Silver sinterable paste and its use for connecting components - Patent Application 20070122997

Abstract

A silver sinterable paste comprising: (A) 5% to 40% by weight of silver flakes having a particle size D90 in the range of 5 μm to 20 μm; (B) 50% to 85% by weight of silver particles having a particle size D90 in the range of 300 nm to 1,000 nm; (C) 10% to 25% by weight of at least one organic solvent; (D) 0% to 2% by weight of at least one cellulose derivative; and (E) 0% to 10% by weight of at least one additive different from components (A) to (D).

Description

[Technical Field]

[0001] The present invention relates to a silver sinterable paste and a method for connecting components in which this silver sinterable paste can be used.

[0002] The term "component" as used herein refers in particular to components used in electronic devices, i.e., electronic components, such as diodes, LEDs (light-emitting diodes), dies, IGBTs (insulated-gate bipolar transistors), MOSFETs (metal oxide semiconductor field effect transistors), ICs (integrated circuits), sensors, heat sinks, resistors, capacitors, coils, connecting elements (e.g., clips), base plates, antennas, lead frames, PCBs (printed circuit boards), flexible electronics, ceramic substrates, metal-ceramic substrates such as DCB substrates (direct copper bonded substrates), IMS (insulated metal substrates), etc.

[0003] Sintering connections of electronic components is common in the fields of power electronics and consumer electronics. Metal sinterable pastes, whose main component is dispersed sinterable metal particles, are frequently used as connecting materials. A notable example of such a sinterable paste is silver sinterable paste, known to those skilled in the art. The sintering connection technique represents a very simple method for stable connection of components. The components to be connected are sandwiched together with their contact surfaces facing each other, with a sinterable connecting material, such as a sinterable paste, applied between them. The sandwich arrangement made using the sinterable paste is then subjected to a drying and sintering step, during which a mechanically strong, electrically and thermally conductive connection between the components is formed. Therefore, a mechanically strong connection of two components is the fixation of one component to or on a second component via their respective contact surfaces.

[0004] The object of the present invention was to provide a metal sinterable paste which is improved in particular with regard to its extrusion behavior. The so-called extrusion behavior of a metal sinterable paste is the undesirable phenomenon that during the sintering process the metal sinterable paste comes out of the edge region of the sandwich arrangement which is to be connected by sintering. This extrusion phenomenon can occur in particular in the case of so-called pressure sintering, when a relatively large amount of metal sinterable paste is located between the connected parts of the sandwich arrangement, i.e. when the layer thickness of the metal sinterable paste is large and / or when the contact surfaces of the relevant parts to be connected to one another are large, for example when the overlap area formed by the connected contact surfaces is greater than 100 mm 2 in the range of over 100mm 2 Super ~500mm 2 Or even larger, it may occur more frequently.

[0005] Surprisingly, this objective (A) 5% by weight to 40% by weight (% by weight), preferably 10% by weight to 30% by weight, particularly preferably 15% by weight to 25% by weight of silver flakes (silver platelets) having a particle size D90 in the range of 5 μm to 20 μm, preferably 7 μm to 18 μm, particularly preferably 8 μm to 15 μm; (B) 50% to 85% by weight, preferably 55% to 80% by weight, and particularly preferably 60% to 75% by weight, of silver particles having a particle size D90 within the range of 300 nm to 1,000 nm, preferably 320 nm to 800 nm, and particularly preferably 350 nm to 500 nm; (C) 10% by weight to 25% by weight, preferably 10% by weight to 20% by weight, particularly preferably 10% by weight to 15% by weight of at least one organic solvent, (D) 0% to 2% by weight, preferably 0.1% to 1% by weight, particularly preferably 0.1% to 0.5% by weight of at least one cellulose derivative, and (E) 0% to 10% by weight of at least one additive different from the components (A) to (D). This can be achieved by providing a silver sinterable paste consisting of:

