turn into metallic State are reducible, so that the finished ceramic element then contains these metals and thereby becomes either conductive or semiconductive and is therefore unsuitable as an insulator.

According to the invention, capillaries lined with metal are produced in the layered ceramic body, which capillaries are then filled with highly conductive metal. To produce this metallic lining, one can start from metal oxides, which are reduced to their pure metallic state during the sintering process. The ceramic mass used here must then sinter out at a temperature which is high enough for this reduction process to take place. Of course, this restriction does not apply if the metallic lining of the capillaries is based on pure metals. In the latter case, however, the ceramic material has to sinter out at a temperature which is high enough for the ceramic to bond with the metal. The adhesion processes that take place between the ceramic and the metals in such a case have not yet been researched in detail. However, there is a large number of empirically determined data on which the temperature values in question can be used as a basis. Many ceramics are known and available that meet the above criteria; Alkaline zirconium china clay and aluminates (Al ₂ O ₃ ) are well suited. In addition, beryllates, forsterites, steatites and mullites have proven to be suitable for many applications.

In addition to the green ceramic lamellae, a paste that can be metallized is prepared as shown in Box 2, which contains refractory metal or metals or metal oxides. This metallizable paste must be at least satisfy the following two conditions, viz

1. When the ceramic is sintered, the metal content that remains must be firmly attached to the surface the ceramic adhere and form a metallic coating on the ceramic and

2. This metal must take up less volume than the paste with which it was brought into the capillaries became.

Almost all refractory metals meet the first condition. These metals have a high melting point and remain essentially unmelted during the sintering process. They have one too good affinity for a sintered ceramic surface and bond during the Sintering process well on this surface. There are therefore preferably used pastes that contain such refractory metals. With such pastes the capillary structure is lined with metal, and molten, conductive material is poured into the metal-lined channels that are created in this way Poured in metal, which then forms the conductors of the circuit after hardening. The refractory metals by means of which the metallic coatings are formed, connect due to their great adhesiveness the individual lamellae on the ceramic material after the capillaries, as mentioned, are poured out. In connection with the invention, the following metals are preferred, their Alloys, oxides or hydrides of the same used, molybdenum, manganese, tungsten, titanium, tantalum, Zirconium, iron, niobium and lithium.

From the above-mentioned second requirement for the paste it follows that the initial volume the paste must be much larger than that of the metal it contains. So if the paste is subjected to the firing process for sintering to drive off the binders and fillers, then the remaining metal must occupy a much smaller volume than the original Paste. The metal content must of course be adjusted so that a sufficient amount of metal remains so that the desired metallic lining of the capillaries can result. If they do the existing amount of metal is insufficient, then

there are interruptions in the metallic structure or punched (box 5 from FIG. 1). At this clothing of the capillaries. Opportunity can add additional holes or channels

So the paste can be made by working it into the block, which then, like a metal powder or a metal oxide powder as described above, are metallically lined, a solvent and a pasty binder 5 The green ceramic block laminated in this way is then in mixes. The pasty binder then provides that sintered for a sintering furnace. This sintering process operates Paste desired additional volume. consists of two phases. During the first phase

The circuits can be cold on the ceramic- the binder is in normal air or in a redulamellen be applied. The associated atmosphere burned out and in the twilight With the materials used in the invention, the compression takes place in a reduced phase the cold processing. It is important that the atmosphere is rende. During the binder extra is not pre-fired for the metallic coating, the temperature is slowly increased, components of the paste seen during the sintering process, so that the binder components and the solvent components temperature or below the same expelled the paste are slowly expelled. Once the so that after the sintering process only the 15 binders and the solvents are expelled the metals forming the metallic lining of the block are cooled to room temperature. Paste left behind. To make the paste voluminous when the green ceramic lamellas are more alkaline

make, terephthalic acid can be added to this zirconium china clay, can burn out, which take place in the area of the ceramic sintering temperature process in such a way that the temperature temperature is volatile, but is not volatile in the range 20 by 150 ° C per hour up to one temperature Lamination temperature. temperature of about 400 ° C is increased. This tem-

After the green lamellas and the metallic temperature of 400 ° C, paste is then applied over 3 hours are prepared, the paste does justice to this. The cooling process then takes place at desired circuit diagram on the green slats room temperature. The one carried out in stages applied (box 3 from Fig. 1). If doing 25 burnout ensures that when it emerges Switching lines are needed that prevent the green charge from causing sudden pressures inside the binder mellen prevail, then for this purpose material will appear that tears the laminated structure could burst green slats in the appropriate places. Once the laminated block from before punched and the punched holes are cooled with the paste (box 6), it can be subjected to compression or filled out. 30 be subjected to sintering according to Box 7.

