WO2020238138A1 - 介面金属共化物的覆盖率检测方法 - Google Patents

介面金属共化物的覆盖率检测方法 Download PDF

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WO2020238138A1
WO2020238138A1 PCT/CN2019/123556 CN2019123556W WO2020238138A1 WO 2020238138 A1 WO2020238138 A1 WO 2020238138A1 CN 2019123556 W CN2019123556 W CN 2019123556W WO 2020238138 A1 WO2020238138 A1 WO 2020238138A1
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coverage
chip
detecting
mixed reagent
compound
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PCT/CN2019/123556
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English (en)
French (fr)
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钟定国
田德文
宋青林
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潍坊歌尔微电子有限公司
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Priority to US17/614,905 priority Critical patent/US12031920B2/en
Publication of WO2020238138A1 publication Critical patent/WO2020238138A1/zh

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    • G—PHYSICS
    • G01—MEASURING; TESTING
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    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
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    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L24/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
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    • H01L24/42—Wire connectors; Manufacturing methods related thereto
    • H01L24/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L24/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
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    • H01L24/98—Methods for disconnecting semiconductor or solid-state bodies
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/8422—Investigating thin films, e.g. matrix isolation method
    • G01N2021/8427—Coatings
    • G01N2021/8433—Comparing coated/uncoated parts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/04042—Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554—External layer
    • H01L2224/05599—Material
    • H01L2224/056—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof
    • H01L2224/05617—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron [B], silicon [Si], germanium [Ge], arsenic [As], antimony [Sb], tellurium [Te] and polonium [Po], and alloys thereof the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
    • H01L2224/05624—Aluminium [Al] as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/45139—Silver (Ag) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/485—Material
    • H01L2224/48505—Material at the bonding interface
    • H01L2224/48507—Material at the bonding interface comprising an intermetallic compound
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
    • H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
    • H01L2224/859—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector involving monitoring, e.g. feedback loop
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/02—Bonding areas ; Manufacturing methods related thereto
    • H01L24/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L24/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L24/42—Wire connectors; Manufacturing methods related thereto
    • H01L24/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L24/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector

Definitions

  • the invention relates to the technical field of circuit welding, and in particular to a method for detecting the coverage of intermetallic compounds.
  • wire bonding is to bond the semiconductor bare chip (Die) welding area with the input/output (I/O, input/output) leads of the microelectronic package or the metal wiring on the substrate
  • IMC intermetallic compound
  • the stability of the metal lead and the pad is judged by detecting the coverage of the IMC. The coverage of the IMC is too high. When it is low, it indicates that the stability of the metal lead and the pad is poor, which may cause the solder to fall off and subsequent reliability failure.
  • the main purpose of the present invention is to provide a method for detecting the coverage of the interface metal co-compound, which aims at removing the silver lead wire through a mixed reagent of fuming nitric acid and fuming sulfuric acid while protecting the integrity of the interface metal co-compound, thereby directly detecting
  • the coverage rate of the intermetallic compound of the interface avoids the operation of flipping the solder ball.
  • the present invention provides a method for detecting the coverage of interfacial metal co-compounds.
  • the method for detecting the coverage of interfacial metal co-compounds includes the following steps:
  • the coverage rate of the intermetallic compound on the aluminum pad is detected.
  • the immersion time of the chip in the mixed reagent is 8 to 12 minutes
  • the immersion temperature is 20°C to 30°C
  • the mixed reagent includes the following components in volume percentage: fuming nitric acid 20% to 50% %, oleum is 50% to 80%.
  • the immersion time of the chip in the mixed reagent is 10 min
  • the immersion temperature is 25° C.
  • the mixed reagent includes the following components in volume percentage: fuming nitric acid 25% and fuming sulfuric acid 75%.
  • the method before the step of immersing the wire-bonded chip in the mixed reagent of fuming nitric acid and fuming sulfuric acid, the method further includes:
  • the chip is cooled.
  • the baking temperature is 150°C to 225°C, and the baking time is 1 hour to 24 hours.
  • the step of immersing the wire-bonded chip in a mixed reagent of fuming nitric acid and fuming sulfuric acid includes:
  • the method before the step of detecting the coverage of the intermetallic compound on the aluminum pad, the method further includes:
  • the chip after washing is dried.
  • the reagent for ultrasonic washing is industrial acetone, and the duration of ultrasonic washing is 0.5 min to 1.5 min.
  • the step of drying the washed chip includes:
  • the washed chip is dried by nitrogen blowing, and the drying time is 1 min to 3 min.
  • the step of detecting the coverage rate of the intermetallic compound on the aluminum pad includes:
  • An image of the interfacial metal alloy on the aluminum pad is acquired through a metallurgical microscope, and the coverage rate is acquired based on the image.
  • the chip after wire bonding is immersed in a mixed reagent of fuming nitric acid and fuming sulfuric acid, and after the silver wire is removed, the Chip, and detect the coverage of the intermetallic compound on the aluminum pad.
  • the invention uses fuming nitric acid in the mixed reagent to remove the silver lead wire, thereby directly detecting the coverage of the interface metal intermetallic compound, avoiding the operation of turning the solder ball, and adopts the fuming sulfuric acid in the mixed reagent in the interface metal intermetallic compound
  • a protective layer is formed on the surface to slow down the corrosion of the interface metal co-compounds.
  • the silver leads are removed while slowing down the interface metal co-compounds as much as possible. Corrosion ensures that the coverage rate of the intermetallic compounds can be directly detected, and the detection results are more accurate.
