DD225126B1 - METHOD FOR PRODUCING MULTILAYER INSULATION STRUCTURES FOR THICK-LAYER ELECTRONICS - Google Patents

Description

2 Al (OR) ₃ -> Al ₂ O ₃ + 3 R + 3 · OR, or

2 Al (R) (OR) ₂ -> Al ₂ O ₃ + 5 · R + -OR

respectively

Si (OR) ₄ -> SiO ₂ + 2 · R + 2 · OR, or

Si (R) (OR) ₃ - ^ SiO ₂ + 3 · R + -OR, or

Si (R) ₂ (OR) ₂ ^ SiO ₂ + 4- R

brought to the pyrolytic primary reaction and used as recrystallization reactants.

3. The method according to claim 1 and 2, characterized in that as active support with "AI ₂ O ₃ "

Max. Min.

Solvent 83.5% by weight 95.0% by weight

Ethyl cellulose 3.0% by weight 3.5% by weight

Triisopropoxy Al 13.5% by weight 1.5% by weight

be used.

4. The method according to claim 1 and 2, characterized in that as active support with "SiO ₂ "

Max. Min.

Solvent 76.4% by weight 94.2% by weight

Ethyl cellulose 3.0% by weight 3.5% by weight

Triethoxy-Al 20.6% by weight 2.5% by weight

be used.

5. The method according to claim 1 to 3, characterized in that preferably Trialkoxiverbindungen of aluminum, such as triisopropoxialane, is used.

6. The method according to claim 1, 2 and 4, characterized in that preferably alkoxy - or Alkylalkoxiverbindungen of silicon, such as tetrabutoxysilane, is used.

7. The method according to claim 1 to 6, characterized in that mixtures are used according to claim 5 and 6 as the active printing carrier.

Field of application of the invention

The invention relates to a method for the production of multilayer insulation structures for the thick-film electronics, their application, especially in the integrated hybrid technology, characterized by the arrangement of at least two printed Leiterzugebenen and electrically isolated by insulation layers.

Thick film multilayer circuits are primarily used as system carriers for high integrated hybrid systems, in which conductor crossings can not be avoided and a high degree of integration is to be realized.

The applications are multivalent in the consumer goods industry in commercial engineering, in medical engineering and in military and space engineering.

Characteristic of the known technical solutions

Multilayer insulation structures are produced in thick film technology using the same screen printing and sintering regime as conductive and resistive structures. For the screen printing process specially developed pastes are used, which consist of functional components, glass binders and print media.

Multilayer insulation structures are produced from paste systems whose solids content mostly consists of pure glass phases and which partially recrystallizes in the sintering zone of the burn-in continuous furnace. These recrystallization layers have

Such stable thermodynamic properties that they repeatedly can pass through the same sintering regime without significant disturbances of the layer structure This allows the iterative Sinterbetneb that allows the composition of the multilayer structure of alternatively arranged conductive and insulating layers By suitable Fensterstruktunerungen the insulating layers can be 2 to 10 conductor structures Realize one another in a way that can be produced by a final hybridization highly integrated circuits The inclusion of also screen-printed resistors is possible and let, inter alia, the implementation of a function calibration with a YAG laser to hybridization, the following components are conventional chips, flip chips , Beam leads, miniature packages and bare ICs, etc. In multilayer insulation pastes, two principles of action with respect to the crystallization mechanism are distinguished

1 The Vitrocerampnnzip is characterized by the use of a fine glass powder ground glass frit, which already contains all the necessary for the crystallization reactants

2 The composite precipitate is characterized by the use of a glass frit ground to ultrafine powder, which as composite is added with a component necessary for the crystallization as ultrafine powder. Multilayer insulation structures are generally transferred in double pressure to a substrate provided with the first sintered conductor. The sintering process of the two insulating layers takes place simultaneously with the firing profile, which is also used to implement the track and resistor structures, ζ B in a 60-minute cycle with a 10-minute hold time at 850 ^° C ± 1 K.

The prototype for the recrystallizing phase in a glass mat is the monoclinic Celsian formation. This is the crystalline formation of a barium aluminosilicate system according to BaO-Al ₂ O ₃ -2SiO ₂ The analytical composition of commercial multi-layer insulation pastes according to the Celsian principle has the following limits

25-35% by weight of SiO ₂

3-6 G ew - ⁰ AB ₂ O ₃

8-16% by weight Al ₂ O ₃

4-8Gew-% CaO

0 ~ 4Gew -% MgO

6-12% by weight of ZnO 20-30% by weight of BaO

In general, the printed and dried Multilayensolationspasten (Ml pastes) are a defined firing profile is subjected in a continuous sintering furnace contains mostly the 60-minute profile with 10 minutes holding time at 85O ⁰ C ± 1 K is applied before the sintering zone to be sintered structures are represented by the burnout In the application of an inert Brandfuhrung (nitrogen), the organic phase must be expelled by pyrolytic Fugazitaten, ie without combustion processes, quantitatively be never Carbontrager at incipient sintering in the pore spaces, since carbon precipitations (Nont, lustrous carbon) the required insulation resistance of 10 ¹² ohms (at a layer thickness of 40 / xm and 1 cm ⁵ base and cover electrode) not guaranteed During the holding time at the sintering temperature d The thermodynamic states which can be expected for the Celsian crystallization (monoclonal) are set. Since this process is bound to the nucleation work with subsequent growth gradients, the typical facts of the nucleation delay or the lack of functionally required crystallization also apply

