ECRI Microelectronics

Capabilities

Thick Film

Thick film hybrid technology is a widely-used technology for the manufacture of a ceramic or other type of circuit boards. Due to its high degree of integration, thick film substrates form the basis of High Density Packages (HDP).

In an initial manufacturing phase, the structures are applied by means of a silk-screen process onto the relevant substrate material such as aluminium oxide (Al203) or alumina (AIN). Conductors, resistors, insulations and overglazes can be manufactured. Gold, silver and platinum or palladium alloys are generally used as conductive materials. The standard thick film process are printing, drying and firing. The firing process at about 850 °C guarantees the final film properties such as electrical values and adhesive strength.

Thick film technology enables a very simple and flexible manufacture of multilayers with several conductive layers on the front and back side of the substrate.

Minimum structure resolutions of 80 - 100 µm can be achieved with this technology.

Printed resistors can be trimmed to a output signal of a hybrid circuit. In principle all electronic components can be assembled on a thick film substrate. Therefore solderable as well as bondable surfaces are available.

Benefits

The benefits compare to traditional printed circuit boards are in the thermal and electrical properties of the thick film substrate material. Ceramics are very heat-conductive and as one of the chip base materials, are therefore optimally matched to the TCE of silicon. The above mentioned structure resolutions and the integration of printed, passive components make a circuit miniaturisation possible.

Applications

Due to the positive properties of the ceramic base material, thick film circuits are used as a priority in areas which are characterised by harsh environmental conditions (high/low temperatures, temperature changes, moisture, vibrations, accelerations etc.). This technology meets the requirements of the highest integration, reliability, lifetime and environmental compatibility.

Areas of application include industrial electronics, medical electronics as well as automotive and aerospace industry.

Process

screen printing

screen-printing

Sintering

sintering

Layer thickness testing

layer-thickness-testing

Laser trimming


laser-trimming

Assembly Center

assembly-center

Bonding

bonding


ECRIM thick film product line capability

Line-width/Space               125 um /100um

Substrates                     Al2O3,  ALN

Conductors               Au,  Ag,  PtAg,  PaAg,  PtPaAu

Bonding                      Au, Si-Al

Hermetic sealed                Metal Package

Resistors’s tolerence             ≤±1%

Resistor TCR                   ±100ppm/℃

Resistor Tracking                ±25ppm/℃

Ω/Sq Resistor Range              1-10M                

Number of multilayers            6 (up)

Size of substrates                120mmx120mm (up)

Inspection standard              MIL-PRF-38534  CLASS H

Annual Total output : 1,000,000 units





Thin Film

Thin film describes a technology for the manufacture of a high-resolution circuit board based on a ceramic or other substrate. Due to its high degree of integration, thin film substrates form the basis of High Density Packages (HDP).

The structuring process is comparable to a traditional circuit board. The adhesive, resistor and metallization films are deposited onto the substrate surface using sputter techniques. This metallisation technology ensures an optimum adhesion of the films onto the substrate. In the subsequent photolithographic and etching processes, these films are structured according to the layout requirements. If necessary, an electroplating of the conductors is possible. Depending on the film thickness, minimum structure resolutions of 5 - 20 µm can be achieved. With the corresponding material and surface combinations, solderable and bondable surfaces can be produced. This enables the usage of the most varied of components up to a bare die assembly. The resistors produced in the thin film can be trimmed to a fixed value or according to a output signal of a hybrid circuit.

Benefits
The benefits compared to traditional printed circuit boards are the thermal and electrical properties of the substrate material as well as the fine line possibilities. The ceramic base material is very heat-conductive and as one of the chip base materials, is optimally matched to the TCE of silicon. With the above mentioned structure resolutions, considerably higher packaging and function densities can be achieved than on a conventional circuit board.

Applications
Thin film circuits meet the highest of requirements relating to reliability, lifetime and environmental compatibility. They are mainly used in the data communication units of automobile construction, telecommunications, medical and aerospace electronics. Through the reproducible electrical properties of the base substrate and the high and precise structure resolution, this technology is particularly well suited for high-frequency applications.

ECRIM thin film product capability

ECRI Microelectronics undertakes processing service of thin film products with different wafer thickness, provides various customized services, processing on a commission basis and process solutions of thin film products, has the processing capability as of thin film evaporation, sputtering, laser etching, electroplating, laser resistance trimming, wafer slicing, etc. and can provide process design schemes for thin film products.


We provide design schemes and products of various types of thin film resistance and resistance network and thin film attenuation slice , and can provide OEM processing of various kinds of ceramic film wafer and microwave wafer. We have cooperated with many microwave design units, and the frequency of manufactured microwave wafer can reach 40G Hz. Our thin film equipment and products take a leading position within the sector, the thin film production line has passed ISO9001:2002 certification, and the quality of our products satisfies the requirements of general specification for hybrid integrated circuit (MIL-PRF-38534).


Table 1 Characteristics and general applications of wafer materials for thin film

Wafer material

Dielectric constant and tolerance

Thermal expansion coefficient (ppm/oK)

Aluminum nitride (AlN)

8.85 +/- 0.35 @ 1 MHz

4.6

Aluminum oxide 99.6% (Al2O3 )

9.9 +/- 0.15 @ 1 MHz

6.5

* Other wafers can be customized separately as per customer’s demand.

