CN111081593B - Tool and method for thinning single chip - Google Patents
Tool and method for thinning single chip Download PDFInfo
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- CN111081593B CN111081593B CN201910907612.1A CN201910907612A CN111081593B CN 111081593 B CN111081593 B CN 111081593B CN 201910907612 A CN201910907612 A CN 201910907612A CN 111081593 B CN111081593 B CN 111081593B
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims abstract description 36
- 239000010408 film Substances 0.000 claims description 52
- 239000000463 material Substances 0.000 claims description 18
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 12
- 239000010410 layer Substances 0.000 claims description 12
- 229910052710 silicon Inorganic materials 0.000 claims description 12
- 239000010703 silicon Substances 0.000 claims description 12
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 claims description 9
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 9
- 238000003698 laser cutting Methods 0.000 claims description 9
- 229920000098 polyolefin Polymers 0.000 claims description 9
- 238000012545 processing Methods 0.000 claims description 7
- 239000003292 glue Substances 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 239000012790 adhesive layer Substances 0.000 claims description 5
- 239000010409 thin film Substances 0.000 claims description 4
- 238000012546 transfer Methods 0.000 claims description 3
- 238000009281 ultraviolet germicidal irradiation Methods 0.000 claims description 3
- 238000007670 refining Methods 0.000 claims 1
- 238000013461 design Methods 0.000 abstract description 12
- 235000012431 wafers Nutrition 0.000 description 37
- 239000012528 membrane Substances 0.000 description 6
- 238000002474 experimental method Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/67005—Apparatus not specifically provided for elsewhere
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- H01L21/67092—Apparatus for mechanical treatment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
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Abstract
The invention discloses a tool for thinning a single chip, which comprises a monocrystalline silicon piece and a thinning film, wherein a round hole is processed in the center of the monocrystalline silicon piece, and the single chip to be thinned is fixed in the round hole through the thinning film; the thickness of the monocrystalline silicon wafer is +/-5 mu m of the thickness of the chip to be thinned, the diameter of the round hole is smaller than 90mm, and the diameter is more than or equal to 2 times of the diagonal line of the chip to be thinned. The invention further discloses a method for thinning the single chip, which comprises the steps of firstly preparing a tool, then fixing the chip by using the tool, setting rough grinding and accurate grinding parameters of a thinning machine, realizing rough grinding thinning and accurate grinding thinning, and ensuring that the thickness, TTV (transverse thickness) and self-strength of the thinned chip meet the design requirements. By utilizing the tool and the method, the thinning of a single chip can be efficiently and stably completed, the thinning of chips with different thickness requirements on the MPW makeup wafer is realized, and the method is simple, practical, easy to realize and strong in operability.
Description
Technical Field
The invention relates to a tool and a method for thinning a single chip, belonging to the technical field of thinning of integrated circuit chips.
Background
Before an integrated circuit design scheme is finalized, a basic design scheme needs to be optimized and improved for many times. To verify the phase schemes, multiple engineering runs must be performed, which can result in the entire run of wafers being scrapped if there is a defect in the design. Each transition from design to wafer comes with a high tape-out cost, which is a high risk investment for the design companies.
MPW (multi-project wafer) is a stream system for assembling a plurality of chips of the same process on the same wafer. The project flow sheet is carried out in an MPW mode, the flow sheet cost can be commonly borne by all projects participating in MPW makeup, and the cost of single project design is greatly reduced. At present, the MPW tape-out mode is widely applied to engineering tape-out in the circuit design stage.
In the chip packaging process, different requirements are put forward on the thickness of the chip due to different requirements of different chips on packaging size, heat dissipation and the like. If the conventional whole wafer thinning mode is used, the thicknesses of the obtained chips are all the same, and obviously the requirements cannot be met.
Disclosure of Invention
The invention solves the problems that: in order to overcome the defects of the prior art, the tool and the method for thinning the single chip are provided, so that the chips with different thickness requirements on the MPW makeup wafer are thinned, and the target thickness, TTV and self strength of the thinned single chip are ensured to meet the design requirements.