In order to be able to exclude this misconduct as possible, at least one paste producer has begun to add the finest powder offset after the Vitroceram and / or composite Celsian germs in ultra-fine powder form According to DE-OS 2,655,085 partially crystalline crystallizers also ZrO ₂ and TiO ₂ type crystal diciters are added Em sonic behavior was described in GB-PS 1 416 981 by the inclusion of these "trubungsoxide" in the sum 5-15Gew-% and in DE-OS 2 714 220 by the inclusion of crystalline ternary oxides in the sum of 10-35Gew - ⁰ O described

In order to overcome the problem of iterative thermal resistance, high insulation resistance and high dielectric strength (withstand voltage testing), it has also been proposed in DE-OS 2 445 140 that the Ml layer arrangement be built up from two layers. The first layer should consist of a borosilicate gas (> 5Gew -% B ₂ O ₃ ,> 55Gew -% SiO ₂ ) and the second layer consist of a glass ceramic with> 20Gew% Knstallanteil All common multilayer insulation pastes, from which the Ml structures are produced by a sintering process, have in common analytically homogeneous ultrafine powders are used. This property is clearly visible in the case of vitroceram glass fibers, even if superfine oxide oxides are used as the second analytically homogeneous phase. Composite glasses also consist of two or more analytically homogeneous phases The partial thermodynamic crystal isolation conditions must be determined by the sintering temperature influence between these Ph Training Schiller, Horte and Wiegmann (Wiss contributions of FS-Universitat Jena, 1981, p. 45) provided information on the type of recrystallization of glasses and specifically on the Celsian problem. Accordingly, the system is BaO-Al ₂ O ₃ - SiO ₂ around glasses with surface nucleation and a growth vector to the interior of the forming Celsianprimarteilchen For this type, it was reported that initially not the thermodynamically stable Celsian phase forms, but those microbe areas, which are characterized by particular concentration ratios of BaO, Al ₂ O ₃ and SiO ₂ The technologically difficult to handle multilayersolation problem finds a surprising explanation with these statements. It is to be criticized in the described technical stand that it is not yet possible to determine the concentration ratios of BaO, Al ₂ O ₃ and SiO ₂ via the present analytically homogeneous glass fine powder or nucleation phases into the border To influence such a way that reproducible and at the same time physically optimal Ml structures arise after the sintering process

From an economic point of view, the value of multi-layer insulation pastes is also evident, as these are offered in part in the price above Ag / Pb conductive pastes on the world market.

Object of the invention

The object of the invention is then to eliminate the disadvantages associated with the prior art described The partial Reckstailisationsmechamsmus of multilayer glass lasers should be freed by a new Wirkpnnzip of the technological uncertainties and made to be influenced by a suitable rule size At the same time a technical-economic overhead and avoided material production

Explanation of the essence of the invention

The inadequate behavior of the known technical solutions and some measures to alleviate this deficiency have been described for the vitroceram and composite type and the anomaly of the thermodynamic equilibrium position and the concentration gradients of the oxidation reactants According to the invention, the object is achieved by the fact that the analytically homogeneous glass and / or seed phases in the Feinstpulvergrenzflachen with a molecular surface occupancy with at least one, the Celsianphase constituent, metal oxide are completely or partially covered and that the required resulting phase In the execution of the inventive features therefore organometallic compounds are used, which are soluble first in the solvents or solvent mixtures without affecting the likewise releasable resin or polymer components and secondly in the burn-out of the sintering unit by pyrolytic reaction sequences give the desired metal oxides

The organometallic compounds to be used are to be selected with regard to their thermal properties so that they are not molecularly volatile, but predominantly characterized only by the elimination of the organic radicals (decomposition) and leaving out the metal oxide phase to the high levels of dissociation enthalpies are no additional requirements, since they are quantitatively exceeded in the Ausbrennzone and thus ensure clear pyrolytic reaction sequences

It has been found to be advantageous in the Celsian Reklstallisation system to design the components Al ₂ O ₃ and SiO ₂ vanabei in order to obtain the possible degrees of freedom for optimum nucleation parameters. In the pressure-carrier mixture, the following substances are additionally dissolved

