Semiconductor device cap opening method
By pasting protective tape on the front of the semiconductor device and cross-linking enhancement, combined with the method of absorbing the open cap solution, the problems of difficult control of the open cap process and high cost of consumables in the prior art are solved, and the cost of the open cap of the semiconductor device is achieved.
Patent Information
- Application Number
- CN202411909924.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-03-28
AI Technical Summary
The existing wet hat opening technology has difficulties in controlling the hat opening process, and the consumables cost is relatively high, making it difficult to meet the cost-effective needs of the semiconductor field.
By pasting the protective stick on the front of the semiconductor device, the parts of the unadhesed protective stick are cross-linked and enhanced. After tearing off the protective stick, the open cap solution drops are absorbed at the position where the protective stick was originally pasted on the front of the semiconductor device, thereby opening the packaging shell of the semiconductor device.
It realizes easy control of the hat opening process and reduces the cost of consumables, and does not require expensive laser machines and is cost-effective.
Smart Images
Figure CN119725087A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present application relate to the field of semiconductor technology, and in particular to a method for opening a cap of a semiconductor device. Background Art
[0002] Semiconductor device wet decapping technology is a technology used to open the semiconductor device package shell. It mainly uses chemical reagents to corrode the packaging material, thereby removing the package shell and exposing the chip. In the fields of semiconductor manufacturing and failure analysis, chip reverse engineering and maintenance, it is often necessary to detect and repair the internal chip structure of the semiconductor chip. Wet decapping is an effective means to open the semiconductor device package shell.
[0003] Existing wet decapping technologies can be divided into two categories. The first is direct wet decapping, which involves placing semiconductor devices directly into a boiling acid mixture. This method is simple to operate, but the decapping process is difficult to control, and the solution can cause excessive corrosion to the chip. It also has the risk of corroding copper binding wires or even breaking wires, affecting subsequent electrical testing. The second is post-laser plastic encapsulation wet decapping, which involves laser digging a pit above the chip for pretreatment, and then dripping a certain amount of boiling acid mixture into the pit. This method is easy to control the decapping process, and the decapping results are of high quality, but the laser machine used for laser pretreatment is expensive, which brings cost pressure.
[0004] Therefore, a method for decapping a semiconductor device is needed, which has an easy-to-control decapping process, low consumables cost, and is economical and efficient, to meet the development needs of the semiconductor field. Summary of the invention
[0005] The purpose of the embodiments of the present application is to provide a method for decapping a semiconductor device, wherein the decapping process is easy to control, the consumables cost is low, and the method is economical and efficient.
[0006] In order to solve the above technical problems, the embodiments of the present application provide a method for opening a cap of a semiconductor device, comprising the following steps:
[0007] S11: Pasting a protective sticker on a portion of the front side of the semiconductor device;
[0008] S12: placing the semiconductor device with the protective film attached thereto in a cross-linking solution and heating the device so as to enhance the cross-linking of the portion of the semiconductor device where the protective film is not attached thereto;
[0009] S13: taking out the semiconductor device from the cross-linking solution and removing the protective film;
[0010] S14: sucking the decapping solution and dropping it on the position where the semiconductor device protective sticker is pasted, and then placing the semiconductor device in the cleaning solution for cleaning;
[0011] S15: Take out the semiconductor device from the cleaning solution and observe the decapping condition. If the chip is not completely leaked, absorb the decapping solution again and drop it on the same position of the semiconductor device for cleaning until the chip is completely leaked.
[0012] The semiconductor device uncapping method provided by the embodiment of the present application is to stick a protective sticker on the front of the semiconductor, cross-link and strengthen the part where the protective sticker is not stuck, and after tearing off the protective sticker, absorb and drip the uncapping solution on the position where the protective sticker was originally stuck on the front of the semiconductor device, so as to open the package shell of the semiconductor device. In this way, the part where the protective sticker is not stuck is cross-linked and strengthened, and is not affected by the corrosion of the uncapping solution, while the part where the protective sticker is stuck is not cross-linked and strengthened, and the uncapping solution uncaps through this position, so that the uncapping process is easy to control, and no expensive laser machine is needed, which is economical and efficient.
[0013] In some embodiments, before attaching the protective sticker to the front side of the semiconductor device, the front side of the semiconductor device is ground.