The technical solution of the invention is as follows:
a tool for thinning a single chip comprises a monocrystalline silicon piece and a thinning film, wherein a round hole is machined in the center of the monocrystalline silicon piece, and a single chip to be thinned is fixed inside the round hole through the thinning film;
the thickness of the monocrystalline silicon wafer is +/-5 mu m of the thickness of the chip to be thinned, the diameter of the round hole is smaller than 90mm, and the diameter is more than or equal to 2 times of the diagonal line of the chip to be thinned.
The TTV and the flatness of the monocrystalline silicon wafer are both not more than 5 micrometers, so that the flatness and the uniform thickness of the tool are ensured.
The diameter of the monocrystalline silicon piece is 5inch or 6inch, so that the problem that the silicon piece is cracked due to the fact that the weight of the monocrystalline silicon piece is large in the transfer process when a large-diameter silicon piece is used is avoided.
The round hole is processed in a low-stress laser cutting mode so as to reduce the thickness of a damaged layer on the edge of the round hole, reduce residual stress caused by processing and ensure the strength of the tool.
The thinning film base material is polyolefin, the thickness is not less than 150um, and the supporting capability of the thinning film on the chip is ensured; the glue layer material is acrylic acid, and thickness is not more than 40um, guarantees the stability of chip in the attenuate process.
The thinned film has the characteristic of UV dispergation, the viscosity before UV is not less than 6000mN/25mm, and the viscosity after UV is not more than 60mN/25 mm.
A method for single chip thinning comprising the steps of:
(1) tooling preparation
Selecting a monocrystalline silicon wafer with the thickness deviation of not more than 5 mu m from the chip to be thinned, and processing a round hole in the center of the monocrystalline silicon wafer by using a low-stress laser cutting mode, wherein the diameter of the round hole is more than or equal to 2 times of the diagonal line of the chip to be thinned and is less than 90 mm;
selecting a thinning film with UV (ultraviolet) glue-dissolving characteristics, wherein the base material is polyolefin, the thickness is not less than 150um, and the supporting capability of the thinning film on a chip is ensured; the glue layer is made of acrylic acid, the thickness is not more than 40um, and the film is thinned; the pre-UV tack is not less than 6000mN/25mm, and the post-UV tack is not more than 60mN/25 mm.
(2) Fixed chip
Placing the monocrystalline silicon wafer with the hole at the center in the step (1) on a workbench of a 5inch or 6inch thinning film pasting machine, placing the pattern surface of the chip upwards in the circular ring, starting the vacuum of the workbench, and normally attaching the film reducing film selected in the step (1) on the tool and the pattern surface of the chip according to a thinning film pasting method;
(3) setting thinning parameters of thinning machine
(4) Thinning
Starting a manual feeding mode of the thinning machine, placing the chip and the tool which are fixed together through the thinning film on a worktable of the thinning machine, adsorbing the thinning film on the worktable of the thinning machine downwards at the moment, starting contact type height measurement, and starting coarse grinding and thinning; and when the thickness of the chip to be removed is 2/3 of the thickness to be removed through coarse grinding and thinning, performing fine grinding and thinning, manually taking out the tool after the chip is thinned to the target thickness, performing UV irradiation dispergation, and separating the thinned chip from the tool.
In the step (3), the rough grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4000-4500r/min, the rotating speed of the worktable of the thinning machine is set to be 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.5-1 μm/s, P2: 0.3-0.5 μm/s, P3: 0.1-0.3 μm/s.
In the step (3), the fine grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4000-4500r/min, the rotating speed of the worktable of the thinning machine is set to be 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.3-0.5 μm/s, P2: 0.2-0.3 μm/s, P3: 0.1-0.2 μm/s.
Compared with the prior art, the invention has the beneficial effects that:
(1) by utilizing the tool and the method, the thinning of a single chip can be realized by utilizing a full-automatic thinning machine, the thinning of chips with different thickness requirements on the MPW makeup wafer is realized, and the target thickness of the thinned single chip is ensured. Compared with the traditional chip thinning method, the thinning workbench is not required to be modified, the wafer thinning workbench can be used for thinning the chip, the modification cost of the workbench is saved, and the efficiency is improved.