  • FIG. 1 is a schematic flow chart of an embodiment of a method for detecting the coverage of intermetallic compounds of the interface according to the present invention
  • FIG. 2 is a schematic flowchart of another embodiment of the method for detecting the coverage of intermetallic compounds of the interface according to the present invention
  • FIG. 3 is a schematic flowchart of another embodiment of the method for detecting the coverage of intermetallic compounds of the interface of the present invention.
  • the coverage rate of the intermetallic compound on the aluminum pad is detected.
  • the present invention provides a solution.
  • the silver lead is removed by the mixed reagent of fuming nitric acid and oleum while protecting the integrity of the interface metal co-compound, thereby directly detecting the coverage of the interface metal co-compound and avoiding solder balls Perform the flip operation.
  • the method for detecting the coverage of the interface metal co-compound includes the following steps:
  • Step S10 immersing the chip after wire bonding in a mixed reagent of fuming nitric acid and oleum, wherein the chip after wire bonding includes silver leads and aluminum pads;
  • the chip after wire bonding is immersed in a mixed reagent of fuming nitric acid and oleum, wherein the chip after wire bonding includes silver leads and aluminum pads.
  • the fuming nitric acid reacts with silver to produce silver nitrate, nitrogen dioxide and water to achieve the purpose of corroding the silver lead.
  • the specific reaction equation is:
  • the fuming sulfuric acid needs to be heated to react with silver, so the removal of silver leads is mainly achieved by mixing the fuming nitric acid in the reagent.
  • the intermetallic compound between the silver lead and the aluminum pad will also be corroded by the mixed reagent. Therefore, the fuming sulfuric acid mainly serves the purpose of delaying the corrosion of the intermetallic compound.
  • the mixed reagent of fuming nitric acid and fuming sulfuric acid can passivate the aluminum bonding pads and generate dense aluminum oxide film.
  • the specific reaction equation is:
  • the interface metal co-compound is an aluminum-silver compound formed by soldering silver leads and aluminum pads. It can react slowly with fuming nitric acid and cannot form an aluminum oxide film, thereby being corroded. It can be corroded under the action of fuming sulfuric acid. An aluminum oxide film is formed to delay the corrosion of the interfacial metal co-compound by fuming nitric acid to ensure the integrity of the inter-metal co-compound after the silver wire is removed.
  • the fuming nitric acid and fuming sulfuric acid can be mixed in any commonly used volume ratio.
  • the immersion time of the chip in the mixed reagent is 8min-12min, and the immersion temperature is 20°C-30°C
  • the mixed reagent includes the following components in volume percentage: fuming nitric acid 20%-50%, fuming sulfuric acid 50%-80%. Since nitrogen dioxide gas is released during the reaction and destroys the aluminum oxide film, it is preferable to put the chip after the wire bonding into the mixed reagent of fuming nitric acid and fuming sulfuric acid. The surface with the silver lead is placed in the mixed reagent to slow down the destruction of the aluminum oxide film.
  • the mixed reagent can also be dropped on the silver lead through a dropper for chemical reaction, but this method is too inefficient, and because it is a strong acid reagent, the operation is more dangerous.
  • Step S20 after the silver lead is removed, take out the chip
  • Step S30 detecting the coverage of the intermetallic compound on the aluminum pad.
  • the soaking time before removing the chip may also be different.
  • the grayish yellow can be observed by naked eyes.
  • the interfacial metal co-compound of, preferably, the immersion time is 8min-12min.
  • the fuming nitric acid in the mixed reagent is used to remove the silver lead wire, thereby directly detecting the coverage of the interface metal co-compound, avoiding the operation of flipping the solder ball, and passing the Fuming sulfuric acid forms a protective layer on the surface of the interface metal alloy to slow down the corrosion of the interface metal alloy.
  • the volume ratio of fuming nitric acid and fuming sulfuric acid, the immersion temperature and the immersion time the silver lead is removed while eliminating the corrosion. It is possible to slow down the corrosion of the intermetallic compounds of the interface, ensure that the coverage of the intermetallic compounds can be directly detected, and the detection result is more accurate.
  • the method further includes:
  • Step S40 baking the chip in a nitrogen environment
  • the chip in the process of immersing the wire-bonded chip in the mixed reagent of fuming nitric acid and fuming sulfuric acid, it will inevitably cause a certain degree of corrosion to the interfacial metal intermetallic compound. Therefore, it is preferable Ground, before soaking, the chip is baked in a nitrogen environment, and the chip is cooled after the baking is completed, so that the interfacial metal eutectic compound grows vertically and the thickness increases. When it is corroded to a certain degree, it does not affect the detection of intermetallic intermetallic compounds. Among them, the nitrogen environment can prevent the silver lead from being oxidized, thereby ensuring the corrosion rate of the silver lead.
  • the baking temperature is too high and the baking time is too long, it will cause the interface metal co-compound to be too thick, so that the coverage of the detected interface metal co-compound will be distorted.
  • the baking temperature is 150°C to 225 °C
  • the baking time is 1h-24h.
  • Step S50 cooling the chip after the baking is completed.
  • the chip after the baking is completed, if the chip is directly put into the mixed reagent of fuming nitric acid and fuming sulfuric acid, the interface metal co-compound in the chip in a high temperature state will interact with the fuming Sulfuric acid reacts and accelerates the corrosion of the interface metal co-compound. Therefore, after the baking is completed, the chip needs to be cooled, generally to room temperature.
