CN112192459B

CN112192459B - Preparation process of diamond wire saw suitable for cutting large-size semiconductor

Info

Publication number: CN112192459B
Application number: CN202011058121.3A
Authority: CN
Inventors: 詹宝华; 李坤堂
Original assignee: Suzhou Weidu New Material Technology Co ltd
Current assignee: Suzhou Weidu New Material Technology Co ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2022-06-28
Anticipated expiration: 2040-09-30
Also published as: CN112192459A

Abstract

The invention discloses a preparation process of a diamond wire saw suitable for cutting a large-size semiconductor, wherein the diamond wire saw consists of diamond abrasive particles, a bus steel wire and a coating, and the preparation process comprises the steps of material preparation, bus pretreatment, core wire preplating, composite sanding, abrasive particle consolidation, steel wire spiraling, drying, wire rewinding and the like; according to the diamond wire saw prepared by the invention, the diameter of a bus steel wire is 0.04-0.14 mm, the grain size of diamond abrasive grains is D50= 5-6.5 μm, the coating thickness delta = 1.8-3 μm, the wave height H = 1-5D of a spiral structure and the wavelength L = 1-5 cm, so that the diamond wire saw is suitable for cutting semiconductor wafers of more than 8 inches; not only reduce disconnected silk rate, reduce surface damage layer, line mark and piece rate, effectively improve the chip removal ability of copper wire, reduce the abnormity among the cutting process, cut efficiency moreover and promote, improve wafer surface quality, have good economy and practical value.

Description

Preparation process of diamond wire saw suitable for cutting large-size semiconductor

Technical Field

The invention relates to a preparation process of a diamond wire saw suitable for cutting a large-size semiconductor.

Background

The diamond abrasive is fixedly connected on the steel wire by an electro-deposition method to prepare a serrated wire cutting tool, which is called a diamond wire saw for short. The most remarkable advantage of the diamond wire saw is that the cutting efficiency is high, 3-5 times higher than that of the traditional straight wire mortar, and the diamond wire saw is widely used for cutting non-metal brittle and hard materials such as silicon wafers, sapphires, semiconductors and magnetic materials. The semiconductor material is expensive, the market demand is increasing day by day, and the production cutting efficiency of the diamond wire cutting can be improved by multiple times, so that higher benefits are obtained.

At present, the semiconductor industry has gradually changed from mortar cutting to diamond wire cutting, and 4-6 inch wafers can be stably cut by using the diamond wire, but semiconductor wafers with the size of 8 inches or more can still be cut only by using the mortar. This is because the following problems exist in the case of wire cutting of large-sized semiconductor wafers with diamond wires: 1) the abrasive particles of the diamond wire are fixed on the steel wire, the hardness of the diamond is very high, and the cutting mode is cutting, so that a deeper damage layer is easily caused on the surface of the wafer; the mortar cutting abrasive particles are in a free state, the cutting mode is grinding, and the damage layer is shallow; the deeper damage layer means more polishing and grinding in the later period, and the loss of raw materials and the loss of working hours are larger. 2) Silicon powder cut off during cutting or diamond that drops need in time discharge, and the chip removal of large size wafer is more difficult, if silicon powder or diamond do not in time discharge, influences cutting ability, increases for a long time cutting to the surface of wafer causes unusual such as line mark. 3) The elastic coefficient of the semiconductor wafer is low, and hidden cracks or fragments are easily caused when the conventional diamond wire is used for cutting, so that great loss is caused.

Disclosure of Invention

Aiming at the existing problems, the invention provides a preparation process of a diamond wire saw suitable for cutting a large-size semiconductor, which is characterized in that the wire breaking rate is reduced, the surface damage layer, the wire mark and the fragment rate are reduced, the chip removal capability of a steel wire is effectively improved, and the abnormity in the cutting process is reduced by optimizing the raw material combination of the diamond wire and carrying out spiral treatment on the diamond wire saw. The specific technical scheme is as follows:

a preparation process of a diamond fretsaw suitable for cutting a large-size semiconductor comprises the following steps of:

1) preparing materials: selecting a steel wire with a proper diameter as a bus of the diamond wire saw; selecting diamond micro powder with proper particle size as diamond abrasive particles of the diamond wire saw; preparing a plating solution system for nickel plating treatment;

