CN117210226A - Corrosive liquid and unsealing method - Google Patents
Corrosive liquid and unsealing method Download PDFInfo
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- CN117210226A CN117210226A CN202311154111.3A CN202311154111A CN117210226A CN 117210226 A CN117210226 A CN 117210226A CN 202311154111 A CN202311154111 A CN 202311154111A CN 117210226 A CN117210226 A CN 117210226A
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- corrosive liquid
- thinning
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- 239000007788 liquid Substances 0.000 title claims abstract description 57
- 238000000034 method Methods 0.000 title claims abstract description 36
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical compound [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 claims abstract description 46
- 229910052740 iodine Inorganic materials 0.000 claims abstract description 46
- 239000011630 iodine Substances 0.000 claims abstract description 46
- NLKNQRATVPKPDG-UHFFFAOYSA-M potassium iodide Chemical compound [K+].[I-] NLKNQRATVPKPDG-UHFFFAOYSA-M 0.000 claims abstract description 45
- 238000005530 etching Methods 0.000 claims abstract description 32
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000005022 packaging material Substances 0.000 claims description 52
- 238000010438 heat treatment Methods 0.000 claims description 35
- 230000007797 corrosion Effects 0.000 claims description 22
- 238000005260 corrosion Methods 0.000 claims description 22
- 238000004140 cleaning Methods 0.000 claims description 21
- 239000003566 sealing material Substances 0.000 claims description 5
- 229910052709 silver Inorganic materials 0.000 abstract description 18
- 239000004332 silver Substances 0.000 abstract description 18
- 239000000463 material Substances 0.000 abstract description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 28
- 238000004506 ultrasonic cleaning Methods 0.000 description 24
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000012778 molding material Substances 0.000 description 7
- 238000002156 mixing Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000007689 inspection Methods 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 238000012536 packaging technology Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
Landscapes
- Encapsulation Of And Coatings For Semiconductor Or Solid State Devices (AREA)
Abstract
The application relates to a corrosive liquid and an unsealing method. The corrosive liquid is prepared from the following components in parts by volume: 25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide. When the etching solution is used for unsealing the plastic package electronic device using the silver bonding wire, the plastic package material can be effectively removed, and meanwhile, the damage to the silver bonding wire is small.
Description
Technical Field
The application relates to the technical field of semiconductors, in particular to a corrosive liquid and an unsealing method.
Background
The main procedures of the semiconductor packaging technology are wafer dicing, chip mounting, wire bonding, plastic package forming and the like. The connection between the lead and the semiconductor internal chip is established by using bonding wires such as gold, aluminum, copper, silver, tin and the like, which is an important procedure link of the semiconductor packaging process. Compared with the gold bonding wire, the silver bonding wire has the advantages of lower production cost, good heat conductivity, good electric conductivity and the like. Silver bonding wires have found wide application in many fields such as semiconductor packaging, integrated circuits, LEDs, and the like. In failure analysis of semiconductor devices, the devices need to be unsealed to expose the internal chips or components for subsequent analysis. Wet unsealing techniques are a more common method of unsealing plastic encapsulated electronic devices. However, when a plastic packaging material is corroded by a traditional unsealing solution to unseal a plastic packaging electronic device, corrosion and damage are easily caused to a silver bonding wire, and further the use and the test of the unsealed electronic device are affected.
Disclosure of Invention
Accordingly, it is necessary to provide an etching solution and an unsealing method. The etching solution has less damage to the silver bonding wire when unsealing the plastic package electronic device using the silver bonding wire.
In a first aspect, the application provides a corrosive liquid prepared from the following components in parts by volume:
25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution;
the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide.
In some embodiments, the etching solution is prepared from the following components in parts by volume:
29-31 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 94-96%, and 0.9-1.1 parts of iodine solution;
the iodine solution comprises the following components in parts by weight: 24-26 parts of water, 0.9-1.1 parts of iodine and 3.9-4.1 parts of potassium iodide.
In a second aspect, the present application provides an unsealing method, comprising:
removing the plastic packaging material of the device to be unsealed by using the corrosive liquid.
In some embodiments, removing the molding material of the device to be unsealed using the etching solution includes:
and carrying out contact corrosion on the plastic packaging material of the device to be unsealed for a plurality of times by using the corrosive liquid, wherein the time of each contact corrosion is 5-10 s.