  • the chip by baking the chip in a nitrogen environment, the chip is cooled after the baking is completed, so that the thickness of the interface metal co-compound is increased, thereby improving the detected interface Accuracy of metal co-compound coverage.
  • the method further includes:
  • Step S60 performing deionized water washing and ultrasonic washing on the chip from which the silver lead is removed;
  • Step S70 drying the chip after washing.
  • the chip with the silver lead can be removed for washing and drying to remove the residues of fuming nitric acid and oleum and other reagents, reducing the influence of these factors on the coverage detection.
  • the chip is rinsed with deionized water, and then ultrasonic cleaning is performed after rinsing.
  • the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 0.5 min to 1.5 min.
  • the chip is dried.
  • the chip after the cleaning is dried by nitrogen blowing, and the drying time is 1 min to 3 min. Among them, drying with nitrogen can avoid interfacial metal co-compounds. Oxidation.
  • the chip from which the silver lead is removed is washed with deionized water and ultrasonic, and the washed chip is dried to reduce reagent residues and other factors.
  • rate detection improves the accuracy of the detected coverage rate.
  • Silver wire removal treatment Put the wire-bonded chip into a baking box, and fill the baking box with nitrogen. After the baking box is filled with nitrogen, start baking, 150°C, baking time Is 24h. After the baking is completed, wait for the chip to cool to room temperature. At a reaction temperature of 30°C, put the surface of the chip with silver leads upside down into the mixed reagent and soak for 12 minutes, where the mixed reagent includes the following components in volume percentage: fuming nitric acid 50%, oleum 50%, after reaching the immersion time, take out the chip.
  • Coverage detection the removed chip is rinsed with deionized water, and then placed in an ultrasonic cleaning machine for cleaning, wherein the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 0.5 min.
  • the washed chip is dried by a nitrogen blow dryer, the drying time is 1 min, and the dried chip is placed under a metallurgical microscope, through a computer associated with the metallographic microscope
  • the program reads the coverage of the interface metal co-compound. By performing the steps of removing silver lines and coverage detection on 10 sets of chips, 10 sets of coverage values are obtained, and after removing the abnormal values of the 10 coverage values, the average number is taken as the coverage result of this test experiment 1 .
  • the immersion time of the chip in the mixed reagent is 12 minutes, the immersion temperature is 30°C, and the mixed reagent includes the following components in volume percentage: fuming nitric acid 50% and fuming sulfuric acid 50%.
  • the coverage rate result 1 of this test experiment is 95.5%, which is in the normal coverage range. Therefore, the coverage rate result is valid.
  • the method of this test experiment can be used to detect the coverage rate of the interface metal co-compound.
  • Silver wire removal process Put the wire-bonded chip into a baking box, and fill the baking box with nitrogen. After the baking box is filled with nitrogen, start baking, 175°C, baking time Is 12h. After the baking is completed, wait for the chip to cool to room temperature. At a reaction temperature of 20°C, put the surface of the chip with silver leads upside down into the mixed reagent and soak for 8 minutes, where the mixed reagent includes the following components in volume percentage: fuming nitric acid 20%, oleum 80%, after reaching the immersion time, take out the chip.
  • Coverage detection the removed chip is rinsed with deionized water, and then placed in an ultrasonic cleaning machine for washing, wherein the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 1 min.
  • the washed chip is dried by a nitrogen blow dryer, the drying time is 2 min, and the dried chip is placed under a metallurgical microscope, and the computer is connected to the metallographic microscope.
  • the program reads the coverage of the interface metal co-compound. By performing the steps of removing silver line processing and coverage detection on 10 sets of chips, 10 sets of coverage values are obtained, and after removing the abnormal values in the 10 coverage values, the average number is taken as the coverage result of this test experiment 2 .
  • the immersion time of the chip in the mixed reagent is 8 minutes, the immersion temperature is 20°C, and the mixed reagent includes the following components in volume percentage: fuming nitric acid 20% and fuming sulfuric acid 80%.
  • the coverage rate result 2 of this test experiment is 96.3%, which is within the normal coverage rate range, so the coverage rate result is valid, and the method of this test experiment can be used to detect the coverage rate of the interface metal co-compound.
  • Silver wire removal process Put the wire-bonded chip into a baking box, and fill the baking box with nitrogen. After the baking box is filled with nitrogen, start baking, 225°C, baking time For 1h. After the baking is completed, wait for the chip to cool to room temperature. At a reaction temperature of 27°C, put the surface of the chip with silver leads upside down into the mixed reagent and soak for 11 minutes, where the mixed reagent includes the following components in volume percentage: fuming nitric acid 40%, oleum 60%, after reaching the immersion time, take out the chip.
  • Coverage detection the removed chip is rinsed with deionized water, and then washed in an ultrasonic cleaning machine, wherein the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 1.5 minutes.
  • the washed chip is dried by a nitrogen blow dryer, the drying time is 3 minutes, and the dried chip is placed under a metallurgical microscope, through a computer associated with the metallographic microscope
  • the program reads the coverage of the interface metal co-compound.
  • the immersion time of the chip in the mixed reagent is 11 minutes, the immersion temperature is 27°C, and the mixed reagent includes the following components in volume percentage: fuming nitric acid 40% and fuming sulfuric acid 60%.
  • the coverage rate result 3 of this test experiment is 97.4%, which is in the normal coverage rate range. Therefore, the coverage rate result is valid.
  • the method of this test experiment can be used to detect the coverage rate of the interface metal co-compound.