[0014] In some embodiments, the protective sticker is tin foil.
[0015] In some embodiments, the cross-linking solution is a diethylenetriamine or triethylenetetramine solution.
[0016] In some embodiments, when the semiconductor device with the protective film attached is placed in a cross-linking solution and heated, the heating method is water bath heating, the heating temperature is controlled within 80° C.-100° C., and the heating time is 4-6 hours.
[0017] In some embodiments, the decapping solution is prepared by mixing fuming nitric acid with a volume concentration of 95%-98% and concentrated sulfuric acid with a volume concentration of 98% in a volume ratio of 3:1.
[0018] In some embodiments, the decapping solution needs to be heated to boiling on a heating platform when used.
[0019] In some embodiments, the cleaning solution is an acetone solution.
[0020] In some embodiments, ultrasonic cleaning is used when the semiconductor device is placed in a cleaning solution for cleaning.
[0021] In some embodiments, the location where the protective sticker is attached to the front side of the semiconductor device is located directly above the chip in the semiconductor device. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.
[0023] Figure 1 is a flow chart of a method for opening a cap of a semiconductor device provided in some embodiments of the present application;
[0024] Figure 2 It is a schematic diagram of the side structure of the semiconductor device after a protective sticker is attached to the front side of the semiconductor device during the semiconductor device capping process provided by some embodiments of the present application;
[0025] Figure 3 is a schematic diagram of the side structure of a semiconductor device after cross-linking enhancement during a semiconductor device capping process provided by some embodiments of the present application;
[0026] Figure 4 It is a schematic diagram of the side structure of the semiconductor device after the cap is opened provided by some embodiments of the present application.
[0027] Explanation of reference numerals: 11 - protective sticker; 12 - chip; 13 - plastic-sealed shell of semiconductor device; 131 - cross-linked reinforced portion of the plastic-sealed shell of semiconductor device; 132 - non-cross-linked reinforced portion of the plastic-sealed shell of semiconductor device. DETAILED DESCRIPTION
[0028] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below in conjunction with the accompanying drawings. However, it will be appreciated by those skilled in the art that in each embodiment of the present application, many technical details are proposed in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed in the present application can also be implemented. The division of the following embodiments is for the convenience of description, and the specific implementation of the present application should not constitute any limitation, and the various embodiments can be combined with each other and referenced to each other without contradiction.
[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.
[0030] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.
[0031] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0032] Semiconductor device wet decapping technology is a technology used to open the semiconductor device package shell. It mainly uses chemical reagents to corrode the packaging material, thereby removing the package shell and exposing the chip. In the fields of semiconductor manufacturing and failure analysis, chip reverse engineering and maintenance, it is often necessary to detect and repair the internal chip structure of the semiconductor chip. Wet decapping is an effective means to open the semiconductor device package shell.
[0033] Existing wet decapping technologies can be divided into two categories. The first is direct wet decapping, which involves placing semiconductor devices directly into a boiling acid mixture. This method is simple to operate, but the decapping process is difficult to control, and the solution can cause excessive corrosion to the chip. It also has the risk of corroding copper binding wires or even breaking wires, affecting subsequent electrical testing. The second is wet decapping after laser encapsulation. This method involves laser digging a pit above the chip for pretreatment, and then dripping a certain amount of boiling acid mixture into the pit. This method is easy to control the decapping process, and the decapping results are of high quality, but the laser machine used for laser pretreatment is expensive, which brings cost pressure to non-professional decapping companies.
[0034] Therefore, a method for decapping a semiconductor device is needed, which has an easy-to-control decapping process, low consumables cost, and is economical and efficient, to meet the development needs of the semiconductor field.
[0035] In order to reduce the cost of the semiconductor device uncapping process and control the uncapping process. Some embodiments of the present application provide a semiconductor device uncapping method, which is to stick a protective sticker on the front of the semiconductor, cross-link and strengthen the part where the protective sticker is not stuck, and after tearing off the protective sticker, absorb the uncapping solution and drip it on the position where the protective sticker was originally stuck on the front of the semiconductor device, so as to open the package shell of the semiconductor device. In this way, the part where the protective sticker is not stuck is cross-linked and strengthened, and is not affected by the corrosion of the uncapping solution, while the part where the protective sticker is stuck is not cross-linked and strengthened, and the uncapping solution uncaps through this position, so that it is easy to control the uncapping process, and there is no need to use an expensive laser machine, which is economical and efficient.
[0036] Combine the following Figures 1 to 4 A method for opening a cap of a semiconductor device provided in some embodiments of the present application includes the following steps:
[0037] S11: Pasting a protective sticker 11 on a portion of the front surface of the semiconductor device;
[0038] Specifically, if Figure 2 As shown, a suitable protective sticker 11 is pasted on the surface of the semiconductor device, just above the chip 12. The protective sticker 11 is slightly larger than the chip 12. The protective sticker 11 cannot react with the cross-linking solution and protects the semiconductor pasting position so that the cap can be opened at this position later.
[0039] S12: placing the semiconductor device with the protective film 11 in a cross-linking solution and heating it to enhance the cross-linking of the part of the semiconductor device where the protective film 11 is not attached;
[0040] Specifically, the main components of the plastic encapsulation material of the semiconductor device shell are silicon dioxide, epoxy resin and phenolic resin. The cross-linking solution has certain chemical components that can react with the epoxy group in the epoxy resin, and can also react with the phenolic hydroxyl group of the phenolic resin. After the reaction, a cross-linking phenomenon occurs, which increases its density. The epoxy resin and the phenolic resin form a tighter three-dimensional network structure. This tight structure can reduce the penetration of corrosive substances. At the same time, the highly cross-linked structure also makes it more difficult for the molecular chains of the epoxy resin and the phenolic resin to be destroyed when corroded, thereby improving the overall corrosion resistance. The protective sticker 11 serves as a mask, and the semiconductor device shell above the chip 12 does not contact the cross-linking solution, and no cross-linking enhancement reaction occurs, providing conditions for subsequent capping.
[0041] S13: taking out the semiconductor device from the cross-linking solution and removing the protective film 11;
[0042] Specifically, the semiconductor device can be taken out from the solution by tearing off the protective film 11 with a small tool such as tweezers, thereby completing the pre-processing work before opening the cap. Figure 3 This is the state of the semiconductor device after the cross-linking process is completed. The dotted line in the figure roughly divides the semiconductor device into a cross-linked part and a non-cross-linked part.
[0043] S14: Absorb the decapping solution and drop it on the sticking position of the semiconductor device protection sticker 11, and then put the semiconductor device into the cleaning solution for cleaning;
[0044] Specifically, a small amount of decapping solution can be sucked with a straw, an ear bulb, a rubber-tipped dropper or other small tools, and a drop is dropped on the surface of the semiconductor device where the protective sticker 11 was originally pasted, and the reaction is allowed to proceed for a period of time, and then the device is placed in a cleaning solution for cleaning. The decapping solution can react with the uncrosslinked part of the semiconductor device, and the cleaning solution can clean and dissolve the product after the reaction, so that corrosion pits are leaked on the surface of the semiconductor device, and the corrosion condition of the semiconductor device can be observed.
[0045] S15: taking out the semiconductor device from the cleaning solution and observing the decapping condition. If the chip 12 is not completely leaked, the decapping solution is again absorbed and dropped on the same position of the semiconductor device for cleaning until the chip 12 is completely leaked.
[0046] Specifically, after observing the uncapping of the semiconductor device, if it is found that the uncapping process is not completed, the uncapping solution can be repeatedly sucked again, reacted and cleaned, and the uncapping situation can be observed until the chip 12 is completely exposed, and the uncapping process is completed. Generally, 5-10 drops are dripped on one side, and after cleaning, 5-10 drops are repeatedly dripped, so that the reaction acid can always be guaranteed to be the original ratio. Figure 4 The semiconductor device is in a state after the decapping process is completed. The chip 12 in the figure is completely exposed, and the opening above the chip 12 is the pit left after the decapping solution is etched. The chip 12 and the bonding wire structure remain intact. The package form of the semiconductor device in the figure is TO-247-3L.
[0047] In addition, the number of drops of the decapping solution finally absorbed is dynamically adjusted with various factors. For example, at the beginning of the experiment, the reaction interface is far away from the chip 12, and the number of drops can be appropriately increased. As the reaction interface gets closer to the chip 12, the number of drops can be reduced. For another example, the initial reaction interface of the package type T0-247 is far away from the chip 12, and the number of drops can be increased. The initial reaction interface of the package type PDFN5*6 is close to the chip 12, and the number of drops can be appropriately reduced.