In some embodiments, each time the etching solution is used to perform contact etching on the plastic packaging material of the device to be unsealed, the method comprises the following steps:
and cleaning the device after contact corrosion.
In some embodiments, removing the plastic package material of the device to be unsealed using the etching solution includes:
and carrying out heating treatment on the device to be unsealed.
In some embodiments, the temperature of the heating treatment is 40 ℃ to 60 ℃.
In some embodiments, the heating treatment time is 8min to 10min.
In some embodiments, before the device to be unsealed is subjected to heat treatment, the method includes:
and thinning the plastic packaging material of the device to be unsealed.
In some embodiments, thinning the plastic package material of the device to be unsealed includes:
and carrying out laser thinning on the plastic packaging material of the device to be unsealed.
In some embodiments, the laser thinning power is 2w to 8.5w.
In some embodiments, the number of times of laser thinning is 2-8, and the time of each time of laser thinning is 1 s-3 s.
When the etching solution is used for unsealing the plastic package electronic device using the silver bonding wire, the plastic package material can be effectively removed, and meanwhile, the damage to the silver bonding wire is small.
Drawings
Fig. 1 is a schematic flow chart of an unsealing method according to an embodiment of the present application;
FIG. 2 is a schematic diagram of laser thinning according to an embodiment of the present application;
fig. 3 is a schematic diagram showing the unsealing effect of the chip in embodiment 1 of the present application;
fig. 4 is a schematic diagram showing the unsealing effect of the chip in embodiment 2 of the present application;
fig. 5 is a schematic diagram showing the unsealing effect of the chip in embodiment 3 of the present application;
fig. 6 is a schematic view showing the effect of unsealing the chip in comparative example 1 of the present application.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second" may include at least one such feature, either explicitly or implicitly. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
The embodiment of the application provides a corrosive liquid which is prepared from the following components in parts by volume: 25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide.
When the etching solution is used for unsealing the plastic package electronic device using the silver bonding wire, the plastic package material can be effectively removed, and meanwhile, the damage to the silver bonding wire is small.
Optionally, the volume fraction of fuming nitric acid is 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 or 35.
Optionally, the fuming nitric acid has a mass concentration of 92%, 93%, 94%, 95%, 96%, 97% or 98%.
Alternatively, the mass fraction of potassium iodide is 3 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, or 5 parts.
In some embodiments, the etching solution is prepared from the following components in parts by volume: 29-31 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 94-96%, and 0.9-1.1 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 24-26 parts of water, 0.9-1.1 parts of iodine and 3.9-4.1 parts of potassium iodide.
In one embodiment, the corrosive liquid is prepared from the following components in parts by volume: 30 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 95%, and 1 part of iodine solution; the iodine solution comprises the following components in parts by weight: 25 parts of water, 1 part of iodine and 4 parts of potassium iodide.
In another embodiment of the present application, a method for preparing an etching solution is provided, including: the preparation method comprises the following steps of mixing the following components in parts by volume: 25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide.
Still another embodiment of the present application provides an unsealing method, including: and removing the plastic packaging material of the device to be unsealed by using the corrosive liquid.
When the corrosion liquid is used for removing the plastic packaging material of the device to be unsealed, the corrosion liquid can effectively remove the plastic packaging material, and meanwhile, the damage to the silver bonding wire is small. It is understood that the device to be unsealed may be a plastic-encapsulated semiconductor device, which illustratively includes an integrated circuit chip.
In some embodiments, removing the molding material of the device to be unsealed using the etching solution includes: and carrying out contact corrosion on the plastic packaging material of the device to be unsealed for a plurality of times by using the corrosive liquid, wherein the time of each contact corrosion is 5-10 s.
The plastic packaging material is subjected to contact corrosion for a plurality of times by using the corrosive liquid, the time of each contact corrosion is 5-10 s, and the damage of the corrosive liquid to the silver bonding wire when the single contact corrosion time is overlong can be reduced. Alternatively, the time per contact etch is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
In some embodiments, removing the molding material of the device to be unsealed using the etching solution includes: and carrying out contact corrosion on the plastic packaging material of the device to be unsealed for a plurality of times by using the corrosive liquid until the device body is completely exposed. It can be understood that the total time of the unsealing process is not limited because of the difference of the packaging materials and the thicknesses of different devices, and the total time of the unsealing process can be adjusted according to the packaging materials and the thicknesses of the different devices until the device body is completely exposed.