  • Silver wire removal process Put the wire-bonded chip into a baking box, and fill the baking box with nitrogen. After the baking box is filled with nitrogen, start baking, 200°C, baking time Is 12h. After the baking is completed, wait for the chip to cool to room temperature. At a reaction temperature of 23°C, put the chip with silver leads on the surface of the chip after cooling up and soak in a mixed reagent for 9 minutes, where the mixed reagent includes the following components in volume percentage: fuming nitric acid 30%, oleum 70%, after reaching the immersion time, take out the chip.
  • Coverage detection the removed chip is rinsed with deionized water, and then placed in an ultrasonic cleaning machine for cleaning, wherein the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 1 min.
  • the washed chip is dried by a nitrogen blow dryer, the drying time is 3 minutes, and the dried chip is placed under a metallurgical microscope, through a computer associated with the metallographic microscope
  • the program reads the coverage of the interface metal co-compound. By performing the steps of removing silver line processing and coverage detection on 10 sets of chips, 10 sets of coverage values are obtained, and after removing the abnormal values of the 10 coverage values, the average number is taken as the coverage result of this test experiment 4 .
  • the immersion time of the chip in the mixed reagent is 9 minutes, the immersion temperature is 23° C., and the mixed reagent includes the following components in volume percentage: fuming nitric acid 30% and fuming sulfuric acid 70%.
  • the coverage rate result 4 of this test experiment is 97.9%, which is within the normal coverage rate range. Therefore, the coverage rate result is valid.
  • the method of this test experiment can be used to detect the coverage rate of the interface metal co-compound.
  • Silver wire removal process Put the wire-bonded chip into a baking box, and fill the baking box with nitrogen. After the baking box is filled with nitrogen, start baking, 200°C, baking time For 1h. After the baking is completed, wait for the chip to cool to room temperature. At a reaction temperature of 25°C, put the surface of the chip with silver leads upside down into the mixed reagent and soak for 10 minutes, where the mixed reagent includes the following components in volume percentage: fuming nitric acid 25%, oleum 75%, after reaching the immersion time, take out the chip.
  • Coverage detection the removed chip is rinsed with deionized water, and then placed in an ultrasonic cleaning machine for cleaning, wherein the ultrasonic cleaning reagent is industrial acetone, and the ultrasonic cleaning time is 0.5 min.
  • the washed chip is dried by a nitrogen blow dryer, the drying time is 2 min, and the dried chip is placed under a metallurgical microscope, and the computer is connected to the metallographic microscope.