 

Table 2 The recommended application method for thin film wafers

Frequency

Recommended thickness

Recommended dimensions of wafer (inch)

≤6 GHz

0.635mm

3 x 3

≤18 GHz

0.380mm

3 x 3

≤40 GHz

0.250mm

3 x 3

>40 GHz

0.125mm

2 x 2

 



Table 3 Reference values for design of common thin-film circuits


Parameter

Typical index

Limit index

Remarks

Wire width/line spacing

≥25μm

10μm

 

Bore size

≥500μm

250μm

Laser cutting

Line precision

3μm

2μm

 

Graphic margin

≥127μm

50μm

 

Resistance precision

≤±10%

±0.1%

Laser resistance trimming (medium resistance)

Thickness of metal layer

≥1μm

3μm

 

 


HTCC

What is HTCC?
HTCC (High Temperature Co-fired Ceramic), using high-melting-point metal heating resistor paste made of tungsten, molybdenum, molybdenum, manganese, is printed on 92~96% alumina cast ceramic according to the requirements of heat circuit design. On the green body, 4 to 8% of the sintering aid is then laminated, and co-fired at 1500 to 1600 ° C at a high temperature. Therefore, it has the advantages of corrosion resistance, high temperature resistance, long life, high efficiency and energy saving, uniform temperature, good thermal conductivity and fast thermal compensation, and is free from lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers, etc. Substance, in line with EU RoHS and other environmental requirements. Due to the high firing temperature, HTCC cannot use low-melting metal materials such as gold, silver, copper, etc., and must use refractory metal materials such as tungsten, molybdenum, manganese, etc. These materials have low conductivity and cause signal delay and other defects, so it is not suitable for A substrate for high speed or high frequency micro-assembled circuits. However, the HTCC substrate has the advantages of high structural strength, high thermal conductivity, good chemical stability, and high wiring density. HTCC ceramic heating sheet is a new type of high-efficiency environmental protection and energy-saving ceramic heating element. The products are widely used in daily life, industrial and agricultural technology, military, science, communication, medical, environmental protection, aerospace and many other fields.

The classification of HTCC
Among the high-temperature co-fired ceramics, ceramics mainly composed of alumina and aluminum nitride are mainly used. Alumina ceramic technology is a relatively mature microelectronic packaging technology. It is made of 92~96% alumina, plus 4~8% sintering aid at 1500-1700°C. The wire material is tungsten and molybdenum. , refractory metals such as molybdenum-manganese. The disadvantages of aluminum nitride substrates are:
(1) The wiring conductor has high resistivity and large signal transmission loss;
(2) High sintering temperature and high energy consumption;
(3) The dielectric constant is higher than that of the low temperature co-fired ceramic dielectric material;
(4) After the aluminum nitride substrate is co-fired with a conductor such as tungsten or molybdenum, the thermal conductivity thereof is decreased;
(5) The outer conductor must be plated with nickel to protect it from oxidation, while increasing the electrical conductivity of the surface and providing a metallization layer capable of wire bonding and soldering component placement.

LTCC
The LTCC (Low Temperature Co-Fired Ceramic) is a ceramic wiring carrier with a multi-layer structure. A flexible raw material (Green Tape) is used as a base. This unsintered film consists of a mixture of glass, ceramic and organic solvents. The firms Heraeus, DuPont and Ferro for example supply this raw material.

In the manufacturing of a LTCC Ceramic, a corresponding number of layers is started through the cutting of the Green Tapes. Prior to their further processing some materials require an additional Temper-Process at about 120 °C. As a second step the different layers are mechanically processed. This means that the adjustment and plated-through holes (Vias) are punched in the tapes. This is followed by a via-filling pressure and the application of the metallisations, resistors and the other films using a thick film-silk screen process. The usual conductive materials are gold, silver, platinum and palladium alloys. The injecting of the layers and the subsequent sintering at about 850 °C - 900 °C produce the finished multilayers. The sintering causes the LTCC material to shrink by about 12% in the x/y direction and 17% in the z-direction. It is particularly the shrinkage on the x/y-level that adversely affects any adherence to the structural precision. In order to prevent this, non-shrinkage material for the x/y-direction (0.1%) has been developed. This positive effect is achieved through a combination of specially developed tape materials. When deploying this material the increase of the shrinkage in the z-direction (about 45%), especially in the utilisation of holes and cut-out sections, must not be ignored. If this is observed in the construction and processing phases then the 0-shrinkage tape is a step forward in comparison to the traditional LTCC tape material.

Benefits
The possibility of processing the layers individually and in different ways prior to the sintering enables the LTCC to also be used as a packaging construction element. In this way cavities, ducts and other forms can be achieved. This technology enables multilayer structures to be achieved in a simple way with integrated, passive components. LTCC also possesses, apart from the thermal conductivity, the same positive features as thick film circuitry. The leakage of waste heat must be carried out via thermal vias if necessary.

Line-width/space                              75um

Line accuracy                                 ≤±5 um

Camber                                        <3mil/in

Embedded component                            resistors, capacitors, inductors

Number of layers                              30(up)

Tape Choice                                   Dupont 951/943   Ferro A6S/M,  Heraeus

Via Size(Min)                                 100 um

Conductor Material                            Ag, Au, Hybrid system

Cavity                                        Open / Embedded

Via Materail                                  Ag, Au, Transitional material

Thermal Via                                   Optional

Size of substrates                            150mmx150mm  (up)

Inspection of  I/O                            Automatic Test and Vision Inspection

Inspection standard                           MIL-PRF-38534  CLASS H

Annual Total output of LTCC Substrate         5,000,000cm2