2) bus pretreatment: pretreating the prepared diamond wire saw bus by using a sodium hydroxide solution, an aminosulfonic acid solution and water to obtain a diamond wire saw core wire with a clean surface;

3) pre-plating a core wire: depositing a pre-plated nickel layer on the diamond wire saw core wire with a clean surface pre-treated in a prepared plating solution system to obtain a pre-plated bus;

4) Compounding and sanding: suspending and dispersing the prepared diamond micro powder in a prepared plating solution system, and compounding and sanding the diamond micro powder on a pre-plated bus by electroplating nickel to be used as abrasive particles of a diamond wire saw to obtain a diamond sand wire;

5) and (3) consolidation of abrasive particles: in the prepared plating solution system, plating a layer of nickel on the diamond sand line obtained by sand coating to consolidate diamond abrasive grains, so that the diamond abrasive grains do not fall off, and thus obtaining a diamond wire saw steel wire;

6) steel wire spiraling: spiraling the diamond wire saw steel wire after the abrasive grains are solidified through a spiral device to obtain a spiral diamond wire; the wave height and the wave length of the spiral diamond wire are adjusted by adjusting the diameter size and the thread pitch of a guide wheel of the spiral device;

7) and (3) drying: drying the moisture on the surface of the spiral diamond wire by an air knife, and further drying by a heating device to obtain the diamond wire saw;

8) taking up: and winding the dried diamond fretsaw on a spool according to the specified tension and winding spacing to obtain the diamond fretsaw suitable for large-size semiconductor cutting.

Preferably, in the step 1), the diameter of the steel wire is 0.04mm to 0.14 mm; the grain diameter of the diamond micro powder is D50-5-6.5 μm; the plating solution system for nickel plating treatment is a nickel sulfamate nickel electroplating system.

In a preferable technical scheme, in the step 2), the bus pretreatment is to sequentially perform cleaning treatment on the diamond wire saw bus through a sodium hydroxide solution → water washing water → an aminosulfonic acid solution → water washing water to obtain a diamond wire saw core wire with a clean surface; the concentration of the sodium hydroxide solution is 60g/L, and the treatment temperature is 60 +/-5 ℃; the concentration of the sulfamic acid solution is 40g/L, and the treatment temperature is 40 +/-5 ℃.

Preferably, in the step 3), the nickel pre-plating layer is deposited, the core wire running speed is 30m/min, the nickel ion concentration of the plating solution is 120 plus or minus 5g/L, the boric acid concentration is 40 plus or minus 2g/L, the temperature is 55 plus or minus 2 ℃, the pH value is 3.6-4.0, and the current is controlled to be 1.6A; the thickness of the nickel pre-plating layer is delta-0.3 mu m.

Preferably, in the step 4), the sand is coated, the running speed of the pre-plated bus is 30m/min, the concentration of nickel ions in the plating solution is 100 +/-5 g/L, the concentration of boric acid is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH value is 4.2-4.6, and the current is 4.5A; the coating thickness of the sand coating is delta 0.8 mu m.

Preferably, in the step 5), the abrasive grains are solidified, the running speed of the diamond sand line is 30m/min, the concentration of nickel ions in the plating solution is 100 +/-5 g/L, the concentration of boric acid is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH value is 3.6-4.0, and the current is 7.5A; the thickness of the consolidated coating was 1.3 μm.

As a preferable technical solution, in step 6), the screw device used for spiraling the steel wire comprises a screw guide wheel and two wire guide wheels arranged at two ends of the screw guide wheel; the spiral guide wheel comprises a threaded rod, and two ends of the threaded rod are fixed on the bearing block through bearings and check rings; and the diamond wire saw steel wire is input into the thread roller of the spiral guide wheel through the thread passing wheel at one end of the spiral guide wheel, is wound and spiraled, and then is output through the thread passing wheel at the other end of the spiral guide wheel, so that the spiral diamond wire is obtained.

Preferably, the wave height H of the spiral diamond wire spiral structure is 1d to 5d, and the wavelength L is 1cm to 5 cm.

As a preferable technical solution, in the step 7), the drying temperature for drying by the heating device is 180 ℃.