[0048] The embodiment of the present application provides a method for opening the cap of a semiconductor device, wherein a protective sticker 11 is attached to the front of the semiconductor, and the part where the protective sticker 11 is not attached is cross-linked and strengthened. After the protective sticker 11 is torn off, an opening solution is absorbed and dripped on the position where the protective sticker 11 was originally attached to the front of the semiconductor device, thereby opening the package shell of the semiconductor device. In this way, the part where the protective sticker 11 is not attached is cross-linked and strengthened, and is not affected by the corrosion of the opening solution, while the part where the protective sticker 11 is attached is not cross-linked and strengthened, and the opening solution opens the cap through this position, thereby making it easy to control the opening process, and no expensive laser machine is required, which is economical and efficient.
[0049] In some embodiments of the present application, before the protective film 11 is attached to the front side of the semiconductor device, the front side of the semiconductor device is ground.
[0050] It should be noted that the packaging form of some semiconductor devices (such as T0-247) has thick plastic packaging materials. In order to shorten the time of opening the cap, the front of the semiconductor device can be ground to reduce its thickness. The front of the device can be flat-ground on sandpaper to reduce its thickness. While thinning, it is necessary to ensure that the binding wires and bonding wires inside the semiconductor device are not damaged.
[0051] In some embodiments of the present application, the protective sticker 11 is tin foil.
[0052] It should be noted that tin foil is a commonly used adhesive paper with adhesive backing, which is easy to apply, easy to obtain, and inexpensive. It does not react with the cross-linking solution and protects the pasted part from the occurrence of enhanced cross-linking reaction.
[0053] In some embodiments of the present application, the cross-linking solution is a diethylenetriamine or triethylenetetramine solution.
[0054] It should be noted that diethylenetriamine (H2N-CH2-CH2-NH-CH2-CH2-NH2) or triethylenetetramine (H2N-CH2-CH2-NH-CH2-CH2-NH-CH2-CH2-NH2) can react with the epoxy group in the epoxy resin, and can also react with the phenolic hydroxyl group of the phenolic resin. After the reaction, the crosslinking density increases, and the epoxy resin and the phenolic resin form a tighter three-dimensional network structure. This tight structure can reduce the penetration of corrosive substances. At the same time, the highly crosslinked structure also makes the molecular chains of the epoxy resin and the phenolic resin less likely to be destroyed when corroded, thereby improving the overall corrosion resistance. The tin foil is used as a protective film to prevent the plastic sealing material of the device above the chip 12 from contacting with diethylenetriamine or triethylenetetramine, and no crosslinking enhancement reaction will occur, providing conditions for the subsequent use of mixed acid dripping acid to open the cap.
[0055] In some embodiments of the present application, when the semiconductor device with the protective film 11 is placed in a cross-linking solution and heated, the heating method is water bath heating, the heating temperature is controlled within 80° C.-100° C., and the heating time is 4-6 hours.
[0056] It should be noted that the device with the tin foil pasted is suspended in a diethylenetriamine or triethylenetetramine solution, the solution is heated in a water bath, the temperature is controlled in the range of 80-100°C, and the reaction time usually takes 4-6 hours. Figure 3 As shown, the cross-linking reaction does not occur only on the surface, but reacts from the outside to the inside in sequence. However, this reaction is a polymer addition reaction. At this temperature and reaction time, it will not react very quickly. Most of the areas covered by the protective film 11 are still in a non-cross-linked and enhanced state, and eventually a circle of semiconductor device plastic package shell cross-linked enhanced parts 131 and a semiconductor device plastic package shell non-cross-linked enhanced part 132 in the middle will be formed. The temperature and reaction time are given as examples, and the specific needs need to be determined according to the thickness of the plastic package material.
[0057] In some embodiments of the present application, the decapping solution is prepared by mixing fuming nitric acid with a volume concentration of 95%-98% and concentrated sulfuric acid with a volume concentration of 98% in a volume ratio of 3:1.
