DE1640474A1 - Resistance material to form an electrical resistance - Google Patents

Description

PATENT Attorney DIPL-ING. H. E. BOHMER

703 BOBLINGEN SINDELFINGER STRASSE 49 TELEPHONE (over 70 31) 6 61 30 40

Boeblingen, July 15, 1966 pu-er

Applicant:

International Business Machines Corporation, Armonk, N.Y., 10 504

Official File number: New registration

File d. Applicant: Docket H 116

Resistance material to form an electrical resistance andes

The invention relates to a resistance material for formation an electrical resistance by applying and baking on a carrier.

Occurs in the manufacture of electronic circuits in micro-construction the problem of producing tightly tolerated resistance values as efficiently as possible. It is known to attach film resistors to a carrier, for example ceramic, to be applied by known printing techniques. After the printing process, these arrangements undergo a burning process put on. The binder originally added to the resistor material evaporates, giving the resistor its final, takes solid form.

The entire manufacturing process is, however, with greater difficulty tied together. Normally, the resistor material is applied to the solid support in a screen printing process, at cUe ~

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BATH ORIGINAL

This process will require certain areas of the screen printing device covered by a polyvinyl emulsion. After the actual printing process, the resistor is burned and then through Removal of superfluous resistor material trimmed to the final value. This trimming process is a rational and in the way of cost-saving mass production. It is therefore the object of the invention to provide a resistor material that from the outset enables the resistors to be manufactured within relatively narrow tolerances without the need for a subsequent trimming process will.

The mask used in the screen printing process may be used for this purpose under no circumstances are exposed to corrosion, as was inevitable when using the known dyes. According to US patent 2 815 it is known to add solvents to the dye from some of which are non-polar in nature. This will somewhat reduce the corrosion of the mask. Similar solutions are according to US patent 2 551 712 and 5 060 O62 known. It is a further object of the invention to further reduce the corrosion still present according to this prior art, so that the sheep limit the Mask used in screen printing is retained over a long period of time and resistors are produced with a relatively very narrow tolerance can.

This object is achieved according to the invention in that the resistor material consists of a mixture of 50 to Q'j> weight ^ of a powdered, electrically conductive dye with 17 to 50% by weight of a binder, which is 20 to 80% by weight of a non-polar, Organic solvent contains that 20 to 80% by weight of a non-polar polymeric resin with a molecular weight of about 500 to 1500 are dissolved in the solvent, and that polystyrene, polyterpene, polyalphamethylstyrene or mixtures thereof are used as the resin.

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BATH ORIGINAL

Further features of the invention emerge from the claims,

In the following some embodiments of the invention Resistance material described.

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164Q474

The resistance material .according to the invention, which is combined with a suitable Carrier material is mixed and fired, consists of 50 up to 83 parts by weight of a divided, electrically conductive dye, which is mixed with 17 to 50% by weight of a carrier. The carrier contains 20 to 80 weight percent of a non-polar hydrocarbon solution. In addition, 20 to 80% by weight of a polymeric resin which is soluble in the hydrocarbon are contained in the carrier and an average molecular weight of about 5CG to 7,000. The resins can be polystyrene, polyterpene, Polyalphamethylatyrcl or the like, as well as mixtures act the same.

The inventive method for producing an electrical resistor comprises the production of a resistance material according to the information just given, which is then done, for example, by means of screen printing is applied to a substrate. The substrate with the applied mixture is then heated up to the firing temperature.

The composition of the resistor material according to the invention is non-polar and does not weaken or worsen the Ewmulsion, which usually for cleaning parts of the screen printing device is used. As a result, these parts have a much longer service life than before. For example, they remain to be printed Patterns clearly and sharply delimited much longer, so that a pattern to be printed can have very tight tolerances.

The carrier within the resistor material consists of solvents with low vapor pressure at room temperature, but relatively high vapor pressure at higher temperatures. By this measure resistances arise that are extremely stable at room temperature. During the production process in which the individual components

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BATH ORIGINAL

are exposed to air pressure, is according to the current state of the Technique part of the carrier material evaporates. Even a small amount of evaporation means a significant change in the Viscosity. This change in viscosity can change the thickness of the resistance layer which could only be compensated by changing other process parameters. But it is expedient to maintain a certain optimally selected viscosity value during the course of the process. The solvent in the resistor material according to the invention has a relatively high vapor pressure at high temperatures. This will cause rapid evaporation of the solvent before and during the firing process.

The invention is also based on the fact that the resistance properties can be controlled by the composition and the amount of resin in the carrier material. This can result in a Resistance produced according to this process significantly reduces the spread of the resistance values.

Because of the non-polarity of the resistor material according to the invention the emulsion used in the screen printing process is not changed. In this printing method chosen as an example, a mask is used in which certain areas are coated with a polyvinyl solution are covered. After the resistive material has been applied to the mask, the desired pattern appears on the substrate. Of the The value of the resistance is determined by the rheological Elgenso adhesion the fast, the nature of the sieve material used, the viscosity of the emulsion and the type of screen printing process. The resistor, which is applied to a ceramic substrate, for example, is then at temperatures of Fired around 700 ° C to 1,000 ° C.

In the resistor material according to the invention, any electrlsoh conductive dyes can be used. A preferred embodiment contains a metal and / or oxide, fritted glass, colloidal Silicon dioxide and ionized additives. As Matall and

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Metal oxides are, for example, silver, indium, antimony, chromium, palladium, copper and mixtures formed from these. A preferred embodiment contains 50 to 50% by weight of finely comminuted precious metal or metal oxide or mixtures of the two, 50 to 70% by weight of comminuted fritted glass and 0 to 5% by weight of silicon dioxide. The dye is ground to a very small particle size of about 1 to 50 / U m. In the exemplary embodiment, the resistance material contains 50 to 85, preferably 70 to 80, dye by weight. The dye is mixed with a non-polar carrier, the dielectric constant of which is less than 3. The carrier consists essentially of a non-polar solvent] and a resin. A surface activator is preferably added to the resistor material as additive2. This additive essentially serves to wet the dye particles so that good distribution is ensured, precipitation is prevented and the image sharpness is thus increased. The carrier material forms about 17 to 50, preferably 20 to 30 weight percentages of the resistance material according to the invention.

The resin added to the resistor material ensures a corresponding Viscosity. The resistor material must namely be sufficiently fluid that it is even suitable for the screen printing process is applicable. On the other hand, it must be strong enough after printing to achieve the desired geometric dimensions stay. Furthermore, the viscosity of the resistor material should remain constant over a wide temperature range.

One embodiment of the invention contains 20 to 80, preferably 30 to 50% by weight of a non-polar linear polymer Resin. The resin has an average molecular weight of about 500 to 7,000, preferably 800 to 1,500. A preferred one

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Embodiment contains linear polystyrene of the form

-CH ₀ - CH -!

This resin is available in various molecular weights. A preferred embodiment is represented by the following values characterizes:

Melting point ⁰ C 100 molecular weight approx. 1500

Imp number 1.06

Density (g cm "^) 1.12 Acid number less than 1.0

Saponification number less than 1.0 Another polystyrene resin is characterized by the following values:

Melting point ⁰ C I50 molecular weight approx. 5000

Imp number 1.06

Density (g cm ~ ⁵ ) 1.10 acid number less than 1.0 saponification number less than 1.0

Another suitable linear polymeric resin suitable for these purposes is polyalphamethyl styrene having the structural formula :

This resin is also available with various molecular weights ". A preferred exemplary embodiment has the following values:

Softening point ^{0 C II6}

Acid number 0

Saponification number 0

Weight related to 15 * 5 ° C 1.07

Molecular weight 850

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Another resin of this type has the following properties: softening point 1 ^ 3

Acid number 0

Saponification number 0

Weight based on 15.5 ° C 1.07 molecular weight 1100

These resins are combined with a solvent. The molecular weight of the thermoplastic resin can be used to control the rheological properties of the resistor material. Namely, a lower molecular weight creates a relatively low viscosity. Polyalphamety1styrene is for the present Particularly well suited for this purpose because it evaporates very quickly during the firing process and there are almost no residues leaves behind. In general, the resin chosen for this purpose should be completely free of active groups, such as Carboxyl, nitrate, halogen, sulfur or nitrogen-containing groups, which polarize the molecules again and thus could worsen the originally desired effect. Such groups could also be toxic or corrosive vapors are produced during the firing process.

