1. The connotation of micro-assembly technology and its relationship with electronic assembly technology

1. Connotation-micro assembly technology (micrcopackging technologu)

It is the abbreviation of microelectronic packging technology, which is a new generation of advanced electronic assembly technology. It assembles highly integrated IC devices and other components on a high-density multilayer substrate through micro-welding interconnection and micro-encapsulation process technology to form a comprehensive high-tech microelectronic product. It is an advanced hybrid microelectronics. technology.

 

2. The relationship between micro-assembly technology and electronic assembly technology

Microelectronics assembly technology The latest development of electronic assembly technology is a new generation of advanced (advanced) electronic assembly technology, which belongs to the fifth generation of electronic assembly technology (from the 1980s to the present). Compared with traditional electronic assembly technology, its characteristic is in the word "micro". The word "micro" has two meanings: one is miniaturization, and the other is aimed at the electronic field.

2. The effect of micro-assembly technology on the development of the whole machine

Micro-assembly technology is an important technical way to give full play to the high-integration, high-speed monolithic IC performance and realize the integration of small, lightweight, multi-functional, and highly reliable electronic systems.

3. Levels and key technologies of micro-assembly technology

1. The level of micro-assembly technology-the micro-assembly level of the whole system can be roughly divided into three levels:

1) Level 1 (chip level)-refers to the packaging of a single chip through ceramic carrier, TAB and flip-chip bonding structure.

 

 

2) Level 2 (component level)-refers to the assembly of various bare chips, carrier IC devices, flip-chip devices, and other micro components on various multilayer boards, with appropriate packaging and heat sinks, to form Electronic components (such as MCM).

3) Level 3 (printed circuit board level)-refers to the assembly of multi-chip components and other microelectronic components, single-chip packaged devices, and other functional components on a large-area multilayer printed circuit board to form large electronic components Or the whole system.

2. Key technologies-the following are the main key technologies of different micro-assembly levels:

1) The main chip-level key technologies-bump formation technology and ball planting technology, KGD technology, TAB technology, fine-pitch wire bonding technology, and fine-pitch lead packaging technology.

2) The main key technologies at the component level-multilayer wiring substrate design, process, materials and testing technology, flip chip bonding, testing and cleaning technology, fine pitch wire bonding technology, chip interconnection reliability evaluation and testing technology, high thermal conductivity Packaging design, process, materials and sealing technology, integration technology of other chip components.

3) The main key technology of the printed board level-circuit segmentation design technology, large-area multi-layer printed circuit board design, technology, materials, testing technology and structure design, process technology and interconnection technology of components and motherboards.

Fourth, the technical connotation, advantages and types of multi-chip modules (MCM)

1. Technical connotation-MCM is the English abbreviation of Multichip module, which is usually translated as multi-chip module (also translated as multi-chip module).

The category of MCM technical term hybrid microelectronics technology is a concentrated expression of the high-level development of hybrid microelectronics technology, and is a kind of advanced hybrid integrated circuit technology.

Regarding the definition of MCM, there are many opinions in the world. From my point of view, qualitatively, MCM should have the following three conditions: (1) a high-density multilayer wiring substrate; (2) containing more than two bare chip ICs (usually large-scale integrated circuits); (3) Assembled in the same package. That is to say, MCM is a high-density microelectronic component that is assembled with more than two bare chip ICs (usually LSI) and other micro components on a high-density multilayer wire substrate and packaged in the same housing.

2. Advantages-MCM technology has the following main advantages.

1) Make the circuit assembly more dense, and further realize the miniaturization and light weight of the whole machine. Compared with the SMT assembly circuit with the same function, the weight of MCM can be reduced by 80%-90%, and its size can be reduced by 70%-80%. In the field of military applications, the miniaturization and lightweight effect of MCM is more obvious. The use of MCM technology can reduce the size of the missile by more than 90%, and the weight can be reduced by more than 80%. The satellite microwave communication system adopts T/R components made by MCM technology, and its volume is only 1/10-1/20 of the original.

2) Further improve performance and achieve high speed. Compared with the usual SMT assembly circuit, the signal transmission speed of MCM can generally be increased by 4-6 times. NEC Company studied the application of MCM in mainframe computers during 1979-1989. From the use of general thick film multilayer wiring to the use of advanced multi-chip components—hybrid multi-chip components, the operating speed of its system was increased by 37 times. Up to 22 billion times per second. The use of MCM technology effectively reduces the interconnection distance, interconnection capacitance, resistance and inductance between high-speed VLSIs, thereby greatly reducing the signal transmission delay.

3) Improve reliability. Statistics show that about 90% of the disappearance of electronic complete machines is caused by packaging and interconnection. Compared with the SMT assembly circuit, MCM has reduced solder joints per unit area by more than 95%, reduced I/O number per unit area by more than 84%, reduced excuses per unit area by more than 75%, and greatly improved heat dissipation and reduced junctions. Temperature, thermal stress and overload stress are greatly reduced, thereby improving reliability by more than 5 times.