In some embodiments, each time the etching solution is used to contact etch the molding material of the device to be unsealed includes: and cleaning the device after contact corrosion. After each contact corrosion, the device is cleaned, so that the residual corrosive liquid is reduced, and the accuracy of the unsealing treatment control can be improved.
In some embodiments, cleaning the device after contact etching includes: the device was first cleaned with water and second cleaned with acetone.
In some embodiments, the first cleaning time is 5s to 10s. Alternatively, the time of the first cleaning is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
In some embodiments, the second cleaning time is 5s to 10s. Optionally, the second cleaning time is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
In some embodiments, removing the molding material of the device to be unsealed using the etching solution includes: and heating the device to be unsealed.
After the device to be unsealed is heated, the plastic packaging material is removed by using the corrosive liquid, so that the corrosive liquid can remove the plastic packaging material at a certain temperature, and the removal effect is good.
In some embodiments, the temperature of the heat treatment is 40 ℃ to 60 ℃. In the temperature range of the heating treatment, the effect of removing the plastic packaging material of the device to be unsealed by using the corrosive liquid is better. Alternatively, the temperature of the heat treatment is 40 ℃, 41 ℃, 42 ℃, 43 ℃, 44 ℃, 45 ℃, 46 ℃, 47 ℃, 48 ℃, 49 ℃, 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, or 60 ℃.
In some embodiments, the time of the heat treatment is 8min to 10min. Optionally, the time of the heat treatment is 8min, 8.2min, 8.4min, 8.6min, 8.8min, 9min, 9.2min, 9.4min, 9.6min, 9.8min, or 10min.
In some embodiments, prior to heat treating the device to be unsealed, comprising: and thinning the plastic packaging material of the device to be unsealed.
After the plastic packaging material of the device to be unsealed is thinned, the plastic packaging material is removed by using the corrosive liquid, so that the contact time between the corrosive liquid and the bonding wire can be reduced, and the damage to the bonding wire in the unsealing process is further reduced.
Referring to fig. 2, in some embodiments, thinning the plastic package material of the device to be unsealed includes: and thinning the plastic packaging material of the device to be unsealed until the bonding wire is exposed out of the plastic packaging material.
The plastic packaging material of the device to be unsealed is thinned until the bonding wire is exposed out of the plastic packaging material, so that the time for removing the plastic packaging material by using corrosive liquid can be reduced to the greatest extent, and the damage to the bonding wire in the unsealing process is further reduced.
In some embodiments, thinning the molding material of the device to be unsealed includes: and carrying out laser thinning on the plastic packaging material of the device to be unsealed. The plastic package material is thinned by using laser, so that the thinning efficiency is higher, and the precision is easy to control.
In some embodiments, the laser thinning is performed at a power of 2W to 8.5W. Alternatively, the laser thinning power is 2W, 2.5W, 3W, 3.5W, 4W, 4.5W, 5W, 5.5W, 6W, 6.5W, 7W, 7.5W, 8W, or 8.5W.
In some embodiments, the number of laser thinning is 2-8, and the time of each laser thinning is 1-3 s. The thickness of each thinning is easy to control through repeated laser thinning, so that the plastic packaging material of the device to be unsealed is conveniently thinned until the bonding wire is exposed out of the plastic packaging material. Alternatively, the number of laser thinning is 2, 3, 4, 5, 6, 7 or 8. Alternatively, each laser thinning is performed for a time of 1s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s, 2s, 2.1s, 2.2s, 2.3s, 2.4s, 2.5s, 2.6s, 2.7s, 2.8s, 2.9s, or 3s.
In some embodiments, removing the molding material of the device to be unsealed with the etching solution further comprises: the unsealed device was subjected to a third cleaning with acetone, a fourth cleaning with water, and a fifth cleaning with ethanol.
In some embodiments, the third cleaning time is 5s to 10s. Optionally, the third cleaning time is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
In some embodiments, the fourth cleaning time is 5s to 10s. Optionally, the fourth cleaning time is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
In some embodiments, the fifth cleaning time is 5s to 10s. Optionally, the fifth cleaning time is 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, 8s, 8.5s, 9s, 9.5s or 10s.