The solvent chosen for the embodiment of the invention is a non-polar, organic solvent with a relatively low vapor pressure at room temperature, namely smaller than 0.01 mm Hg, preferably between 0.001 and 0.01 mm Hg. At higher temperatures, the vapor pressure should assume relatively high values, so that rapid evaporation is guaranteed during the firing process. At 100 ° C the vapor pressure should be around 10 to mm Hg. The solvent consists of 20 to 80, preferably 50 to 70 weight ^ carrier material.

A preferred example of a non-polar solvent used as

0 0 9 8 4 3/06 8

Carrier is used is ethylnaphthalene, phenylcyclohexane, strongly aliphatic hydrocarbine mixtures, aromatic naphthalene hydrocarbon mixtures as well as mixtures of the substances just mentioned. A preferred embodiment of the invention contains aromatic Naphthalene-hydrocarbon mixtures having the following properties:

O.

distillation C. IBP 232 5 % 243 Specific gravity at 15.5 ° C 0.9285 10 247 20th 250 Kauri butanol No. cc 73 30th 253 40 256 Flavorings # 65 50 259 60 263 Boiling range 232 - 309 ⁰ C 70 268 80 274 90 284 95 292 End point 309

Another strong aliphatic solvent used in petroleum distillation has the following properties:

Gravity at 15.5 ⁰ C 0, 8174

Viscosity at 38 ^° C. 35.4

Aniline point ⁰ C 76.4

Kauri Butanol No. cc 28.1 Flavorings and unsaturated substances

% 17 009843/0684

distillation C. IBP 246 5 % 251 10 252 20th 253 30th 254 40 255 50 256 60 257 70 258 80 259 90 262 95 263 EP 273

- ίο -

Suitable surface activators, referred to above as additives, which can be added to the carrier, are non-ionized derivatives from ethyl glycol, alkyaryl sulfonate, fatty acid esters, polyoxyethylene and the same. Nonyl-phenoxy-polyoxyethylene-ethanol is preferred for the present purposes.

After the printing process already described above, the arrangement is dried at about 70 to 500 ° C. in 15 to 45 minutes so that the solvent can evaporate. Subsequently, the assembly is fired at Tempereturen 700-1000 ⁰ C over 2 to 100 minutes. The arrangement is then cooled to room temperature.

Some preferred exemplary embodiments of the method according to the invention are shown below.

example 1

The electrically conductive dye was finely divided from the following:

Dry mixed fabrics:

Palladium oxide 22.8% by weight

Silver 17.8 weight ^

Glass' 56.4 wt- ^

SiO ₂ 3 weight- ^

The following materials became three examples of the substrate compiled:

No. 1 aromatic solvent 57% by weight polystyrene resin 37% by weight

Additive (nonyl-phenoxy-polyethylene-ethanol) 6 weight- ^

No. 2 aromatic solvent 57 weight # Polyalphamethyl styrene

(Amoco 18-290) 37 Weight- ^

Addition 6 weight ^

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No. 3 aromatic solvent 57% by weight polyalphamethylstyrene

(Amoco 18-240) 37 Weight # Addition 6 weight- $

Three different resistor pastes were produced from these three solvents in conjunction with the dye described above. In each case the proportion of the dye was 80 % by weight and the proportion of the carrier material was 20% by weight.

