JPS60164329A - Drying method for semiconductor substrate - Google Patents

Abstract

PURPOSE:To increase the cleanness, mass productivity and economization of the titled semiconductor substrate by a method wherein the semiconductor substrate is dipped in the hot water of the specific temperature or above as a dripping method to be performed after washing process, and after hot water has been sprayed from above, the substrate is passed through a dry inert gas tunnel. CONSTITUTION:The semiconductor wafer 2, located in a carrier, for which washing process has been finished, is placed in a vessel 5, and the contaminants adhered to the semiconductor wafer 2 are washed away by the shower spray 4 of the hot wafer tower (90-100 deg.C) 3 located in a vessel 5. At this time, the hot water collected at the bottom part of the vessel is exhausted using a suction pump 6. Then, the suction pump is stopped, the shower spray is jetted on the wafer until the hot water overflows, the suction pump 6 is operated in the state wherein the entire wafer is dipped, and the hot water is exhausted. When a wafer 12 and a carrier 11 have been sent on a belt 15 after the above-mentioned operation has been repeated two or three times, inert gas 14 which passes through a clean filter system 13 is sent to the carrier through the upper part and the lower side 17 of the wafer, and the hot water adhered to the surface of the wafer is evaporated in the tunnel. According to this drying method, the through-put in the cleanness and the mass-production of the large-diameter wafer can be improved.

Description

[Detailed description of the invention] (Technical field) The present invention relates to a method for drying a semiconductor substrate.

In semiconductor LSI manufacturing, the diameter of the substrate is becoming larger year by year. However, various apparatuses for individual processes have been developed for this purpose, and the centrifugal separation method, steam drying method, hot air drying method, etc. are known as draining and drying apparatuses.

(Prior Art) However, in the above-mentioned centrifugal drying method, since the substrate is rotated at high speed, the substrate collides with the carrier, crushing the wafer periphery and causing scratches, which is the main cause of SB dust. Furthermore, there are many problems that cause a decrease in the yield of LSIs, such as generation of dust from the device and re-adhesion of dust once removed from the evaporator.

Furthermore, as the diameter increases, the weight increases and the throughput decreases.

On the other hand, in steam drying, impurities (dust, carbide) contained in the organic solvent tend to remain on the substrate surface, and it is inferior to centrifugal drying in terms of cleanliness and mass productivity. It is also disadvantageous in terms of economy.

Furthermore, in the hot air drying method, since the inert gas is strongly applied directly to the wafer surface, there are problems with cleanliness, such as the fact that dust contained in the gas tends to adhere.

As described above, the conventional drying methods have problems in the cleanliness of the wafer surface, mass productivity, and economic efficiency.

(Objects and Structure of the Invention) The drain drying method of the present invention includes steps of immersion in hot water (90 to 100°C) and shower spraying, and a step of passing an inert gas through a tunnel. It is an object of the present invention to provide a drying method that is excellent in substrate surface cleanliness, mass productivity, and economic efficiency as a processing method for large-diameter substrates.

(Principle and operation) The principle and operation of the present invention is to first immerse the semiconductor substrate in a carrier from a pool tank at room temperature in hot water of 90℃ or higher. Can be heated. In addition, as a secondary effect, contaminants from the previous process (
Soluble ions, dust) are easily dissolved in hot water, and the cleaning effect (
(by dipping or shower spray) can also be expected.

Next, the substrate coated with hot water heated to over 90°C is
Inert gas at room temperature and highly clean (dry air, nitrogen)
By guiding the hot water into the tunnel, the hot water on the substrate easily evaporates and leaves within a short period of time.

Next, examples of the present invention will be described using schematic diagrams.

(Example) - The wafers that have undergone the normal cleaning process are stored in a carrier (made of Teflon or quartz) and stocked in a pure water pool tank. Figure 1 (5) shows the pool tank, Figure 1 shows the hot water tank and shower spray, Figure 1 0 shows the inert gas tunnel,
Figure 1 (goods) shows the unloading section. These four → (b)
The flow of →(C)-+CD) may be carried out automatically or manually. In the process shown in Fig. 1), a semiconductor wafer 2 in a carrier (quartz or Teflon) is moved from the top of a tank 5 to a shower spray 4 in a hot water tower (90-100°C) 3 to wash away contaminants on the wafer. . At the same time, the hot water accumulated at the bottom of the tank is discharged by the suction pump 6 (or by opening the drain 6'). After performing this shower cleaning for 2 to 3 minutes, the suction pump 6 is stopped and a shower spray is sprayed onto the wafer until the hot water in the tank overflows. The pump 6 is activated to drain the hot water again. This operation is repeated two to three times to complete the wafer heating and cleaning process. Next, Fig. 1 shows the wafer 12 and carrier 1 heated to ~90°C or higher in the drying process of Q.
1 onto the belt 15. This belt is fed at a certain speed.

The carrier of 1 passes through the clean filter system 13 and inert gas 14 from above the wafer (parallel to the wafer) to the underside 17. The hot water attached to the wafer surface is ~1
It evaporates inside the tunnel because it has been heated to nearly 00°C.

Hot water falling from the wafer surface is stored in 16 and discharged. The belt is preferably made of Teflon, and of course has a mesh or lattice shape to allow the inert gas to flow from the top. After this drying process is completed, the material is sent to the unloading section at No. 1 [East 0].

(Effects) As described in the examples, a wafer was dried by a combination of the hot water cleaning and inert gas tunnel process of the present invention, and evaluated using a dust inspection device using a laser method. The number of dust particles on the φ wafer is 10 to 100 particles/piece.
It was Eve. In the drying method of the present invention, the average dryness was less than 1/wafer. Furthermore, with the drying method of the present invention, there is almost no concern about the occurrence of scratches. Furthermore, when the dried Ueno® was oxidized according to the present invention, no crystal defects were generated.

As described above, the drying method of the present invention improves the cleanliness of large-diameter wafers and the throughput for mass production compared to conventional methods, making it an excellent method for drying semiconductor substrates.

[Brief explanation of drawings]

Figure 1 is a schematic diagram 1 showing the drying method according to the present invention, where (A) is the pool tank, 〇 is the hot water/shower spray system, (C) is the inert gas tunnel, and (1)) is the unloading section. be. In this Figure 1, 1...Ueno-carrier, 2...Semiconductor';'Eva, 3...
Shower system, 4... Spray nozzle, 5
・・・・・・I toughness, 6... Aspirator - (6
'...or drain valve), 1-1...carrier, 12...wafer, 13...
Clean filter, 14...Inert gas, 1
5...Conveyor belt, 16...Water discharge/return, 17...J non-emission gas flow. Figure 1 (C) (D)

Claims (1)

[Claims] After the semiconductor substrate cleaning process, there are multiple methods for draining the semiconductor substrate: immersing the semiconductor substrate in hot water of 90°C or higher, spraying the hot water over the top of the substrate, and then passing through a dry inert gas tunnel. A method for drying a semiconductor substrate, comprising: