What is chip encapsulation?

What is the encapsulation on top of an integrated circuit chip? 50 points

One of the roles of the integrated circuit package is to protect the chip from environmental protection, to avoid contact between the chip and the external air. Therefore, according to the specific requirements of different categories of integrated circuits and the use of places, to take different processing methods and the selection of different encapsulation materials, in order to ensure that the encapsulation structure of the airtightness to meet the requirements of the provisions of the requirements. Integrated circuits in the early days of the encapsulation material is the use of organic resins and waxes of the mixture of fixed, with the filling or filling method to achieve the encapsulation, obviously poor reliability. Rubber has also been applied to sealing, due to its heat resistance, oil resistance and electrical properties are not ideal and eliminated. Currently widely used, the most reliable performance of hermetic sealing materials are glass - metal sealing, ceramic - metal encapsulation and low-melting glass - ceramic sealing. In the mass production and cost reduction needs, plastic model package has been a large number of emergence, it is a thermosetting resin through the mold for heating and pressing to complete, its reliability depends on the characteristics of organic resins and additives and molding conditions, but because of its poor heat resistance and moisture absorption, can not be comparable with the performance of other sealing materials, is still a semi-hazardous or non-hazardous sealing materials.　With the maturity of chip technology and the rapid increase in chip yield, the rear sealing costs account for the proportion of the cost of the entire integrated circuit is also getting bigger and bigger, encapsulation technology changes and development of the ever-changing, dazzling.

What is chip packaging for pcb?

Each chip has a datasheet, which describes the application, structure, package, and material number. When you do a decal in Power PCB, you need to refer to the datasheet for the description of the structure and package, which includes the size, shape, and order of each pad.

How is the chip package differentiated.

Chip package at a glance:

1, BGA (ball grid array)

Ball Grid Array, one of the surface mount packages. On the back of the printed substrate in accordance with the display mode to create a spherical bump to replace the pin, the front of the printed substrate assembly LSI chip, and then sealed with molded resin or potting method. It is also called a bump array carrier (PAC). This is a package for multi-pin LSIs with more than 200 pins. The package body can also be made smaller than QFP (Quad Flat Pack). For example, a 360-pin BGA with 1.5 mm pin center distance is only 31 mm square, while a 304-pin QFP with 0.5 mm pin center distance is 40 mm square. Moreover, the BGA does not need to worry about the pin deformation problem of the QFP. This package was developed by Motorola in the U.S., and was first adopted in devices such as portable telephones, and is likely to be popularized in personal computers in the U.S. in the future. Initially, the center distance between the pins (bumps) of BGA was 1.5mm and the number of pins was 225, and now some LSI manufacturers are developing 500-pin BGAs. The problem with BGAs is the appearance check after reflow. It is not clear whether there is an effective cosmetic inspection method. Some believe that the connection can be considered stable due to the large center distance of the solder and can only be handled by functional checking. Motorola USA refers to packages sealed with molded resin as OMPAC, and packages sealed by potting methods as GPAC (see OMPAC and GPAC).

2, BQFP (quad flat package with bumper)

With buffer pads on all four sides of the pin flat package. one of the QFP package in the package body of the four corners of the protrusion (cushioning) in order to prevent bending and deformation of the pins in the delivery process. This package is used by U.S. semiconductor manufacturers mainly for circuits such as microprocessors and ASICs. The pin center distance is 0.635mm, and the number of pins ranges from 84 to about 196 (see QFP).

3, touch solder PGA (butt joint pin grid array)

Surface mount PGA alias (see surface mount PGA).

4, C - (ceramic)

The notation for ceramic packages. For example, CDIP indicates a ceramic DIP, a symbol often used in practice.

5, Cerdip

Ceramic double in-line package sealed with glass, used for ECL RAM, DSP (digital signal processor) and other circuits. Cerdip with a glass window is used for UV-erased EPROMs and microcomputer circuits with internal EPROMs. The pin center distance is 2.54mm, and the number of pins is from 8 to 42. In Japan, this package is called DIP-G (G means glass sealed).

6, Cerquad

One of the surface mount packages, that is, with the lower sealing ceramic QFP, used to package logic LSI circuits such as DSP. Cerquad with a window is used to package EPROM circuits. It has better heat dissipation than plastic QFP and can accommodate 1.5 to 2W of power under natural air-cooling conditions. However, the package cost is 3 to 5 times higher than plastic QFP. The pin center distance is 1.27mm, 0.8mm, 0.65mm, 0.5mm, 0.4mm and other specifications. The number of pins ranges from 32 to 368.