[0006] In a preferred embodiment, (A) 5% to 40% by weight, preferably 10% to 30% by weight, particularly preferably 15% to 25% by weight, of silver flakes having a particle size D10 in the range of 0.5 μm to 2 μm, preferably 0.7 μm to 1.5 μm, D50 in the range of 2.4 μm to 4 μm, preferably 3 μm to 3.8 μm, and D90 in the range of 5 μm to 20 μm, preferably 7 μm to 18 μm, particularly preferably 8 μm to 15 μm; (B) 50% to 85% by weight, preferably 55% to 80% by weight, and particularly preferably 60% to 75% by weight, of silver particles having a particle size D10 within the range of 90 nm to 150 nm, preferably 100 nm to 120 nm, D50 within the range of 150 nm to 250 nm, preferably 200 nm to 220 nm, and D90 within the range of 300 nm to 1,000 nm, preferably 320 nm to 800 nm, and particularly preferably 350 nm to 500 nm; (C) 10% by weight to 25% by weight, preferably 10% by weight to 20% by weight, particularly preferably 10% by weight to 15% by weight of at least one organic solvent, (D) 0% to 2% by weight, preferably 0.1% to 1% by weight, particularly preferably 0.1% to 0.5% by weight of at least one cellulose derivative, and (E) 0% to 10% by weight of at least one additive different from the components (A) to (D). The silver sinterable paste is composed of:

[0007] The terms "particle size D10" or "particle size D90" used herein in connection with silver flakes (A) refer to the primary particle diameter below which 10% of the particles or 90% of the particles fall, respectively, as determined by static automated analysis of a microscopic image. The term "particle size D50" used herein in connection with silver flakes (A) refers to the volume-average primary particle diameter, as determined by static automated analysis of a microscopic image. The equivalent circular area diameter (ECAD) can be conveniently used as a measure of primary particle diameter (see Renliang Xu et al.: "Comparison of sizing small particles using different technologies", Powder Technology, Elsevier, Basel (CH), vol. 132, no. 2-3, June 24, 2003 (2003-06-24), pages 145-153). Static automated analysis of microscopic images can be carried out according to the dry determination method, for example using the Morphologi 4 measurement system from Malvern Instruments.

[0008] The terms "particle size D10" or "particle size D90" used herein in connection with silver particles (B) refer to the primary particle diameter, which can be determined by laser diffraction, below which 10% of the particles or 90% of the particles fall, respectively. The term "particle size D50" used herein in connection with silver particles (B) refers to the volume-average primary particle diameter, which can be determined by laser diffraction. The equivalent circular area diameter (ECAD) can be conveniently used as a measure of primary particle diameter (see Renliang Xu et al.: "Comparison of sizing small particles using different technologies", Powder Technology, Elsevier, Basel (CH), vol. 132, no. 2-3, June 24, 2003 (2003-06-24), pages 145-153). Laser diffraction measurements can be performed according to the wet determination method using a corresponding particle size measuring instrument, such as a Malvern Instruments Mastersizer 3000 or Mastersizer 2000. In the wet determination method, for example, 1 g of type (B) silver particles can be dispersed in 200 ml of ethanol using ultrasound as part of the sample preparation.

[0009] Component (A) is silver flakes having a particle size D90 in the range of 5 μm to 20 μm, preferably 7 μm to 18 μm, and particularly preferably 8 μm to 15 μm. The silver flakes preferably have a particle size D10 in the range of 0.5 μm to 2 μm, preferably 0.7 μm to 1.5 μm, a D50 in the range of 2.4 μm to 4 μm, preferably 3 μm to 3.8 μm, and a D90 in the range of 5 μm to 20 μm, preferably 7 μm to 18 μm, and particularly preferably 8 μm to 15 μm.

[0010] The aspect ratio of silver flakes can be, for example, greater than 5:1, e.g., from greater than 5:1 to several hundred:1. The aspect ratio of a particle describes the quotient of the particle's maximum and minimum linear expansion, and therefore the particle's shape. For avoidance of doubt, for particles in the form of flakes, the quotient of the maximum and minimum linear expansion is the quotient of the maximum length extent and the flake thickness. This can be determined by evaluating electron microscopy images using a scanning electron microscope and determining the dimensions of a statistically significant number of individual particles.