(2) The invention can measure the thickness of the tool in real time, realize the monitoring of the thickness of a single chip, improve the thinning precision, control the thickness deviation of the thinned chip to be within +/-1 mu m at one time, ensure that the target thickness and TTV of the thinned chip meet the design requirements, and avoid the problems of insufficient thinning precision and repeated thinning caused by insufficient experience in the traditional 'blind thinning'.
(3) When the chip is thinned, the residual stress of the chip is thinned through two steps of coarse grinding and fine grinding, and the strength of the thinned chip is ensured to meet the design requirement.
(4) By utilizing the tool and the method, the thinning of a single chip can be efficiently and stably completed, and the method is simple, practical, easy to implement and high in operability.
Drawings
FIG. 1 is a schematic view of the tooling of the present invention;
FIG. 2 is a flow chart of a single chip thinning process;
fig. 3 is a schematic diagram of single chip thinning.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples.
According to the invention, the single chip which meets the design requirement is thinned by using a special tool and a conventional wafer thinning machine and optimizing thinning process parameters.
As shown in FIG. 1, the tool is obtained by processing a monocrystalline silicon wafer 1, a round hole 2 is processed in the center of the monocrystalline silicon wafer 1, and a single chip 3 to be thinned is fixed in the round hole 2 through a thinning film 4.
The thickness of the monocrystalline silicon wafer is +/-5 mu m of the thickness of the chip to be thinned, and the synchronous thinning of the tool and the chip is realized.
The TTV and the flatness of the monocrystalline silicon wafer are not more than 5 mu m, so that the flatness and the uniform thickness of the tool are ensured.
The diameter of the monocrystalline silicon piece is 5inch or 6inch, so that the problem that the silicon piece is cracked due to the fact that the weight of the monocrystalline silicon piece is larger in the transfer process when a large-diameter silicon piece is used is avoided.
The processing method of the round hole is low-stress laser cutting, so that the thickness of a damaged layer at the edge of the round hole is reduced, the residual stress caused by processing is reduced, and the strength of the tool is ensured.
The diameter of the circular hole is smaller than 90mm, so that on one hand, the strength of the circular ring tool is ensured, on the other hand, the height measuring device can be in contact with the tool to measure the height in real time, and the thickness of the chip is detected through the thickness of the tool; meanwhile, the diameter of the round hole is not less than 2 times of the diagonal line of the chip to be thinned, and the installation size of the chip to be thinned is guaranteed.
The base material of the thin film 4 is polyolefin, the thickness is not less than 150um, and the supporting capability of the thin film 4 to the chip is ensured; the glue layer material is acrylic acid, and thickness is not more than 40um, guarantees the stability of chip in the attenuate process. The thinned film has the characteristic of UV dispergation, the viscosity before UV is not less than 6000mN/25mm, and the viscosity after UV is not more than 60mN/25 mm.
The wafer thinning machine is special wafer thinning equipment and is not suitable for thinning a single chip, when the wafer thinning machine is used for thinning the single chip, the conventional wafer thinning technological parameters are required to be optimized, and the main technological parameters of the thinning machine comprise the main shaft rotating speed, the workbench rotating speed and the main shaft feeding speed (P1, P2 and P3).
The invention optimizes the key process parameters of coarse grinding and accurate grinding of the thinning machine:
the rotation speed of the rough grinding and accurate grinding main shaft is optimized to 4000-4500r/min, the removal amount of the grinding wheel per revolution is reduced within the allowable range of equipment capacity, the grinding force is reduced, and the chip is prevented from falling off in the thinning process;
the rotation speed of the rough grinding workbench and the finish grinding workbench is optimized to be 50-200r/min, the direction is the same as the rotation direction of the main shaft, the grinding force is reduced, and the chips are prevented from falling off in the thinning process;
the rough grinding main shaft feed speed is optimized to be P1: 0.5-1 μm/s, P2: 0.3-0.5 μm/s, P3: 0.1-0.3 μm/s;
the feeding speed of the fine grinding main shaft is optimized to be P10.3-0.5 mu m/s, P20.2-0.3 mu m/s and P30.1-0.2 mu m/s, the removal amount in unit time is reduced, the grinding force is reduced, and the chips are prevented from falling off in the thinning process.