  • the program reads the coverage of the interface metal co-compound. By performing the steps of removing silver line processing and coverage detection on 10 sets of chips, 10 sets of coverage values are obtained, and after removing the abnormal values in the 10 coverage values, the average number is taken as the coverage result of this test experiment 5 .
  • the immersion time of the chip in the mixed reagent is 10 minutes, the immersion temperature is 25° C., and the mixed reagent includes the following components in volume percentage: fuming nitric acid 25% and fuming sulfuric acid 75%.
  • the coverage result 5 of this test experiment is 98.5%, which is in the normal coverage range. Therefore, the coverage result is valid.
  • the method of this test experiment can be used to detect the coverage of the interface metal co-compound.
  • any of the test experiments in test experiments 1-5 can detect the coverage of the interface metal co-compound through the metallographic microscope, and the interface metal detected in any test experiment in the test experiments 1-5
  • the coverage rate of the co-compound is in the normal coverage range, and the coverage result is valid. Therefore, it can be used to detect the coverage of the inter-metal co-compound.
  • the mixed reagent of fuming nitric acid and fuming sulfuric acid can remove the silver lead while protecting the interface metal.
  • the integrity of the common compound can directly detect the coverage of the interface metal common compound and avoid the operation of flipping the solder ball.

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Abstract

一种介面金属共化物的覆盖率检测方法，包括以下步骤：将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘（S10）；在银制引线去除后，取出所述芯片（S20）；检测铝制焊盘上介面金属共化物的覆盖率（S30）。检测方法利用混合试剂中的发烟硝酸去除银制引线，实现了直接检测介面金属共化物的覆盖率的目的，避免了将焊球进行翻转的操作，同时通过混合试剂中的发烟硫酸减缓对介面金属共化物的腐蚀，保证了介面金属共化物的覆盖率检测的准确性。

Description

介面金属共化物的覆盖率检测方法 技术领域
本发明涉及电路焊接技术领域，尤其涉及介面金属共化物的覆盖率检测方法。
背景技术
在芯片封装工艺中，引线键合(WB，Wire Bonding)是将半导体裸芯片(Die)焊区与微电子封装的输入/输出(I/O，input/output)引线或基板上的金属布线焊盘用金属引线连接起来的工艺技术。在引线键合后，金属引线和焊盘之间会生成介面金属共化物(IMC，Intermetallic Compound)，一般通过检测IMC的覆盖率来判断金属引线与焊盘的稳定性，在IMC的覆盖率过低时，表明金属引线与焊盘的稳定性较差，可能导致焊接脱落以及后续可靠性失效。
在通过引线键合将银制引线焊接到铝制焊盘上时，若检测IMC的覆盖率，则需要在去除铝制焊盘后将焊球进行翻转，然而这种翻转方式操作难度大，翻转成功率太低，实现较为困难。
上述内容仅用于辅助理解本发明的技术方案，并不代表承认上述内容是现有技术。
发明内容
本发明的主要目的在于提供一种介面金属共化物的覆盖率检测方法，旨在通过发烟硝酸和发烟硫酸的混合试剂去除银制引线的同时保护介面金属共化物的完整性，进而直接检测介面金属共化物的覆盖率，避免了将焊球进行翻转的操作。
为实现上述目的，本发明提供一种介面金属共化物的覆盖率检测方法，所述介面金属共化物的覆盖率检测方法包括以下步骤：
将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘；
在所述银制引线去除后，取出所述芯片；
检测所述铝制焊盘上介面金属共化物的覆盖率。
可选地，所述芯片在所述混合试剂中的浸泡时长为8min～12min，浸泡温度为20℃～30℃，所述混合试剂包括下述体积百分比的组分：发烟硝酸20％～50％，发烟硫酸50％～80％。
可选地，所述芯片在所述混合试剂中的浸泡时长为10min，浸泡温度为25℃，所述混合试剂包括下述体积百分比的组分：发烟硝酸25％，发烟硫酸75％。
可选地，所述将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡的步骤之前，还包括：
在氮气环境下对所述芯片进行烘烤；
在烘烤完成后对所述芯片进行冷却。
可选地，所述烘烤温度为150℃～225℃，烘烤时长为1h～24h。
可选地，所述将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡的步骤包括：
