JPH10214813A - Method and apparatus for cleaning semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure uniformity of cleaning effect on the wafer surface by jetting water vapor and a gas onto the surface of a semiconductor wafer immersed in a cleaning liquid. SOLUTION: A cleaning liquid is fed into a cleaning tank 11 and a semiconductor wafer 10 is immersed in it. Then, water vapor and a gas are supplied from a water vapor and gas jet part 13 while adjusting, for example, the H2 O concentration in the cleaning liquid so as to be kept constant, and thereby the flow of fresh cleaning liquid is generated on the surface of the semiconductor wafer 10 immersed in the cleaning liquid and at the same time a physical force due to the water vapor and the gas acts on the surface of the semiconductor wafer 10 so that the foreign matters on the wafer surface can uniformly be removed. Further, even in the case where hydrolysis reaction takes place, uniformity in the wafer surface can be improved. Therefore, the uniformity of cleaning efficiency on the wafer surface can be ensured and the yield of the semiconductor device production can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for cleaning a semiconductor wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art At present, cleaning techniques for semiconductor wafers are still mainly of the wet batch immersion type. Dry cleaning has difficulty in removing particles, and has not been completely replaced by wet cleaning. Further, the spray cleaning is inferior to the batch type in particle removal ability, and has a problem in suppressing generation of watermarks. At present, its use is limited to a specific step such as resist removal. The wet batch immersion method has excellent particle removing ability, and the cleaning effect on the back surface is the most excellent as compared with other cleaning methods. Therefore, the wet immersion method will be mainly used in the wafer cleaning technology regardless of whether it is a batch or a single wafer.

In wet cleaning, the purpose of removing particles and metal contamination is cleaning using a cleaning solution (hereinafter referred to as APM) composed of ammonia / hydrogen peroxide / water. Also, a wet immersion method using phosphoric acid is used for removing the silicon nitride film and the silicon nitride oxide film. Hereinafter, an example of the above-described conventional APM cleaning apparatus and its cleaning method will be described with reference to the drawings.

FIG. 4 shows a conventional wet batch immersion type APM cleaning apparatus. In FIG.
Is a semiconductor wafer, 51 is a cleaning tank composed of an outer tank and an inner tank, and 52 is a wafer carrier. Reference numeral 53 denotes a return portion of the cleaning liquid circulation line in the tank, reference numeral 54 denotes a circulation pump, reference numeral 55 denotes a filter, reference numeral 56 denotes an in-line heater, which circulates the cleaning liquid in the cleaning tank 51 and filters particles with the filter 55. 57 is a buffer tank, 58 is an ultrasonic oscillator, and 59 is an ultrasonic oscillator for supplying a signal to the ultrasonic oscillator 58.

[0005] The operation of the APM cleaning apparatus configured as described above will be described below. First, a predetermined cleaning solution volume ratio, for example, 29% NH ₄ OH, 31% H ₂ O ₂ and H ₂
An APM cleaning solution having a volume ratio with O of 1: 1: 8 is applied to the cleaning tank 51.
Put in. Then, the circulating pump 54 and the in-line heater 56 are operated to circulate the cleaning liquid and stabilize the cleaning liquid at a predetermined temperature, for example, 50 to 70 ° C. Thereafter, the semiconductor wafer 50 is put into the cleaning tank 51, and the ultrasonic oscillator 59 is operated to irradiate the semiconductor wafer 50 with ultrasonic waves from the ultrasonic vibrator 58, thereby cleaning the semiconductor wafer 50 and removing particles and metal contamination. . At this time, since the components in the cleaning liquid evaporate or the cleaning liquid decreases when the semiconductor wafer 50 is taken out, the cleaning liquid may be additionally supplied periodically. Further, since the cleaning liquid is circulated through the filter 55, particles introduced into the cleaning tank 51 every time the wafer is processed are removed by the filter 55.

FIG. 5 shows a conventional wet batch immersion type phosphoric acid cleaning apparatus. In FIG. 5, reference numeral 60 denotes a semiconductor wafer, 61 denotes a cleaning tank including an outer tank and an inner tank, and 62 denotes a wafer carrier. 63 is a return portion in the tank of the cleaning liquid circulation line, 64 is a circulation pump, 65 is a filter, 66 is an in-line heater, and the cleaning tank 6
The cleaning liquid in 1 is circulated and particles are filtered by the filter 65. Reference numeral 67 denotes an additional pure water supply device that functions to keep the water concentration in the phosphoric acid constant during the high-temperature treatment.

[0007] The operation of the phosphoric acid cleaning apparatus configured as described above will be described below. First, 85% phosphoric acid is put into the cleaning tank 61. Then, the circulation pump 64 and the in-line heater 66 are operated to circulate the cleaning liquid and stabilize the cleaning liquid at a predetermined temperature, for example, 150 to 160 ° C.
At this time, since the cleaning liquid is circulated through the filter 65, particles introduced into the cleaning tank 61 for each wafer processing are removed by the filter 65. The replenishing amount of pure water is adjusted by the additional pure water supply device 67 so that the boiling point of phosphoric acid becomes the target temperature, and the temperature is kept constant in the boiling state. This is to stabilize the etching rate of the silicon nitride film. After that, the semiconductor wafer 60 is placed in the cleaning tank 61.
To remove the silicon nitride film and the silicon nitride oxide film.

