What is the principle of component cover opening detection? Detailed explanation of chip unsealing

Date：2021-09-24 16:57:00 Views：4827

Chip unsealing, also known as component cover opening and cap opening, is a commonly used destructive detection method in failure analysis. Make local corrosion for the fully packaged IC, so that the IC can be exposed, keep the chip function intact, and keep die, bond pads, bond wires and even lead - from damage, so as to prepare for the next chip failure analysis experiment, facilitate observation or other tests (such as FIB and Emmi), and the function is normal after decap. So what is the principle of Kaifeng? Now let's take you to learn more.

Component unsealing is also known as component cover opening and cap opening principle

Remove the package on the surface of the components by using chemical or physical methods, and observe the lead connection inside the components. As a common method of opening the cover, the automatic unsealing machine has the following defects: the automatic unsealing machine is relatively expensive, and most enterprises and laboratories have not been equipped with it. The automatic unsealing machine is suitable for opening the cover of components in batches; Most of Kaifeng does not have the quantity and conditions for batch operation.

Application of chip unsealing decap:

Chip unsealing, epoxy resin removal, IGBT silica gel removal, sample thinning

Contents of chip unsealing decap:

1. IC unsealing (front / back) QFP, QFN, sot, to, dip, BGA, cob, etc

2. Sample thinning (except ceramics and metals)

3. Laser marking

Types and methods of chip unsealing?

According to the packaging materials and forms, the packaging types of electronic components include glass packaging (diode), metal shell packaging, ceramic packaging, plastic packaging, flip chip packaging, 3D laminated packaging, etc. the lead bonding wires include aluminum wire, gold wire and copper wire. The methods of unsealing include mechanical unsealing, chemical corrosion unsealing and laser unsealing.

The main steps of sample preparation technology for failure analysis include opening the package and removing the passivation layer. For multilayer chips, it is necessary to remove the interlayer medium. However, the metallization layer and the medium directly below the metallization layer must be retained, as well as the silicon material. In order to observe the internal defects of the chip, section plane technology and dyeing technology are often used.

Chemical unsealing:

The packaging material of plastic encapsulated devices is mainly epoxy molding compound. With epoxy resin as the matrix resin, phenolic resin as the curing agent, plus some fillers (such as fillers, flame retardants, colorants, coupling agents and other trace components), under the action of heat and curing agent, the epoxy ring opening of epoxy resin reacts with phenolic resin to produce cross-linking and curing, making it a thermosetting plastic, which is epoxy molding compound. The type and proportion of epoxy resin directly affect the flow characteristics, thermal properties and electrical properties of epoxy plastics.

Plastic packaging devices need to be opened by chemical corrosion method, which can be divided into chemical dry corrosion and chemical wet corrosion.

Laser unsealing:

Copper bonding wire has the advantages of cost advantage, high conductivity and thermal conductivity, low generation rate of intermetallic compounds and better reliability at high temperature. It has gradually become a good substitute for gold aluminum bonding wire and is used in the packaging of dense wire bonding. Generally, the copper bonding wire is used for plastic packaging, and the chemical unsealing method is used for unsealing. Due to the chemical action between acid and copper lead, the copper bonding wire will be corroded while removing the plastic packaging material, losing the significance of unsealing. Therefore, for copper wire bonded devices, laser unsealing method can be used. The laser unsealing machine removes the molding compound on the packaging machine by laser to avoid the corrosion damage to the copper lead caused by the direct unsealing method.

The laser unsealing machine sets the unsealing area and size by the computer, controls the laser energy and scanning times, and completes the sealing of copper wire bonded packaging devices. The laser wavelength is usually 1064nm, the power is 4.5w, and the laser level is class-4.

The laser unsealing method is mainly used in the following occasions

(1) Failure analysis of semiconductor devices. The high efficiency and removal of plastic packaging materials can replace the traditional low efficiency chemical unsealing and solve the damage of chemical unsealing to copper wires and internal devices.

(2) Validation of plastic packaging process design and process parameters. It solves the problem that X-ray fluoroscopy cannot detect the punching collapse of aluminum wire after plastic packaging, and makes it possible to carefully observe the wiring points of copper wire and gold wire after complete unpacking.

(3) It is applied to the module manufacturer. During the incoming inspection, the device is fully opened to observe whether there are design or production defects inside.

The above is the related content of "component cover opening detection" brought by the core creation detection. Through this article, I hope it can be helpful to you. If you like this article, you might as well continue to pay attention to our website, and we will bring more wonderful content later. If you have any needs related to the inspection and testing of electronic products, please call Chuangxin testing, and we will serve you wholeheartedly.