JPS6215824A - Treatment of semiconductor wafer - Google Patents

Abstract

PURPOSE:To clean the surface of a wafer without strain on the wafer and without vapor of organic solvent between wirings, by washing the contaminant on the surface with chemical, washing and removing the chamical with super pure water, substituting the moisture with the vapor of the organic solvent, and decomposing the remaining organic material by the projection of ultraviolet rays. CONSTITUTION:A carrier 1, in which wafers to be washed are put, is placed on a loader part 2 and immersed in chemical. Then, the chemical on the wafer is washed and removed with super pure water in a washing tank 5. Thereafter, the chemial on the wafer is washed and removed with the super pure water in washing tanks 7 and 8. At this time, the washing is sufficiently performed until the resistivity value of the washing water in the washing tank 8 becomes 16MOMEGA.cm or more. Then the wafer is immersed in a vapor tank 9 of isopropyl alcohol, and the moisture on the wafer is substituted with the vapor of the isopropyl alcohol and the mosture is removed. In an ultraviolet-ray device 12, ultraviolet rays are uniformly projected on both upper and lower surfaces of the wafer 11 mounted on quartz rollers 35. The ultraviolet rays are emitted from ultraviolet-ray lamps 38 to the wafer and also reflected by reflecting plates 39 to the wafer. The inorganic material is decomposed by the light and evaporated. In order to remove the evaporated material, clean oxygen gas is supplied through an oxygen-gas feeding port 40 and the evaporated material is exhausted through an exhaust port 37.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for processing a semiconductor wafer 1, such as washing, rinsing, and drying in a semiconductor manufacturing process.

Conventional technology Conventional semiconductor Ueno・ (hereinafter abbreviated as “Uenohe”) 26
A method in which the sheets are set and immersed in order in various cleaning tanks, water washing tanks, etc. 9. After being pulled up and processed, they are placed in a spinner as a carrier and dried using a high-speed rotation centrifugal separation method. P2A23-2 etc. □ in 1 steamer and 2 tanks of organic solvent: Transfer surface water to sea urchins.
Generally, a method of drying by replacing with organic solvent vapor is widely used.

Problems to be Solved by the Invention However, in the spinner drying method, the amount of electrostatic charge 7M is large, which causes the phenomenon that dust is adsorbed on the dried wafer, and the water separated by centrifugation is """ in the drying tank. It bounces off the tank wall and leaves stains on the tank. In addition, recently, the line width of semiconductor circuits has progressed toward miniaturization of 21Im1 or less, and plasma etching and ion etching have been used for microfabrication, and the etched wiring portion becomes a knife edge that is nearly perpendicular. Therefore, centrifugal separation using a spinner has the disadvantage that moisture between the wires cannot be reliably removed.

In the organic solvent vapor drying method, since the etched wiring part is a fine pattern with a line width of 2 μm or less and has a knife edge close to a right angle, the organic solvent vapor replacing water does not completely vaporize and dry the wiring. It has the disadvantage that it remains in between.

Therefore, the present invention provides a method for processing semiconductor wafers that can remove moisture and organic solvent between fine interconnections with a line width of 2 μm or less.

Means for Solving the Problem In the wafer processing method of the present invention to solve the problem, first, the contaminants on the wafer are thoroughly cleaned with an optimal chemical solution to remove the contaminants on the wafer. Next, the chemical solution adhering to the wafer surface is washed with so-called ultrapure water having a resistivity of 10 MΩ·α or more. At this time, wash thoroughly with water until the specific resistance value of the washing water becomes 1 eMΩ·m or more. Next, the moisture on the wafer is replaced with organic solvent vapor to remove the moisture, and then the organic matter remaining between the fine interconnects with a line width of 2 μm or less is photolyzed by ultraviolet irradiation, and the photodecomposed product is vaporized. be.

Operation The present invention cleans the wafer surface by first removing contaminants on the wafer, then removing residual chemical, removing residual moisture, and removing residual organic matter in this order by the method described above.

Example Below A semiconductor wafer (hereinafter referred to as “wafer”) of an example of the present invention
The processing method for (abbreviated as ) will be explained with reference to the drawings.

In FIG. 1, first, a carrier 1 containing 25 wafers to be cleaned is placed on a loader part 2, then the carrier 1 is chucked and conveyed to a cleaning tank 4 by an automatic conveying means 3 capable of vertical and horizontal movement. and immerse it in the chemical solution. The processing conditions in the cleaning tank 4 are shown below. NHoH:H has a chemical composition suitable for removing inorganic and organic substances from contaminants on wafers.
Using 2O2:H20=1:2 nia, heating to 70-80°C, and constantly circulating and filtering the chemical solution to remove dust generated during processing.

Next, in a washing tank 6, the chemical solution on the wafer is washed away with ultrapure water. Next, it is immersed in the chemical solution again in the cleaning tank 6. Washing tank 6
The processing conditions are shown below.

Using HCl:H2O2:H20 = 1 = 2:6, which is a chemical composition suitable for removing heavy metals in contaminants on wafers, heating to 70 to 80 °C and removing dust generated during processing. Constantly circulate and filter the chemical solution to remove it.

Next, the chemical solution on the wafer is washed away with ultrapure water in washing tanks 7 and 8. At this time, sufficient water washing is carried out until the specific resistance value of the washing water in the washing tank 8 increases to 16 MΩ or more.

Next, the wafer is immersed in an inpropyl alcohol vapor bath 9, and the moisture on the wafer is replaced with isopropyl alcohol vapor to remove the moisture. At this time, if fine particulate dust is mixed in the inpropyl alcohol, there is a risk that it will diffuse into the steam and adhere to the wafer, so a steam drying tank shown in FIG. 2 is used. In the steam drying tank shown in FIG. 2, inpropyl alcohol is thoroughly filtered from the supply tank 24 through the pump 2 and filter 30, and
Supply to 9. In the processing liquid tank 19, it is heated by a heater 2o, and the temperature is controlled by a temperature sensor 22 and a temperature regulator 21, and the liquid is turned into steam. The steam is filtered through a filter 18 and supplied to the steam tank 9. By the above method, the wafer 11 in the carrier 1 is processed by removing dust in the liquid and vapor. To explain the steam drying tank in more detail, the liquid level in the processing liquid tank 19 is adjusted using a liquid level gauge 27. Supply tank 24 by controller 28
automatically supplied from The vapor pressure in the processing liquid tank 19 is adjusted by opening and closing a pressure regulating valve 25, and the vapor is converted into liquid by a condenser 26 and returned to the supply tank 24. Steam tank 9
Then, an automatic door 16 is provided at the top to prevent steam from going outside, and a cooling tank 16 is provided to convert the steam to liquid. and return it to the supply tank 24.

Next, the carrier 1o is rotated 90 degrees so that the wafer 11 is horizontal, and the carrier 1o is set at the entrance of the ultraviolet irradiation device. Ultraviolet irradiation device 1 shown in Figure 3
2, one wafer 11 in the carrier 1° is pushed out one by one by a pusher 32 connected to an air cylinder 31 and placed on a quartz roller 36. At this time, the sensor 34 confirms that the wafer 11 has passed, and sends a signal to the vertical drive cylinder 33 to automatically raise the carrier 10 one pitch at a time. Automatic door 3 at the entrance of the ultraviolet irradiation device 12
6 to open and close automatically. In the ultraviolet irradiation device 12, the front and back surfaces of the wafer 11 placed on the quartz roller 35 are uniformly irradiated with ultraviolet rays emitted from an ultraviolet lamp 38 and ultraviolet rays reflected by a reflecting plate 39 to photodecompose and vaporize organic substances. In order to remove vaporized substances, clean oxygen gas is supplied through the oxygen gas supply port 4o, and is exhausted and removed through the exhaust port 37. As a result, organic matter remaining between fine interconnections with a line width of 2 μm or less is photodecomposed by ultraviolet irradiation, and vaporized matter is removed by exhaust.

The passage of the wafer 11 that has been irradiated with ultraviolet rays is confirmed by the sensor 41, and the automatic door 42 at the exit is opened and closed, and the wafer 11 is sent out of the chamber '1'. Further, a signal is sent to the drive mechanism 45 of the vacuum bin set 43 to drive it, and the back surfaces of the wafers 11 that have come out of the apparatus are chucked with the vacuum tweezers 43 and stored one by one in the cassette 13. Further, the cassette 13 is automatically lowered by the pitch of one wafer by the vertical drive mechanism 44. Next, after the 26 wafers have been stored, the carrier 13 is transferred to the unloader part 14 to complete the wafer processing.

Effects of the Invention As a processing method for semiconductor wafers having fine wiring with a line width of 2 μm or less, contaminants on the surface are cleaned with a chemical solution, then the chemical solution adhering to the wafer surface is removed by washing with ultrapure water, and then After replacing the moisture on the wafer with organic solvent vapor to remove the moisture, the organic matter remaining on the wafer is photodecomposed by ultraviolet irradiation, and the generated vapor is removed by exhaust, leaving a stain on the wafer. Furthermore, the wafer surface can be cleaned without leaving moisture or organic solvent vapor substituted for water between the wiring lines.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the processing steps of a semiconductor wafer 1 in implementations of the present invention S., J, and FIG. 2 is a front sectional view of a steam drying tank including the steam tank 9 in FIG.
FIG. 3 is a front sectional view of the ultraviolet irradiation device in FIG. 1. 1.10.13...Carrier, 2...
・Loader part, 3...Automatic transport means, 4, 6・
...Cleaning tank, 5, 7. 8...Water tank, 9...Steam tank, 11...Wafer, 1
2... Ultraviolet irradiation device, 14... Part of unloader.

Claims (1)

[Claims] Contaminants on the surface of the semiconductor wafer are cleaned with a chemical solution, then the chemical solution adhering to the surface of the semiconductor wafer is removed by washing with ultrapure water, and then the moisture on the semiconductor wafer is replaced with vapor of an organic solvent. A method for processing a semiconductor wafer, the method comprising: removing moisture from the semiconductor wafer, photodecomposing the organic matter remaining on the semiconductor wafer by irradiating it with ultraviolet rays, and exhausting the generated vapor to clean the surface of the semiconductor wafer. .