Referring to fig. 1, in some embodiments, the unsealing method includes the steps of:
s100: carrying out laser thinning on the device to be unsealed until the bonding wire is exposed out of the plastic packaging material, wherein the power of the laser thinning is 2W-8.5W, the times of the laser thinning are 2-8 times, and the time of each laser thinning is 1 s-3 s;
s200: carrying out heating treatment on the device subjected to laser thinning, wherein the heating treatment temperature is 40-60 ℃, and the heating treatment time is 8-10 min;
s300: preparing an etching solution as an unsealing solution, wherein the etching solution is prepared from the following components in parts by volume: 25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide; carrying out contact corrosion on the plastic packaging material of the device subjected to the heating treatment for 5-10 s each time by dividing the corrosive liquid into a plurality of times until the device body is completely exposed, and cleaning the device by sequentially using water and acetone after carrying out contact corrosion on the plastic packaging material of the device to be unsealed each time by using the corrosive liquid;
s400: and cleaning the unsealed device treated by the corrosive liquid sequentially by using acetone, water and ethanol.
In the unsealing method, part of the plastic packaging material can be removed by laser thinning, so that the treatment time of the plastic packaging material by using the corrosive liquid is shortened, and the probability of damaging the silver bonding wire by the corrosive liquid is reduced. Meanwhile, by controlling the power, single treatment time and times of laser thinning, the laser thinning can be controlled until the bonding wire is just exposed out of the plastic packaging material, so that the time for removing the plastic packaging material by using corrosive liquid is reduced as much as possible. Further, the device is unsealed by using an etching solution obtained by mixing fuming nitric acid and iodine solution, and the etching solution has less damage to the silver bonding wire. Further, before the plastic packaging material is removed by using the corrosive liquid, the device is subjected to heating treatment, and the heated device is treated by using the corrosive liquid so as to increase the removal effect of the corrosive liquid on the plastic packaging material. Meanwhile, the etching liquid is used for carrying out contact etching on the device for multiple times, the time of each contact etching is controlled, and the device is cleaned after each contact etching. The contact time between the corrosive liquid and the silver bonding wire can be controlled, and the damage to the silver bonding wire is reduced.
In some embodiments, the unsealing method is the steps of:
(1) Carrying out laser thinning on the device to be unsealed until the bonding wire is exposed out of the plastic packaging material, wherein the power of the laser thinning is 2W-8.5W, the times of the laser thinning are 2-8 times, and the time of each laser thinning is 1 s-3 s;
(2) Carrying out heating treatment on the device subjected to laser thinning, wherein the heating treatment temperature is 40-60 ℃, and the heating treatment time is 8-10 min;
(3) Preparing an etching solution as an unsealing solution, wherein the etching solution is prepared by mixing the following components in parts by volume: 25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution; the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide; carrying out contact corrosion on the plastic packaging material of the device subjected to the heating treatment for 5-10 seconds each time by dividing the corrosive liquid into a plurality of times until the device body is completely exposed, and cleaning the device by sequentially using water and acetone after carrying out contact corrosion on the plastic packaging material of the device to be unsealed each time by using the corrosive liquid;
(4) And cleaning the unsealed device treated by the corrosive liquid sequentially by using acetone, water and ethanol.
A further embodiment of the present application provides a semiconductor device obtained by unsealing using any one of the above-described unsealing methods.
The following are specific examples
Example 1
Preparing a corrosive liquid: 250ml of water is measured in an conical flask, 35g of potassium iodide and 10g of iodine are added, and the mixture is stirred uniformly, so that the iodine is completely dissolved, and an iodine solution is obtained. 30ml of fuming nitric acid with the mass concentration of 92% and 1ml of iodine solution are taken and mixed to obtain corrosive liquid.
The chip unsealing method comprises the following steps:
(1) And (3) determining the size and the position of the chip and the thickness of the plastic packaging material above the chip by utilizing X-ray inspection, and carrying out laser thinning on the plastic packaging material above the chip until the top of the bonding wire is exposed. Parameter setting of laser thinning: the power of the laser thinning is 3.5W, the processing times of the laser thinning are 8 times, and the time of each laser thinning is 2s.
(2) And starting a heating table switch, setting the temperature to 60 ℃, and placing the chip subjected to laser thinning on a heating table for heating for 8min.
(3) 3 drops of the prepared corrosive liquid are taken by a dropper and dripped into a groove formed by laser thinning of the device, after reaction for 10s, the device is clamped, ultrasonic cleaning is sequentially carried out on the device for 10s by using water, and then ultrasonic cleaning is carried out on the device for 10s by using acetone.