The paste is then dried by using the sintering takes place at a relatively high rate

Paste coated lamellas in an oven at a reduced temperature in a reducing atmosphere, relatively low temperature of about 150 ° F. If the paste contains pure metal then it will be baked for 60 minutes. The paste can cause oxidation due to the reducing atmosphere can also be air dried. As soon as the 35 prevents the sintering temperature. If against it Paste is dry, the green lamellae, which contains the paste, then becomes through the metal oxide With the schematics provided, stacked and reducing atmosphere the metal oxide into the melamellated. This is done on a stacking template that reduces tall. It has been shown that in a redu pens has in certain places. The green, decorative atmosphere during the sintering process too Lamellae are some oxides on the 40 corresponding to these pins, which are in different ceramic Ma-places punched so that the pins are contained in materials when stacking, can be reduced; penetrate the punched holes and so an exact Aus this can be prevented by making a The direction of the individual lamellas in the stack guarantees a certain amount of water vapor from the reducing is performed (Box 4). The stack is then loaded, atmosphere is added during the sintering process, 45 The sintering of alkaline zirconia china clay presses and at 40 to 100 ° C for 3 to 10 minutes is preferably done by changing the temperature in warmed up. As a result, the thermoplastic levels of 200 to 800 ° C per hour are formed on the Sinteschen green lamellas raise a uniform temperature of 1285 ° C through adhesion, which is then used for licher contiguous block. must act for about 3 hours. Following that

F i g. 2 shows the green lamellas 10, 12, 14, the 50 is cooled down again to room temperature, and are printed with circuit diagram lines 16, 18, 20. Except in the same sequence of steps as the heating-up one are through holes 22, 24 and 26 before the process took place. The burnout process can be done with seen. The section 30 of the green lamella curses the sintering process in a single heat with the hole 22 and the section 32 can be combined with the process. You save yourself Hole 24. As shown in FIG. 2 a, the cooling after the burnout corresponds to 55 Current path, starting from circuit diagram line 16 process.

the green lamella 10 over the hole 22 to the It has been shown that with the just beAbschnitt 30 and from there via the hole 24 on the written processes two different types of Section 32 and from there on to the hole 26. F i g. Form 3 capillaries. The first type of capillary is shows the arrangement from FIG. 2a according to a tubular arrangement and lined with metal addition to a block. From Fig. 3 can be seen, the second is lined with a porous grid, but forms that with the chosen arrangement of the switching one continuous connection over its entire length a closed one, spread over all three slats. The two types of capillaries are therefore for the extending circuit results. intended purpose. The laminated, ge

After the lamination according to Box 4 has burned through, the ceramic with its capillary channels is in was performed, the pressure is removed F i g. 4 shown idealized. The ceramic 40 is made and the block cooled to room temperature. Now from a monolithic contiguous then it is cut to the final shape - block, the capillaries with a metallic lining

7 8

42, 44 has. Some of the capillaries extend wide pipe by applying metallic paste vertically to the drawing plane of FIG. 4 and are prepared with. No signs were found on the fourth lamella, 47, 48 and 50. special lines provided, they only served as

The capillaries are now filled with liquid metal shielding for the lines on the third level of high electrical conductivity. To this 5 melle. The metallic paste consisted of 40 g of MoO ₃ - the ceramic is placed in a bath of molten powder to which 13.5 g of additives have been added. The metal (e.g. copper or aluminum) used in a binder contains a volatile solvent and is immersed in a negative pressure atmosphere. With the pasty binder. The above-mentioned components underpressure, the gas is expelled from the capillaries and mixed into a paste. This paste was expelled, and it was ensured that gas could not be introduced into the holes of the green lamellae and bubbles could remain, which then interrupted the lines on the lamellae when the poured metal had cooled down with it. The slats were then stacked, and cause gene in the conduit. The binder was then burned out at 400 ° C. Indicated that one did not need a high closing for this purpose in a dry hydrogen vacuum. It is sufficient to heat the block to 1210 ° C for 1 hour in the atmospheric 15 atmosphere. Subsequently, the block was cut along the pre-cut all the gas from the capillary system through the ridden line, and there molten metal was expelled. found a capillary filled with metallic molyb-

In the immersion bath, the molten metal penetrates as it was lined. The capillary was then

due to capillary forces in the capillary system so filled by placing the block in a copper bath for 5 minutes

(Box 8 from Fig. 1) and then forms the closed- of 1140 ° C in the presence of a dry water-

Senen conductor 52, which is shown in FIG. 5 was immersed in the substance atmosphere. It then became

extends the entire capillary system and once again a cross-section through the capillary is made by adhesion

forces on the metallic lining 42 adheres. makes, and it turned out that this is completely with

The capillaries can also be filled with conductive metal 25 copper. It turned out that none of them can be filled by placing pieces of metal at the openings of the capillary metal alloys or other intermetallic systems, which then have formed molten formations, but rather that an excellent conductor has been formed as a result of the capillary forces melted,
penetrate the capillaries and fill the capillary system. 30 Example 2