[0058] Specifically, fuming nitric acid (c = 95-98%) and concentrated sulfuric acid (c = 98%) are heated to boiling on a heating platform in a volume ratio of 3:1, and the mixed acid is taken with a rubber-tipped dropper and dripped on the original tin foil cover position, and then the device is placed in an acetone solution for ultrasonic cleaning. The uncapping process is completed by dripping instead of directly placing the device in the mixed acid beaker. This is because if the semiconductor device is directly placed in the mixed acid, the concentration of the two acids in the mixed acid will decrease with the reaction, and the product will also enter the solution. At this time, when the concentration of fuming nitric acid is as low as dilute nitric acid, it will begin to react with metals such as Cu, thereby affecting the uncapping process.
[0059] In some embodiments of the present application, the decapping solution needs to be heated to boiling on a heating platform when in use.
[0060] Specifically, the decapping solution is heated to 250 degrees Celsius when in use, and then heated until the acid bubbles up, so that the mixed acid and the molding compound can fully react at high temperature.
[0061] In some embodiments of the present application, the cleaning solution is an acetone solution.
[0062] It should be noted that acetone is an organic solvent that can effectively dissolve the products of the reaction between the plastic packaging material and the mixed acid. Acetone is extremely volatile. After the semiconductor device is taken out of the acetone solution, the acetone evaporates quickly, making it convenient to continue dripping the decapping solution or taking pictures for observation.
[0063] In some embodiments of the present application, ultrasonic cleaning is used when the semiconductor device is placed in a cleaning solution for cleaning.
[0064] It should be noted that the use of an ultrasonic instrument can help acetone dissolve the product faster.
[0065] In some embodiments of the present application, the position where the protective sticker 11 is attached to the front side of the semiconductor device is located directly above the chip 12 in the semiconductor device.
[0066] It should be noted that the pasting position of the protective film 11 determines the subsequent opening position of the cap. The precise opening position and the dripping form can prevent the acid from excessively corroding the chip 12 or the binding wire. If there is no precise window opening position, the reaction area cannot be reduced, which will lead to a higher demand for the amount of acid solution, which is not conducive to control. Therefore, the precise pasting position is particularly important for the precise control of the opening of the cap.
[0067] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.
Claims
1. A method for opening a cap of a semiconductor device, characterized in that: The steps include: Pasting a protective sticker on a portion of the front side of the semiconductor device; Placing the semiconductor device with the protective film attached thereto in a cross-linking solution and heating the device so as to enhance the cross-linking of the portion of the semiconductor device where the protective film is not attached thereto; Taking the semiconductor device out of the cross-linking solution and removing the protective sticker; Absorbing the decapping solution and dropping it on the position where the semiconductor device protective sticker is pasted, and then placing the semiconductor device in the cleaning solution for cleaning; The semiconductor device is taken out from the cleaning solution and the decapping condition is observed. If the chip is not completely leaked, the decapping solution is again absorbed and dropped on the same position of the semiconductor device for cleaning until the chip is completely leaked.
2. The semiconductor device capping method according to claim 1, characterized in that: Before sticking the protective sticker on the front side of the semiconductor device, the front side of the semiconductor device is ground.
3. The semiconductor device capping method according to claim 1, characterized in that: The protective sticker is tin foil.
4. The semiconductor device capping method according to claim 1, characterized in that: The cross-linking solution is a diethylenetriamine or triethylenetetramine solution.
5. The method for removing a cap from a semiconductor device according to claim 1, characterized in that: When the semiconductor device with the protective sticker is placed in a cross-linking solution and heated, the heating method is water bath heating, the heating temperature is controlled within 80° C.-100° C., and the heating time is 4-6 hours.
6. The semiconductor device capping method according to claim 1, characterized in that: The decapping solution is prepared by mixing fuming nitric acid with a volume concentration of 95%-98% and concentrated sulfuric acid with a volume concentration of 98% in a volume ratio of 3:
1.
7. The semiconductor device cap removal method according to claim 6, characterized in that: The decapping solution needs to be heated to boiling on a heating platform when in use.
8. The semiconductor device capping method according to claim 1, characterized in that: The cleaning solution is an acetone solution.
9. The semiconductor device capping method according to claim 8, characterized in that: Ultrasonic cleaning is used when the semiconductor device is placed in a cleaning solution for cleaning.
10. The semiconductor device cap removal method according to claim 1, characterized in that: The position where the protective sticker is pasted on the front side of the semiconductor device is located directly above the chip in the semiconductor device.