Cross section sample preparation method and auxiliary grinding tool for high-order packaging chip

Abstract

The invention discloses a section sample preparation method of a high-order packaged chip and an auxiliary grinding tool, and the section sample preparation method comprises the steps: carrying out the first pretreatment of the high-order packaged chip, and obtaining a first high-order packaged chip sample; carrying out second pretreatment on the first high-order packaging chip test to obtain a second high-order packaging chip sample; placing the second high-order packaging chip sample in an auxiliary grinding tool for clamping, and grinding the second high-order packaging chip sample to an observation position line through a grinding machine to form a to-be-observed position surface; and carrying out observation pretreatment on the ground to-be-observed surface to obtain a section sample. According to the section sample preparation method, the tightness of connection of all parts in the high-order packaging chip can be enhanced, the stability and reliability of subsequent grinding are guaranteed, interface layering and crystal grain group cracking in the high-order packaging chip are avoided, meanwhile, the stress uniformity during grinding is guaranteed through the auxiliary grinding tool, and the service life of the high-order packaging chip is prolonged. The effectiveness of section sample preparation is further ensured, and cracking of a crystal grain group and offset and dislocation of a grinding section are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of high-level packaged chip detection, and in particular to a cross-section sample preparation method and an auxiliary grinding tool for a high-level packaged chip. Background Art

[0002] As the market demand for semiconductor performance continues to grow, semiconductor packaging is also constantly improving. From typical wire bonding packaging, to subsequent flip chip packaging that can provide more I / O interfaces, to advanced high-end packaging such as the popular 2.5D packaging, the difficulty of the process technology has risen sharply, and the resulting reliability problems have also increased. Correspondingly, the detection and analysis of packaged chips has become more difficult. Cross-sectional sampling is one of the important means of analyzing device manufacturing technology. The internal structure of the chip is dissected by grinding, and a scanning electron microscope is used to check whether there are defects in the internal structure of the package. And improve the production process through existing defects.

[0003] In the related technologies, high-end packaged chips generally have the characteristics of large size, small and complex structure, and susceptibility to stress. Conventional cross-section sampling technology will cause high-end packaged chips to have disadvantages such as artificially introduced interface stratification, grain group cracking, and grinding section offset. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In view of this, the present invention provides a cross-sectional sampling method and an auxiliary grinding tool for a high-level packaged chip, wherein the cross-sectional sampling method can enhance the tightness of the connection between the components in the high-level packaged chip through a first pretreatment and a second pretreatment, thereby ensuring the stability and reliability of subsequent grinding, and avoiding interface stratification and cracking of grain groups inside the high-level packaged chip. At the same time, through the auxiliary grinding tool, the stress uniformity during grinding is ensured, thereby further ensuring the effectiveness of the cross-sectional sampling and avoiding cracking of the grain group and offset and misalignment of the ground cross section.

[0006] Specifically, the following technical solutions are included:

[0007] An embodiment of the first aspect of the present invention provides a cross-sectional sample preparation method for a high-level packaged chip, wherein the high-level packaged chip comprises a cover plate and a substrate, wherein the cover plate and the substrate enclose a containing space, wherein a copper column and a crystal grain group are sequentially arranged on a side of the substrate facing the cover plate, wherein the copper column is connected to the substrate via a bottom filling glue, and the crystal grain group is connected to the cover plate via a Tim glue, wherein the cross-sectional sample preparation method comprises the following steps:

[0008] Performing a first preprocessing on the high-order packaged chip to obtain a first high-order packaged chip sample;

[0009] Performing a second preprocessing on the first high-order packaged chip test to obtain a second high-order packaged chip sample;

[0010] The second high-order packaged chip sample is placed in an auxiliary grinding tool for clamping, and ground to the observation position line by a grinder to form a position surface to be observed;

[0011] The ground surface to be observed is subjected to pre-observation treatment to obtain a cross-sectional sample.

[0012] Optionally, the first preprocessing includes:

[0013] Preparing the high-level package chip;

[0014] Grinding the cover plate of the high-level packaged chip to reduce the cover plate to 1 / 10 of the original thickness;

[0015] A through hole is drilled on the cover plate, wherein the through hole is located at a position on the cover plate away from the grain group;

[0016] Injecting thermosetting epoxy resin AB glue into the high-level package chip through the through hole until the glue surface at the through hole is stable;

[0017] The high-level packaged chip after the injection of glue is cured to obtain the first high-level packaged chip sample.

[0018] Optionally, the step of stabilizing the adhesive surface at the through hole comprises:

[0019] Filling the cavity between the cover plate and the substrate by injecting the thermosetting epoxy resin AB glue having a ratio of 10:1 into the through hole;

[0020] When the liquid level of the thermosetting epoxy resin AB glue reaches the position of the through hole, the high-order packaged chip is vacuumed through the through hole;

[0021] If the liquid level drops, repeat the previous step, otherwise proceed to the next step;

[0022] The high-level packaged chip after the injection of glue is cured to obtain the first high-level packaged chip sample.

[0023] Optionally, the second preprocessing includes:

[0024] The first high-level packaged chip sample is wrapped with room temperature curing epoxy resin AB glue with a ratio of 2:1, and the substrate is exposed to the outside;

[0025] Grinding the substrate of the first high-level packaged chip sample to thin the substrate to 1 / 3 of the original thickness;

[0026] The substrate outside the epoxy resin AB glue package is cut off to obtain the second high-level packaged chip sample.

[0027] Optionally, the auxiliary grinding tool includes a fixture, a pneumatic telescopic cylinder and a bracket, the fixture is configured to clamp the high-order packaged chip; the pneumatic telescopic cylinder is connected to the fixture; the bracket includes a fixed section and a movable section, the fixed section is fixedly connected to the grinder, one end of the movable section is hinged to an end of the fixed section away from the grinder, and the other end of the movable section is hinged to the pneumatic telescopic cylinder, and grinding to the surface to be observed by the grinder includes:

[0028] Draw an observation position line between the cover plate and the substrate, and place the second high-order packaged chip sample in the fixture, wherein the observation position line is parallel to the grinder and protrudes from a side of the fixture close to the grinder;

[0029] Pushing the fixture toward the grinder by the pneumatic telescopic cylinder until the second high-level packaged chip sample is in contact with the grinder, and then starting the grinder;

[0030] Grinding to a first position by a first sandpaper, grinding to a second position by a second sandpaper, grinding to a third position by a third sandpaper, and grinding by a fourth sandpaper;

[0031] The second high-level package chip sample ground by the fourth sandpaper is placed under a microscope for observation to see whether the grinding section coincides with the observation position line. If yes, proceed to the next step, otherwise repeat the previous step;

[0032] The observation position plane is formed.