[0011] Silver flakes are, for example, 1m 2 / g~5m 2 The specific surface area (m 2 / g) can be determined by BET measurements according to DIN ISO 9277:2014-01 (static volumetric method, gas used: nitrogen).

[0012] Silver flakes are, for example, 1 g / cm 3 ~5g / cm 3 The compacted density (g / cm) can be in the range of 0.01 to 0.01. The compacted density (g / cm) can be calculated by further compacting the solid by tamping or shaking. 3 ) can be determined in accordance with DIN EN ISO 787-11:1995-10.

[0013] Silver flakes are typically coated, and the weight specifications given herein include the weight of any coating on the silver flakes.

[0014] The silver flakes can include pure silver (at least 99.9% silver purity by weight) flakes and / or silver alloy flakes with up to 10% by weight of at least one other alloying metal. Examples of suitable alloying metals are copper, gold, nickel, palladium, platinum, and aluminum. Pure silver flakes are preferred.

[0015] The coating can be a layer that adheres firmly to the surface of the silver flakes. Typically, it is an organic coating. The proportion of the organic coating can be, for example, in the range of 0.5% to 1.5% by weight, based on the silver or silver alloy. Generally, such an organic coating can contain 90% to 100% by weight of one or more fatty acids and / or fatty acid derivatives. Examples of fatty acid derivatives include, inter alia, fatty acid salts and fatty acid esters. Examples of fatty acids include caprylic acid (octanoic acid), capric acid (decanoic acid), lauric acid (dodecanoic acid), myristic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), oleic acid (9-octadecenoic acid), arachidic acid (eicosanoic acid / icosanoic acid), behenic acid (docosanoic acid), and lignoceric acid (tetracosanoic acid).

[0016] When DSC analysis (differential scanning calorimetry, dynamic differential calorimetry) of coated silver flakes is performed at a temperature range of, for example, 25°C to 400°C, with a heating rate of 10 K / min and air access, the coating of the silver flakes can be characterized by one or two exothermic peaks in a temperature range such as, for example, 200°C to 270°C.

[0017] When TGA analysis (thermogravimetric analysis) of the coated silver flakes is performed at a temperature range of, for example, 25°C to 400°C, with a heating rate of 10 K / min and air access, the coating of the silver flakes can be characterized by a weight loss in the range of, for example, 0.7 wt% to 1.5 wt%, starting at, for example, 130°C to 150°C and ending at, for example, 220°C to 240°C.

[0018] Type (A) silver flakes are available, for example, from Metalor or Ames Goldsmiths.

[0019] Component (B) is silver particles having a particle size D90 in the range of 300 nm to 1,000 nm, preferably 320 nm to 800 nm, and particularly preferably 350 nm to 500 nm. Preferably, the silver particles have a particle size D10 in the range of 90 nm to 150 nm, preferably 100 nm to 120 nm, a D50 in the range of 150 nm to 250 nm, preferably 200 nm to 220 nm, and a D90 in the range of 300 nm to 1,000 nm, preferably 320 nm to 800 nm, and more preferably 350 nm to 500 nm. The silver particles of component (B) are so-called submicron silver particles, which should not be confused with even smaller nanosilver particles having a D90 particle size of less than 250 nm.

[0020] The silver particles are not silver flakes. The aspect ratio of silver particles is significantly smaller than that of silver flakes, for example, in the range of 1:1 to 5:1. Ideal spherical particles have an aspect ratio of 1:1. The aspect ratio of silver particles in the range of 1:1 to 5:1 means that the silver particles have, for example, a spherical, substantially spherical, ellipsoidal, oval, or irregular shape, but are by no means flake-shaped.

[0021] The silver particles can include particles of pure silver (at least 99.9% silver by weight) and / or particles of a silver alloy with up to 10% by weight of at least one other alloying metal. Examples of suitable alloying metals are copper, gold, nickel, palladium, platinum, and aluminum. Pure silver particles are preferred.

