JPS62118528A - Processing of semiconductor device - Google Patents

Abstract

PURPOSE:To enable even drying up process to be performed while cutting water film evenly from the end of a wafer by a method wherein, in the cleaning process before sir-knife drying process, an oxide film is formed by chemical processing on an exposed substrate surface to be etched while leaving the oxide film. CONSTITUTION:When an MOS capacitor is formed, a LOCOS (SiO2) separating the capacitor and a pattern on an exposed Si substrate surface to be a capacitor coexist together on one main surface of a wafer. This wafer is cleaned up for the minutes in a cleaning solution with mixing ratio of e.g. NH4OH:H2O2:H2 O=1:2:7. An oxide film around 1mum thick is formed on Si by this cleaning process. After sufficient washing, the oxide film is immersed in a solution with mixing ratio of e.g. H2O:HF=500:1 to be etched by around 0.5mum leaving it by around 0.5nm. After sufficient washing, the oxide film is airknife-dried up later to form a capacitor SiO2 and then a polysilicon electrode is formed to form an MOS capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of Industry-1- The present invention relates to a process for manufacturing a non-conductor integrated circuit. In particular, as a pre-process of the diffusion furnace, silicon (Sl)
) relates to a method for cleaning wafers.

BACKGROUND OF THE INVENTION 2. Description of the Related Art As the diameter of semiconductor wafers increases and factories become more automated, single-wafer processing processes are increasing.

Batch-type spin drying (centrifugal dehydration) is currently the mainstream for drying after cleaning wafers. Leaf air knife drying (method of spraying high-pressure gas) is much more suitable for working efficiency -1-1.

However, the drying method was changed to an air knife, and then a capacitor 5i02 was formed, a polycone electrode was formed on it, a MOS capacitor was made, and the yield of the capacitor 5i02 was measured. However, the yield of the capacitor SiO2 was significantly inferior to that obtained by similarly determining the yield using the conventional spin dry method.

In the process of manufacturing semiconductor integrated circuits, even if the air knife drying method is used, the yield of the capacitor 5i02 is the same as that of the spin drying method. After forming an oxide film on the substrate surface by chemical treatment, etching is performed so that the oxide film remains, and then air drying treatment is performed.
This is a method for processing a semiconductor device.

J: According to the above means, it'd be Q1, hydrophilic 810
2 surface.

The hydrophobic Si surface is formed by chemical treatment on one main surface and leaves a ζ oxide film, making the entire main surface of the wafer hydrophilic.
Even if air knife drying is used, the water film is evenly cut from the edge of the wafer, making it possible to dry the wafer uniformly.

Example Hereinafter, one embodiment of the present invention will be explained.

In an actual device, when forming a MOS capacitor, ten sides of the wafer are used as Lo for separating the capacitors.
Cos(SiO2) and a pattern on the exposed surface of the 81 substrate which becomes a capacitor coexist.

For example, this wafer is treated with NH4OH:H2O2:H20=1:2 near
, 70" (:). This lA7 cleaning forms an oxide film of about 1 nm on the Si. After thorough water washing, for example, H2O:HF2600:1.
The oxide film is etched by approximately 0.6 nm and approximately 0.5 nm is left behind.

After thoroughly washing with water, air knife drying is performed, and then a capacitor 5102 is formed, and a polysilicon electrode is further formed thereon to form a MOS capacitor. H2O:H
By varying the immersion time in the F=500:1 solution, MO
Create an S capacitor, and calculate the yield of capacitor 5102 and
The results of investigating the relationship with H2O:HF:600:1 liquid immersion time are shown in the figure. The yield of capacitor 5102 was determined as follows. That is, Locos(Si0
P burr (100) 10 with a mixture of 2) and Sl patterns
A 6-inch wafer with a length of ~150m was cleaned and dried with an air knife, and then capacitors 5i02 were
300 MOS capacitors were fabricated per 6-inch wafer.

A MOS capacitor whose current flows when 15V is applied to the polysilicon electrode is 1 μA or less is considered to be a good product.6
, the yield of capacitor 5102 was determined. According to this example, as shown in the figure, a chemical cleaning solution (NH40H
:H2O2:H2〇21:2 (near, 70'C) in which the oxide film of approximately I Jim remains even a little, that is, when immersion in H2O:HF:500:1 is for less than 3 minutes. In this case, the yield of capacitor 5i02 is equivalent to that of the conventional spin-drying method.1 In particular, within 0.2 to 2 minutes, the yield of capacitor 5i02 is equivalent to
It is the highest.

As described above, the present invention improves the yield of capacitor 5i02 when using the air knife drying method, which is easy to adapt to factory automation and large-diameter wafers, in the process of manufacturing semiconductor integrated circuits. The practical effect is particularly great in reducing bit defects when used in the manufacturing process of dynamic memories that use capacitors in the memory.

6 pages/

[Brief explanation of drawings]

The figure is an example of characteristics in an embodiment of the present invention. 5 is a characteristic diagram showing the relationship between the HF liquid immersion time and the yield of the capacitor 5102. FIG.

Claims (1)

[Claims] A method for processing a semiconductor device, comprising forming an oxide film by chemical treatment in a cleaning step, and then performing air drying treatment with the oxide film remaining.