JPH03261162A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To eliminate influence due to static electricity by forming cooling pure water of a dicing step into pure water having 0.2MOMEGAcm or less of specific resistance, and forming a tray in a picking-up step to a conductive tray. CONSTITUTION:In a dicing step of cutting a wafer while cooling it with cooling pure water, the pure water is formed to pure water having 0.2MOMEGAcm or less of specific resistance, and a tray is formed to a conductive tray in a picking-up step for picking up a chip from a wafer through cleaning and drying steps and aligning on the tray. Thus, static electricity generated at the wafer or chip at the time of treating the chip can be eliminated to prevent influence of static electricity of the wafer, etc.

Description

[Detailed Description of the Invention] [Summary] Regarding the chip processing step of a method for manufacturing a semiconductor device, static electricity generated on a wafer or chip during the chip processing step is eliminated, and the semiconductor device is made unaffected by static electricity. The purpose of the present invention is to provide a manufacturing method, which includes: a dicing step in which the wafer is cut after being cooled with cooling pure water; a cleaning and drying step in which the wafer cut into chips in the dicing step is washed and dried; and a pick-up step of picking up chips and arranging them on a tray, the cooling pure water used in the dicing step has a specific resistance of 0.
The water is purified to a purity of 2 MΩcm or less, and the bottom of the tank is prepared so that the tray in the pickup step is made into a conductive tray.

[Industrial Field of Application] The present invention relates to a chip processing step in a method of manufacturing a semiconductor device.

The thickness of the gate oxide film of recent MOS transistors is 3.
The number of people is getting thinner by about 00 people. If the gate oxide film is thin, the device may be destroyed due to static electricity generated during the chip processing process.

[Prior Art] A chip processing step of a conventional semiconductor device manufacturing method will be described.

First, the wafer is cut with a dicing device.

At this time, dicing is performed while flowing pure water over the top surface of the wafer in order to cool the wafer and blade.

This pure water for cooling has a specific resistance of 12MΩcm to 18MΩc.
A size of about m is used.

Next, the wafer cut into chips in the dicing process is washed and dried using a spinner.

After cleaning and drying, chips are picked up from the wafer using air tweezers or the like and placed in a non-conductive chip tray made of ABS resin.

[Problems to be Solved by the Invention] However, in the case of a MOS transistor having a thin gate oxide film with a thickness of 300 Å or less, the conventional method described above requires
Static electricity is generated on the wafer or chip, causing fluctuations in the threshold value of the MOS transistor ■A8, and gate leakage current ■. There was a problem with the occurrence of

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that eliminates static electricity generated on a wafer or chip during a chip processing step and prevents the semiconductor device from being affected by static electricity.

[Means for Solving the Problems] The above object includes a dicing step in which the wafer is cut before being cooled with cooling pure water, and a cleaning and drying step in which the wafer cut into chips in the dicing step is washed and dried. and a pick-up step of picking up chips from the wafer and arranging them on a tray, wherein the cooling pure water in the dicing step is purified water with a specific resistance of 0.2 MΩCm or less, It is distantly related to a method of manufacturing a semiconductor device characterized in that the tray is a conductive tray.

[Function] According to the present invention, static electricity generated on the wafer or chip during the chip processing process can be eliminated, and the influence of static electricity on the wafer or the like can be prevented.

[Embodiment] A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

The dicing process will be explained using FIGS. 1 and 2.

FIG. 1 is a sectional view of the dicing device.

FIG. 2 is an explanatory diagram of the dicing device. FIG. 5A is a front view of the main parts of the dicing apparatus, and FIG. 1B is a side view of the main parts of the dicing apparatus.

An adhesive tape 6 is placed on the frame 4, and the wafer 2 is stuck onto the adhesive tape 6 with the adhesive of the adhesive tube 6. The adhesive tape 6 of the frame 4 is vacuum-adsorbed onto the chuck table 8 of the dicing device, and the wafer 2
Fix it on the dicing device.

The upper part of a blade 10 equipped with a diamond cutter for cutting the wafer 2 is protected by a flange cover 12. Nozzles 14 for spraying cooling water onto the wafer through the flange cover 12 are arranged on both sides of the lower part of the blade 10.

The wafer 2 is cut by a predetermined depth while moving the blade 10, which rotates at a high speed of about 30,000 rpm, along the dicing line of the wafer 2.

The depth of cut varies depending on whether it is a half cut or a full cut.

Half-cutting is a method of cutting on a dicing line to a depth of approximately 2/3 of the thickness of the wafer.

Full cut is a method in which the wafer is completely cut by cutting into the adhesive part of the adhesive tape until the incision is made.

The pure water sprayed from the nozzle 14 is used to absorb spoilage generated during cutting of the wafer 2 and maintain the quality of the wafer 2. Pure water at a temperature of usually about 20 to 25° C. is sprayed onto the wafer 2 .

Conventionally, the specific resistance of this cooling pure water was 12 MΩCm to 18
A material of about MΩcm was used.

Therefore, the static electricity generated on the wafer 2 could not be discharged.

In this example, the specific resistance of cooling water is reduced to about 0.2 MΩcm to 0.05 MΩcm by mixing CO2 gas into pure cooling water using a CO2 bubbler (not shown). .

By doing this, the threshold value VT of the MOS transistor,
variation in gate leakage current I. can prevent the occurrence of

Note that setting the specific resistance of the cooling water to 0.2 MΩcm or less also has the effect of preventing the SL powder generated during dicing from adhering to the pads of the chip due to static electricity. Also,
If the specific resistance of the cooling water is too low, the acidity of the cooling water will be high and the blade 10 will be corroded. Therefore, it is desirable that the specific resistance of the cooling water be 0.05 MΩcm or more.

After the dicing process, the process moves to a cleaning and drying process. The washing and drying process will be explained using FIG. 3.

FIG. 3 shows a spinner washer/dryer. Figure (a) is a plan view of the spinner washer/dryer, figure <b) is a plan view of the state in which wafers are placed on the spinner washer/drier, and figure (C) is a plan view of the spinner washer/dryer.
) is a side view of a state in which a wafer is placed on a spinner washer/dryer.

The spinner table 20 fixes the wafer 2 separated into a large number of chips 30 and rotates during cleaning and drying.

A vacuum groove 22 for sucking and fixing the wafer 2 is provided on the upper surface of the spinner table 20.

A rotating wafer 2 is placed on the surface of the spinner table 20.
A splash prevention bottle 24 is provided to prevent the bottle from falling off due to rotation.

A cleaning nozzle 26 for discharging water for cleaning the wafer 2 and a drying nozzle 28 for discharging N2 gas for drying are provided above the spinner table 20.

After the dicing process, the wafer 2 is removed from the chuck table 8 of the dicing machine together with the adhesive tape 6 of the frame 4, and then transferred to the spinner table 20 of the spinner washer/dryer.
Fixed.

While rotating the spinner table 20 at a rotation speed of about 800 rpm, a water pressure of 2 to 3 kg// is applied from the cleaning nozzle 26.
cm2, specific resistance mixed with CO□ gas 0.2MΩcm
Apply the following cleaning water to the spinner table 2 for 20 to 30 seconds.
If the pressure of the cleaning water is high, static electricity is likely to occur, so in this example, the water pressure of the cleaning water was set at 2 to 3 kg/cm.
m2.

Next, the drying process will be explained.

While rotating the spinner table 20 at a rotation speed of approximately 2500 rpm, a pressure of 5 to 7 kg/kg is applied from the drying nozzle 28.
Cm2 of N2 gas is blown onto the upper surface of the wafer 2 on the spinner table 20 for 20 to 30 seconds to dry the wafer 2.

Next, chip separation after drying the wafer will be explained.

When the wafer 2 is half-captured in the guising process, the chips 30 are not yet separated. Full power・
In the case of sorting, each chip 30 is separated, but
It is held in place by adhesive tape.

Therefore, the subsequent processing is slightly different between half-cut and full-force/soto.

FIG. 4 shows a chip separation method when the wafer 2 is half-cut.

The half-cut wafer 2 has a depth of about 2/3 along the dicing line. 1!40 is formed〈
Figure 4(a)).

The wafer 2 is sandwiched from both sides with a non-adhesive vinyl chloride tape 42 with a thickness of about 70 μm, for example, and pressure is applied from the back side of the wafer 2 using a stainless steel roller 44 to crack it into a large number of chips 30 ( Figure 4 (
b)〉.

The tape 42 is peeled off from the wafer that has been divided into chips 30. At this time, ions are blown using an ion blow generator (not shown) to prevent the generation of static electricity.
Figure (c)).

By doing this, it is possible to obtain a chip 30 that is not affected by static electricity (FIG. 4(d)), and the gate leakage current I of the MOS transistor can be obtained.

It is possible to prevent the occurrence of

Next, the case of full cut will be explained.

In the case of full cutting, each chip 30 has already been separated, so the above-mentioned process is not necessary. Therefore, there is no need for ion blowing.