[0033] Optionally, the pre-observation treatment of the ground surface to be observed includes:

[0034] Placing the second high-level package sample forming the observation position surface on the auxiliary grinding tool, with the surface to be observed facing the grinding machine;

[0035] Replace the sandpaper on the grinder with a polishing velvet cloth so that the surface to be observed is in contact with the polishing velvet cloth, and start the grinder to perform polishing;

[0036] The polished second high-level packaging sample is placed in pure water for cleaning;

[0037] The cleaned second high-level packaging sample is dried by nitrogen and then baked to obtain a cross-sectional sample, which is then observed.

[0038] The embodiment of the second aspect of the present invention provides an auxiliary grinding tool for a high-order packaged chip, which is used for grinding a cross-section sample of a high-order packaged chip. The auxiliary grinding tool is arranged above a grinder, and the auxiliary grinding tool comprises:

[0039] A clamp is configured to clamp the high-level packaged chip and to place the surface of the high-level packaged chip to be observed toward the grinding machine;

[0040] A pneumatic telescopic cylinder connected to the fixture, and the pneumatic telescopic cylinder is located at an end of the fixture away from the grinder;

[0041] The bracket comprises a fixed section and a movable section, wherein the first end of the fixed section is fixedly connected to the grinder, the second end of the fixed section is hinged to the first end of the movable section, and the second end of the movable section is hinged to the pneumatic telescopic cylinder.

[0042] Optionally, the fixture comprises:

[0043] a first support plate;

[0044] A second support plate, arranged opposite to the first support plate;

[0045] A connecting plate, used to connect the first supporting plate and the second supporting plate, wherein the connecting plate is provided with a connecting hole, and the connecting hole is connected to the pneumatic telescopic cylinder;

[0046] Wherein, a clamping assembly is provided between the first supporting plate and the second supporting plate.

[0047] Optionally, the clamping assembly comprises:

[0048] a first clamping member connected to the first support plate, the first clamping member comprising at least one first threaded rod and a first clamping plate, the first threaded rod being movably connected to the first support plate, and the first clamping plate being located between the first support plate and the second support plate;

[0049] a second clamping member connected to the second support plate, the second clamping member comprising at least one second threaded rod and a second clamping plate, the second threaded rod being movably connected to the second support plate, and the second clamping plate being located between the first support plate and the second support plate;

[0050] Wherein, the high-order packaged chip is located between the first clamping plate and the second clamping plate.

[0051] Optionally, the pneumatic telescopic cylinder comprises:

[0052] A cylinder body, wherein a piston rod is disposed in the cylinder body, and the piston rod divides the cylinder body into a first chamber and a second chamber, wherein the first chamber is located at an end away from the grinder;

[0053] A first inflatable bag is connected to the first chamber through a first connecting pipe, and a pressure regulating valve is provided on the first connecting pipe;

[0054] a second inflatable bag, connected to the second chamber via a second connecting pipe;

[0055] Wherein, the second end of the movable section is hinged to the cylinder body.

[0056] The cross-sectional sample preparation method and auxiliary grinding tool of the high-order packaged chip provided by the embodiment of the present invention, wherein the cross-sectional sample preparation method includes a first pretreatment and a second pretreatment of the high-order packaged chip, and the external structure of the high-order packaged chip after the two pretreatments becomes thinner, and finally a second high-order packaged chip sample is obtained, thereby reducing the thickness of the second high-order packaged chip sample, and in the subsequent grinding in the direction perpendicular to the thickness, the stress on the second high-order packaged chip sample can be reduced, and the grain group collapse caused by excessive stress concentration can be avoided; at the same time, through the first pretreatment and the second pretreatment, the connection between the internal components of the high-order packaged chip can be made tighter, ensuring the stability and reliability of the subsequent grinding, and effectively avoiding the interface stratification and grain group collapse of the high-order packaged chip. Grinding in the direction perpendicular to the thickness by the auxiliary grinding tool can ensure the uniformity of stress during the grinding process, avoid the collapse of the grain group and the displacement and dislocation of the grinding section, and further ensure the effectiveness of the final cross-sectional sample preparation.

[0057] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0059] Figure 1 A flow chart of the steps of a cross-section sample preparation method according to an embodiment of the present invention;

[0060] Figure 2 A schematic diagram of a high-level package chip according to an embodiment of the present invention;

[0061] Figure 3 is an internal schematic diagram of a high-level package chip according to an embodiment of the present invention;

[0062] Figure 4 A schematic diagram of a high-order packaged chip sample after the first pre-processing according to an embodiment of the present invention;

[0063] Figure 5 A schematic diagram of a high-order packaged chip sample after a second pretreatment according to an embodiment of the present invention;

[0064] Figure 6 is a schematic diagram of an auxiliary grinding tool according to an embodiment of the present invention;

[0065] Figure 7 Schematic diagram of a clamp according to an embodiment of the present invention.

[0066] in, Figures 2 to 7 The corresponding relationship between the reference numerals and the component names is as follows:

[0067] 100 high-level packaged chip, 101 substrate, 102 bottom filling glue, 103 copper pillar, 104 grain, 105 Tim glue, 106 cover plate, 107 cavity, 108 thermosetting epoxy resin AB glue, 109 room temperature curing epoxy resin AB glue, 200 auxiliary grinding tool, 210 fixture, 211 first support plate, 212 second support plate, 213 connecting plate, 214 first threaded rod, 215 first clamping plate, 216 second threaded rod, 217 second clamping plate, 220 pneumatic telescopic cylinder, 230 bracket, 231 fixed section, 232 movable section, 233 corner screw, 300 grinder. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] Before further describing the embodiments of the present invention in detail, the directional nouns involved in the embodiments of the present invention, such as "upper part", "lower part" and "side part", do not have the meaning of limiting the protection scope of the present invention.