[0022] Silver particles are, for example, 1 m 2 / g~8m 2 The specific surface area (m 2 / g) can be determined by BET measurements according to DIN ISO 9277:2014-01 (static volumetric method, gas used: nitrogen).

[0023] Silver particles, for example, 3 g / cm 3 ~6g / cm 3The compacted density (g / cm) can be in the range of 0.01 to 0.01. The compacted density (g / cm) can be calculated by further compacting the solid by tamping or shaking. 3 ) can be determined in accordance with DIN EN ISO 787-11:1995-10.

[0024] The silver particles are typically coated, and the weight specifications given herein include the weight of the coating on the silver particles.

[0025] The coating can be a layer that adheres firmly to the surface of the silver particles. Typically, it is an organic coating. The proportion of the organic coating can be, for example, in the range of 0.5% to 1.5% by weight, based on the silver or silver alloy. Generally, such an organic coating can contain 90% to 100% by weight of one or more fatty acids and / or fatty acid derivatives. Examples of fatty acid derivatives include, in particular, fatty acid salts and fatty acid esters. Examples of fatty acids include caprylic acid (octanoic acid), capric acid (decanoic acid), lauric acid (dodecanoic acid), myristic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), margaric acid (heptadecanoic acid), stearic acid (octadecanoic acid), oleic acid (9-octadecenoic acid), arachidic acid (eicosanoic acid / icosanoic acid), behenic acid (docosanoic acid), and lignoceric acid (tetracosanoic acid).

[0026] When DSC analysis of coated silver particles is performed, for example, in the temperature range of 25°C to 400°C, at a heating rate of 10 K / min and with air access, the coating on the silver particles can be characterized by one or two exothermic peaks in the temperature range of, for example, 200°C to 270°C.

[0027] When TGA analysis of the coated silver particles is performed at a temperature range of, for example, 25°C to 400°C, with a heating rate of 10 K / min and air access, the coating of the silver particles can be characterized by a weight loss in the range of, for example, 0.9 wt% to 1.4 wt%, starting at, for example, 140°C to 160°C and ending at, for example, 230°C to 250°C.

[0028] Type (B) silver particles are available, for example, from Ames Goldsmiths.

[0029] Component (C) is at least one organic solvent. Examples of suitable organic solvents include terpineol, N-methyl-2-pyrrolidone, ethylene glycol, dimethylacetamide, 1-tridecanol, 2-tridecanol, 3-tridecanol, 4-tridecanol, 5-tridecanol, 6-tridecanol, isotridecanol, 2-ethyl-1,3-hexanediol, 2-(2-ethylhexyloxy)-ethanol, benzyl alcohol, diethylene glycol monobutyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, dibasic esters (preferably the dimethyl esters of glutaric acid, adipic acid or succinic acid, or mixtures thereof), glycerol, diethylene glycol, triethylene glycol, and aliphatic, especially saturated, aliphatic hydrocarbons having 5 to 32 carbon atoms, more preferably 10 to 25 carbon atoms, and even more preferably 16 to 20 carbon atoms.

[0030] Component (D), an optional but preferably included component in the silver sinterable paste according to the present invention, is at least one cellulose derivative, examples of which include methyl cellulose, ethyl cellulose, ethyl methyl cellulose, carboxy cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose.

[0031] Optional component (E) is at least one additive different from components (A) through (D). Examples include surfactants, antifoaming agents, wetting agents, and corrosion inhibitor additives.

[0032] Component (E) preferably does not contain any glass particles (glass frit). In other words, the silver sinterable paste according to the present invention preferably does not contain any glass particles.

[0033] Component (E) particularly preferably does not contain any thermally decomposable metal precursors (metal precursor compounds), i.e., does not contain any metal precursors that can decompose into the corresponding metals during the sintering process. Corresponding silver precursors that are sometimes customary in prior art silver sinterable pastes, such as silver oxide, silver carbonate, silver lactate, etc., are therefore particularly preferably not contained in component (E). In other words, the silver sinterable paste according to the invention particularly preferably does not contain any thermally decomposable metal precursors. The absence of such metal or silver precursors has also been shown to have a positive effect on the storage stability of the silver sinterable paste according to the invention.