4) Easy to implement functions. MCM can assemble components with multiple functions such as analog circuits, digital circuits, optoelectronic devices, microwave devices, sensors and their chip components, and form electronic components and subsystems through high-density interconnection. Or system. The computer system developed by Hughes Reserch laboratory using three-dimensional multi-chip component technology is a typical example of MCM implementation of system-level components.

3. Types and characteristics-usually according to the structure and process of the high-density multilayer wiring substrate used in MCM, MCM can be divided into the following types.

1) Laminated MCM (MCM-L, where L is the first letter of the English word "Laminate" for "Laminate") has also become an L-type multi-chip module, which is composed of a high-density multilayer printed circuit board Multi-chip components are characterized by low production costs and relatively mature manufacturing processes, but the wiring density is not high enough, and their assembly efficiency and performance are low. They are mainly used in products below 30MHz and 100 solder joints/in² and the application environment is not too harsh Consumer electronics and personal computers.

2) Thick-film ceramic MCM (MCM-C, where C is the first letter of the English name "Ceramic"), is composed of high-density thick-film multilayer wiring substrates or high-density co-fired ceramic multilayer substrates Multi-chip components. Its main characteristics are high wiring density, moderate manufacturing cost, can withstand harsher use environments, and have high reliability. Especially the MCM-C composed of low-temperature co-fired ceramic multilayer substrates is easy to use on multilayer substrates. The components are embedded in the center to further reduce the volume to form a multi-functional microelectronic assembly. MCM-C is mainly used in 30-50MHz high-reliability medium and high-end products. Including automotive electronics and mid-to-high-end computers and digital communications.

3) Deposition-type MCM (MCM-D, where D is the first letter of the English name Deposition for "deposition"), which is a multi-chip module composed of a high-density thin-film multilayer wiring substrate. Its main features are high wiring density and assembly efficiency, as well as good transmission characteristics, frequency characteristics and stability.

4) Hybrid MCM-H (MCM-C/D and MCM-L/D, in which the English letters C, D, and L have the same meaning as above), which is a multi-chip module composed of a high-density hybrid multi-layer substrate. This is an advanced type of multi-chip module, which has the best performance/price ratio, high assembly density, and lower noise and wiring delay than other types of MCM. This is because the hybrid multi-layer substrate combines different multi-layer substrate process technologies to give play to their respective strengths. Especially suitable for huge, high-speed computer systems, high-speed digital communication systems, high-speed signal processing systems and notebook computer subsystems.

5. Electrical connection between components and motherboard (PCB)

Require

1) Electrical requirements

Signal interconnection

Power/ground interconnection

2) Heat dissipation capacity

3) Mechanical ability

4) I/O requirements

Main types of links

1) ZIF plug-in pin connection (see Figure A below)

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Figure A ZIF pin connection

2) Spring connection (see figure B below)

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Figure B Spring connection

3) The insert rod is firmly connected (see Figure C below)

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Figure C Fastening connection of plunger

4) Flexible circuit ZIP interconnection

6. Three-digit multi-chip module (3D-MCM) technology definition, advantages and types

Definition-refers to the multi-chip module technology (also known as MCM-V) that realizes high-density assembly of semiconductor chips in the three directions of X, Y, and Z.

Advantages-higher assembly density can be achieved (the assembly density can reach 200%, while the highest assembly efficiency of 2D-MCM is 90%), smaller size, lighter weight, more functions, and better performance. Even one component can be realized as a complete system.

Type-mainly consists of the following two types

1) 2D-MCM stack assembly

2) Chip stack assembly (through wire bonding or bumps, TAB, etc.)

Seven, the definition of thick film hybrid circuit and its application characteristics

definition

Thick-film hybrid integrated circuits (referred to as thick-film hybrid circuits or thick-film circuits) use thick-film paste or ink screen printing and sintering technology to form thick-film wiring and soldering on ceramic substrates or other high thermal conductivity substrates. Area and thick film resistors to form a thick film circuit film substrate, and then use surface mount technology (SMT) and bonding technology to assemble semiconductor chips and other chip components to form a microcircuit with a certain function.

Application characteristics

Thick film circuits have the characteristics of high power density, large carrying current, high voltage, good high-frequency characteristics, small size, high reliability and stability, flexible design, and easy realization of multi-function microcircuits. They are especially suitable for making small and reliable power Circuits (including DC/DC converters, DA/AC converters, AC/DC converters, AC power supplies, drivers, power amplifiers, voltage regulators, etc.) and high-density, high-reliability multi-function microcircuits are widely used in aerospace, Electronic systems such as guidance, remote control, power, fuze, control, inertial navigation and signal processing in the fields of aviation, ships, weapons, radar, electronic countermeasures, communications, automobiles, and computers.