1 Preparation of Al ₂ O ₃ Trialkoxialuminiumverbindungen 2Al (OR) ₃ - ^ Al ₂ O ₃ + 3 R + 3 OR or

2Al (R) (OR) ₂ - ^ Al ₂ O ₃ +5 R + OR

2 For the preparation of SiO ₂ Tetraalkoxisilan- or Alkylalkoxiverbindungen of Si Si (OR) ₄ - ^ SiO ₂ + 2 R + 2 OR, or

Si (R) (OR) ₃ - ^ SiO ₂ + 3 R + OR, or

Si (R) ₂ (OR) ₂ -> SiO ₂ + 4 R

The symbol R stands for any desired and expedient organic radicals, preferably for alkane groups. The compounds with the OR and R symbolization characterize the cleaved radical structures, which are pyrolytically burned analogously to the printing resin resins or polymers when an oxidative furnace operation is used Drucktrager only as auxiliary material, for carrying out the screen printing and for fixing the layers to the substrate, are used, find the novel print media part of the input into the sintered layer structure, whereby they also assume the character of a base material with respect to the layer composition and the previous effect while Of the sintering process, the latter can be referred to as "active" Drucktrager, which then differ by definition from the conventional "passive" Drucktragern

Exemplary embodiments

Mathematically, it can be assumed that the average inner surface, as measured by the BET method, is about 2-3m ² g "'. For this parameter the print carrier has to be modified so that a Assignment of the surfaces with 1 to 4 pyrolytic oxides from the group ALX ₃ and SiX ₄ takes place

Here, X represents selected compounds from the group of alkanes or alkane oxides. For the example according to the invention, the molecular volumes of Al ₂ O ₃ and SiO _{2 were set to} 1 ns ratio to the BET surface area. The compounds mentioned in the exemplary embodiment are on this basis Limits maximum and minimum have been determined

The concentrations of these substances can also be effective above and below the stated range. The mathematically required data are accessible from the relevant table booklets. Active print carrier with ,, AI ₂ O ₃ "

Max Mm

Solvent 83.5% by weight 95.0% by weight

Ethyl cellulose 3.0% by weight 3.5% by weight

Tnisopropoxi Al 13.5% by weight 1.5% by weight

Active print carrier with "SiO ₂ "

Max. Min.

Solvent 76.4% by weight 94.2% by weight

Ethyl cellulose 3.0% by weight 3.5% by weight

Triethoxy-Al 20.6% by weight 2.5% by weight

The solvents used are terpineols and alkanols, and other polymers can be used instead of ethylcellulose.

Example 1:

The following are used to prepare an A ^ Gv active printing substrate:

92.0% solvent (terpineol, alkanol) 3.5% ethyl cellulose N300 (Hercules) 4.5% Al (C ₃ H ₇ O) ₃ H

This print carrier is dispersed with the Ml ultrafine powder in a ratio of 30 to 70 and homogenized on a three-roll mill.

Example 2:

For the preparation of a SiO ₂ -active print carrier are used:

90.0% solvent (terpineol, alkanol) 3.5% ethylcellulose N300 (Hercules) 6.5% Si (C ₂ H ₅ O) ₄

This print carrier is dispersed with the Ml ultrafine powder in a ratio of 30 to 70 and homogenized on a three-roll mill.

Example 3:

For the production of an Al ₂ O ₃ and SiO ₂ -active print carrier, use is made of:

89.0% solvent (terpineol, alkanol) 3.5% ethylcellulose N 300 (Hercules) 3.0% Al (C ₃ H ₇ O) ₃ -I 4.5% Si (C ₂ H ₅ J ₄

This print carrier is dispersed with the Ml ultrafine powder in a ratio of 30 to 70 and homogenized on a three-roll mill.

The further processing of the mixtures mentioned, for example, is carried out according to the usual paste processing technologies for the production of multilayer insulation structures. The necessary for the screen printing process adjustment of the dynamic viscosity is increased by the addition of a higher molecular weight alcohol, eg. As of terpineol made.

During the burn-out process in a sintered continuous furnace, the entire organic phase is removed from the composite by pyrolytic burns. The oxidic phases of the recrystallization additives also form in this zone.

In the sintering zone, for example at 850 ⁰ C with 10 minutes holding time, the crystallization of the Celsianstruktur occurs in the glass matrix. It has been found useful to print multilayer insulation structures twice, but to individually dry and simultaneously sinter.

By means of the process according to the invention, those metal oxides, which cause a Celsian nucleation with subsequent crystal growth, are transferred via the print carrier to the ultrafine surface of the powder. This process can be influenced by the additive concentration within wide limits.

This technical solution of a hitherto largely unexplored state creates reproducible layer electronic conditions in multilayer structure, without the need for higher expenses are noted.

Claims (2)

claims: 1. A process for the production of multilayer insulation structures for the thick-film technique, which are prepared from Feinstglaspulvern after Vitroceram and / or composite principle and organic print media and partially recrystallized during the sintering process in the molten glass to Bariumalumosilikatphase Celsian, characterized in that the defined Rekristallisationsverhalten on the print substrate molecularly dissolved compounds of aluminum and / or silicon are transferred to the interfaces of the ultrafine powders and converted into the reactive oxidic form during the sintering process. 2. The method according to claim 1, characterized in that dissolved in printing media consisting of solvents and organic polymers, in addition to the einzulispergierenden Glasfeinstpulvern alkoxy and / or alkoxy / alkane compounds of aluminum and / or silicon and during the sintering process accordingly