As shown in fig. 2, the present invention provides a method for thinning a single chip, which comprises the following specific steps:
(1) tooling preparation
Selecting a monocrystalline silicon wafer 1 with the thickness deviation of not more than 5 mu m from the chip to be thinned, and processing a round hole 2 in the center of the monocrystalline silicon wafer by using a low-stress laser cutting mode, wherein the diameter of the round hole is more than or equal to 2 times of the diagonal line of the chip to be thinned and is less than 90 mm;
selecting a thinning film 4 with UV debonding characteristics, wherein the base material is polyolefin, the thickness is not less than 150um, and the supporting capability of the thinning film on the chip is ensured; the glue layer is made of acrylic acid, the thickness of the glue layer is not more than 40um, the viscosity of the thinned film is not less than 6000mN/25mm before 4UV, and the viscosity of the thinned film is not more than 60mN/25mm after UV.
(2) Fixed chip
And (3) placing the prepared monocrystalline silicon wafer on a workbench of a 5inch or 6inch thinning film sticking machine, placing the pattern surface of the chip in an upward manner inside the circular ring, starting the workbench to be vacuumized, and normally sticking the film according to a thinning film sticking method.
(3) Adjustment of thinning parameters
The rough grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4000-4500r/min, the rotating speed of the worktable of the thinning machine is set to be 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.5-1 μm/s, P2: 0.3-0.5 μm/s, P3: 0.1-0.3 μm/s;
the fine grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4000-4500r/min, the rotating speed of the worktable of the thinning machine is set to be 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.3-0.5 μm/s, P2: 0.2-0.3 μm/s, P3: 0.1-0.2 μm/s.
(4) Thinning
Starting a manual feeding mode of the thinning machine, placing the chip and the tool which are fixed together through the thinning film on a worktable of the thinning machine, adsorbing the thinning film on the worktable of the thinning machine downwards at the moment, opening a contact type height measurement, and starting coarse grinding and thinning; when the thickness of the coarse grinding and thinning removal reaches 2/3 of the thickness to be removed, fine grinding and thinning are carried out, after the thickness is thinned to the target thickness, the tool is manually taken out, UV irradiation is carried out for dispergation, and the thinned chip is separated from the tool.
Fig. 3 is a schematic diagram of single chip thinning.
Example 1:
the thickness of the chip to be thinned is 400 mu m, and the diagonal length of the chip is 10 mm.
A method for thinning a single chip comprises the following specific steps:
(1) tooling preparation
The 5inch monocrystalline silicon wafer with the original thickness is thinned to 400 microns (the thickness deviation is 2 microns), and a round hole which is concentric with the silicon wafer and has the diameter of 20mm is cut in the center of the silicon wafer in a low-stress laser cutting mode.
And selecting a thinning film, wherein the base material is polyolefin and has the thickness of 150um, the adhesive layer material is acrylic acid and has the thickness of 30 um. The thinning film has the characteristic of UV dispergation, and the viscosity before UV is 6000mN/25mm, and the viscosity after UV is 50mN/25 mm.
(2) Chip fixation
And (3) placing the prepared monocrystalline silicon wafer on a workbench of a 5inch thinning film pasting machine under the environment that the temperature is 20-30 ℃ and the humidity is 35-45%, placing the pattern surface of the chip upwards in the circular ring, starting the vacuum of the workbench, and normally attaching the selected thinning film in the step (1) on the tool and the pattern surface of the chip according to a thinning film pasting method.
(3) Adjustment of thinning parameters
The rough grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of a main shaft of the thinning machine is set to be 4000r/min, the rotating speed of a worktable of the thinning machine is set to be 50r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.5 μm/s, P2: 0.3 μm/s, P3: 0.1 μm/s;
the fine grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of a main shaft of the thinning machine is set to be 4000r/min, the rotating speed of a worktable of the thinning machine is set to be 50r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.3 μm/s, P2: 0.2 μm/s, P3: 0.1 μm/s.