Example 2 to 4 -

The resistor material described in Example 1 was applied to five different substrates. Furthermore, the change in Resistance values examined at different firing intervals. In the following table, the first digit is in the top one Line shows the time in minutes in which the resistor arrangement was heated from room temperature to the final firing temperature. The middle digit means the time in which the resistor arrangement the full firing temperature to room temperature. The firing temperature was 755 + 5 C. ·

Change in resistance values in% Mixture 1 5.0-13-15.0 Ii7.5- 13-17.5l21.0-13-21, Οΐ25.4-13-25, ^ 9> ^ 29Ρ | (

No. 1 50.3 % 74.2 ^ 89.3 % 100.0 % 109.4 % No. 2 84.4 % 85.7 % 99.4 % 100.0 % 105.2 % No. 3 83 5% 86.6% 93% * 3 100.0% i04,6%

The values of the resistance in the penultimate column were used as reference values used, soften the other resistance values as a percentage are related. The mix no. 1 with the carrier matadLal 1 leaves

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the resistance values fluctuate by a total of about 59 % at the various burning intervals given above. Mixtures nos. 2 and 3 fluctuate by much smaller values. This clearly demonstrates the stabilizing effect of the polyalphamethyl resin in the carrier material.

Examples 5 to 8

In the following examples, the resistor material according to the invention was used compared to a known resistor material. The known resistor material contained a dye with the following Components:

Silver 13.8 - 15/3 weight ^

Palladium 10.7-13.2 weight- ^ lead-boron-alumina-silicate glass 36.8-43.5 weight- ^ The proportion of the dye in the resistor material was 65-68 weight- #. The carrier material contained 10 to 15 % ethyl cellulose, which was dissolved in a mixture of alpha and beta terpeneol. With such a resistor material, the resistor materials according to the invention according to No. 1 and No. 3 in Examples 2 to 4 were compared. The results are shown in the following table:

Temperature coefficient (25 to 100 ° C)

mixture 15.0 -13-15 , 0110, 5-13-1 « , 5125, 5-13-25 , 5129.0-13-29.0 6th known 4th , 5 4th , 0 3.7 3, 8th number 1 -0 , 2 -0 Λ -0 , 5 -0, 4th No. 3 -1 , 2 -1 , 2 - 1.4 -1,

In this table, the digits in the top line have the same meaning as in the explanation of Examples 2 to 4j of the comparison]

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of the measured average temperature coefficient shows the significantly smaller changes in the temperature coefficient for Mixtures No. 1 and No. J5 during different firing intervals compared to the relatively strong changes in the known mixture. The maximum change in this case is the known Mixture 0.9, while the change in mixture no. 1 is only 0.6 and in mixture no. 3 only 0.2.

When using the resistance materials according to the invention can therefore the electrical resistance and the temperature coefficient are kept within narrow limits, even if production-related Changes in the firing intervals occur.

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Claims (4)

Patent pending 1. Resistance material to form an electrical resistance by applying and firing on a carrier, characterized in that the resistance material consists of a mixture of 50 to 85% by weight of a powdered, electrically conductive one Dyes with 17 to 50% by weight of a binder, the 20 to 80 weight ^ of a non-polar, organic solvent contains that in the solvent 20 to 80% by weight of a non-polar polymeric resin with a molecular weight of about 500 to 1,500 are dissolved, and that the resin is polystyrene, polyterepene, polyalphamethylstyrene or mixtures thereof are used. 2. Resistance material according to claim 1, characterized in that the resistance material consists of 70 to 80 weight ^ dye consists of 50 to 50 weight ^ one of powdered Metal and metal oxide existing mixture contains, in particular silver, palladium, tin, Indtira, chromium, as well as mixtures the same and that 50 to 70 weight- ^ finely divided fritted glass and 0 to 5 weight ^ silicon dioxide are added. 3. Resistance material according to claims 1 and 2, characterized in that 20 to JO weight ^ of the resistance material consist of binder which contains 50 to 70 weight ^ of a non-polar organic solvent, with a vapor pressure of 0.001 to 0.01 mm Hg at room temperature and 10 to 20 mm Hg at 100 ⁰ C, and for Äthylnaphtalen, Phenylzyklohexan and aromatic naphtha hydrocarbon mixtures having a boiling point of 232-309 ⁰ C, a highly aliphatic 009843 / 068A Hydrocarbon mixture with a boiling point between 246 and ⁰ C and / or mixtures thereof. 4. Resistance material according to claims 1 to 3 * characterized in that that the binder contains from 0 to 10% by weight of an additive and that as additives, polyethylene, glycol derivatives and / or mixtures thereof are used. 009843/0684