将所述芯片中附有银制引线的平面朝上放入所述混合试剂中。
可选地，所述检测所述铝制焊盘上介面金属共化物的覆盖率的步骤之前，还包括：
对去除所述银制引线的所述芯片进行去离子水冲洗和超声波洗涤；
对洗涤后的所述芯片进行干燥处理。
可选地，所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为0.5min～1.5min。
可选地，所述对洗涤后的所述芯片进行干燥处理步骤包括：
通过氮气吹干洗涤后的所述芯片，所述干燥的时长为1min～3min。
可选地，所述检测所述铝制焊盘上介面金属共化物的覆盖率的步骤包括：
通过金相显微镜获取所述铝制焊盘上介面金属共化物的图像，并根据所述图像获取所述覆盖率。
本发明实施例提出的介面金属共化物的覆盖率检测方法，将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，在所述银制引线去除后，取出所述芯片，并检测所述铝制焊盘上介面金属共化物的覆盖率。本发明通 过混合试剂中的发烟硝酸去除银制引线，从而直接检测介面金属共化物的覆盖率，避免了将焊球进行翻转的操作，并通过混合试剂中的发烟硫酸在介面金属共化物表面生成保护层，以减缓对介面金属共化物的腐蚀，通过控制发烟硝酸与发烟硫酸的体积比、浸泡温度和浸泡时长，在去除银制引线的同时尽可能减缓对介面金属共化物的腐蚀，保证了可以对介面金属共化物的覆盖率直接检测，且检测结果更加准确。
附图说明
图1为本发明介面金属共化物的覆盖率检测方法的一实施例的流程示意图；
图2为本发明介面金属共化物的覆盖率检测方法另一实施例的流程示意图；
图3为本发明介面金属共化物的覆盖率检测方法再一实施例的流程示意图。
本发明目的的实现、功能特点及优点将结合实施例，参照附图做进一步说明。
具体实施方式
应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。
本发明实施例的主要解决方案是：
将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘；
在所述银制引线去除后，取出所述芯片；
检测所述铝制焊盘上介面金属共化物的覆盖率。
由于现有技术中，在通过引线键合将银制引线焊接到铝制焊盘上时，若检测IMC的覆盖率，则需要在去除铝制焊盘后将焊球进行翻转，然而这种翻转方式操作难度大，翻转成功率太低，实现较为困难。
本发明提供一种解决方案，通过发烟硝酸和发烟硫酸的混合试剂去除银制引线的同时保护介面金属共化物的完整性，进而直接检测介面金属共化物 的覆盖率，避免了将焊球进行翻转的操作。
参照图1，在一实施例中，所述介面金属共化物的覆盖率检测方法包括以下步骤：
步骤S10，将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘；
在本实施例中，将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘。在具体反应过程中，发烟硝酸与银反应，可生成硝酸银、二氧化氮以及水，以实现腐蚀银制引线的目的，具体的反应方程式为：
Ag+2HNO 3(浓)＝AgNO 3+NO 2↑+H 2O，
而发烟硫酸需要在加热条件下才可与银发生反应，因此去除银制引线主要通过混合试剂中的发烟硝酸实现。而银制引线与铝制焊盘之间的介面金属共化物，同样会被混合试剂腐蚀，因此，发烟硫酸主要起到延缓腐蚀介面金属共化物的目的。发烟硝酸和发烟硫酸的混合试剂可使铝制焊盘钝化，生成致密的氧化铝薄膜，具体的反应方程式为：
2Al+6HNO 3(浓)＝Al 2O 3+6NO 2↑+3H 2O，
2Al+3H 2SO 4(浓)＝Al 2O 3+3SO 2↑+3H 2O，
因此铝制焊盘不会被腐蚀。
此外，介面金属共化物是由银制引线和铝制焊盘焊接形成的铝银化合物，可与发烟硝酸缓慢反应，无法生成氧化铝薄膜，从而被腐蚀，而在发烟硫酸的作用下可形成氧化铝薄膜，从而延缓发烟硝酸对介面金属共化物的腐蚀，以保证在银制引线去除后介面金属共化物的完整性。在制备发烟硝酸和发烟硫酸的混合试剂时，发烟硝酸和发烟硫酸可以常用的任意体积比进行混合。为了保证在去除银制引线的同时，最大程度地延缓对介面金属共化物的腐蚀，优选地，所述芯片在所述混合试剂中的浸泡时长为8min～12min，浸泡温度为20℃～30℃，所述混合试剂包括下述体积百分比的组分：发烟硝酸20％～50％，发烟硫酸50％～80％。由于反应过程中有二氧化氮气体放出，破坏氧化铝薄膜，因此，优选地，在将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡时，将所述芯片中附有银制引线的平面朝上放入所述混合试剂中， 以减缓氧化铝薄膜被破坏的速度。当然，也可将混合试剂通过滴管滴在银制引线上进行化学反应，但是这种方式效率过低，且由于是强酸试剂，操作比较危险。
步骤S20，在所述银制引线去除后，取出所述芯片；
步骤S30，检测所述铝制焊盘上介面金属共化物的覆盖率。
在本实施例中，由于不同芯片上介面金属共化物的厚度可能不同，因此取出所述芯片前的浸泡时间也可能不同，一般以在所述银制引线去除后，可通过肉眼观察到灰黄色的介面金属共化物为准，优选地，浸泡时长为8min～12min。在取出所述芯片后，通过金相显微镜获取所述铝制焊盘上介面金属共化物的图像，并根据所述图像获取所述覆盖率，然后对多组芯片或多个铝制焊盘重复步骤(1)和(2)，以获取多组覆盖率数值，在去掉覆盖率中的异常值后计算平均值作为覆盖率结果，其中，覆盖率的具体计算可通过软件程序等工具进行，且正常的覆盖率一般大于70％，在此不再赘述。
在本实施例公开的技术方案中，通过混合试剂中的发烟硝酸去除银制引线，从而直接检测介面金属共化物的覆盖率，避免了将焊球进行翻转的操作，并通过混合试剂中的发烟硫酸在介面金属共化物表面生成保护层，以减缓对介面金属共化物的腐蚀，通过控制发烟硝酸与发烟硫酸的体积比、浸泡温度和浸泡时长，在去除银制引线的同时尽可能减缓对介面金属共化物的腐蚀，保证了可以对介面金属共化物的覆盖率直接检测，且检测结果更加准确。
在另一实施例中，如图2所示，在上述图1所示的实施例基础上，步骤S10之前，还包括：
步骤S40，在氮气环境下对所述芯片进行烘烤；
在本实施例中，在将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡的过程中，不可避免地会对介面金属共化物造成一定程度的腐蚀，因此，优选地，在浸泡前，在氮气环境下对所述芯片进行烘烤，在烘烤完成后对所述芯片进行冷却，以使介面金属共化物纵向生长，厚度增加，这样，在介面金属共化物遭到一定程度腐蚀的情况下，不影响介面金属共化物的检测，其中，氮气环境可使银制引线不被氧化，从而保证银制引线的腐蚀速率。若烘烤温度过高，烘烤时长过长，会导致介面金属共化物过厚，这样检测到 的介面金属共化物的覆盖率就会失真，优选地，所述烘烤温度为150℃～225℃，烘烤时长为1h～24h。