[0070] To make the technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0071] Figure 1 The present invention is a flowchart of the steps of a cross-section sample preparation method according to an embodiment of the present invention.

[0072] like Figure 1As shown, an embodiment of the present invention provides a cross-sectional sample preparation method for a high-level packaged chip. The high-level packaged chip 100 includes a cover plate 106 and a substrate 101. The cover plate 106 and the substrate 101 enclose a receiving space. A copper column 103 and a die group are sequentially arranged on a side of the substrate 101 facing the cover plate 106. The copper column 103 is connected to the substrate 101 through a bottom filling glue 102, and the die group is connected to the cover plate 106 through a Tim glue 105. The cross-sectional sample preparation method includes the following steps:

[0073] Step 1, performing a first pretreatment on the high-order packaged chip to obtain a first high-order packaged chip sample;

[0074] Step 2, performing a second preprocessing on the first high-order packaged chip test to obtain a second high-order packaged chip sample;

[0075] Step 3, placing the second high-order packaged chip sample in an auxiliary grinding tool for clamping, and grinding it to the observation position line by a grinder to form a position surface to be observed;

[0076] Step 4, pre-processing the ground surface to be observed to obtain a cross-sectional sample.

[0077] Among them, the cross-sectional sample preparation method includes performing a first pretreatment and a second pretreatment on the high-order packaged chip 100. After the two pretreatments, the external structure of the high-order packaged chip 100 becomes thinner, and finally a second high-order packaged chip sample is obtained, which reduces the thickness of the second high-order packaged chip sample. In the subsequent grinding in the direction perpendicular to the thickness, the stress on the second high-order packaged chip sample can be reduced, and the grain group collapse caused by excessive stress concentration can be avoided; at the same time, through the first pretreatment and the second pretreatment, the connection between the internal components of the high-order packaged chip 100 can be made tighter, ensuring the stability and reliability of the subsequent grinding, and effectively avoiding the interface stratification and grain group collapse of the high-order packaged chip 100. Grinding in the direction perpendicular to the thickness by the auxiliary grinding tool 200 can ensure the uniformity of stress during the grinding process, avoid the collapse of the grain group and the displacement and dislocation of the grinding section, and further ensure the effectiveness of the final cross-sectional sample preparation.

[0078] Specifically, the currently common high-end packaged chips 100 are relatively large in size, and there are multiple structures and interfaces between structures in the same cross-section, such as between the substrate 101 and the bottom filling glue 102, between the grain group and the bottom filling glue 102, between the grain group and the Tim glue 105, etc. If the existing grinding method is used for manual grinding, the staff needs to hold the sample for a long time for grinding, which consumes a lot of manpower and increases the sample preparation cost; at the same time, it is difficult for the staff to control the balance of the stress on the sample during the grinding process, and it is easy to introduce excessive external stress, delamination of the interface between the structures, cracks and defects in the grain group itself, resulting in failure of cross-section sample preparation, and cracks and defects caused by external stress are also difficult to correctly judge the problems in the process production, affecting the improvement of the production process steps. The sample preparation method of the present application performs a first pretreatment and a second pretreatment before grinding, so as to increase the bonding strength between the internal structures of the high-level packaged chip 100 and make the stress of each structure reach a balanced state, and grinds the observation surface through the cooperation of the auxiliary grinding tool 200 and the grinder 300, which can reduce labor costs, adjust the stress during the grinding process, ensure the effectiveness of cross-section sample preparation, and ensure the accuracy of subsequent analysis and detection of the high-level packaged chip 100, which is helpful to improve the production process steps and improve the quality of subsequent production of high-level packaged chips 100.

[0079] Figure 2 A schematic diagram of a high-level package chip according to an embodiment of the present invention; Figure 3 is an internal schematic diagram of a high-level package chip according to an embodiment of the present invention; Figure 4 Schematic diagram of a high-order packaged chip sample after the first pre-processing according to an embodiment of the present invention.

[0080] In a possible implementation, Figures 2 to 4 As shown, the first preprocessing includes:

[0081] Step 101, preparing a high-level package chip;

[0082] Step 102, grinding the cover plate of the high-level packaged chip to reduce the cover plate to 1 / 10 of the original thickness;

[0083] Step 103, drilling a through hole on the cover plate, wherein the through hole is located at a position on the cover plate away from the die group;

[0084] Step 104, injecting thermosetting epoxy resin AB glue into the high-level package chip through the through hole until the glue surface at the through hole is stable;

[0085] Step 105 , curing the glue-injected high-level packaged chip to obtain a first high-level packaged chip sample.

[0086] The sample in this embodiment is a high-end package chip 100 such as FCBGA / COWOS / FOP / POP flip-chip, wherein Figure 2 and Figure 3 As shown, the high-level packaged chip 100 includes a cover plate 106 and a substrate 101, the cover plate 106 and the substrate 107 enclose a receiving space, the substrate 101 is provided with a copper column 103 and a crystal group in sequence on the side facing the cover plate 106, the copper column 103 is connected to the substrate 101 through the bottom filling glue 102, and the crystal group is connected to the cover plate 106 through the Tim glue 105. It can be understood that the copper column 103 can also be a BGA solder ball, the substrate 101 is a resin fiber copper-clad multi-layer PCB board, a DBC ceramic substrate or an AMB ceramic substrate, and the cover plate 10 is a metal heat dissipation cover plate or a ceramic cover plate.