(4) Repeating the step (3) for three times, wherein the surface of the chip is completely exposed.
(5) And carrying out ultrasonic cleaning on the device, firstly carrying out ultrasonic cleaning on the device for 5s by using acetone, then carrying out ultrasonic cleaning on the device for 5s by using water, finally carrying out ultrasonic cleaning on the device for 5s by using alcohol, and then taking out the device and drying the device.
Referring to fig. 3, the unsealed chip was observed under a microscope, and it can be seen that the surface of the chip was completely exposed and the bonding wires remained intact.
Example 2
Preparing a corrosive liquid: 250ml of water is measured in an conical flask, 40g of potassium iodide and 10g of iodine are added, and the mixture is stirred uniformly, so that the iodine is completely dissolved, and an iodine solution is obtained. Mixing 30ml of fuming nitric acid with the mass concentration of 95% with 1ml of iodine solution to obtain corrosive liquid.
The chip unsealing method comprises the following steps:
(1) And (3) determining the size and the position of the chip and the thickness of the plastic packaging material above the chip by utilizing X-ray inspection, and carrying out laser thinning on the plastic packaging material above the chip until the top of the bonding wire is exposed. Parameter setting of laser thinning: the power of the laser thinning is 5W, the processing times of the laser thinning are 5 times, and the time of each laser thinning is 2s.
(2) And starting a heating table switch, setting the temperature to 60 ℃, and placing the chip subjected to laser thinning on a heating table for heating for 10min.
(3) 3 drops of the prepared corrosive liquid are taken by a dropper and dripped into a groove formed by laser thinning of the device, after reaction for 10s, the device is clamped, ultrasonic cleaning is sequentially carried out on the device for 10s by using water, and then ultrasonic cleaning is carried out on the device for 10s by using acetone.
(4) Repeating the step (3) for three times, wherein the surface of the chip is completely exposed.
(5) And carrying out ultrasonic cleaning on the device, firstly carrying out ultrasonic cleaning on the device for 10s by using acetone, then carrying out ultrasonic cleaning on the device for 10s by using water, finally carrying out ultrasonic cleaning on the device for 10s by using alcohol, and then taking out the device and drying the device.
Referring to fig. 4, the unsealed chip was observed under a microscope, and it can be seen that the surface of the chip was completely exposed and the bonding wires remained intact.
Example 3
Preparing a corrosive liquid: 250ml of water is measured in an conical flask, 45g of potassium iodide and 10g of iodine are added, and the mixture is stirred uniformly, so that the iodine is completely dissolved, and an iodine solution is obtained. Mixing 30ml of fuming nitric acid with the mass concentration of 98% with 1ml of iodine solution to obtain corrosion liquid.
The chip unsealing method comprises the following steps:
(1) And (3) determining the size and the position of the chip and the thickness of the plastic packaging material above the chip by utilizing X-ray inspection, and carrying out laser thinning on the plastic packaging material above the chip until the top of the bonding wire is exposed. Parameter setting of laser thinning: the power of the laser thinning is 3W, the processing times of the laser thinning are 6 times, and the time of each laser thinning is 2s.
(2) And starting a heating table switch, setting the temperature to be 50 ℃, and placing the chip subjected to laser thinning on a heating table for heating for 10min.
(3) 2 drops of the prepared corrosive liquid are taken by a dropper and dripped into a groove formed by laser thinning of the device, after reaction for 10s, the device is clamped, ultrasonic cleaning is sequentially carried out on the device for 10s by using water, and ultrasonic cleaning is carried out on the device for 10s by using acetone.
(4) Repeating the step (3) six times, and completely exposing the surface of the chip.
(5) And carrying out ultrasonic cleaning on the device, firstly carrying out ultrasonic cleaning on the device for 10s by using acetone, then carrying out ultrasonic cleaning on the device for 10s by using water, finally carrying out ultrasonic cleaning on the device for 10s by using alcohol, and then taking out the device and drying the device.
Referring to fig. 5, the unsealed chip was observed under a microscope, and it can be seen that the surface of the chip was completely exposed and the bonding wires remained intact.
Comparative example 1
And (3) arrangement of an unsealing solution: mixing fuming nitric acid with the mass concentration of 95% and concentrated sulfuric acid with the mass concentration of 98% according to the volume ratio of 3:1 to obtain an unsealing solution.