7, CLCC (ceramic leaded chip carrier)

Ceramic chip carrier with pins, one of the surface mount packages, the pins lead from the four sides of the package, in the shape of a ding.

The windowed ones are used to package UV-erased EPROMs and microcomputer circuits with EPROMs, etc. This package is also known as QFJ, QFJ, QFJ, QFJ, and QFJ. This package is also known as QFJ, QFJ-G (see QFJ).

8, COB (chip on board)

Chip on board package, is one of the bare chip mounting technology, semiconductor chip cross-mounted on the printed circuit board, the chip and the substrate of the electrical connection with the lead stitching method to achieve the chip and the substrate of the electrical connection with the lead stitching method to achieve, and covered with resin to ensure reliability. Although COB is the simplest bare chip placement technology, its packaging density is far less than TAB and flip-chip soldering technology.

9, DFP (dual flat package)

Dual side pin flat package. It is S...... >>

What is the principle of chip packaging?

The package with vinyl means COB (Chip On Board) package, right?

COB packaging process is as follows:

The first step: expand the crystal. Expansion machine will be provided by the manufacturer of the entire sheet of LED wafer film uniform expansion, so that attached to the surface of the film tightly arranged LED grains to pull apart, easy to stab the crystal.

The second step: adhesive backing. Expand the crystal of the crystal expansion ring on the surface of the backing machine has scraped a good layer of silver paste, backed with silver paste. Point silver paste. Applicable to bulk LED chips. The use of dispensing machine will be the appropriate amount of silver paste point in the PCB printed circuit board.

Step 3: Put the crystal expansion ring prepared with silver paste into the stabbing frame, and the operator will stab the LED wafer with the stabbing pen on the PCB printed circuit board under the microscope.

The fourth step: the PCB printed circuit board will be stabbed crystal into the thermal cycle oven at a constant temperature for a period of time, to be removed after the silver paste is cured (can not be left for a long time, otherwise the LED chip plating will be baked yellow, i.e., oxidation, to the bonding caused by the difficulties). If there are LED chip bonding, you need the above steps; if only IC chip bonding is canceled above steps.

Step 5: Sticky chip. With a dispenser in the PCB printed circuit board IC location on the appropriate amount of red glue (or black glue), and then use anti-static equipment (vacuum suction pen or sub) will be IC die correctly placed on the red glue or black glue.

Step 6: Drying. Stick the good die into the thermal cycle oven on a large flat heating plate at a constant temperature for a period of time, you can also natural curing (longer time).

Step 7: Bonding (wire). The use of aluminum wire bonding machine will be the chip (LED grain or IC chip) and PCB board corresponding pad aluminum wire for bridging, that is, the COB of the inner lead welding.

Step 8: Pre-test. The use of special testing tools (according to different uses of COB has different equipment, simple is a high-precision voltage stabilized power supply) to detect the COB board, will not pass the board back to repair.

Step 9: dispensing. The use of dispensing machine will be blended AB glue appropriate amount of points to the Bonding good LED grains, IC is encapsulated with black glue, and then according to customer requirements for the appearance of the package.

Step 10: Curing. Sealed the adhesive PCB printed circuit board into the thermal cycle of the oven at a constant temperature, according to the requirements of different drying time can be set.

Step 11: Post-test. Encapsulated PCB printed wiring board and then use a special test tool for electrical performance testing, distinguish between good and bad advantages and disadvantages.

Step 12: grinding. According to the customer's requirements for the thickness of the product grinding (generally soft PCB).

Step 13: cleaning. Clean and wash the product.

Step 14: air drying. After cleaning the product secondary air drying.

Step 15: Test. The success or failure of the test is determined in this step (there is no better way to remedy a bad piece).

Step 16: Cutting. Cut the large PCB into the size required by the customer

Seventeenth step: packaging, factory. Packaging the product.

The melting point of the black glue is relatively low, in the stands when the first wire and so on with the black glue package, and then loaded with chips and other easier to break the original, in the addition of a black glue, because of the latter addition of the black glue is less, to ensure that the package will not damage the original.

Introduction to chip packaging

Installation of semiconductor integrated circuits with the chip shell, play a role in placing, fixing, sealing, protecting the chip and enhance the electrical and thermal properties, but also communicate with the chip's internal world and the bridge to the external circuitry - the chip on the point of contact with a wire connected to the package shell pin, these pins and through the printed circuit board. These pins in turn through the printed circuit board wires and other devices to establish a connection. Therefore, the package plays an important role for the CPU and other LSI integrated circuits

What materials are used for chip packaging

The most important are epoxy resin and ceramic.

What is the difference between the chip package DIP and SOP

The former is a double in-line package, the latter is the most common type of SMD package. The following chart (labeled N is DIP, labeled D is SOP) -

Semiconductor packaging, semiconductor packaging is what it means

Semiconductor Packaging Introduction:

Semiconductor production process consists of wafer fabrication, wafer testing, chip packaging, and post-packaging testing. Semiconductor packaging refers to the wafer through the test in accordance with the product model and functional requirements of the process to get an independent chip process. Packaging process is: from the wafer before the process of wafer scribing process, was cut into small wafers (Die), and then cut the chip with glue mounted to the corresponding substrate (lead frame) frame of the island, and then the use of ultra-fine metal (gold, tin, copper, aluminum) wire or conductive resin will be the wafer's bonding pads (Bond Pad) to connect to the substrate's corresponding pins (Lead) , and constitute the required circuit; and then the independent chip with a plastic shell to be encapsulated to protect the plastic sealing, but also a series of operations, such as post-curing (Post Mold Cure), cut ribbing and molding (Trim & Form), plating (Plating) and printing and other processes. After the package is completed for finished product testing, usually after the inspection (Ining), testing (Test) and packaging (Packing) and other processes, and finally into the warehouse shipments. Typical encapsulation process is: scribing, loading, keying, plastic sealing, de-flashing, electroplating, printing, rib cutting and molding, appearance inspection, product testing, packaging and shipping.

1 Semiconductor Device Packaging Overview

Electronic products are composed of semiconductor devices (integrated circuits and discrete devices), printed circuit boards, wires, machine frames, shells and displays, etc., of which the integrated circuits are used to process and control the signals, discrete devices is usually a signal amplification, printed circuit boards and wires are used to connect the signals, machine frames and shells are to play the role of support and protection, the display part is as a part of the human body with the human body. The role of the display part is as a communication interface with people. So the semiconductor device is the main and important part of the electronic products, in the electronics industry, "the rice of industry" reputation.

China in the 1960s developed and produced its own first computer, which occupies an area of about 100 m2 or more, and now the portable computer is only the size of a book bag, and the future of the computer may only be the same size as a pen or smaller. This rapid reduction in the size of the computer and its increasingly powerful is a good proof of the development of semiconductor technology, the credit is mainly attributed to: (1) the integration of semiconductor chips and wafer manufacturing (Wafer fabrication) in the improvement of photolithography precision, making the chip increasingly powerful and the size of the smaller; (2) the improvement of semiconductor packaging technology This greatly improves the density of integrated circuits on printed circuit boards, making the volume of electronic products significantly reduced.

Semiconductor assembly technology (Assembly technology) is mainly reflected in the improvement of its packaging type (Package) continues to develop. Usually referred to as assembly (Assembly) can be defined as: the use of film technology and micro-connection technology will be semiconductor chips (Chip) and frame (Leadframe) or substrate (Sulbstrate) or plastic sheet (Film) or printed circuit board in the conductor part of the connection in order to lead to the wiring pins, and through the plastic insulating medium potting fixed to constitute the overall three-dimensional structure of the process technology. Structure of the process technology. It has the role of circuit connection, physical support and protection, external field shielding, stress buffer, heat dissipation, excessive size and standardization. From the triode era of insertion type package and the 1980s surface mount package, the development of the current module package, system package, etc., the previous generation has studied a lot of packaging forms, each new form of encapsulation may need to use new materials, new technology or new equipment.

The driving force behind the development of semiconductor packaging is price and performance. The end customers of the electronics market can be divided into three categories: home users, industrial users and national users. Family users are characterized by cheap and low performance requirements; national users require high performance and price is usually dozens of times or even thousands of times the average user, mainly in the military and aerospace, etc.; industrial users are usually the price and performance are between the above two. Low price requirements on the basis of the original cost reduction, so that the material used the less the better, the greater the one-time output the better. High performance requires a long product life, can withstand high and low temperatures and high humidity and other harsh environments. Semiconductor manufacturers are always looking for ways to reduce costs and improve performance, but of course there are other factors such as environmental requirements and patent issues that force them to change the package type.

2 The Role of Packaging

Packaging (Package) for the chip is necessary and critical. Packaging can also be said to refer to the installation of semiconductor integration ...... >>

What type of package does this chip belong to.

Bound packages, commonly known as bull shit, are the cheapest and are susceptible to moisture leading to failure.

What are the common chip packages

First, DIP dual in-line package

DIP (DualIn-line Package) refers to the use of dual in-line form of integrated circuit chip package, the vast majority of small and medium-sized integrated circuits (ICs) are used in this form of packaging, the number of pins is usually The number of pins generally does not exceed 100. The CPU chip in DIP package has two rows of pins, which need to be inserted into the chip socket with DIP structure. Of course, it can also be directly inserted into the same number of holes and geometric arrangement of the circuit board for welding. DIP packages should be especially careful when inserting and removing the chip from the chip socket to avoid damage to the pins.

DIP package has the following characteristics:

1. Suitable for PCB (Printed Circuit Board) on the through-hole welding, easy to operate.

2. The ratio between chip area and package area is larger, so the volume is also larger.

Intel series CPU 8088 is used in this package form, cache (Cache) and early memory chips are also this package form.

Second, QFP plastic square flat package and PFP plastic flat component package

QFP (Plastic Quad Flat Package) package of the chip pin-to-pin distance is very small, the pin is very thin, the general large-scale or ultra-large integrated circuits are used in this form of packaging, and the number of pins is generally more than 100. With this form of packaging chip must be used SMD (surface mount device technology) will be the chip and the motherboard welding up. SMD mounted chips do not have to punch holes in the motherboard, generally on the surface of the motherboard with a well-designed corresponding pins of the soldering points. Chip pins aligned with the corresponding soldering points, can be realized with the motherboard welding. With this method of welding on the chip, if you do not use a special tool is very difficult to dismantle down.

PFP (Plastic Flat Package) way to package the chip and QFP way is basically the same. The only difference is that QFP is generally square, while PFP can be either square or rectangular.

QFP/PFP packages have the following characteristics:

1. Suitable for SMD surface mounting technology in the PCB circuit board mounting wiring.

2. Suitable for high frequency use.

3. Easy to operate, high reliability.

4. The ratio between chip area and package area is small.

Intel series CPU 80286, 80386 and some 486 motherboards use this package form.

Third, PGA Pin Grid Array Package

PGA (Pin Grid Array Package) chip package form in the chip inside and outside of a number of square-shaped pins, each square-shaped pins along the perimeter of the chip spaced a certain distance apart. According to the number of pins, can be surrounded by 2-5 circles. For installation, the chip is inserted into a specialized PGA socket. In order to make the CPU easier to install and remove, starting with the 486 chip, there is a CPU socket called ZIF, which is specifically designed to meet the requirements of the PGA-packaged CPU in terms of installation and removal.

ZIF (Zero Insertion Force Socket) is a zero-insertion force socket. By gently lifting the wrench on this type of socket, the CPU can be easily and effortlessly inserted into the socket. Then the wrench is pressed back to its original position, and the special structure of the socket itself generates a squeezing force to firmly contact the CPU pins with the socket, so there is absolutely no problem of poor contact. To remove the CPU chip, simply lift the socket wrench gently, then the pressure is lifted and the CPU chip can be easily removed.

The PGA package has the following features:

1. Easy plug-and-play operation and high reliability.

2. Adaptable to higher frequencies.

Intel series CPU, 80486 and Pentium, Pentium Pro are used in this package form.

Fourth, the BGA ball grid array package

With the development of integrated circuit technology, the packaging requirements for integrated circuits are more stringent. This is because the packaging technology is related to the functionality of the product, when the frequency of the IC is more than 100MHz, the traditional packaging may produce the so-called "CrossTalk" phenomenon, and when the number of pins of the IC is greater than 208 Pin, the traditional packaging has its own degree of difficulty. Therefore, in addition to the use of QFP package, most of today's high pin number of chips (such as graphics chips and chipsets, etc.) have turned to the use of BGA (Ball Grid Array Package) packaging technology. BGA appeared to become a CPU, motherboards, such as south/north bridge chips, high-density, high-performance, multi-lead ...... >>