(4) Thinning
The manual material loading mode of opening equipment will place chip and frock together fixed through the attenuate membrane on the attenuate machine workstation, and the attenuate membrane face adsorbs downwards on the attenuate machine workstation this moment, opens contact height measurement, begins the coarse grinding attenuate, gets rid of when thickness reaches 2/3 of waiting to get rid of thickness as the coarse grinding attenuate, carries out the correct grinding attenuate. After finishing the attenuate, manually take out the frock and the chip of accomplishing the attenuate, carry out UV and shine the debond, take off the chip of accomplishing the attenuate from the frock, openly upwards put into the chip box.
Experiments prove that the target thickness deviation of the disposable thinned chip is controlled within +/-1 um, the thickness deviation TTV in the chip is controlled within +/-1 um, the thickness of a damaged layer on the back is controlled within 10um, the residual stress is small, and the strength is high.
Example 2:
the thickness of the chip to be thinned is 400 mu m, and the diagonal length of the chip is 10 mm.
A method for thinning a single chip comprises the following specific steps:
(1) tooling preparation
The 5inch monocrystalline silicon wafer with the original thickness is thinned to 400 microns (the thickness deviation is 2 microns), and a circular hole which is concentric with the silicon wafer and has the diameter of 70mm is cut in the center of the silicon wafer in a low-stress laser cutting mode.
And selecting a thinning film, wherein the base material is polyolefin, the thickness is 170um, the adhesive layer material is acrylic acid, and the thickness is 30 um. The thinned film has the characteristic of UV dispergation, the UV front viscosity is 7500mN/25mm, and the UV back viscosity is 50mN/25 mm.
(2) Chip fixation
And (3) placing the prepared monocrystalline silicon wafer on a workbench of a 5inch thinning film pasting machine under the environment that the temperature is 20-30 ℃ and the humidity is 35-45%, placing the pattern surface of the chip upwards in the circular ring, starting the vacuum of the workbench, and normally attaching the selected thinning film in the step (1) on the tool and the pattern surface of the chip according to a thinning film pasting method.
(3) Adjustment of thinning parameters
The rough grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of a main shaft of the thinning machine is set to be 4200r/min, the rotating speed of a workbench is set to be 60r/min, the rotating direction is the same as the rotating direction of the main shaft, and the feeding speed of the main shaft is set to be P10.6 mu m/s, P20.4 mu m/s and P30.2 mu m/s;
the fine grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of a main shaft of the thinning machine is set to be 4200r/min, the rotating speed of a workbench is set to be 60r/min, the rotating direction is the same as the rotating direction of the main shaft, and the feeding speed of the main shaft is set to be P10.4 mu m/s, P20.25 mu m/s and P30.15 mu m/s.
(4) Thinning
The manual material loading mode of opening equipment will be placed on the attenuate machine workstation through chip and the frock that the attenuate membrane is fixed together, and the attenuate membrane face adsorbs downwards on the attenuate machine workstation this moment, opens the contact height finding, and the coarse grind attenuate begins, and when the coarse grind attenuate gets rid of thickness and reaches 2/3 that wait to get rid of thickness, the fine grinding attenuate. After finishing the attenuate, manually take out the frock and the chip of accomplishing the attenuate, carry out UV and shine the debond, take off the chip of accomplishing the attenuate from the frock, openly upwards put into the chip box.
Experiments prove that the target thickness deviation of the disposable thinned chip is controlled within +/-1 um, the thickness deviation TTV in the chip is controlled within +/-1 um, the thickness of a damaged layer on the back is controlled within 10um, the residual stress is small, and the strength is high.
Example 3:
the thickness of the chip to be thinned is 400 mu m, and the diagonal length of the chip is 10 mm.
A method for thinning a single chip comprises the following specific steps:
(1) tooling preparation
The 6inch monocrystalline silicon wafer with the original thickness is thinned to 400 microns (the thickness deviation is 2 microns), and a round hole which is concentric with the silicon wafer and has the diameter of 90mm is cut in the center of the silicon wafer in a low-stress laser cutting mode.