[0087] Specifically, the cover plate 106 is first thinned and ground on the side away from the grain group. The high-order packaged chip 100 is placed on the grinder 300, with the cover plate 106 facing the sandpaper side of the grinder 300. The sandpaper used is 110 to 130 mesh sandpaper, and the rotation speed of the grinder 300 is 380 r / min to 420 r / min. In this embodiment, 120 mesh sandpaper is used and the rotation speed of 400 r / min is used to grind the cover plate 106 for 10 to 30 minutes until the thickness of the cover plate 106 is thinned to 1 / 10 of the original thickness (the original thickness of the cover plate is 1 mm to 2 mm). This can reduce the strength of the cover plate 106 and facilitate the subsequent grinding of the observation surface. After the cover plate 106 is thinned, a diamond drill is used to drill through holes on the cover plate 106. The through holes should avoid the grain group to avoid artificial damage to the grain group and affect the subsequent analysis and detection of the high-level packaged chip 100. It also helps to fill the gaps between the structures in the future. The diameter of the through hole is usually 2mm to 4mm. In this embodiment, the through hole diameter is selected to be 3mm. Thermosetting epoxy resin AB glue 108 is injected from the through hole into the inside of the high-level packaged chip 100 through a needle syringe (needle diameter 1mm) until the thermosetting epoxy resin AB glue 108 fills all the gaps between the cover plate 1061 and the substrate 101. The high-level packaged chip 100 injected with the thermosetting epoxy resin AB glue 108 is then cured to obtain a first high-level packaged chip sample, such as Figure 4 shown.

[0088] In a feasible implementation manner, the step of stabilizing the adhesive surface at the through hole includes:

[0089] The cavity between the cover plate and the substrate is filled by injecting a thermosetting epoxy resin AB glue having a ratio of 10:1 into the through hole;

[0090] When the liquid level of the thermosetting epoxy resin AB glue reaches the through-hole position, the high-order package chip is vacuumed through the through-hole;

[0091] If the liquid level drops, repeat the previous step, otherwise proceed to the next step;

[0092] The high-level packaged chip after the injection is cured to obtain a first high-level packaged chip sample.

[0093] Among them, the ratio of the thermosetting epoxy resin AB glue 108 injected into the high-level package chip 100 is 10:1, that is, A is epoxy resin, B is curing agent, and the volume ratio of epoxy resin and curing agent is 10:1. Usually, the cavity 107 between the cover plate 106 and the substrate 101 and the gaps between the structures are filled with the thermosetting epoxy resin AB glue 108 to ensure the tightness and reliability of the connection between the structures and avoid interface stratification between the structures during grinding; when the liquid level of the thermosetting epoxy resin AB glue 108 reaches the through hole, the inside of the high-level package chip 100 is vacuumed through a vacuum instrument and the through hole to ensure that each gap can be filled with the thermosetting epoxy resin AB glue 108, thereby ensuring the reliability of the tight connection of each structure. Usually, the vacuuming is performed for 5 to 10 minutes at a time. When the liquid level drops, the thermosetting epoxy resin AB glue 108 is injected into the high-level package chip 100 through the through hole again. When the liquid level reaches the through hole again, the vacuum treatment is performed again for 5 to 10 minutes until the liquid level of the thermosetting epoxy resin AB glue 108 in the high-level package chip 100 stops dropping. When the liquid level of the thermosetting epoxy resin AB glue 108 in the high-level package chip 100 is stable, the high-level package chip 100 is placed in a high-temperature box to cure the thermosetting epoxy resin AB glue 108 to ensure the reliability of the connection of each structure in the high-level package chip 100. The temperature is usually 75°C to 85°C, and it is heated for more than 2 hours to complete the curing of the thermosetting epoxy resin AB glue 108. In this embodiment, the temperature is heated at 80°C for 2 hours to obtain the first high-level package chip sample.

[0094] It should be noted that the brand of the thermosetting epoxy resin AB glue 108 used in this embodiment is ALLIED; model: A glue (epoxy resin EpoxyBond 110-Part A); B glue (epoxy resin EpoxyBond 110-Part B); A glue is the main agent, and B glue is the curing agent; the purchased A glue and B glue are configured when used, and the volume ratio of 10:1 is because the curing efficiency and hardness of the thermosetting epoxy resin AB glue 108 after curing are relatively good under this ratio, which can improve the tightness of the connection between the internal components of the high-level packaged chip and increase the strength of each component, avoid splitting between the components during grinding and avoid cracks in the parts themselves.

[0095] Figure 5Schematic diagram of a high-order packaged chip sample after the second pre-processing according to an embodiment of the present invention.

[0096] In a possible implementation, Figure 5 As shown, the second preprocessing includes:

[0097] Step 201, wrapping a first high-level packaged chip sample with a room temperature curing epoxy resin AB glue with a ratio of 2:1, and exposing the substrate to the outside;

[0098] Step 202, grinding the substrate of the first high-level packaged chip sample to thin the substrate to 1 / 3 of the original thickness;

[0099] Step 203, cutting off the substrate outside the epoxy resin AB glue package to obtain a second high-level packaged chip sample.

[0100] The first high-order packaged chip is packaged by using a room temperature curing epoxy resin AB glue 109, and the substrate does not need to be packaged. The room temperature curing epoxy resin AB glue 109 mainly covers the outer periphery of the cover plate 106 above the substrate 101. The ratio of the room temperature curing epoxy resin AB glue 109 is 2:1, that is, A is epoxy resin, B is curing agent, and the volume ratio of epoxy resin to curing agent is 2:1. The factory ratio of the room temperature curing epoxy resin AB glue 109 is 2:1. The curing effect is best under this ratio. The substrate 101 of the first high-level packaged chip sample wrapped with the room temperature curing epoxy resin AB glue 109 is thinned, that is, the side of the substrate 101 away from the cover plate 106 is ground, so that the substrate 101 is thinned to 1 / 3 of the original thickness (the thickness of the original substrate 101 is 1 mm to 3 mm), which can reduce the strength of the substrate 101 and facilitate the subsequent grinding of the observation surface; after the substrate 101 is thinned, the substrate 101 outside the epoxy resin AB glue 109 is cut off to obtain a second high-level packaged chip, such as Figure 5 shown.

[0101] For example, the room temperature curing epoxy resin AB glue 109 and the thermosetting epoxy resin AB glue 108 have different specific chemical compositions; the hardness of the room temperature curing epoxy resin AB glue 109 after curing and the fluidity before curing are worse than those of the thermosetting epoxy resin AB glue 109, so the thermosetting epoxy resin AB glue 108 is used for internal filling, and the room temperature curing epoxy resin AB glue 109 is used for external structure protection.

