JPH0579944U - Semiconductor wafer dryer - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the semiconductor wafer 20 from being contaminated in the vapor tank 11. The cost of the vapor tank 11 is reduced and the durability is improved. [Structure] The vapor tank 11 and the bread 12 are made of Ni. The inner surface of the vapor tank 11 and the entire surface of the pan 12 are mirror-finished, and those surfaces are covered with a passivation film by HF treatment. Ni whose surface is coated with a passivation film by HF treatment does not release Ni ions.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a semiconductor wafer dryer using vapor such as IPA.

[0002]

[Prior Art]

 The manufactured semiconductor wafer is subjected to cleaning for several steps, and the surface is dried after the final cleaning. As the dryer, for example, an IPA steam dryer using steam of isopropyl alcohol (IPA) is often used. The structure of this dryer will be described with reference to FIG.

The IPA vapor dryer 10 has a vapor tank 11 that stores the IPA liquid. A pan 12 is supported above the IPA liquid in the tank.

When drying, first, a large number of semiconductor wafers 20 are aligned and held in a carrier 21 and set in a pan 12. Next, the IPA liquid in the bath is heated by the heater 13 to be evaporated, and the vapor is brought into contact with the semiconductor wafer 20 set in the pan 12. As a result, the IPA vapor adheres to the surface of the semiconductor wafer 20, absorbs moisture, and the surface is dried. The IPA that has absorbed water and returned to a liquid is discharged from the bottom of the pan 12 through the drain 14 to the outside of the tank.

The IPA vapor that has not been used for drying the semiconductor wafer 20 is cooled and condensed by a cooler 15 provided along the upper inner surface of the vapor tank 11 and discharged to the outside of the tank through a drain pan 16. Below the cooler 15 in the tank is the IPA vapor zone.

In such an IPA vapor dryer 10, the material is important in order to prevent the contamination of the semiconductor wafer 20, and quartz is normally used for the vapor tank 11 and the pan 12. In some cases, a dryer is also used in which these are made of SUS316 material and the surface of which is mirror-finished.

[0007]

[Problems to be solved by the device]

 However, the vapor tank 11 and the pan 12 made of quartz are very expensive, and there is a problem that the pan 12 is easily broken during maintenance or the like.

In that respect, the vapor tank 11 and the bread 12 made of SUS316 are inexpensive and have high strength against impact. However, the IPA vapor and the surface of the SUS316 material cause a delicate chemical reaction, and various metal ions are released from the surface, which may adhere to the surface of the semiconductor wafer 20 and deteriorate the quality of the semiconductor wafer 20. Moreover, although the surface of the SUS316 material is mirror-finished, fine irregularities are present, and therefore, particles of about 0.1 μm may be generated during drying and adhere to the surface of the semiconductor wafer 20.

On the other hand, the quartz vapor tank 11 and the pan 12 also undergo a delicate chemical reaction with the IPA vapor, and Na ions are also released from this and a defect that the Na ions are attached to the surface of the semiconductor wafer 20 has recently been found. It was It is explained that this is because a small amount of Na is contained in the quartz component.

As described above, the conventional IPA vapor dryer 10 has not yet completely prevented the semiconductor wafer 20 from being contaminated, even though sufficient attention is paid to its material.

An object of the present invention is to provide a semiconductor wafer dryer which has a significantly lower risk of wafer contamination than conventional ones, is low in price, and has high durability.

[0012]

[Means for Solving the Problems]

 The semiconductor wafer dryer of the present invention contains a vapor drying liquid in a vapor tank, sets the semiconductor wafer in a pan supported above the liquid surface, and heats and evaporates the liquid in the vapor tank. In a semiconductor wafer drier for drying semiconductor wafers in a pan with the vapor, the vapor tank and the pan are made of Ni, and at least the surface in contact with the liquid or vapor is mirror-finished, and the surface is subjected to HF treatment. It is characterized in that it is coated with a passive film.

[0013]

[Action]

 Ni whose surface is coated with a passivation film by HF treatment has no risk of releasing metal ions from the surface.

[0014]

【Example】

 An embodiment of the present invention will be described below with reference to FIG.

The present semiconductor wafer dryer is an IPA vapor dryer 10, and its vapor tank 11 and pan 12 are made of Ni. It is desirable that the purity of Ni is 99.99% or more. The inner surface of the vapor tank 11 and the entire surface of the pan 12 are mirror-finished and covered with a passivation film by HF treatment.

[0016] The mirror finish eliminates surface irregularities and prevents generation of fine particles. The HF treatment is performed with an aqueous solution of 50% HF + H ₂ O (1: 100), for example. By this treatment, the native oxide film on the surface of Ni is removed, and instead a passive film having high gas release resistance is formed. The thickness of the passivation film is preferably 0.15 to 0.25 μm.

In the present semiconductor wafer dryer, metal ions are not released from the vapor tank 11 and the pan 12 into the tank, and the IPA liquid in the tank and the vapor generated from the IPA liquid are not contaminated with metal ions. Therefore, the semiconductor wafer 20 set in the pan 12 is prevented from being contaminated by metal ions. Further, the vapor tank 11 and the pan 12 made of Ni are cheaper than those made of quartz and have high strength against impact even in consideration of the cost required for the HF treatment.

In the above embodiment, the inner surface of the vapor tank 11 and the entire surface of the bread 12 are subjected to the HF treatment. However, the present invention is not limited to this. For example, the inner surface of the vapor tank 11 above the IPA vapor zone may be covered. The part may be excluded from the target of the HF process. Further, the drain pan 16 and the like may be made of Ni, and the surface thereof may be mirror-finished and HF-treated.

[0019]

[Effect of the device]

 As is clear from the above description, the semiconductor wafer drier of the present invention prevents metal ions from adhering to the surface of the semiconductor wafer dried in the vapor tank and prevents the deterioration of the quality. In addition, the Ni material is cheaper than quartz, has a significantly high strength against impact, is hardly damaged, and has a long service life. Therefore, it is extremely economical.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an IPA steam dryer.

[Explanation of symbols]

 10 IPA Steam Dryer 11 Vapor Tank 12 Pan 13 Heater 15 Cooler 20 Semiconductor Wafer 21 Carrier

Claims (1)

[Scope of utility model registration request] 1. A vapor-drying liquid is contained in a vapor tank, a semiconductor wafer is set in a pan supported above the liquid level, the liquid in the vapor tank is heated and evaporated, and the pan is heated by the vapor. In the semiconductor wafer dryer for drying the semiconductor wafer therein, the vapor tank and the pan are made of Ni, at least the surface in contact with the liquid or vapor is mirror-finished, and the surface is covered with a passivation film by HF treatment. A semiconductor wafer dryer characterized in that