Passive electronic components from nano-precision engineered materials

• US 5,952,040 A
• Filed: 10/11/1996
• Issued: 09/14/1999
• Est. Priority Date: 10/11/1996
• Status: Expired due to Term

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: Nanomaterials Research Corp.
• Inventors: Yadav, Tapesh, Yang, Mark L.
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): BARR, MICHAEL E
• Application Number:
  US08/730,661
• Time in Patent Office: 1,068 Days
• Field of Search: 427/125, 427/126.3, 427/376.2, 427/419.2, 427/79, 427/189, 156/73.1, 156/306.3
• US Class Current: 427/126.3
• CPC Class Codes: B01J 2219/00135 Electric resistance heaters
• CPC Class Codes: B01J 2219/00177 controlling the pH
• CPC Class Codes: B01J 2219/0018 controlling the conductivity
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 5/00 Nanobiotechnology or nanomedicine, e.g. protein engineering or drug delivery
• CPC Class Codes: C01P 2002/02 Amorphous compounds
• CPC Class Codes: C01P 2002/60 Compounds characterised by their crystallite size
• CPC Class Codes: C01P 2004/38 cube-like
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2006/10 Solid density
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C04B 2111/00844 for electronic applications
• CPC Class Codes: C04B 35/00 Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 35/62222 obtaining ceramic coatings coating of mortars, concrete, artificial or natural stone or ceramics C04B41/45; laminated ceramic products B32B18/00; coating metallic materials C23; coating of glass C03C17/00, applying ceramic coatings on silicon for semi-conductor purposes H01L
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4547 characterised by the grain distribution
• CPC Class Codes: C04B 41/5027 Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5116 : Ag or Au
• CPC Class Codes: C04B 41/52 : Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
• CPC Class Codes: C04B 41/89 : for obtaining at least two superposed coatings having different compositions
• CPC Class Codes: H01C 7/112 : ZnO type
• CPC Class Codes: H01G 4/12 : Ceramic dielectrics H01G4/085 takes precedence
• CPC Class Codes: H01G 4/33 : Thin- or thick-film capacitors thin- or thick-film circuits H01L27/00; capacitors without a potential-jump or surface barrier specially adapted for integrated circuits, details thereof, multistep manufacturing processes therefor H01L28/40

Abstract

Nanosize powders with particle size smaller than the critical length for specific material properties are used to form the ceramic layers of passive electronic components. Ceramic substrates are coated with electrodes, which are then coated with a ceramic layer from a suspension, preferably a low viscosity suspension, of nanoscale powders. The ceramic layer is dried at low temperatures (preferably below 200 ° C.) and it is sintered to high density (preferably above 90%) at moderate temperatures (preferably low and less than 1,000 ° C.). Once sintered, an electrode layer is coated on top of the ceramic layer to yield an electrode/ceramic/electrode structure.

Claims

1. A process for producing a ceramic-layer structure for passive electronic components comprising the following steps:

preparing a suspension of ceramic material in powder form having particle size smaller than the largest one of mean free path, domain size or skin depth in said ceramic material;

depositing said powder of ceramic material over a substrate to form a nanostructured ceramic layer;

sintering said ceramic layer at a temperature sufficient to densify the ceramic layer;

and processing the ceramic layer to from the passive electronic component.

2. The process of claim 1, wherein said ceramic material in powder form consists of particles having an average grain size less than about 100 nm with a standard deviation less than about 25 nm.

3. The process of claim 1, wherein said sintering temperature is less than about 1,050°

C.

4. The process of claim 1, wherein said ceramic material in powder form consists of particles having an average grain size less than about 100 nm with a standard deviation less than about 25 nm, and said sintering temperature is less than about 1,050°

C.

5. The process of claim 1, wherein said sintering temperature is less than 950°

C.

6. The process of claim 1, wherein said ceramic material in powder form consists of particles have an average grain size less than about 100 nm with a standard deviation less than about 25 nm, and said sintering temperature is less than 950°

C.

7. The process of claim 1, further comprising the step of pressing said nanostructured ceramic layer after the deposition step.

8. The process of claim 1, wherein said suspension of ceramic material consists of a liquid suspension;

and further comprising the step of sonicating the suspension prior to the deposition step.

9. The process of claim 8, further comprising the step of pressing said nanostructured ceramic layer after the deposition step.

10. The process of claim 1, further comprising the steps of depositing a predetermined number of alternate electrode and ceramic layers over said nanostructured ceramic layer prior to performing the sintering step, so as to produce a multilayered structure.

11. The process of claim 1, further comprising the steps of depositing an electrode layer over said nanostructured ceramic layer after the sintering step, depositing a new ceramic layer over said electrode layer, sintering said new ceramic layer, and repeating these steps to form a multilayered structure.

12. A process for producing a ceramic-layer structure for passive electronic components from a precursor ceramic material, comprising the following steps:

evaporating the precursor ceramic material in a gaseous atmosphere in a thermal reactor, thereby creating a vapor/gas mixture;

quenching said vapor/gas mixture by effecting its expansion through a pressure drop, thereby causing the formation of a nanopowder of ceramic material in a product gas, the nanopowder having particle size smaller than the largest one of mean free path, domain size or skin depth in said ceramic material;

separating said nanopowder of ceramic material from said product gas;

depositing the nanopowder of ceramic material over a supporting substrate to form a ceramic layer;

sintering said ceramic layer at a temperature sufficient to densify said ceramic layer;

and processing the ceramic layer to from the passive electronic component.

13. The process of claim 12, wherein said nanopowder consists of particles having an average grain size less than about 100 nm.

14. The process of claim 12, wherein said sintering temperature is less than about 1,100°

C.

15. The process of claim 12, wherein said nanopowder consists of particles having an average grain size less than about 100 nm and said sintering temperature is less than about 1,100°

C.

16. The process of claim 12, wherein said sintering temperature is less than about 950°

C.

17. The process of claim 12, wherein said nanopowder consists of particles having an average grain size less than about 100 nm and said sintering temperature is less than about 950°

C.

18. A process for producing a dielectric-layer structure for capacitors comprising the following steps:

depositing a layer of electrode material over a supporting substrate to form a first electrode layer;

depositing nanoscale particles of dielectric material over said electrode layer to form a dielectric layer, the nanoscale particles having particle size smaller than the largest one of mean free path, domain size or skin depth in said dielectric material;

depositing another layer of electrode material over said dielectric layer to form a second electrode layer;

sintering said dielectric layer at a temperature sufficient to densify the dielectric layer; and

processing then dielectric layer structure to form the capacitor.

19. The process of claim 18 wherein said nanoscale particles have an average grain size less than about 100 nm.

20. The process of claim 18, wherein said electrode material is silver and said temperature is less than about 950°

C.

21. The process of claim 18, wherein said nanoscale particles have an average grain size less than 100 nm, said electrode material is silver and said temperature is less than 950°

C.