步骤S50，在烘烤完成后对所述芯片进行冷却。
在本实施例中，在烘烤完成后，若直接将所述芯片放入发烟硝酸和发烟硫酸的混合试剂中，则处于高温状态的所述芯片中的介面金属共化物会与发烟硫酸进行反应，加快介面金属共化物的腐蚀，因此在烘烤完成后，需对所述芯片进行冷却，一般冷却至室温即可。
在本实施例公开的技术方案中，通过在氮气环境下对所述芯片进行烘烤，在烘烤完成后对所述芯片进行冷却，使介面金属共化物的厚度增加，从而提高检测到的介面金属共化物覆盖率的准确性。
在再一实施例中，如图3所示，在上述图1所示的实施例基础上，步骤S30之前，还包括：
步骤S60，对去除所述银制引线的所述芯片进行去离子水冲洗和超声波洗涤；
步骤S70，对洗涤后的所述芯片进行干燥处理。
在本实施例中，在检测覆盖率之前，可去除所述银制引线的所述芯片进洗涤和干燥处理，以去除发烟硝酸和发烟硫酸等试剂的残留，减少这些因素对覆盖率检测的影响。首先通过去离子水对所述芯片进行冲洗，在冲洗后，再进行超声波洗涤，优选地，超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为0.5min～1.5min。在超声波洗涤后，对所述芯片进行干燥处理，优选地，通过氮气吹干洗涤后的所述芯片，所述干燥的时长为1min～3min，其中，使用氮气吹干可避免介面金属共化物的氧化。
在本实施例公开的技术方案中，通过对去除所述银制引线的所述芯片进行去离子水冲洗和超声波洗涤，并对洗涤后的所述芯片进行干燥处理，减少试剂残留等因素对覆盖率检测的影响，提高检测到的覆盖率的准确性。
基于上述实施例中任一实施例所述的方案，可进行以下多个测试实验，以检测介面金属共化物的覆盖率检测方法的可行性。
测试实验1
去银线处理：将引线键合后的芯片放入烘烤箱，并将向所述烘烤箱中填充氮气，待所述烘烤箱中充满氮气后开始烘烤，150℃，烘烤时长为24h。在烘烤完成后，等待所述芯片冷却至室温。在30℃的反应温度下，将冷却完成后的所述芯片中附有银制引线的平面朝上放入混合试剂中浸泡12min，其中，混合试剂包括下述体积百分比的组分：发烟硝酸50％，发烟硫酸50％，在达到浸泡时长后，取出所述芯片。
覆盖率检测：将取出的所述芯片通过去离子水进行冲洗，再放入超声波清洗机中洗涤，其中所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为0.5min。将洗涤完成的所述芯片通过氮气吹干仪进行干燥处理，所述干燥的时长为1min，并将干燥完成后的所述芯片置于金相显微镜下，通过与所述金相显微镜关联的计算机程序读取介面金属共化物的覆盖率。通过对10组芯片执行去银线处理以及覆盖率检测的步骤，得到10组覆盖率数值，在去除所述10个覆盖率数值中的异常值后取平均数作为本测试实验的覆盖率结果1。
在本测试实验中，所述芯片在所述混合试剂中的浸泡时长为12min，浸泡温度为30℃，混合试剂包括下述体积百分比的组分：发烟硝酸50％，发烟硫酸50％。
经检测，本测试实验的所述覆盖率结果1为95.5％，处于正常的覆盖率范围，因此所述覆盖率结果有效，本测试实验的方法可用于检测介面金属共化物的覆盖率。
测试实验2
去银线处理：将引线键合后的芯片放入烘烤箱，并将向所述烘烤箱中填充氮气，待所述烘烤箱中充满氮气后开始烘烤，175℃，烘烤时长为12h。在烘烤完成后，等待所述芯片冷却至室温。在20℃的反应温度下，将冷却完成后的所述芯片中附有银制引线的平面朝上放入混合试剂中浸泡8min，其中，混合试剂包括下述体积百分比的组分：发烟硝酸20％，发烟硫酸80％，在达到浸泡时长后，取出所述芯片。
覆盖率检测：将取出的所述芯片通过去离子水进行冲洗，再放入超声波清洗机中洗涤，其中所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长 为1min。将洗涤完成的所述芯片通过氮气吹干仪进行干燥处理，所述干燥的时长为2min，并将干燥完成后的所述芯片置于金相显微镜下，通过与所述金相显微镜关联的计算机程序读取介面金属共化物的覆盖率。通过对10组芯片执行去银线处理以及覆盖率检测的步骤，得到10组覆盖率数值，在去除所述10个覆盖率数值中的异常值后取平均数作为本测试实验的覆盖率结果2。
在本测试实验中，所述芯片在所述混合试剂中的浸泡时长为8min，浸泡温度为20℃，混合试剂包括下述体积百分比的组分：发烟硝酸20％，发烟硫酸80％。
经检测，本测试实验的所述覆盖率结果2为96.3％，处于正常的覆盖率范围，因此所述覆盖率结果有效，本测试实验的方法可用于检测介面金属共化物的覆盖率。
测试实验3
去银线处理：将引线键合后的芯片放入烘烤箱，并将向所述烘烤箱中填充氮气，待所述烘烤箱中充满氮气后开始烘烤，225℃，烘烤时长为1h。在烘烤完成后，等待所述芯片冷却至室温。在27℃的反应温度下，将冷却完成后的所述芯片中附有银制引线的平面朝上放入混合试剂中浸泡11min，其中，混合试剂包括下述体积百分比的组分：发烟硝酸40％，发烟硫酸60％，在达到浸泡时长后，取出所述芯片。
覆盖率检测：将取出的所述芯片通过去离子水进行冲洗，再放入超声波清洗机中洗涤，其中所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为1.5min。将洗涤完成的所述芯片通过氮气吹干仪进行干燥处理，所述干燥的时长为3min，并将干燥完成后的所述芯片置于金相显微镜下，通过与所述金相显微镜关联的计算机程序读取介面金属共化物的覆盖率。通过对10组芯片执行去银线处理以及覆盖率检测的步骤，得到10组覆盖率数值，在去除所述10个覆盖率数值中的异常值后取平均数作为本测试实验的覆盖率结果3。
在本测试实验中，所述芯片在所述混合试剂中的浸泡时长为11min，浸泡温度为27℃，混合试剂包括下述体积百分比的组分：发烟硝酸40％，发烟硫酸60％。
经检测，本测试实验的所述覆盖率结果3为97.4％，处于正常的覆盖率 范围，因此所述覆盖率结果有效，本测试实验的方法可用于检测介面金属共化物的覆盖率。
测试实验4
去银线处理：将引线键合后的芯片放入烘烤箱，并将向所述烘烤箱中填充氮气，待所述烘烤箱中充满氮气后开始烘烤，200℃，烘烤时长为12h。在烘烤完成后，等待所述芯片冷却至室温。在23℃的反应温度下，将冷却完成后的所述芯片中附有银制引线的平面朝上放入混合试剂中浸泡9min，其中，混合试剂包括下述体积百分比的组分：发烟硝酸30％，发烟硫酸70％，在达到浸泡时长后，取出所述芯片。