In a preferable technical scheme, in the step 8), the tension of the winding on the spool is 10N-15N, and the winding distance is 0.6 mm-1.8 mm; the obtained diamond wire saw suitable for large-size semiconductor cutting has the outer diameter of 132 +/-2 mu m

The invention has the beneficial effects that:

(1) the diamond wire prepared by the process of the invention is used for cutting large-size semiconductor wafers, and is suitable for cutting semiconductor wafers of more than 8 inches; the cutting time is 3 h/knife, the mortar cutting time is 12 h/knife, and the cutting efficiency is improved by 4 times.

(2) The diameter of a bus used by the diamond wire is 0.04mm-0.14mm, the wire is broken by 40N-55N, the large wire breaking rate is low, the common slicing machine at present can be met, the reconstruction or the purchase of new equipment is not needed, and the cost of customers is reduced.

(3) The average diameter of the diamond used by the diamond wire is 5-6.5 microns, the average diameter of the silicon carbide used by the mortar wire is 10-20 microns, and the strength and sharpness of the diamond are much higher than those of the silicon carbide, so that the diamond size can be small when the same cutting force is achieved, the seam is thinner during cutting, the loss of silicon material is less, and the raw material cost of customers is reduced.

(4) The diameter of a bus used by the diamond wire is 0.04-0.14 mm, the average diameter of the diamond is 5-6.5 microns, and compared with the prior semiconductor diamond wire (the bus is 0.07-0.10 mm, the average diameter of the diamond is 8-12 microns) which is cut under 8 inches, the diamond wire has larger breakage and lower wire breakage rate in the cutting process.

(5) The diamond of the invention has smaller grain diameter, small impact force during cutting, shallower surface damage layer, less line marks and lower fragment rate.

(6) The value of the wafer more than 8 inches is high, the wafer is applied to high-end electronic products, and the wire breakage and the deep damage layer are not allowed, so that the conventional proportioning diamond wire cannot meet the requirements, and the proportioning diamond wire can effectively solve the current problems.

(7) The diamond wire is spirally processed, the defect that the conventional diamond wire is weak in chip removing capacity is effectively overcome, so that the cutting machine can be used for cutting large-size semiconductors, the cutting efficiency is improved, the surface quality of wafers is improved, and the cutting machine has good economic and practical values.

Drawings

FIG. 1 is a schematic diagram of a steel wire structure of a diamond wire saw manufacturing process suitable for cutting a large-size semiconductor;

FIG. 2 is a schematic view of a spiral device used for the steel wire spiraling in the manufacturing process of a diamond wire saw suitable for cutting a large-sized semiconductor.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and the accompanying drawings. It should be apparent that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention. The specific embodiment is as follows:

example 1

The embodiment is to prepare a diamond wire saw suitable for cutting a large-size semiconductor; as shown in fig. 1, the diamond wire saw is composed of diamond abrasive grains, a bus steel wire and a coating, in this embodiment, a 120um matrix steel wire is used to match with a diamond fine powder with D50 ═ 6um to produce an electroplated diamond wire, and the preparation process comprises the following steps:

1) Preparing materials: selecting the nickel-plated diamond micro powder with the diameter of 6 mu m D50, wherein the weight gain of nickel is 40%; the diameter of the bus steel wire is 120 mu m; and the plating solution is ready for the nickel plating treatment.

2) Bus pretreatment: respectively treating the bus steel wire with 60g/L of sodium hydroxide solution at 60 +/-5 ℃, washing water, 40g/L of sulfamic acid solution at 40 +/-5 ℃ and washing water to obtain a core wire with a clean surface;

3) pre-plating a bus: the pretreated steel wire is deposited with a pre-plated nickel layer in a nickel sulfamate nickel electroplating system, the thickness of the plating layer is 0.3 mu m, the running speed is 30m/min, the concentration of nickel ions is 120 +/-5 g/L, the concentration of boric acid is 40 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH value is 3.6-4.0, and the current is 1.6A.

4) Compounding and sanding: in a nickel sulfamate nickel plating system, diamond with D50 of 6um is suspended and dispersed in a plating solution, the diamond composite is coated on a bus through nickel electroplating, the thickness of the plating layer is 0.8 mu m, the running speed is 30m/min, the concentration of nickel ions is 100 +/-5 g/L, the concentration of boric acid is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH value is 4.2-4.6, and the current is 4.5A.