The following is a mixture example for a

preferably used alkaline zirconium porcelain Here the paste from example 1 was

Earth as the starting material for the green ceramic- phthalic acid is added to the volume of the paste

lamellae specified. to enlarge. The paste then consisted of 4.7 g

Tr _aa v _m 7C0 35 MoO ₃ , 10.5 g of terephthalic acid and 5.76 g of the

: \ 206 mentioned binders 163 c. These substances were

Q og ο ο ^ en then g ^em i ^scnt and ground to an equal

³ 201 'rs? shaped paste. Ten green ceramic

ggV * slats are provided that are approximately 25mm square

³ 1501e ⁴ ° £ ^ro ^ ^{were un} d were stacked. In the top

α * -ir * "Vt A ic ™ 'Jfq lamella, 22 ¹ A mm thick holes were punched,

distilled H, O 2500 cm ³ , _Λ . ", _T .., _e,. ^ö . '

² and eleven parallel conductors were placed on the second load

The specified materials were printed on mixed melle. Each of these prepared leaders

and ground. The milling process extended over was ¹ U mm wide. The remaining slats were

8 hours, then the material was dried, 45 used as a support. The stack of lamellas pulverized and then for 2 ¹ Iz hours at 1100 ° C was then, as in Example 1, burned, and the heated to convert the carbonates into carbon dioxide 1285 ° C. This temperature was driving. 3 hours a. The resulting capillary

Following this, the powder was finely powdered- 5 ° structure was checked through a cross-section,

ized. Resins were then added to this mass, and it was found that the capillaries had porous structures.

Had solvents, moisture and plasticizing agents and were lined with molybdenum,

mixed in. To 400 g so calcined alkaline The sintered ceramic was then in an aluminum

Zirconia china clay was immersed in a meal of minium bath at 700 ° C and through a

9 hours the following additives mixed in: 55 new cut checked. It turned out to be in place

Polyvinyl butryl 36.0 g ^de f capillaries, continuous conductors of good quality

Tereitol 8 0 2 have arisen, with the aluminum well at the

Dibutyl phthalate '.'. '.'. '" 12.2g porous molybdenum structure within the capillaries

60/40 Toluin / Ethanoi '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.. 144 ^ 0 g adhered.

Cyclohexanone 121.0 g Example 3

. . In this example, refractory metal was turned on

Example 1 Place of metal oxide for the metallic lining

Four green ceramic lamellas made from alka- dung were used. The paste contained 3.52 g of molybdenum,

Lischer zirconia china clay used, two holes 65 0.88 g manganese, 5.25 g terephthalic acid and 4.15 g

were in each case in the two top layers of the aforementioned binder 163 c. The paste

Lamellas with a ¹ U mm thick drill was used in conjunction with a lamellar structure, such as

drilled. ^{A 1} A mm was applied to the third lamella in Example 2, and it was, as in FIG

Example 2, burned out and sintered. There were capillaries of the type as in Example 2.

Example 4

In this example, the terephthalic acid from Example 3 was not used. The paste passed from 18.5 g molybdenum, 1.5 g manganese and 5.0 g of the binder 163 c.

The firing operations were carried out in exactly the same way as in Examples 2 and 3. One result was obtained porous molybdenum-manganese structure in the capillaries, corresponding to that from example 2 or 3. This structure was then filled with copper in a copper bath, and a conductor structure resulted, corresponding to the capillary system as described in Example 2.

Claims (9)

Patent claims: 1. Process for the production of multilayer ao electrical circuit elements on ceramic Base, characterized in that a ceramic block with a metal-lined Capillary system is produced according to the desired line system and that then the capillary system is filled with molten metal. 2. The method according to claim 1, characterized in that the ceramic block is produced is broken by green ceramic lamellae, corresponding to the capillary system, and in the breakthroughs and on their surfaces with a metallic one, a voluminous one that can be expelled Addition-containing paste are coated, which are then stacked to form a block and heated to expel the additives and then sintered. 3. The method according to claim 1 and / or 2, characterized in that for generating the metallic lining, the paste contains a metallic component, which is expelled and assumes or maintains its metal state during the sintering process. 4. The method according to claim 3, characterized in that the metallic portion is a Refractory metal powder is. 5. The method according to claim 3, characterized in that the metallic portion is an in hot environment is a reducible compound of refractory metal. 6. The method according to one or more of the preceding claims, characterized in that that the heating of the block takes place in a reducing atmosphere. 7. The method according to one or more of the preceding claims, characterized in, that the metal filling of the capillary system takes place by placing the sintered block in immersing a bath of molten metal. 8. The method according to one or more of claims 1 to 6, characterized in that The metal filling of the capillary system takes place by applying metal to the externally accessible Parts of the capillary system are applied, and that this metal is then melted will. 9. The method according to one or more of the preceding claims, characterized in, that the metal filling of the capillary system takes place in a negative pressure atmosphere. 1 sheet of drawings