覆盖率检测：将取出的所述芯片通过去离子水进行冲洗，再放入超声波清洗机中洗涤，其中所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为1min。将洗涤完成的所述芯片通过氮气吹干仪进行干燥处理，所述干燥的时长为3min，并将干燥完成后的所述芯片置于金相显微镜下，通过与所述金相显微镜关联的计算机程序读取介面金属共化物的覆盖率。通过对10组芯片执行去银线处理以及覆盖率检测的步骤，得到10组覆盖率数值，在去除所述10个覆盖率数值中的异常值后取平均数作为本测试实验的覆盖率结果4。
在本测试实验中，所述芯片在所述混合试剂中的浸泡时长为9min，浸泡温度为23℃，混合试剂包括下述体积百分比的组分：发烟硝酸30％，发烟硫酸70％。
经检测，本测试实验的所述覆盖率结果4为97.9％，处于正常的覆盖率范围，因此所述覆盖率结果有效，本测试实验的方法可用于检测介面金属共化物的覆盖率。
测试实验5
去银线处理：将引线键合后的芯片放入烘烤箱，并将向所述烘烤箱中填充氮气，待所述烘烤箱中充满氮气后开始烘烤，200℃，烘烤时长为1h。在烘烤完成后，等待所述芯片冷却至室温。在25℃的反应温度下，将冷却完成后的所述芯片中附有银制引线的平面朝上放入混合试剂中浸泡10min，其中，混合试剂包括下述体积百分比的组分：发烟硝酸25％，发烟硫酸75％，在达到 浸泡时长后，取出所述芯片。
覆盖率检测：将取出的所述芯片通过去离子水进行冲洗，再放入超声波清洗机中洗涤，其中所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为0.5min。将洗涤完成的所述芯片通过氮气吹干仪进行干燥处理，所述干燥的时长为2min，并将干燥完成后的所述芯片置于金相显微镜下，通过与所述金相显微镜关联的计算机程序读取介面金属共化物的覆盖率。通过对10组芯片执行去银线处理以及覆盖率检测的步骤，得到10组覆盖率数值，在去除所述10个覆盖率数值中的异常值后取平均数作为本测试实验的覆盖率结果5。
在本测试实验中，所述芯片在所述混合试剂中的浸泡时长为10min，浸泡温度为25℃，混合试剂包括下述体积百分比的组分：发烟硝酸25％，发烟硫酸75％。
经检测，本测试实验的所述覆盖率结果5为98.5％，处于正常的覆盖率范围，因此所述覆盖率结果有效，本测试实验的方法可用于检测介面金属共化物的覆盖率。
由以上结果可以看出，测试实验1-5中任一测试实验均可通过金相显微镜检测到介面金属共化物的覆盖率，并且测试实验1-5中任一测试实验中检测到的介面金属共化物的覆盖率均处于正常的覆盖率范围，覆盖率结果有效，因此可用于检测介面金属共化物的覆盖率，通过发烟硝酸和发烟硫酸的混合试剂去除银制引线的同时保护介面金属共化物的完整性，从而直接检测介面金属共化物的覆盖率，避免了将焊球进行翻转的操作。
此外，在经相同生产工艺进行引线键合后的芯片中，介面金属共化物本身的覆盖率是非常接近的，因此可以认为每一芯片中介面金属共化物本身的覆盖率是相同的。因此测试实验1-5中，通过金相显微镜检测到的覆盖率结果越大，则越接近介面金属共化物本身的覆盖率，检测到的覆盖率结果也越准确。在测试实验1-5中覆盖率结果按照以下顺序依次变大：覆盖率结果1，覆盖率结果2，覆盖率结果3，覆盖率结果4，覆盖率结果5，因此检测到的覆盖率的准确性按照以下顺序依次变优：覆盖率结果1，覆盖率结果2，覆盖率结果3，覆盖率结果4，覆盖率结果5。
需要说明的是，在本文中，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者系统不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者系统所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括该要素的过程、方法、物品或者系统中还存在另外的相同要素。
上述本发明实施例序号仅仅为了描述，不代表实施例的优劣。
以上仅为本发明的优选实施例，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (10)

  1. 一种介面金属共化物的覆盖率检测方法，其特征在于，所述介面金属共化物的覆盖率检测方法包括以下步骤：
    将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡，其中，所述引线键合后的芯片中包括银制引线和铝制焊盘；
    在所述银制引线去除后，取出所述芯片；
    检测所述铝制焊盘上介面金属共化物的覆盖率。
  2. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述芯片在所述混合试剂中的浸泡时长为8min～12min，浸泡温度为20℃～30℃，所述混合试剂包括下述体积百分比的组分：发烟硝酸20％～50％，发烟硫酸50％～80％。
  3. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述芯片在所述混合试剂中的浸泡时长为10min，浸泡温度为25℃，所述混合试剂包括下述体积百分比的组分：发烟硝酸25％，发烟硫酸75％。
  4. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡的步骤之前，还包括：
    在氮气环境下对所述芯片进行烘烤；
    在烘烤完成后对所述芯片进行冷却。
  5. 如权利要求4所述的介面金属共化物的覆盖率检测方法，其特征在于，所述烘烤温度为150℃～225℃，烘烤时长为1h～24h。
  6. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述将引线键合后的芯片放入发烟硝酸和发烟硫酸的混合试剂中浸泡的步骤包括：
    将所述芯片中附有银制引线的平面朝上放入所述混合试剂中。
  7. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述检测所述铝制焊盘上介面金属共化物的覆盖率的步骤之前，还包括：
    对去除所述银制引线的所述芯片进行去离子水冲洗和超声波洗涤；
    对洗涤后的所述芯片进行干燥处理。
  8. 如权利要求7所述的介面金属共化物的覆盖率检测方法，其特征在于，所述超声波洗涤的试剂为工业丙酮，超声波洗涤的时长为0.5min～1.5min。
  9. 如权利要求7所述的介面金属共化物的覆盖率检测方法，其特征在于，所述对洗涤后的所述芯片进行干燥处理步骤包括：
    通过氮气吹干洗涤后的所述芯片，所述干燥的时长为1min～3min。
  10. 如权利要求1所述的介面金属共化物的覆盖率检测方法，其特征在于，所述检测所述铝制焊盘上介面金属共化物的覆盖率的步骤包括：
    通过金相显微镜获取所述铝制焊盘上介面金属共化物的图像，并根据所述图像获取所述覆盖率。
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