[0034] An essential inventive feature of the silver sinterable paste according to the invention is considered to be that it has a combination of a relatively small proportion of silver flakes of type (A) and a relatively large proportion of submicron silver particles of type (B), and particularly preferably does not have a proportion of the above-mentioned metals or silver precursors.

[0035] The sum of the weight percentages of components (A) to (E) is 100% by weight, based on the silver sinterable paste according to the present invention. Therefore, the silver sinterable paste according to the present invention can be produced by mixing components (A) to (C), (A) to (D), or (A) to (E). In this case, conventional equipment known to those skilled in the art, such as a stirrer, a three-roll mill, a guided jet mixer, and / or a dispersion mixer, can be used.

[0036] The silver sinterable paste according to the invention can be used in sintering methods, such as those described above. Sintering is understood to mean connecting two or more components by heating while preventing the silver flakes and silver particles from reaching a liquid phase. The solid mechanical connection formed here is simultaneously electrically and thermally conductive, and the connection consists essentially or almost entirely of silver. In this respect, the invention also relates to a method for connecting components, which comprises (1) providing a sandwich arrangement comprising at least two components and a silver sinterable paste according to the invention located between the components, (2) optionally, but preferably, drying the silver sinterable paste, and (3) sintering the sandwich arrangement. Drying is understood to mean the removal of organic solvents from the applied sinterable paste according to the invention. When working with a silver sinterable paste according to the invention, steps (1), (2) and (3) form a sequence of steps of the type (1)-(2)-(3), with step (2) being optional. In one embodiment of the method carried out using a silver sinterable paste according to the invention, step (1) can already include drying, and therefore step (2) can be omitted. In another embodiment, step (1) does not include drying or only partially includes drying, and optional step (2) can be omitted or preferably performed. If step (2) is omitted here, it can be performed during step (3) or overlap with this step.

[0037] If the component does not already consist of metal, it can comprise at least one metal contact surface, for example in the form of a metal coating layer, via which the above-mentioned sandwich arrangement is produced within the scope of the method according to the invention.

[0038] In step (1), two or more components are first brought into contact with one another. The contact is effected via the silver sinterable paste according to the invention, which is optionally already dried. For this purpose, a sandwich arrangement is provided in which the silver sinterable paste according to the invention is located in each case between two of the at least two components. The term "sandwich arrangement" means an arrangement in which the two components are located one above the other and are arranged substantially parallel to one another.

[0039] The sandwich arrangement can be produced by methods known from the prior art, in which the relevant metal contact surface of one of the components is provided with the silver sinterable paste according to the invention, and the other component is then placed with its metal contact surface on the silver sinterable paste applied to the metal contact surface of the first component.

[0040] The application of the silver sinterable paste according to the invention to the relevant metal contact surfaces of one of the components can be carried out by conventional methods, for example by printing methods such as screen printing or stencil printing. On the other hand, the silver sinterable paste according to the invention can also be applied by dispensing techniques such as jetting, pin transfer or by immersion.

[0041] The wet film thickness of the silver sinterable paste according to the invention is preferably in the range of 20 μm to 400 μm. The preferred wet film thickness depends, for example, on the selected application method. If the silver sinterable paste according to the invention is applied, for example, by screen printing, a wet film thickness of, for example, 20 μm to 60 μm may be preferred. If application is carried out, for example, by stencil printing, the preferred wet film thickness may be, for example, in the range of 20 μm to 400 μm. For example, in the case of dispensing techniques, the preferred wet film thickness may be, depending on the application tool used, for example, in the range of 20 μm to 400 μm, for example, in the range of 20 μm to 100 μm when using a hollow needle, or in the range of 50 μm to 400 μm when using a wide-slot nozzle that simultaneously acts as a doctor blade.