And selecting a thinning film, wherein the base material is polyolefin, the thickness is 170um, the adhesive layer material is acrylic acid, and the thickness is 40 um. The thinned film has the characteristic of UV dispergation, the UV front viscosity is 7500mN/25mm, and the UV back viscosity is 60mN/25 mm.
(2) Chip fixation
Placing the prepared monocrystalline silicon wafer on a workbench of a 6inch thinning film sticking machine under the environment that the temperature is 20-30 ℃ and the humidity is 35% -45%, placing the pattern surface of the chip upwards in the circular ring, starting the vacuum of the workbench, and normally attaching the selected thinning film in the step (1) on the tool and the pattern surface of the chip according to a thinning film sticking method.
(3) Adjustment of thinning parameters
The rough grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of a main shaft of the thinning machine is set to be 4500r/min, the rotating speed of a worktable of the thinning machine is set to be 200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 1 μm/s, P2: 0.5 μm/s, P3: 0.3 μm/s;
the fine grinding and thinning parameters of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4500r/min, the rotating speed of the worktable of the thinning machine is set to be 200r/min, and the rotating direction is the same as the rotating direction of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.5 μm/s, P2: 0.3 μm/s, P3: 0.2 μm/s.
(4) Thinning
And starting a manual feeding mode of the equipment, placing the chip and the tool which are fixed together through the thinning film on the workbench of the thinning machine, adsorbing the thinning film on the workbench of the thinning machine downwards at the moment, opening the contact type height measurement, and starting thinning. After finishing the attenuate, manually take out the frock and the chip of accomplishing the attenuate, carry out UV and shine the debond, take off the chip of accomplishing the attenuate from the frock, openly upwards put into the chip box.
(4) Thinning
The manual material loading mode of opening equipment will place chip and frock together fixed through the attenuate membrane on the attenuate machine workstation, and the attenuate membrane face adsorbs downwards on the attenuate machine workstation this moment, opens contact height measurement, begins the coarse grinding attenuate, gets rid of when thickness reaches 2/3 of waiting to get rid of thickness as the coarse grinding attenuate, carries out the correct grinding attenuate. After finishing the attenuate, manually take out the frock and the chip of accomplishing the attenuate, carry out UV and shine the debond, take off the chip of accomplishing the attenuate from the frock, openly upwards put into the chip box.
Experiments prove that the target thickness deviation of the disposable thinned chip is controlled within +/-1 um, the thickness deviation TTV in the chip is controlled within +/-1 um, the thickness of a back surface damage layer is controlled within 10um, the residual stress is small, and the strength is high.
The content not described in detail in the present specification is common knowledge to those skilled in the art.
Claims (9)
1. The utility model provides a frock for single-chip attenuate which characterized in that: the tool comprises a monocrystalline silicon wafer (1) and a thinning film (4), a round hole (2) is machined in the center of the monocrystalline silicon wafer (1), and a single chip (3) to be thinned is fixed inside the round hole (2) through the thinning film (4);
the thickness of the monocrystalline silicon piece (1) is +/-5 mu m of the thickness of the chip to be thinned, the diameter of the round hole (2) is smaller than 90mm, and the diameter is more than or equal to 2 times of the diagonal line of the chip to be thinned.
2. The tooling for single chip thinning according to claim 1, wherein: the TTV and the flatness of the monocrystalline silicon wafer (1) are not more than 5 microns, and the flatness and the uniform thickness of the tool are ensured.
3. The tooling for single chip thinning according to claim 1, wherein: the diameter of the monocrystalline silicon piece (1) is 5inch or 6inch, so that the problem that the silicon piece is cracked due to the fact that the weight of the monocrystalline silicon piece is larger in the transfer process when a large-diameter silicon piece is used is avoided.
4. The tooling for single chip thinning according to claim 1, wherein: the round hole (2) is processed in a low-stress laser cutting mode so as to reduce the thickness of a damaged layer on the edge of the round hole, reduce residual stress caused by processing and ensure the strength of the tool.