NASA has developed the computing component of the missile guidance computer using thick-film hybrid integration technology. Among them, a 2.88in square thick film multilayer wiring substrate is used to assemble 5 large-scale semiconductor integrated circuit chips, 12 medium-scale semiconductor integrated circuit chips (TTL), 6 chip capacitors and 6 chip resistors, 629 pieces Bonding interconnect wires.

Using thick film integration technology to make thick film hybrid integrated DC/DC converters is a large category of thick film hybrid circuits. The power range of its products is 1W-120W, the maximum current is 20A, the number of output channels is from single to three, the switching frequency is 300KHz-550KHz, the power density of domestic 120W DC/DC converter products reaches 78W/in³, the output voltage is 15V, and the output The current is 8A, the efficiency is 85%, and the ripple is <100 mV. The electrical performance is the same as that of INTEROINT similar products, and the functional density is higher than that of INTEROINT similar products (the latter is 66.3W/in³), and it can also produce high-voltage output (160V-900V) thick film hybrid integrated DC/DC converters.

Advantages of using thick film hybrid circuit technology to make DC/DC power supplies:

1) Reduce product volume and weight

Compared with the conventional PCB board assembly power supply, the weight can be reduced by 30%-60%, and the volume can be reduced by 25%-70%

2) Improve power density (25%-70%)

3) Improve the micro-assembly density to 30-40 components/square centimeter

4) Extended operating temperature range (-55℃-125℃)

5) Improve reliability and frequency.

For example, the power density and weight comparison of a 100W DC/DC power supply:

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Thick film hybrid integrated filters include two types: power filters (passive) and signal filters (active). The former is also called WMI filter, used in conjunction with DC/DC power supply, input 16V-40V, output circuit maximum 15A, insertion loss 40db (at 500kHz); the latter is a useful frequency model by suppressing or attenuating unnecessary frequency signals, press There are many different functional requirements. The thick-film hybrid integrated programmable filter composed of integrated operational amplifier + RC is a kind of signal filter.

Thick film hybrid integrated AC power supply includes: single-phase 400Hz and 16kHz AC power supply, 500Hz AC power supply, 500Hz motor AC power supply, 8kHz AC power supply, etc.

The thick film hybrid integrated driver includes various motor servo circuits, including DC motor servo circuits, stepper motor drive circuits, high-power motor drives, permanent magnet motor drive circuits, power amplifiers, etc.

8. Definition of thin film hybrid circuit and its application characteristics

1. Definition

Using physical vapor deposition (PVD, evaporation, sputtering and ion plating, etc.) or chemical vapor deposition (CVD) process and wet etching (photolithography) or dry etching (plasma etching, etc.) pattern formation technology, on the substrate Thin-film components and wiring are formed on the surface, and then micro-components (mostly new chips and chip components) are assembled to form a micro-circuit with a certain function.

The distinction between "thin film" and "thick film" is mainly based on the process technology, rather than the film thickness (although the thickness is different, as mentioned in GJB548, the film thickness is usually less than 5 microns).

2. Application features

Thin film circuits have the following characteristics: high accuracy, good stability, good high-frequency characteristics, high assembly density, and fast signal transmission speed. Its application is mainly in three aspects:

1) High-precision conversion circuits, such as high-digit (12-18 digits) digital/analog, analog/digital conversion circuits, shaft angle digital conversion circuits, f/V and V/f converters, etc. (high precision and good stability specialty).

2) High-frequency and microwave circuits (using the characteristics of good high-frequency characteristics), the application frequency of thin-film lumped parameter microwave hybrid integrated circuits can be as high as 15-30GC, if combined with distributed parameter circuits, it can be used for 60GC.

3) Signal and data processing circuit (using the characteristics of thin lines, high wiring density and fast signal transmission speed).

Among the microwave circuits used in the communication field, thin-film hybrid circuits account for about 80%. In the attack radar of the F-111 fighter, the high-frequency part uses the thin-film hybrid circuit, and the intermediate frequency uses the thick-film circuit. Compared with the original discrete component circuit, the whole machine is 75% smaller in volume and 63% smaller in weight. It is reliable The performance has been increased by 3.5 times. The airborne radar data processing system of the F-22 fighter adopts MCM-D (Hughes Corporation) with the title of thin film technology, which reduces the weight of the airborne radar by 96% and the volume by 93%. In the 1980s, the American Weibo Company successfully developed an 18-bit hybrid integrated D/A converter using thin-film hybrid circuit technology for the first time, with a linear accuracy of 0.008%, which was the world's most accurate S/A converter at that time.

9. Types and application characteristics of co-fired ceramic multilayer substrates

1. Type

1) High temperature co-fired ceramic multilayer substrate (HTCC)

2) Low temperature