[0042] Following application of the silver sinterable paste according to the invention to the metal contact surface of one of the components, the metal contact surface of this component, optionally already provided with a partially or completely dried silver sinterable paste, is brought into contact, via the silver sinterable paste, with the corresponding metal contact surface of the component to be connected to it. Thus, a layer of undried, partially dried or completely dried silver sinterable paste according to the invention is positioned between the components to be connected to form a sandwich arrangement.

[0043] According to a preferred embodiment, the proportion of organic solvent in the silver sinterable paste after drying is, for example, 0% to 5% by weight, based on the initial proportion of organic solvent in the silver sinterable paste according to the invention. In other words, during drying according to this preferred embodiment, for example, 95% to 100% by weight of the organic solvent(s) originally contained in the silver sinterable paste according to the invention is / are removed.

[0044] The drying temperature in step (2), if performed, is preferably in the range of 100°C to 150°C. Typical drying times are, for example, in the range of 5 minutes to 45 minutes. To help reduce drying times, a vacuum, for example, a pressure in the range of 100 mbar to 300 mbar, can be used.

[0045] After completion of step (1) or step (2), the sandwich arrangement is finally subjected to a sintering process. This sintering step (3) of the method according to the invention can be carried out under pressure or without pressure. Carrying out the method without pressure means that a sufficiently strong connection can be achieved between the parts, despite the absence of mechanical pressure. As already mentioned at the beginning, the silver sinterable paste according to the invention is characterized by a low, or preferably even non-existent, extrusion behavior. In other words, the silver sinterable paste according to the invention is particularly suitable for the method according to the invention, which is designed as pressure sintering.

[0046] The actual sintering is carried out at temperatures of, for example, 200°C to 280°C and, as mentioned above, can be carried out as a pressureless process or, more advantageously, as a pressure sintering with little or no extrusion behavior.

[0047] In the case of pressure sintering, the process pressure is preferably less than 30 MPa, more preferably less than 15 MPa, For example, the process pressure is in the range of 1 MPa to 30 MPa, more preferably in the range of 5 MPa to 15 MPa.

[0048] The sintering time is, for example, within a range of 2 to 90 minutes, for example, within a range of 2 to 5 minutes, in the case of pressure sintering, and within a range of 30 to 75 minutes in the case of non-pressure sintering.

[0049] The sintering process can be carried out in any atmosphere that is not particularly subject to any restrictions. Thus, on the one hand, sintering can be carried out in an oxygen-containing atmosphere. On the other hand, sintering can also be carried out in an oxygen-free atmosphere or in a vacuum. In the context of the present invention, an oxygen-free atmosphere is understood to mean an atmosphere in which the oxygen content is 300 ppm by weight or less, preferably 100 ppm by weight or less, and even more preferably 50 ppm by weight or less.

[0050] Sintering is carried out in conventional equipment suitable for sintering, in which the above-mentioned process parameters can be set. [Example]

[0051] 1. Preparation of silver sinterable paste: Silver sinterable pastes 1 to 5 according to the invention and comparative pastes C1 to C3 were prepared according to Table 1 (all specifications in weight %). For this purpose, an organic solvent and optionally ethyl cellulose were first homogenized at 80° C. to form a solvent system. Subsequently, silver flakes and silver particles were added to the solvent system in small portions and thoroughly dispersed.

[0052] 2. Evaluation of silver sinterable paste: a) Preparation of a test structure to serve as a model: The inventive silver sinterable pastes 1 to 5 and comparative pastes C1 to C3 were applied to the relevant silver metal-coated copper-ceramic substrates by stencil printing in a wet film thickness of 300 μm. Immediately thereafter, each area of ​​the printed silver sinterable paste was provided with a further silver metal-coated copper-ceramic substrate (20 mm × 20 mm) over its entire area. The sandwich arrangement thus produced was dried in a normal air atmosphere at 120°C for 10 minutes. Subsequent pressure sintering was carried out in a hot press at 230°C and 12 MPa for 5 minutes under a nitrogen atmosphere (less than 100 ppm oxygen).

