JPS63220526A - Washing method - Google Patents

Abstract

PURPOSE:To improve yield and quality by injecting wash water from a pair of oppositely arranged nozzles and making wash water to collide and making a turbulent flow generated abut against the surface of a substrate to be washed positioned on the sides of the nozzles and washing the surface of the substrate. CONSTITUTION:A pair of nozzle 10, 10' are disposed oppositely, wash water is injected simultaneously from a pair of the nozzles and made to collide and a turbulent flow generated is made to abut against the surface of a wafer 11 positioned on the sides of the nozzles and the surface of the wafer is washed. When an electrode window for an EP memory element is washed, both wash water is made to collide and a turbulent flow is generated when wash water is injected from a pair of opposed nozzles 10, 10'. The turbulent flow represents a spiral vortex, etc., the direction of a water current made to collide by the positioning of the wafer 11 on the sides of the nozzles is changed to the side, and the water current collides with the surface of the wafer by a certain hydraulic pressure. Consequently, wash water in the fine deep electrode window 6 is exchangeed, and the inside of the window is washed. Accordingly, the yield and quality of an IC are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Cleaning water sprayed from a pair of nozzles collides to generate a turbulent flow, and the turbulent flow is applied to the surface of a substrate to be cleaned located on the side of the nozzles to clean it. This improves the effectiveness of cleaning the surfaces of wafers, photomasks, and the like.

[Industrial Application Field] The present invention relates to a cleaning method, and particularly to a cleaning method in a wafer process.

As is well known, semiconductor devices such as ICs have elements formed on the surface of a wafer (semiconductor substrate) and are completed into IC chips through a wafer process. This process is always accompanied by cleaning.

On the other hand, ICs are becoming increasingly highly integrated and each element is becoming smaller.
The surface of the wafer is subjected to fine processing, and due to the miniaturization, a sufficient cleaning effect cannot be obtained after the etching process, and an improvement is desired.

[Prior art] A common cleaning method that has been practiced in the past is to fill a washing container with washing water and immerse it in the water, an outline of which is shown in Figure 1 (tag, (b)). .

Figure 1(a) shows a one-way overflow cleaning method, where 1 is a wafer, 2 is a water container filled with cleaning water, and cleaning water (for example, pure water) is poured from the water inlet 2. In this method, the washing container 3 is filled with water, and the washing water is exchanged by overflowing the washing water from the washing container 3. Recently, a method has also been used in which such a cleaning method is automated and a wafer holder (not shown) holding a wafer is moved up and down to improve the cleaning effect.

FIG. 1 fbl shows a drain type cleaning method, in which a large amount of cleaning water is poured into the washing container 3 from the water inlet 2 to fill it up, and then water is rapidly drained from the drain port 4 to fill the washing container 3. This cleaning method involves emptying the container and filling it with water again.

Of course, such cleaning methods are also being automated.

[Problems to be Solved by the Invention] However, in the above-mentioned cleaning method, the cleaning water flows horizontally across the wafer surface, so when cleaning inside the fine deep holes formed in the wafer surface, There is a drawback that the amount of cleaning water is not sufficient and it is difficult for the cleaning water to enter the hole and replace it, resulting in poor cleaning effect in the hole.

For example, FIG. 3 shows a cross-sectional view of an electrode window formed in an EP memory element, and the electrode window 6 provided in the insulating film 5 has a hole diameter of 1 μmφ and a depth of 1 to 1.5 μm. It is difficult to completely clean by replacing the cleaning water into the fine deep holes. Therefore, if the inside of the electrode window 6 is insufficiently cleaned and an aluminum electrode is deposited in the hole in the next step, the inside of the electrode window and the deposited aluminum electrode may be washed away by a small amount of the etching solution or pretreatment solution remaining. The contact resistance increases as a result of corrosion, and impurities due to liquid leakage diffuse, reducing yield and quality.

The present invention provides a wafer to solve these problems.
This paper proposes a cleaning method.