5) And (3) consolidation of abrasive particles: in a nickel sulfamate nickel plating system, a layer of nickel is plated after sanding to solidify diamond, the thickness of a plating layer is 1.3um, the running speed is 30m/min, the concentration of nickel ions is 100 +/-5 g/L, the concentration of boric acid is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH value is 3.6-4.0, and the current is 7.5A.

6) Steel wire spiraling: the steel wire is spiraled through a group of specially designed spiral guide wheels, as shown in fig. 2, the wave height is adjusted by adjusting the diameter of the spiral guide wheels, and the wavelength is adjusted by adjusting the thread pitch of the guide wheels. The screw device used for the steel wire spiraling comprises a spiral guide wheel and two wire passing wheels arranged at two ends of the spiral guide wheel as shown in fig. 2; the spiral guide wheel comprises a threaded rod, and two ends of the threaded rod are fixed on the bearing block through a bearing and a check ring; and the diamond wire saw steel wire is input into the thread roller of the spiral guide wheel through the thread passing wheel at one end of the spiral guide wheel, is wound and spiraled, and then is output through the thread passing wheel at the other end of the spiral guide wheel, so that the spiral diamond wire is obtained.

7) And (3) drying: drying the water on the surface of the steel wire by an air knife, and drying the steel wire by a heating device (the temperature is 180 ℃).

8) Taking up: and (3) winding the dried diamond wire saw on a spool appointed by a customer according to the specified tension (10N-15N) and the winding distance (0.6 mm-1.8 mm), thus obtaining the diamond wire saw suitable for large-size semiconductor cutting and with the outer diameter of 132 +/-2 microns.

Example 2

This example also prepared a diamond wire saw suitable for cutting a large-sized semiconductor, and was different from example 1 in that the generatrix of the diamond wire saw was a wire having a diameter of 140 μm, and the diamond powder used had a particle size of D50-5.0 μm. The other steps are the same as the example 1, and the specification of the finished product of the electroplated diamond wire is 150 +/-2 mu m.

Example 3

This example also prepared a diamond wire saw suitable for cutting a large-sized semiconductor, and was different from example 1 in that the core wire was a 130 μm diameter steel wire, and the diamond powder used had a particle size of D50-6.5 μm. The other steps are the same as the example 1, and the specification of the finished product of the electroplated diamond wire is 143 +/-2 mu m.

Example 4 comparative example

In this example, the cutting performance of the diamond wire saw prepared in examples 1 to 3 was measured, including breaking force, wire breakage rate and damage layer thickness, and the results are shown in table 1, by using a mortar wire and a conventional diamond wire as a comparison:

TABLE 1 test results of cutting Performance of each wire saw

Test itemEyes of a user	Mortar line	Example 1	Example 2	Example 3	Conventional diamond wire
						Diameter of bus (mum)	115	120	140	130	70
Abrasive grain size D50(μm)	25	6	5	6.5	8.5
						Abrasive grain morphology	Free state	In a consolidated state	In a consolidated state	In a consolidated state	In a consolidated state
Equivalent outer diameter (mum)	165	132	150	143	85
						Break force (N)	36	38	54	40	18
Percentage of filament breakage (%)	1	0.8	0.5	0.6	50
						Thickness of damaged layer (μm)	10	8	6	7	25

From the above table, the conventional diamond wire has low breakage, the wire breakage rate is higher than 50% when a large-size wafer is cut, and the damage layer is as high as 25 μm and cannot be used; the mortar line abrasive particles are in a free state, grinding is carried out during cutting, and the cutting time is 12 h/knife; the diamond wire abrasive particles are in a solidified state, cutting is performed during cutting, the cutting force is strong, the cutting time is 3 h/knife, and the cutting efficiency is improved by 4 times. The breaking force of the diamond wire is 40-55N and is higher than 36N of the mortar wire, the plating layer protects the bus, and the wire breaking rate is lower than that of the mortar wire. In addition, the equivalent outer diameter of the diamond wire is 130-155 mu m, the equivalent outer diameter of the mortar wire is 165 mu m, the seam is thinner during cutting, and more than 10 pieces of single-blade extra-blades are produced. Meanwhile, the diamond wire which is not bought adopts the diamond with the diameter of D50 being 5-5.5 mu m, the grain size is very small, and the cutting damage layer is lower than that of the mortar wire. Through comprehensive comparison, the cost of the diamond wire is reduced by about 80% compared with the traditional mortar wire cutting.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A preparation process of a diamond wire saw suitable for cutting a large-size semiconductor is characterized by comprising the following steps: the diamond wire saw consists of diamond abrasive particles, a bus steel wire and a coating, and the preparation process comprises the following steps:

1) Preparing materials: selecting a steel wire with the diameter of 0.12-0.14 mm as a bus of the diamond wire saw; selecting diamond micropowder with the grain diameter of D50= 5-6 μm as diamond abrasive grains of the diamond wire saw; preparing a nickel sulfamate nickel electroplating system for nickel plating treatment;

2) bus pretreatment: pretreating the prepared diamond wire saw bus by using a sodium hydroxide solution, an aminosulfonic acid solution and water to obtain a diamond wire saw core wire with a clean surface; the bus pretreatment is to sequentially wash the diamond wire saw bus through a sodium hydroxide solution → water washing water → an aminosulfonic acid solution → water washing water to obtain a diamond wire saw core wire with a clean surface; the concentration of the sodium hydroxide solution is 60g/L, and the treatment temperature is 60 +/-5 ℃; the concentration of the sulfamic acid solution is 40g/L, and the treatment temperature is 40 +/-5 ℃;

3) pre-plating core wires: depositing a pre-plated nickel layer on the diamond wire saw core wire with a clean surface in a prepared plating solution system to obtain a pre-plated bus; the deposited nickel pre-plating layer has the core wire running speed of 30m/min, the nickel ion concentration of the plating solution is 120 +/-5 g/L, the boric acid concentration is 40 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH is = 3.6-4.0, and the current is controlled to be 1.6A; the thickness of the pre-plated nickel layer is 0.3 mu m;

4) Compounding and sanding: suspending and dispersing the prepared diamond micro powder in a prepared plating solution system, and compounding and sanding the diamond micro powder on a pre-plated bus by electroplating nickel to be used as abrasive particles of a diamond wire saw to obtain a diamond sand wire; the composite sand coating is carried out, the traveling speed of the preplating bus is 30m/min, the concentration of nickel ions in the plating solution is 100 +/-5 g/L, the concentration of boric acid is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH is = 4.2-4.6, and the current is 4.5A; the thickness of the sand coating is 0.8 mu m;

5) and (3) consolidation of abrasive particles: in the prepared plating solution system, plating a layer of nickel on the diamond sand line obtained by sand coating to consolidate diamond abrasive grains, so that the diamond abrasive grains do not fall off, and thus obtaining a diamond wire saw steel wire; the abrasive particles are solidified, the running speed of the diamond sand line is 30m/min, the nickel ion concentration of the plating solution is 100 +/-5 g/L, the boric acid concentration is 35 +/-2 g/L, the temperature is 55 +/-2 ℃, the pH is = 3.6-4.0, and the current is 7.5A; the thickness of the consolidated coating is 1.3 mu m;

the spiral device used for spiraling the steel wire comprises a spiral guide wheel and two wire passing wheels arranged at two ends of the spiral guide wheel; the spiral guide wheel comprises a threaded roller, and two ends of the threaded roller are fixed on the bearing block through bearings and check rings; inputting the diamond wire saw steel wire into a thread roller of the spiral guide wheel through a thread passing wheel at one end of the spiral guide wheel, winding and spiraling the wire saw steel wire, and outputting the wire saw steel wire through a thread passing wheel at the other end of the spiral guide wheel to obtain a spiral diamond wire; the wave height H =1 d-5 d and the wavelength L =1 cm-5 cm of the spiral structure of the spiral diamond wire;

7) And (3) drying: drying the moisture on the surface of the spiral diamond wire by an air knife, and further drying by a heating device to obtain the diamond wire saw; the drying temperature of the heating device is 180 DEG C

8) Taking up: and winding the dried diamond wire saw on a spool according to the specified tension and winding spacing to obtain the diamond wire saw suitable for large-size semiconductor cutting, wherein the tension of the wound wire wound on the spool is 10N-15N, the winding spacing is 0.6 mm-1.8 mm, and the outer diameter of the obtained diamond wire saw suitable for large-size semiconductor cutting is 132 +/-2 microns.