[0053] b) Evaluation of extrusion behavior: The sintered test structures were visually evaluated for the extent to which unwanted extrusion of the silver sinterable paste had occurred at the edges.

[0054] If during the sintering process no extruded sinterable paste was visible sintering at the edges below the contact surface of the loaded substrate, the extrusion behavior was rated as "+" (no unwanted extrusion).

[0055] Push-out behavior was classified as "low" if sintered silver sinterable paste was visible on less than 20% of the peripheral edge of at least one edge of the test structure adjacent to the loaded silver metallized copper-ceramic substrate.

[0056] Push-out behavior was classified as "high" if sintered silver sinterable paste was visible on more than 50% of the peripheral edge of at least one edge of the test structure adjacent to the loaded silver metallized copper-ceramic substrate.

[0057] c) Determination of shear strength: For the determination of the shear strength, the parts were sheared with a shear chisel at a rate of 2 mm / min at 20° C. The force was recorded by a 10 kN load cell (Zwick Roell Z010, Germany) instrument.

[0058] [Table 1] *Fatty acid coated silver flakes: D90: 9μm, D50: 3μm, D10: 1μm **Fatty acid coated silver particles: D90: 400nm, D50: 200nm, D10: 105nm

Claims

1. (A) 5% to 40% by weight of silver flakes having a particle size D90 in the range of 5 μm to 20 μm; (B) 50% to 85% by weight of silver particles having a particle size D90 in the range of 300 nm to 1,000 nm; (C) 10% to 25% by weight of at least one organic solvent; (D) 0% to 2% by weight of at least one cellulose derivative, and (E) 0% to 10% by weight of at least one additive different from components (A) to (D). A silver sinterable paste comprising:

2. The silver flakes have a particle size D10 in the range of 0.5 μm to 2 μm and a D50 in the range of 2.4 μm to 4 μm, and the silver particles have a particle size D10 in the range of 90 nm to 150 nm and a D50 in the range of 150 nm to 250 nm. The silver sinterable paste of claim 1.

3. 3. The silver sinterable paste of claim 1 or 2, wherein the silver flakes have an aspect ratio of greater than 5:

1.

4. The specific surface area of ​​the silver flakes is 1 m ２ / g to 5m ２ The silver sinterable paste according to any one of claims 1 to 3, wherein the silver sintering paste has a sinterability of 1 / g.

5. The compacted bulk density of the silver flakes is 1 g / cm ３ ~5g / cm ３ The silver sinterable paste according to any one of claims 1 to 4, wherein the silver sintering paste is in the range of

6. The silver sinterable paste according to any one of claims 1 to 5, wherein the aspect ratio of the silver particles is in the range of 1:1 to 5:

1.

7. The specific surface area of ​​the silver particles is 1 m ２ / g~8m ２ The silver sinterable paste according to any one of claims 1 to 6, wherein the silver sintering paste has a sinterability of 1 / g.

8. The packed bulk density of the silver particles is 3 g / cm ３ ~6g / cm ３ The silver sinterable paste according to any one of claims 1 to 7, wherein the silver sintering paste is in the range of

9. The silver sinterable paste according to any one of claims 1 to 8, wherein the at least one cellulose derivative is selected from the group consisting of methyl cellulose, ethyl cellulose, ethyl methyl cellulose, carboxy cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, and hydroxymethyl cellulose.

10. The silver sinterable paste according to any one of claims 1 to 9, which does not contain glass particles.

11. The silver sinterable paste according to any one of claims 1 to 10, which does not contain any thermally decomposable metal precursor.

12. 12. A method for connecting components, comprising: (1) providing a sandwich arrangement comprising at least two components and the silver sinterable paste of any one of claims 1 to 11 positioned between the components; (2) optionally drying the sinterable paste; and (3) sintering the sandwich arrangement.

13. 13. The method of claim 12, wherein sintering is carried out under pressure or pressureless.

14. The method according to claim 12 or 13, wherein the component is a component used in an electronic device.

Images