[Means for Solving the Problems] The purpose is to install a pair of nozzles 10. as shown in FIG.
10' are arranged to face each other, and the turbulent flow generated by jetting cleaning water simultaneously from the pair of nozzles and colliding with each other is brought into contact with the surface of the wafer 11 located on the side of the nozzle, and the surface of the wafer 11 is cleaned. This is accomplished by a wafer cleaning method. In addition, FIG. 1 (al shows a top view seen from above, FIG. 1 (bl shows a side view seen from the side).

[Operation] That is, the present invention causes cleaning water injected from a pair of nozzles to collide to generate a turbulent flow, and the turbulent flow is applied to the Univer surface,
The aim is to allow cleaning water to flow into even the minute, deep holes and replace them. This increases the cleaning effect inside the micropores.

[Example] Examples will be described in detail below with reference to two drawings.

FIG. 2 shows the above-described E
This diagram shows the case of cleaning the electrode window of a P memory element.
When cleaning water is injected from a pair of opposing nozzles, both cleaning waters collide, creating turbulent flow. The turbulent flow is a vortex or the like, and if a wafer is placed on the side of the turbulent flow, the colliding water flow will be diverted to the side and hit the wafer surface with a certain amount of water pressure.

By doing so, the cleaning water inside the fine deep electrode window 6 is exchanged, and the inside of the window is cleaned.

FIG. 3 is a diagram showing one embodiment of the cleaning method according to the present invention, in which a pair of nozzles 2o consisting of a plurality of nozzles 2o are arranged above the wafer 11, and the wafer is located below. The unibar is held by a wafer chuck (not shown) and rotated at a speed of about 10 to 20 times/minute. A nozzle with a tip diameter of several diameters is used, and a water stream with a water pressure of 5 kg/ci collides with the tip of the nozzle to create a turbulent flow, and the turbulent flow is applied to the wafer surface for cleaning. When cleaning is completed, the wafer is automatically moved left and right to clean the next wafer.

In addition to this method, various cleaning method configurations can be considered in combination with the conventional immersion method.

According to the implementation results, better results were obtained compared to the conventional dipping method, and FIG. FIG. 3 is a cross-sectional view of a measurement sample in which an electrode window 16 has been opened by etching with a mixed solution of ammonium and hydrofluoric acid. When such a wafer was cleaned by the conventional immersion method and the cleaning method according to the present invention to form an aluminum wiring 17, the threshold voltage of the transistor characteristics was measured, and it was found to be 0.98.
Values of ~1.10V were obtained. On the other hand, in the conventional overflow one-way system, the threshold voltage is 0.6 to 0.7V.
It was about.

Therefore, the cleaning method according to the present invention is sufficiently effective in cleaning wafers with minute elements, is easily adaptable to automatic processing, and uses less water for cleaning than the immersion method. It also has the effect of saving money.

[Effects of the Invention] As is clear from the above explanation, the cleaning method according to the present invention is greatly useful for improving the yield and quality of ICs.

[Brief explanation of the drawing]

FIGS. 1A and 1B are diagrams showing the cleaning principle according to the present invention, FIG. 2 is a diagram explaining the cleaning state, and FIG. 3 is a diagram showing an embodiment of the cleaning method according to the present invention. Figure 4 is a cross-sectional view of the measurement sample, Figures 5 (al and b) are diagrams showing the conventional cleaning method, and Figure 6 is a diagram showing the problems of the conventional method. In the figure, 1.11 is a wafer (semiconductor substrate), 10.10' is a nozzle, 20 is a plurality of pairs of nozzles, 5.13 is an insulating film, 6.16 is an electrode window, and I7 is an aluminum wiring.・ρSuakyoyoyoyoyoprinciple 6notsum Figure 1 Release θ41SXl-77 ・Sibued 5yosenyuho7) mth
Figure 2 Kizuna Moe 〃・〃, shi 5 +, 73i/l-lol λε flight no T Figure 3 Cross-sectional view of yi υ inertia Figure 4

Claims (1)

[Claims] A pair of nozzles are arranged to face each other, and the turbulent flow generated by jetting cleaning water from the pair of nozzles and colliding with each other is brought into contact with the surface of the substrate to be cleaned located on the side of the nozzle, thereby cleaning the substrate. A cleaning method characterized by: