CN110010554B

CN110010554B - Physical self-destruction device packaging structure based on water-absorbent resin

Info

Publication number: CN110010554B
Application number: CN201910230535.0A
Authority: CN
Inventors: 王向展; 夏好松
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2019-03-26
Filing date: 2019-03-26
Publication date: 2020-10-20
Anticipated expiration: 2039-03-26
Also published as: CN110010554A

Abstract

The invention discloses a physical self-destruction device packaging structure based on water-absorbent resin, which comprises: the device comprises a ceramic packaging tube shell, a polyester gauze, water-absorbent resin, a hard metal thin layer with sharp corners, an alumina ceramic substrate and a chip. The hardness of the hard metal thin layer with the sharp angle is higher than that of the alumina ceramic substrate, and meanwhile, the hard metal thin layer has toughness and is not easy to deform and can move in the vertical direction along with the change of the volume of the water-absorbent resin layer.

Description

Physical self-destruction device packaging structure based on water-absorbent resin

Technical Field

The invention belongs to the field of information security, and particularly relates to a method and a packaging structure for a physical self-destruction device.

Background

With the rapid development of semiconductor industry and microelectronic technology, electronic devices and electronic equipment have become an essential part of human life, and play more and more important roles in information security, national defense and military industry, telecommunication, life education, medical health, and the like. The protection of information in the chip not only relates to national defense and military security, but also relates to the protection of personal privacy, enterprise intellectual property and the like.

At present, chemical corrosion, energetic chips and a mode of introducing stress to break the chips are mainly adopted in the aspect of realizing the self-destruction of the chips at home and abroad. The principle of chemical corrosion is that metal electrodes, silicon dioxide and silicon materials are corroded by acid or alkali, the method is to wrap acid drops or alkali drops in a device by using polymers, the chemical properties of the acid drops or the alkali drops are easy to change along with the change of the external environment in the long-term storage process, and in addition, potential safety hazards and environmental pollution can also exist when the acid or the alkali is added into the device; the energy-containing chip is prepared by filling thermite or preparing porous silicon, and has the principle that CuO or Bi2O3 nano powder and aluminum are subjected to thermite reaction under certain conditions to release a large amount of heat or explode to cause the chip to be self-destructed, the requirement on the triggering temperature is high, and certain danger is caused after triggering; the stress is introduced by etching a groove with a certain depth-width ratio on the back of the silicon wafer according to the fracture strength or fracture toughness of silicon and filling an expandable material, wherein the material expands to generate stress to break the chip. The method has no potential safety hazard and does not pollute the environment. Most of the self-destruction devices adopting the three modes adopt a thermal triggering mode, a common chip can reach 70-80 ℃ in a long-time working process, the local working temperature of some chips for special application can reach more than 100 ℃, the self-destruction device with low thermal triggering temperature can be triggered to self-destroy in a normal working process, and the self-destruction device with high thermal triggering temperature can hardly reach a desired triggering temperature point. Therefore, there is a need for a non-thermally triggered stress-inducing physical self-destruct electronic device.

The water-absorbent resin is a functional polymer material which contains strong hydrophilic groups such as hydroxyl, carboxyl and the like and has a certain degree of crosslinking and a three-dimensional network structure, is irregular in shape, hydrophilic groups react with water to form hydrogel after water-absorbent resin particles meet water, the volume of the water-absorbent resin particles can be expanded to hundreds or even thousands of times of the self volume, and water is difficult to extrude by pressurization. The raw material source is starch or cellulose, etc., and the starch and the cellulose can be decomposed and completely degraded under the action of microorganisms, so that the environment-friendly biological material is nontoxic, does not pollute the environment and does not have potential safety hazard.

Single crystal silicon is a brittle material at room temperature, has an elastic modulus of 130Gpa and a fracture toughness of about 0.7Mpa · m1/2, and when the temperature T > Tm (melting point of silicon), single crystal silicon is transformed from brittle to plastic and the fracture toughness increases rapidly. The theoretical breaking strength of the monocrystalline silicon is about 5Gpa, and due to the existence of various defects such as microcracks, the actual breaking strength of the monocrystalline silicon is only 200-700 MPa.

The alumina ceramic substrate is a brittle material, the elastic modulus of the alumina ceramic substrate is 400Gpa, the elastic modulus of the alumina ceramic substrate is more than twice of that of monocrystalline silicon, and the fracture toughness of the alumina ceramic substrate is 3 Mpa.m 1/2, which is 4-5 times of that of the monocrystalline silicon.

Disclosure of Invention

Aiming at the problems in the prior art, the invention designs a physical self-destruction device packaging structure based on water-absorbent resin based on the current device manufacturing and packaging process, and the sectional view of the current standard ceramic packaging device structure is shown in figure 1. On the basis of the ceramic packaging device, a groove and a water absorption hole array 4 are machined in an existing packaging tube shell 3 through laser cutting, a water absorption resin layer 6 is filled in the groove, the water absorption resin rapidly expands after water is triggered to generate stress so that the ceramic substrate 2 and the chip 1 are strained, and the ceramic substrate and the chip are broken when the stress generated by the expansion of the water absorption resin is greater than the breaking strength of the ceramic substrate and the chip so that the device is self-destructed.

The technical scheme of the invention is a device packaging structure for self-destroying a chip, and the section view of the physical self-destroying device packaging structure based on water-absorbent resin is shown in figure 2: the structure comprises a ceramic packaging tube shell 3, a terylene gauze 5, water-absorbent resin 6, a hard metal thin layer 7, an alumina ceramic substrate 2 and a chip 1. The hardness of the hard metal thin layer 7 is higher than that of the alumina ceramic substrate 2, and meanwhile, the hard metal thin layer is tough and not easy to deform, and a raised sharp corner exists in the central area on the metal hard thin layer.

Furthermore, a layer of terylene gauze 5 is padded on the water absorption hole array 4 in the groove, and then a water absorption resin layer 6 is filled.

Further, a hard metal thin layer 7 having the same area as the groove is disposed on the water absorbent resin layer 6, and the hard metal thin layer 7 is not fixed and can move in the vertical direction according to the volume change of the water absorbent resin layer 6. And finally, bonding the aluminum oxide ceramic substrate 2 and the chip 1 above the groove.

The invention has the beneficial effects that:

1. compared with a mode of adding acid or alkali into a device for chemical corrosion, the design adopts a mode of filling the expansion material to introduce stress, so that the pollution of acid or alkali is avoided, and potential safety hazards are avoided.

2. Compared with the non-degradability of other expansion materials, the raw material source of the water-absorbing resin is starch or cellulose, which can be completely decomposed under microorganisms, and the water-absorbing resin is environment-friendly.

3. The self-destruction device designed by the invention is based on water triggering, and solves the problems that the device with a low triggering temperature point in a thermal triggering mode is easy to self-destroy in the normal working process and the device with a high triggering temperature point is difficult to trigger.

4. The invention makes sharp corners on the metal hard thin layer 7, stress concentration can occur at the sharp corners after water is triggered, cracks appear at the sharp corners firstly, and the local area of the silicon wafer can be controlled to be broken firstly by controlling the positions of the sharp corners.

Drawings

Fig. 1 is a cross-sectional view of a current standard ceramic packaged device structure.

Fig. 2 is a cross-sectional view of a physical self-destruction device packaging structure based on water-absorbent resin designed by the invention.

Fig. 3 is a flow chart of a manufacturing process of the ceramic package device designed by the invention.

TABLE 1. description of the meaning of the invention given by reference numerals in FIGS. 1 and 2

Serial number	Description of the meanings	Serial number	Description of the meanings
				1	Chip and method for manufacturing the same	2	Alumina ceramic substrate
3	Ceramic packaging tube shell	4	Water suction hole array
				5	Polyester fibre gauze	6	Water absorbent resin layer
7	Thin layer of hard metal

FIG. 4 is a simulation model of the sharp corner on the metal foil and the alumina ceramic substrate.

Fig. 5 is a stress distribution diagram between two points ab after the displacement of the steel ball in the 4mm by 4mm square groove in fig. 4 is 0.02 mm.

Fig. 6 is a stress distribution diagram between two points cd after the displacement of the steel ball in the 4mm by 4mm square groove of fig. 4 is 0.02 mm.

Detailed Description

As an optional technical scheme, only a groove is processed on the packaging tube shell 3, a polymer capable of being pyrolyzed is used for wrapping water drops and is mixed with water-absorbing resin, the polymer capable of being pyrolyzed is decomposed to release the water drops after being triggered at a certain temperature, and the water-absorbing resin absorbs water to expand to generate stress so that the chip is broken and self-destructed.

The first embodiment.

A cross-sectional view of a first embodiment of the invention is shown in fig. 2, a device manufacturing process is shown in fig. 3, a groove and a water absorption hole array 4 are processed in a standard packaging tube shell 3 in fig. 1 by laser cutting, a polyester gauze 5, a water absorption resin layer 6 and a hard thin layer 7 with sharp corners are sequentially filled in the groove, then a ceramic substrate 2 and a chip 1 are bonded, and finally a tube shell cap is sealed. In this example, a square groove of 4mm by 4mm in area was machined in the package casing under the 96% alumina ceramic substrate 2, and the size of the ceramic substrate 2 was 8mm by 0.125 mm. Since the hydrogel formed after the water-absorbent resin 6 absorbs water sufficiently can expand to two hundred times of its own volume, taking fig. 4 as a simulation model, and assuming that the hard sheet 7 with sharp corners displaces 0.02mm, the stress distribution on the ceramic substrate 2 can be obtained, as shown in fig. 5 and 6, the stress concentration at the central point of the ceramic substrate 2 has reached the breaking strength of the alumina ceramic material of 400Mpa, and meanwhile, a second stress concentration region exists at the groove boundary in the transverse direction, and cracks first appear from the central point to the second stress concentration region to propagate.

Example two

Example a package with a recess and a suction hole array 4 is produced by opening the mould according to the package structure of fig. 2, and the following device manufacturing process is the same as in example one.

EXAMPLE III

The embodiment of the invention is based on the first embodiment, and is to mix, solidify and form the polymer liquefaction and the water-absorbing resin which are solid at normal temperature and can be quickly dissolved in water, and then fill the groove in the figure 2. The specific implementation measure is to take polyethylene glycol which is easy to dissolve in water as an example, solid polyethylene glycol is placed at a temperature higher than the melting point of the polyethylene glycol to be liquefied, water-absorbing resin is mixed into the polyethylene glycol, the polyethylene glycol is solidified at normal temperature, and a solidified sample is cut into a shape with the size of a groove and is filled into the groove.

Example four

In the embodiment of the invention, on the basis of the first embodiment, the water-absorbing resin and the material which has strong capillary action and is easy to absorb water, such as paper fiber, cotton fiber or polyester fiber, are mixed and filled in the groove in the figure 2.

EXAMPLE five

In the embodiment, the groove is processed into the circular groove on the basis of the first embodiment, and different from the first embodiment, the water-absorbent resin 6 has a stress concentration region only at the central point on the ceramic substrate 2 after water absorption and expansion, the stress distribution is distributed in a circular ring shape with the central point as a circle center, and the crack starts to appear from the central point, but the crack propagation direction is not controllable.

Claims

1. The utility model provides a physics self-destruction device packaging structure based on water-absorbent resin, this structure contains chip, the hard thin slice of metal of taking the closed angle, water-absorbent resin, dacron gauze, alumina ceramics base plate, ceramic package tube shell, its characterized in that: introduce water-absorbent resin in the ceramic package device, be provided with the recess in the ceramic package tube, from the bottom up sets gradually dacron gauze in the recess, water-absorbent resin and the hard thin slice of metal that takes the closed angle, the hard thin slice of metal that takes the closed angle can remove along with the volume change on water-absorbent resin layer, the chip sets up on alumina ceramic substrate, alumina ceramic substrate bonds in the recess top, the closed angle of the hard thin slice of metal that takes the closed angle is towards alumina ceramic substrate, the hardness of the hard thin slice of metal that takes the closed angle is greater than alumina ceramic substrate.

2. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: the bottom of the groove is provided with a water absorption hole array, and the polyester gauze is positioned above the water absorption hole array.

3. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: the material of the water-absorbent resin is as follows: the mixture of the water-absorbent resin and the pyrolyzable polymer wrapping the water drops can be decomposed to release the water drops after being triggered at a certain temperature.

4. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: the material of the water-absorbent resin is as follows: a mixture of a polymer which is solid at normal temperature and rapidly soluble in water and a water-absorbent resin.

5. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 4, wherein: the polymer which is solid at normal temperature and can be quickly dissolved in water is polyethylene glycol.

6. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: the material of the water-absorbent resin is as follows: a mixture of paper, cotton or polyester fibers and a water-absorbent resin.

7. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: hard metal flakes with sharp corners have raised sharp corners in the central region.

8. The physical self-destruction device packaging structure based on water-absorbent resin as claimed in claim 1, wherein: the groove is square or round.