5. The tooling for single chip thinning according to claim 1, wherein: the base material of the thin film (4) is polyolefin, the thickness is not less than 150um, and the supporting capability of the thin film on the chip is ensured; the glue layer material is acrylic acid, and thickness is not more than 40um, guarantees the stability of chip in the attenuate process.
6. The tooling for single chip thinning according to claim 5, wherein: the thinning film has the characteristic of UV dispergation, the pre-UV viscosity is not less than 6000mN/25mm, and the post-UV viscosity is not more than 60mN/25 mm.
7. A method for single chip thinning, characterized by comprising the steps of:
(1) tooling preparation
Selecting a monocrystalline silicon wafer (1) with the thickness deviation of not more than 5 mu m from the chip to be thinned, and processing a round hole (2) in the center of the monocrystalline silicon wafer by using a low-stress laser cutting mode, wherein the diameter of the round hole is more than or equal to 2 times of the diagonal line of the chip to be thinned and is less than 90 mm;
selecting a thinning film (4) with UV (ultraviolet) debonding characteristics, wherein the base material is polyolefin, the thickness is not less than 150um, and the supporting capability of the thinning film on the chip is ensured; the adhesive layer is made of acrylic acid, and the thickness of the adhesive layer is not more than 40 um; before UV, the viscosity is not less than 6000mN/25mm, and after UV, the viscosity is not more than 60mN/25 mm;
(2) fixed chip
Placing the monocrystalline silicon wafer with the hole at the center in the step (1) on a workbench of a 5inch or 6inch thinning film pasting machine, placing the pattern surface of the chip upwards in the circular ring, starting the vacuum of the workbench, and normally attaching the thinning film (4) selected in the step (1) on the tool and the pattern surface of the chip according to a thinning film pasting method;
(3) setting thinning parameters of thinning machine
(4) Thinning
Starting a manual feeding mode of the thinning machine, placing the chip and the tool which are fixed together through the thinning film on a worktable of the thinning machine, adsorbing the thinning film on the worktable of the thinning machine downwards at the moment, opening a contact type height measurement, and starting coarse grinding and thinning; when the thickness of the coarse grinding and thinning removal reaches 2/3 of the thickness to be removed, fine grinding and thinning are carried out, after the thickness is thinned to the target thickness, the tool is manually taken out, UV irradiation is carried out for dispergation, and the thinned chip is separated from the tool.
8. The method for single chip thinning according to claim 7, wherein in the step (3), the parameters of the rough grinding and thinning of the thinning machine are set as follows:
the rotating speed of the main shaft of the thinning machine is 4000-4500r/min, the rotating speed of the worktable of the thinning machine is 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.5-1 μm/s, P2: 0.3-0.5 μm/s, P3: 0.1-0.3 μm/s.
9. Method for single chip thinning according to claim 7, characterized in that in step (3) the parameters of the refiner refining thinning are set as follows:
the rotating speed of the main shaft of the thinning machine is set to be 4000-4500r/min, the rotating speed of the worktable of the thinning machine is set to be 50-200r/min, and the rotating direction is the same as that of the main shaft; the feed speed of the main shaft of the thinning machine is set to be P1: 0.3-0.5 μm/s, P2: 0.2-0.3 μm/s, P3: 0.1-0.2 μm/s.
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| CN101308778A (en) * | 2008-06-06 | 2008-11-19 | 无锡中微高科电子有限公司 | Thinning method of semiconductor chip |
| CN106584263A (en) * | 2016-12-22 | 2017-04-26 | 清华大学 | Large-scale chip thinning method based on nanometer diamond particles |
| JP2018060912A (en) * | 2016-10-05 | 2018-04-12 | 株式会社ディスコ | Processing method |
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| CN101308778A (en) * | 2008-06-06 | 2008-11-19 | 无锡中微高科电子有限公司 | Thinning method of semiconductor chip |
| JP2018060912A (en) * | 2016-10-05 | 2018-04-12 | 株式会社ディスコ | Processing method |
| CN106584263A (en) * | 2016-12-22 | 2017-04-26 | 清华大学 | Large-scale chip thinning method based on nanometer diamond particles |
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