[0102] It should be noted that since the strength of the grains 104 in the internal grain group is lower than the strength of the cover plate 106 and the substrate 101, the strength of the cover plate 106 and the substrate 101 is effectively reduced after the cover plate 106 and the substrate 101 are thinned. When the surface to be observed is subsequently ground, the cover plate 106, the substrate 101 and the internal grains 104 can be ground with the same grinding intensity. While ensuring effective grinding, the cracking of the grains 104 caused by excessive grinding intensity is avoided, thereby ensuring the effectiveness of cross-section sampling and the accuracy and reliability of subsequent analysis and detection of the high-order packaged chip 100.

[0103] In this embodiment, in the grinding of the substrate 101, the sandpaper is 110-130 mesh, and the rotation speed of the grinder 300 is 280r / min to 320r / min. In this embodiment, the sandpaper of 120 mesh is used, and the rotation speed of the substrate 101 is 300r / min for grinding for 15min. It can be understood that since the hardness of the material of the substrate 101 is lower than the hardness of the material of the cover plate 106, the rotation speed of grinding the substrate 101 can be lower than the rotation speed of grinding the cover plate 106. The manufacturer of the room temperature curing epoxy resin AB glue 109 used in this embodiment is Shenzhen Jingtao Electronic Technology Co., Ltd.; A glue model 2015-H-50A, B glue model: 2015-R-50B; room temperature curing epoxy resin AB glue 109 needs to be configured when used, and the configuration ratio is the specified ratio of this model of glue. Package thickness: Covering chip surface thickness 3mm to 6mm.

[0104] In a feasible implementation, the auxiliary grinding tool 200 includes a fixture 210, a pneumatic telescopic cylinder 220 and a bracket 230, wherein the fixture 210 is configured to clamp the high-level packaged chip 100; the pneumatic telescopic cylinder 220 is connected to the fixture 210; the bracket 230 includes a fixed section 231 and a movable section 232, wherein the fixed section 231 is fixedly connected to the grinder 300, one end of the movable section 232 is hinged to one end of the fixed section 231 away from the grinder 300, and the other end of the movable section 232 is hinged to the pneumatic telescopic cylinder 220, and grinding to the surface to be observed by the grinder 300 includes:

[0105] Step 301, draw an observation position line between the cover plate and the substrate, place the second high-level packaged chip sample in the fixture, the observation position line is parallel to the grinder, and the observation position line protrudes from the side of the fixture close to the grinder;

[0106] Step 302, pushing the fixture toward the grinder by means of a pneumatic telescopic cylinder until the second high-level packaged chip sample fits the grinder, and then starting the grinder;

[0107] Step 303, grinding to a first position by using a first sandpaper, grinding to a second position by using a second sandpaper, grinding to a third position by using a third sandpaper, and grinding by using a fourth sandpaper;

[0108] Step 304, placing the second high-level package chip sample ground by the fourth sandpaper under a microscope for observation, and checking whether the grinding section coincides with the observation position line. If yes, proceed to the next step, otherwise repeat the previous step;

[0109] Step 305, forming an observation position plane.

[0110] It should be noted that the auxiliary grinding tool 200 includes a clamp 210, a pneumatic telescopic cylinder 220 and a bracket 230. The clamp 210 is configured to clamp the high-level packaged chip 100; the pneumatic telescopic cylinder 220 is connected to the clamp 210; the bracket 230 includes a fixed section 231 and a movable section 232. The fixed section 231 is fixedly connected to the grinder 300, one end of the movable section 232 is hinged to an end of the fixed section 231 away from the grinder 300, and the other end of the movable section 232 is hinged to the pneumatic telescopic cylinder 220.

[0111] The cover plate 106 and / or the substrate 101 of the second high-level packaged chip sample is scribed by a diamond pen, that is, Figures 2 to 4 The observation position line is marked on the left, right, front and back sides. The cross section exposed after grinding to the observation position line is the observation position surface. Usually the observation position surface is Figures 2 to 4 The front, back, left, and right sides of the sample are then clamped by the fixture 210 of the auxiliary grinding tool 200, and the side with the observation position line protrudes from the fixture 210 of the auxiliary grinding tool 200 to facilitate grinding of this position, and the observation position line is set parallel to the sandpaper of the grinder 300. The pneumatic telescopic cylinder 220 pushes the fixture 210 to drive the second high-order packaged chip sample toward the grinder 300 until the end of the second high-order packaged chip sample fits with the grinder 300, and the grinder 300 is turned on to start grinding. The position between the grinder 300 and the second high-order packaged chip sample can also be adjusted by the bracket 230. Since the fixed section 231 of the bracket 230 is fixedly connected to the grinder 300, the two ends of the movable section 232 are respectively hinged with the fixed section 231 and the pneumatic telescopic cylinder 220. The pneumatic telescopic cylinder 220 and the fixed section 231 are connected, so that the pneumatic telescopic cylinder 220 and the fixed section 231 are always balanced. By changing the hinge angle of the movable section 232 and the fixed section 231, the pneumatic telescopic cylinder 220 can be raised and lowered. For example, when the pneumatic telescopic cylinder 220 is raised, the angle between the movable section 232 and the fixed section 231 is greater than 90°. When the pneumatic telescopic cylinder 220 is lowered, the angle between the movable section 232 and the fixed section 231 is less than 90°. The two hinged positions are locked by the corner bolt 233 to ensure the reliability of the hinge angle.

[0112] In this embodiment, the rotation speed of the grinder 300 is first adjusted to 200r / min, and the second high-level packaged chip test is ground using 120-mesh sandpaper (first sandpaper) to a position 1mm away from the grain (first position); then, the 400-mesh sandpaper (second sandpaper) is replaced for grinding to the end of the bottom filling glue 102 away from the grain 104 (second position); the 800-mesh sandpaper (third sandpaper) is replaced for grinding to the end of the bottom filling glue 102 close to the grain 104 (third position); finally, 2000-mesh sandpaper (fourth sandpaper) is used for grinding to near the observation position line. The grain 104 refers to the grain 104 near one end of the observation position line. Since the grinding of the position far from the grain 104 needs to be done quickly, a coarser sandpaper is used for grinding. As the grinding position gets closer to the grain 104, finer sandpaper is used for grinding. This ensures grinding accuracy and prevents excessively coarse sandpaper from causing wear on the observation surface, thereby affecting subsequent analysis and detection of the high-level packaged chip 100. In other words, the step-by-step fine grinding can ensure grinding efficiency on the one hand, and reliability and effectiveness of grinding the observation surface on the other hand.