The chip unsealing method comprises the following steps:
(1) And (3) determining the size and the position of the chip and the thickness of the plastic packaging material above the chip by utilizing X-ray inspection, and carrying out laser thinning on the plastic packaging material above the chip until the top of the bonding wire is exposed. Parameter setting of laser thinning: the power of the laser thinning is 3.5W, the processing times of the laser thinning are 8 times, and the time of each laser thinning is 2s.
(2) And starting a heating table switch, setting the temperature to 120 ℃, and placing the chip subjected to laser thinning on a heating table for heating for 10min.
(3) 2 drops of the prepared unsealing solution are taken by a dropper and dripped into a groove formed by laser thinning of the device, after reaction for 10s, the device is clamped, ultrasonic cleaning is sequentially carried out on the device for 10s by using water, and ultrasonic cleaning is carried out on the device for 10s by using acetone.
(4) Repeating the step (3) for five times, wherein the surface of the chip is completely exposed.
(5) And carrying out ultrasonic cleaning on the device, firstly carrying out ultrasonic cleaning on the device for 10s by using acetone, then carrying out ultrasonic cleaning on the device for 10s by using water, finally carrying out ultrasonic cleaning on the device for 10s by using alcohol, and then taking out the device and drying the device.
Referring to fig. 6, the unsealed chip was observed under a microscope, and it was found that the chip surface was completely exposed, but the bonding wires were all corroded.
The components of each corrosive liquid in examples 1 to 3 are shown in the following table 1:
TABLE 1
The parameters and unsealing treatment results of each unsealing method in examples 1 to 3 and comparative example 1 are shown in table 2 below:
TABLE 2
Referring to fig. 3 to 6 again, it can be seen that, compared with the conventional unsealing solution, the unsealing treatment of the chip to be unsealed by using the corrosive liquid of the present application can remove the plastic sealing material, so that the bonding wire remains intact under the condition that the surface of the chip is completely exposed.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. The scope of the application is therefore intended to be covered by the appended claims, and the description and drawings may be interpreted in accordance with the contents of the claims.
Claims (10)
1. The corrosive liquid is characterized by being prepared from the following components in parts by volume:
25-35 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 92-98%, and 0.5-2 parts of iodine solution;
the iodine solution comprises the following components in parts by weight: 20-30 parts of water, 0.5-1.5 parts of iodine and 3-5 parts of potassium iodide.
2. The corrosive liquid of claim 1, wherein the corrosive liquid is prepared from the following components in parts by volume:
29-31 parts of fuming nitric acid, wherein the mass concentration of the fuming nitric acid is 94-96%, and 0.9-1.1 parts of iodine solution;
the iodine solution comprises the following components in parts by weight: 24-26 parts of water, 0.9-1.1 parts of iodine and 3.9-4.1 parts of potassium iodide.
3. An unsealing method, comprising:
the plastic packaging material of the device to be unsealed is removed by using the etching liquid according to any one of claims 1 to 2.
4. A method of unsealing according to claim 3, wherein removing plastic sealing material of the device to be unsealed using the etching liquid comprises:
and carrying out contact corrosion on the plastic packaging material of the device to be unsealed for a plurality of times by using the corrosive liquid, wherein the time of each contact corrosion is 5-10 s.
5. The unsealing method according to claim 4, wherein each time the etching liquid is used to contact-etch a plastic sealing material of a device to be unsealed, comprising:
and cleaning the device after contact corrosion.
6. A method of unsealing according to claim 3, wherein prior to removing the plastic sealing material of the device to be unsealed using the etching liquid comprises:
and carrying out heating treatment on the device to be unsealed.
7. The unsealing method according to claim 6, wherein the temperature of the heat treatment is 40 ℃ to 60 ℃;
and/or the heating treatment time is 8-10 min.
8. An unsealing method according to claim 6, characterized in that before the device to be unsealed is subjected to heat treatment, it comprises:
and thinning the plastic packaging material of the device to be unsealed.
9. The unsealing method of claim 8, wherein thinning the plastic sealing material of the device to be unsealed comprises:
and carrying out laser thinning on the plastic packaging material of the device to be unsealed.
10. The unsealing method according to claim 9, wherein the power of the laser thinning is 2w to 8.5w; and/or the number of the groups of groups,
the laser thinning times are 2-8, and the laser thinning time is 1-3 s each time.
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