JP2803850B2 - Semiconductor substrate surface cleaning method - Google Patents

Description

The present invention relates to a method for cleaning a surface of a semiconductor substrate. More particularly, the present invention relates to a method for cleaning a semiconductor substrate surface which can easily remove particles and powder attached to the surface without damaging the substrate surface.

(Conventional technology and its problems) Conventionally, in the semiconductor industry, for a silicon condenser wafer or the like serving as a substrate, a plurality of objects are moved from a manufacturing maker to a device mounting and circuit forming process in a loaded state. Often transported.

In this case, usually, a substrate such as a wafer is loaded via fine particles such as ceramic powder or powder, thereby making it easy to separate the substrates one by one. These fine particles and powder also have properties as a release material.

In the handling of this conventional substrate, it is necessary to remove fine particles or powder such as ceramics attached to the surface, and further dust and the like before forming elements, circuits, and the like. Surface buffing and the like have been performed as simple means.

However, in the method of cleaning the surface such as buff polishing, when there is a step formed on the semiconductor substrate, it is difficult to remove particles, powders, etc. existing in the step, and the step corner is hardly removed. There was a problem that damage was inevitable.

In order to solve such a problem, it is necessary to remove particles or powder by blowing jet air to the stepped portion,
Although it has been studied, it is difficult to remove when the blowing pressure is small by ordinary jet air blowing, and when the pressure is large, as shown in FIGS. When trying to remove particles, powder (c) or dust remaining in the step (a) of (a) by air (d), the step (a) is prevented from being damaged or damaged (o). I couldn't.

The present invention has been made in view of the above circumstances, and provides a new method capable of easily removing fine particles and powder adhering to a substrate surface without causing surface damage. It is characterized by.

(Means for Solving the Problems) According to the present invention, as a solution to the above problems, fine particles or powdery substances are sprayed onto a semiconductor substrate surface by a Coanda spiral flow generated by introducing a pressurized fluid. The present invention provides a method for cleaning the surface of a semiconductor substrate, characterized in that the surface is removed.

The Coanda spiral flow used in the present invention is completely different from laminar flow or turbulent flow, which is known as the conventional concept of fluid motion, and is different from turbulent flow even under the condition of fluid motion belonging to the turbulent flow region. The exercise state has been found by the inventor of the present invention. The present inventor has already proposed a forming method.

In other words, the Coanda spiral flow is a fluid flow that moves at a high speed in the pipe direction while turning, and is formed by adding a radial vector of the pipe to the flow vector of the fluid introduced in the pipe direction. Can be. In this case, a negative pressure of a strong suction force is formed on the opposite side of the Coanda spiral flow in the traveling direction, and a boundary layer based on the swirling flow is formed near the inner wall of the pipe.

The present invention utilizes the characteristics of such Coanda spiral flow to clean the surface of a semiconductor substrate. An important point in using this method is that the direction of the Coanda spiral flow proceeds. Is to effectively scatter fine particles and powder present on the substrate surface, and such an action is not seen in the conventional turbulent airflow blowing. By this characteristic action, the processing efficiency of the surface cleaning is improved, and furthermore, the damage and destruction of the substrate surface such as the step portion are suppressed.

Hereinafter, the method of the present invention will be described with reference to the attached drawings.

FIG. 1 shows an example of the present invention together with the Coanda spiral flow generating device.

In the example shown in FIG. 1, for example, an annular slit (3) for pressurizing and introducing a fluid such as air or an inert gas is provided in a main cylinder (2) facing a nozzle outlet (1). The slit (3) is provided with a supply pipe (7) for supplying a fluid such as air or an inert gas.

The main pipe (2) has a gradually increasing diameter similarly from the nozzle outlet (1) toward the slit (3), and forms a smoothly curved wall surface (5). Further, an auxiliary cylinder (4) is provided at the end opposite to the nozzle outlet (1),
An inlet (6) for air or non-slip gas is formed. In this case, on the side opposite to the wall surface (5) of the slit (3), the wall surface (8) of the auxiliary cylinder (4) is bent at a right angle or an acute angle.

The slits (3) are arranged such that their intervals can be adjusted. The structure of the supply pipe (7) for supplying the pressurized fluid is not particularly limited. A distribution chamber (9) can also be provided to enable a uniform supply.

Regarding the inclination angle (θ) of the main cylinder, tan θ is 1/3 to 1/10
It is preferred that the degree is

For example, in the Coanda spiral flow generation nozzle which can be exemplified as described above, air as a pressurized fluid is introduced from the slit (3) into the main cylinder (2). The pressure at this time can be appropriately set to about 4 kg / cm ² . Of course, this value is not limiting. As a result, the motion vector of the air and the motion vector of the fluid such as air from the inlet (6) are synthesized, and the spiral motion (10) is generated. This spiral motion (10) causes the fluid velocity to concentrate in the direction of the traveling axis together with the swirling flow. If necessary, a jet pipe (11) may be connected to the nozzle outlet (1).

As the pressurized fluid, air or an inert gas, and if necessary, a reactive gas can also be used.

Next, the present invention will be described in more detail with reference to examples.

Example The nozzle shown in FIG. 1 was used. The nozzle outlet diameter at this time was 23 m / m. Θ is set to tan θ = 1/6. The distance between the nozzle outlet and the sample was 30 m / m, and the surface of the loaded Si wafer was cleaned via the SiO ₂ powder. In this case, 1.5 kgf / cm ² of pressurized air was blown on the substrate surface. No surface damage was observed, and the surface cleanliness was extremely good. When the cleaning treatment was performed by the conventional air jet method under the same conditions, the surface was roughened, and damage at the step was recognized.

(Effects of the Invention) As described in detail above, by spraying the fluid by the Coanda spiral flow of the present invention, it is possible to remove fine particles and powdery substances adhering to the substrate surface without damaging the substrate surface. Moreover, this method is extremely simple.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the nozzle of the present invention. FIG. 2 is a cross-sectional view showing the disadvantages of the conventional air jet cleaning. 1 ... nozzle outlet 2 ... main cylinder 3 ... slit 4 ... auxiliary cylinder 5 ... wall surface 6 ... introduction port 7 ... supply pipe 8 ... wall surface 9 ... distribution chamber 10 ... spiral motion 11 ... Squirting pipe

Claims (3)

(57) [Claims] 1. A method for cleaning a surface of a semiconductor substrate, comprising spraying the fluid onto a surface of the semiconductor substrate by a Coanda spiral flow generated by introducing a pressurized fluid to remove fine particles or powdery substances. 2. The method according to claim 1, wherein the pressurized fluid is air or an inert gas. 3. The method for cleaning a surface of a semiconductor substrate according to claim 1, wherein the surface of each of the loaded substrates is cleaned via a ceramic powder.