[0113] It should be noted that the pneumatic telescopic cylinder 220 is retracted, the fixture 210 is loosened to remove the second high-order packaged chip sample, and the second high-order packaged chip sample that has been preliminarily ground by the fourth sandpaper is placed under a microscope to observe whether the grinding position at this time is consistent with the position of the surface to be observed. If they are consistent, the surface to be observed is obtained. If not, the second high-order packaged chip sample is placed back in the fixture 210 and grinding is continued until the grinding position observed under the microscope is consistent with the position of the surface to be observed.

[0114] In a feasible implementation manner, the ground surface to be observed is subjected to pre-observation treatment including:

[0115] Step 401, placing the second high-level package sample with the observation position surface formed on the auxiliary grinding tool, with the surface to be observed facing the grinding machine;

[0116] Step 402, replacing the sandpaper on the grinder with a polishing cloth so that the surface to be observed is in contact with the polishing cloth, and starting the grinder to perform a polishing process;

[0117] Step 403, washing the polished second high-level package sample in pure water;

[0118] Step 404 , drying the cleaned second high-level package sample with nitrogen and then baking it to obtain a cross-sectional sample, and observing the cross-sectional sample.

[0119] Among them, the second high-order packaged chip sample with the surface to be observed is put back into the fixture 210 and clamped, and the surface to be observed is facing the grinder 300; the sandpaper on the grinder 300 is replaced with polishing flannel cloth, and the angle of the movable section 232 of the pneumatic telescopic cylinder 220 is adjusted so that the surface to be observed is in contact with the polishing flannel cloth, and the grinder 300 is turned on to polish the surface to be observed to reduce the presence of artificial defects on the surface to be observed after sandpaper grinding; after polishing, the second high-order packaged chip sample is removed from the auxiliary grinding tool 200 and placed in clean water for cleaning; after the clean water treatment, it is blown dry and dried to finally obtain a cross-sectional sample, and the cross-sectional sample is subsequently analyzed and tested, and the production process steps are improved according to the analysis and test results to improve the production quality of subsequent high-order packaged chips 100.

[0120] It should be noted that in the present embodiment, the rotation speed of the grinder 300 during the polishing process is 150 r / min, and the polishing time is 1 to 3 minutes. The water cleaning time is more than 2 minutes, and the drying is carried out by nitrogen to prevent the surface of the position to be observed from reacting with other gases and affecting the accuracy of the subsequent analysis and detection results. Finally, the sample is dried at a temperature of 60° C. for 1 hour to obtain the final cross-section sample.

[0121] In summary, it can be seen that the thinning of the cover plate 106 and the substrate 101 can effectively reduce the strength of the cover plate 106 and the substrate 101, so that the strength of the cover plate 106 and the substrate 106 is close to the strength of the grain 104, so that when the cover plate 106, the substrate 101 and the grain 104 are ground at the same time in the subsequent process, the grinding speed and stress can be basically kept consistent, avoiding damage to the grain 104 caused by excessive speed and stress, and ensuring the success rate of cross-section sample preparation. The high-level package chip 100 is filled with thermosetting epoxy resin AB glue 108 to ensure the tightness of the connection between the internal structures of the high-level package chip 100, and the high-level package chip 100 is coated with room temperature curing epoxy resin AB glue 109. On the one hand, it ensures that the stress of the internal structures of the high-level package chip 100 reaches a balanced state, and on the other hand, it can reduce the vibration transmitted to the various structures of the high-level package chip 100 during the grinding process, avoiding damage to the grain 104 during grinding, and ensuring the accuracy of subsequent cross-section sample preparation analysis and detection. Finally, the auxiliary grinding tool 200 is used instead of manual hand-held, which can reduce manpower and the cost of cross-section sample preparation on the one hand, and on the other hand, the stress applied to the high-level packaged chip 100 can be adjusted through the pneumatic telescopic cylinder 220, and different stresses can be adjusted for different grinding positions, thereby improving the effectiveness of cross-section sample preparation.

[0122] Figure 6 Schematic diagram of an auxiliary grinding tool according to an embodiment of the present invention.

[0123] like Figure 6 As shown, another embodiment of the present invention provides an auxiliary grinding tool 200 for a high-level packaged chip, which is used for grinding a cross-section sample of a high-level packaged chip 100. The auxiliary grinding tool 200 is disposed above a grinder 300, and the auxiliary grinding tool 200 includes:

[0124] The clamp 210 is configured to clamp the high-level packaged chip 100 and place the surface of the high-level packaged chip 100 to be observed toward the grinding machine;

[0125] A pneumatic telescopic cylinder 220 is connected to the fixture 210, and the pneumatic telescopic cylinder 220 is located at one end of the fixture 210 away from the grinder 300;

[0126] The bracket 230 includes a fixed section 231 and a movable section 232 . The first end of the fixed section 231 is fixedly connected to the grinder 300 , the second end of the fixed section 231 is hinged to the first end of the movable section 232 , and the second end of the movable section 232 is hinged to the pneumatic telescopic cylinder 220 .

[0127] The second high-level packaged chip sample is clamped by the fixture 210 to ensure the stability of the second high-level packaged chip sample during the grinding process, and to avoid the second high-level packaged chip test from moving, causing the grinding section to shift, affecting the effectiveness of the final cross-section sample preparation. The pneumatic telescopic cylinder 220 controls the contact force between the fixture 210 and the grinder 300 to ensure that the second high-level packaged chip sample is subjected to balanced stress, and to avoid partial stress concentration leading to failure of cross-section sample preparation. The bracket 230 includes a fixed section 231 and a movable section 232. One end of the fixed section 231 is fixedly connected to the grinder 300. The other end of the fixed section 231 is hinged to the first end of the movable section 232 through an angle screw 233. The second end of the movable section 232 is hinged to the pneumatic telescopic cylinder 220, so that the pneumatic telescopic cylinder 220 is always parallel to the fixed section 231, that is, the second high-level packaged chip sample clamped by the fixture 210 is parallel to the grinder 300. By changing the angle between the movable section 232 and the fixed section 231, the distance between the second high-level packaged chip sample and the grinder 300 is adjusted. When the angle between the movable section 232 and the fixed section 231 is greater than 90°, the fixture 210 takes the second high-level packaged chip sample away from the grinder 300. When the angle between the movable section 232 and the fixed section 231 is less than 90°, the fixture 210 takes the second high-level packaged chip sample close to the grinder 300.

[0128] Figure 7 Schematic diagram of a clamp according to an embodiment of the present invention.

[0129] In a possible implementation, Figure 7 As shown, the fixture 210 includes:

[0130] A first supporting plate 211;

[0131] A second support plate 212, arranged opposite to the first support plate 211;

[0132] A connecting plate 213 is used to connect the first supporting plate 211 and the second supporting plate 212. The connecting plate 213 is provided with a connecting hole, and the connecting hole is connected to the pneumatic telescopic cylinder 220;

[0133] A clamping assembly is provided between the first support plate 211 and the second support plate 212 .

[0134] It should be noted that the first support plate 211 and the second support plate 212 of the clamp 210 are arranged in parallel, and one end of the first support plate 211 and the second support plate 212 are connected by a connecting plate 213, so that the clamp 210 is U-shaped, and the open end of the clamp 210 is set toward the grinder 300, and the connecting plate 213 is fixedly connected to the pneumatic telescopic cylinder 220.

[0135] It can be understood that a clamping assembly is provided between the first support plate 211 and the second support plate 212, and the second high-order packaged chip sample is clamped by the clamping assembly to avoid slippage during the grinding process and ensure the accuracy of the grinding position. On the one hand, the success rate of cross-section sample preparation is improved, and on the other hand, the force balance of various parts of the second high-order packaged chip sample during grinding can be ensured to ensure the consistency of grinding.

[0136] In a feasible embodiment, the clamping assembly includes:

[0137] A first clamping member connected to the first support plate 211, the first clamping member includes at least one first threaded rod 214 and a first clamping plate 215, the first threaded rod 214 is movably connected to the first support plate 211, and the first clamping plate 215 is located between the first support plate 211 and the second support plate 212;

[0138] A second clamping member connected to the second support plate 212, the second clamping member includes at least one second threaded rod 216 and a second clamping plate 217, the second threaded rod 216 is movably connected to the second support plate 212, and the second clamping plate 217 is located between the first support plate 211 and the second support plate 212;

[0139] The high-level packaged chip 100 is located between the first clamping plate 215 and the second clamping plate 217 .

[0140] It should be noted that the clamping assembly includes a first clamping plate 215 and a second clamping plate 217, which are located between the first support plate 211 and the second support plate 212, and the first clamping plate 215 is movably connected to the first support plate 211 through the first threaded rod 214, and the position of the first clamping plate 215 is adjusted by adjusting the distance the first threaded rod 214 extends into the first support plate 211 and the second support plate 212. Similarly, the second clamping plate 217 is movably connected to the second support plate 212 through the second threaded rod 216, and the position of the second clamping plate 217 is adjusted by adjusting the distance the second threaded rod 216 extends into the first support plate 211 and the second support plate 212, thereby clamping the second high-order packaged chip sample through the first clamping plate 215 and the second clamping plate 217.

[0141] It is understandable that two first threaded rods 214 can be set, and the two first threaded rods 214 are located at both ends of the first clamping plate 215, and two second threaded rods 216 can be set, and the two second threaded rods 216 are located at both ends of the second clamping plate 217. This can ensure the uniformity of clamping the second high-order packaged chip sample, and further ensure the uniformity of the force on the second high-order packaged chip sample.

[0142] In a feasible implementation, the pneumatic telescopic cylinder 220 includes:

[0143] A cylinder body, wherein a piston rod is arranged in the cylinder body, and the piston rod divides the cylinder body into a first chamber and a second chamber, wherein the first chamber is located at an end away from the grinder;

[0144] A first inflatable bag is connected to the first chamber through a first connecting pipe, and a pressure regulating valve is provided on the first connecting pipe;

[0145] A second inflatable bag is connected to the second chamber through a second connecting pipe;

[0146] The second end of the movable section 232 is hinged to the cylinder body.

[0147] It should be noted that, by allowing air to enter the first chamber and exhausting air from the second chamber, the piston rod is extended, driving the fixture 210 and the second high-level packaged chip sample to approach the grinder 300. On the contrary, when the first chamber exhausts air and the second chamber enters air, the piston rod drives the fixture 210 and the second high-level packaged chip sample away from the grinder 300. The initial contact position between the second high-level packaged chip sample and the grinder 300 can be adjusted by the angle of the movable section 232. After the grinder 300 starts grinding, the extension of the piston rod in the pneumatic telescopic cylinder 220 always ensures that the grinding end surface of the second high-level packaged chip sample is in contact with the grinder 300, thereby ensuring the effectiveness of grinding. The gas flow rate entering the first chamber per unit time is controlled by the pressure regulating valve, and then the contact pressure between the second high-level packaged chip sample and the grinder 300 can be adjusted to achieve the effect of stress regulation. For example, when the grinding position is far away from the crystal grain 104, the gas volume can be increased to speed up the grinding speed. When the grinding position is closer to the crystal grain 104, the gas volume is gradually reduced to reduce the contact pressure between the second high-level packaged chip sample and the grinder 300, thereby avoiding excessive grinding and affecting the accuracy and success rate of cross-section sample preparation.

[0148] In the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0149] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only.

[0150] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cross-section sample preparation method for a high-level packaged chip, the high-level packaged chip comprises a cover plate and a substrate, the cover plate and the substrate enclose a containing space, a copper column and a die group are sequentially arranged on a side of the substrate facing the cover plate, the copper column is connected to the substrate by a bottom filling glue, and the die group is connected to the cover plate by a Tim glue, characterized in that: The cross-section sample preparation method comprises the following steps: Performing a first preprocessing on the high-order packaged chip to obtain a first high-order packaged chip sample; Performing a second preprocessing on the first high-order packaged chip test to obtain a second high-order packaged chip sample; The second high-order packaged chip sample is placed in an auxiliary grinding tool for clamping, and ground to the observation position line by a grinder to form a position surface to be observed; The ground surface to be observed is subjected to pre-observation treatment to obtain a cross-sectional sample.

2. The cross-section sample preparation method of a high-level packaged chip according to claim 1, characterized in that: The first pretreatment comprises: Preparing the high-level package chip; Grinding the cover plate of the high-level packaged chip to reduce the cover plate to 1 / 10 of the original thickness; A through hole is drilled on the cover plate, wherein the through hole is located at a position on the cover plate away from the grain group; Injecting thermosetting epoxy resin AB glue into the high-level package chip through the through hole until the glue surface at the through hole is stable; The high-level packaged chip after the injection of glue is cured to obtain the first high-level packaged chip sample.

3. The cross-section sample preparation method of a high-level packaged chip according to claim 2, characterized in that: The adhesive surface at the through hole is stabilized, which includes: Filling the cavity between the cover plate and the substrate by injecting the thermosetting epoxy resin AB glue having a ratio of 10:1 into the through hole; When the liquid level of the thermosetting epoxy resin AB glue reaches the position of the through hole, the high-order packaged chip is vacuumed through the through hole; If the liquid level drops, repeat the previous step, otherwise proceed to the next step; The high-level packaged chip after the injection of glue is cured to obtain the first high-level packaged chip sample.

4. The cross-section sample preparation method of a high-level packaged chip according to claim 1, characterized in that: The second pretreatment comprises: The first high-level packaged chip sample is wrapped with room temperature curing epoxy resin AB glue with a ratio of 2:1, and the substrate is exposed to the outside; Grinding the substrate of the first high-level packaged chip sample to thin the substrate to 1 / 3 of the original thickness; The substrate outside the epoxy resin AB glue package is cut off to obtain the second high-level packaged chip sample.

5. The cross-section sample preparation method of a high-level packaged chip according to claim 1, characterized in that: The auxiliary grinding tool includes a fixture, a pneumatic telescopic cylinder and a bracket, wherein the fixture is configured to clamp the high-level packaged chip; the pneumatic telescopic cylinder is connected to the fixture; the bracket includes a fixed section and a movable section, wherein the fixed section is fixedly connected to the grinder, one end of the movable section is hinged to an end of the fixed section away from the grinder, and the other end of the movable section is hinged to the pneumatic telescopic cylinder, and grinding to the surface to be observed by the grinder includes: Draw an observation position line between the cover plate and the substrate, and place the second high-order packaged chip sample in the fixture, wherein the observation position line is parallel to the grinder and protrudes from a side of the fixture close to the grinder; Pushing the fixture toward the grinder by the pneumatic telescopic cylinder until the second high-level packaged chip sample is in contact with the grinder, and then starting the grinder; Grinding to a first position by a first sandpaper, grinding to a second position by a second sandpaper, grinding to a third position by a third sandpaper, and grinding by a fourth sandpaper; The second high-level package chip sample ground by the fourth sandpaper is placed under a microscope for observation to see whether the grinding section coincides with the observation position line. If yes, proceed to the next step, otherwise repeat the previous step; The observation position plane is formed.

6. The cross-section sample preparation method of a high-level packaged chip according to claim 5, characterized in that: The pre-observation treatment of the ground surface to be observed comprises: Placing the second high-level package sample forming the observation position surface on the auxiliary grinding tool, with the surface to be observed facing the grinding machine; Replace the sandpaper on the grinder with a polishing cloth so that the surface to be observed is in contact with the polishing cloth, and start the grinder to perform polishing; Washing the polished second high-level packaging sample in pure water; The cleaned second high-level packaging sample is dried by nitrogen and then baked to obtain a cross-sectional sample, which is then observed.

7. An auxiliary grinding tool for high-level packaged chips, used for grinding cross-section samples of high-level packaged chips, wherein the auxiliary grinding tool is arranged above a grinding machine, and is characterized in that: The auxiliary grinding tool comprises: A clamp is configured to clamp the high-level packaged chip and to place the surface of the high-level packaged chip to be observed toward the grinding machine; A pneumatic telescopic cylinder connected to the fixture, and the pneumatic telescopic cylinder is located at an end of the fixture away from the grinder; The bracket comprises a fixed section and a movable section, wherein the first end of the fixed section is fixedly connected to the grinder, the second end of the fixed section is hinged to the first end of the movable section, and the second end of the movable section is hinged to the pneumatic telescopic cylinder.

8. The auxiliary grinding tool for high-level packaged chips according to claim 7, characterized in that: The fixture comprises: a first support plate; A second support plate, arranged opposite to the first support plate; A connecting plate, used to connect the first supporting plate and the second supporting plate, wherein the connecting plate is provided with a connecting hole, and the connecting hole is connected to the pneumatic telescopic cylinder; Wherein, a clamping assembly is provided between the first supporting plate and the second supporting plate.

9. The auxiliary grinding tool for high-level packaged chips according to claim 8, characterized in that: The clamping assembly comprises: a first clamping member connected to the first support plate, the first clamping member comprising at least one first threaded rod and a first clamping plate, the first threaded rod being movably connected to the first support plate, and the first clamping plate being located between the first support plate and the second support plate; a second clamping member connected to the second support plate, the second clamping member comprising at least one second threaded rod and a second clamping plate, the second threaded rod being movably connected to the second support plate, and the second clamping plate being located between the first support plate and the second support plate; Wherein, the high-order packaged chip is located between the first clamping plate and the second clamping plate.

10. The auxiliary grinding tool for high-level packaged chips according to claim 7, characterized in that: The pneumatic telescopic cylinder comprises: A cylinder body, wherein a piston rod is disposed in the cylinder body, and the piston rod divides the cylinder body into a first chamber and a second chamber, wherein the first chamber is located at an end away from the grinder; A first inflatable bag is connected to the first chamber through a first connecting pipe, and a pressure regulating valve is provided on the first connecting pipe; a second inflatable bag, connected to the second chamber via a second connecting pipe; Wherein, the second end of the movable section is hinged to the cylinder body.

Images