However, although Full Cut traditionally used vinyl chloride tape as the adhesive tape, there has been a recent trend toward using UV tape made of polyethylene or polypropylene. Therefore, after the dicing process of wafer 2, this UV
The tape is irradiated with ultraviolet rays to chemically change the adhesive of the UV tape to remove the adhesive and make it easier to pick up the chip 30.

Next, the pickup process will be explained using FIG. 5.

In the pick-up process, the divided chips are used with air tweezers.
This is the process of transporting it to a tray using a soto or the like.

4 to 5 kg/kg to the suction port 52 at the tip of the air tweezers 50.
A suction force of about cm 2 is applied to the chip 30 so that it is attracted to the corner of the chip 30, and the chip 30 is transferred to a tray 56 made of conductive resin.

At this time, ions are blown from the ion blow generator 54.

By using a conductive resin tray 56 (trade name: TOYOLAC PANEL) instead of the conventional non-conductive ABS resin tray, static electricity generated in the chip 30 can be eliminated. Furthermore, by blowing ions from the ion blow generator 54, generation of static electricity can be reliably prevented, and MO
Fluctuations in the threshold value V714 of the S transistor and generation of gate leakage current I0 can be prevented.

Furthermore, it is effective to perform the steps up to the above in a clean bench equipped with a pulser.

A clean bench with a pulser attached will be explained using FIG. 6.

The clean bench has an air filter 66 on the ceiling that allows only particles of about 0.3 μm to pass through, and is surrounded by a conductive sheet 62. Top surface of clean bench ceiling ζ
A fan 64 is also provided to introduce air into the bench.

A pulse par 70 is provided on the lower surface of the near filter 66, and a large number of electrodes 72 are arranged below the pulse par 70. The pulser 70 is connected to the pulse generator 68.

When each of the above steps is performed in a clean bench, ions are generated from the electrode 72 provided on the pulser 70 by the pulses generated by the pulse generator 68, and the charged chip is also neutralized, contributing to quality improvement.

As described above, according to this embodiment, static electricity generated on the chip can be eliminated or the generation of static electricity can be prevented in each step of the semiconductor device manufacturing process. can prevent the occurrence of Even if the gate oxide films of MOS transistors, BiMO3h transistors, etc. become thinner as semiconductor devices become more highly integrated in the future, this embodiment can prevent breakdown due to static electricity.

The present invention is not limited to the above-mentioned embodiments, and various modifications are possible.

For example, in the case of a kick-up process after full cutting, a pick-up device other than air tweezers may be used to move the chip.

[Effects of the Invention] As described above, according to the present invention, static electricity generated on a wafer or chip can be eliminated during a two-chip processing step, and chip defects caused by static electricity can be prevented, thereby contributing to quality improvement.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a guishing process according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a guishing process according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram of a guishing process according to an example of the present invention. 4 is a diagram of a wafer cracking process according to an embodiment of the present invention. FIG. 5 is an explanatory diagram of a big-up process according to an embodiment of the present invention. FIG. 6 is an explanation of a clean bench equipped with a pulse bar. It is a diagram. In the figure, 2... Wafer 4... Frame 6... Adhesive tape 8... Chuck table 10... Blade 12... Flange cover 14... Nozzle 20... Spinner table 22...・Vacuum groove 24...Splash prevention pin 26...Cleaning nozzle 28...Drying nozzle 30...Tip 40...Spring 42...Tape 44...Roller 50...Air tweezers 52... Suction port 54... Ion blow generator 56... Tray 62... Sheet 64... Fan 66... Air filter 68... Pulse generator 70... Pulse bar 72...・1 pole

Claims (1)

[Claims] 1. A dicing step in which the wafer is cut while being cooled with cooling pure water, a cleaning and drying step in which the wafer cut into chips in the dicing step is washed and dried, and chips are removed from the wafer. A method for manufacturing a semiconductor device comprising a pick-up step of picking up and arranging them on a tray, wherein the cooling pure water in the dicing step is purified water with a specific resistance of 0.2 MΩcm or less, and the tray in the pick-up step is made into a conductive tray. A method for manufacturing a semiconductor device, characterized in that: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the pickup step is performed in an atmosphere that does not generate static electricity. 3. The method of manufacturing a semiconductor device according to claim 2, wherein the pickup step is performed in a clean bench equipped with a pulse bar that does not generate static electricity in the atmosphere. 4. The method of manufacturing a semiconductor device according to claim 2, wherein the pickup step is performed in an atmosphere filled with ions that do not generate static electricity.