[0008]

However, the conventional A
In the PM cleaning apparatus, a problem that ultrasonic waves are not irradiated by the wafer carrier 52 holding the semiconductor wafer 50 or the like due to the ultrasonic rectilinearity occurs, and the cleaning efficiency is locally reduced in the plane of the semiconductor wafer 50. was there.

Further, in the conventional phosphoric acid cleaning apparatus, bubbles may be generated due to sudden evaporation of the supplied water, and the position of the semiconductor wafer 60 loaded in the wafer carrier 62 may be shifted. There is a problem that the semiconductor wafer 60 is broken by replacement. further,
There is also a problem that a concentration distribution of water is locally generated in the phosphoric acid in the cleaning tank 61 and the removal characteristics of the silicon nitride film and the silicon nitride oxide film become non-uniform in the wafer surface.

The present invention has been made in view of the above problems, and provides a method of cleaning a semiconductor wafer and a cleaning apparatus for the same, which can ensure uniformity of cleaning efficiency in a wafer surface.

[0011]

According to a first aspect of the present invention, there is provided a method of cleaning a semiconductor wafer, wherein the semiconductor wafer is immersed in a cleaning solution, and water vapor and gas are jetted onto the surface of the semiconductor wafer to remove foreign substances on the semiconductor wafer. Things. According to the method for cleaning a semiconductor wafer according to the first aspect of the present invention, by blowing steam and gas onto the surface of the semiconductor wafer immersed in the cleaning liquid, a flow of fresh cleaning liquid is generated on the surface of the semiconductor wafer, and water vapor is generated on the semiconductor wafer surface. In addition, a physical force due to the gas acts to remove the foreign matter in the wafer surface uniformly.

According to a second aspect of the present invention, there is provided a method for cleaning a semiconductor wafer, wherein the semiconductor wafer is immersed in a cleaning solution comprising ammonia, hydrogen peroxide solution and water, and water vapor and gas are continuously or intermittently jetted onto the surface of the semiconductor wafer. Foreign matter on the semiconductor wafer. According to the method for cleaning a semiconductor wafer according to claim 2, the surface of the semiconductor wafer is continuously or intermittently jetted with water vapor and gas on the surface of the semiconductor wafer immersed in a cleaning liquid comprising ammonia, hydrogen peroxide solution and water. As a result, a flow of a fresh cleaning liquid is generated, and a physical force of water vapor and gas acts on the surface of the semiconductor wafer, so that particles and metal contaminants attached to the wafer surface can be uniformly removed.

According to a third aspect of the present invention, a semiconductor wafer having a silicon nitride film and a silicon oxynitride film formed thereon is immersed in a cleaning solution comprising phosphoric acid, and is continuously or intermittently formed on the surface of the semiconductor wafer. This is to remove the silicon nitride film and the silicon nitride oxide film on the semiconductor wafer by ejecting water vapor and gas.
According to the method for cleaning a semiconductor wafer according to claim 3, a flow of a fresh cleaning liquid on the surface of the semiconductor wafer by continuously or intermittently ejecting water vapor and gas onto the surface of the semiconductor wafer immersed in the cleaning liquid comprising phosphoric acid. Occurs, and a physical force due to water vapor and gas acts on the surface of the semiconductor wafer, thereby uniformly removing the silicon nitride film and the silicon nitride oxide film in the wafer surface.

According to a fourth aspect of the present invention, there is provided an apparatus for cleaning a semiconductor wafer, comprising: a cleaning tank containing a cleaning liquid having a capacity to immerse the semiconductor wafer; And a gas ejection section. According to the semiconductor wafer cleaning apparatus according to claim 4, by jetting water vapor and gas on the surface of the semiconductor wafer immersed in the cleaning liquid, a flow of fresh cleaning liquid is generated on the surface of the semiconductor wafer immersed in the cleaning liquid, Physical force due to water vapor and gas acts on the surface of the semiconductor wafer, so that foreign substances in the wafer surface can be uniformly removed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment A semiconductor wafer cleaning method and a cleaning apparatus according to a first embodiment of the present invention will be described with reference to FIG. This embodiment relates to a batch immersion type wet cleaning apparatus.

In FIG. 1, reference numeral 10 denotes a semiconductor wafer, 1
Reference numeral 1 denotes a cleaning tank composed of an outer tank and an inner tank, 12 denotes a wafer carrier, and 13 denotes a water vapor and gas ejection section provided at the bottom of the cleaning tank 11 so that water vapor and gas can be ejected onto the surface of the semiconductor wafer 10. It is. The steam and gas jetting section 13 is formed of a box-shaped body made of a perforated plate, and is connected to a steam and gas supply device (not shown).

The operation of the batch immersion wet cleaning apparatus configured as described above will be described below. First, a cleaning liquid is poured into the cleaning tank 11 and the semiconductor wafer 10
Immerse. The cleaning liquid includes a cleaning liquid (APM cleaning) composed of ammonia / hydrogen peroxide / water, a cleaning liquid composed of phosphoric acid, and the like, but is not limited thereto. Then, an inert gas such as water vapor and N ₂ is supplied from the water vapor and gas jetting section 13 to the vicinity of the surface of the semiconductor wafer 10 in the cleaning liquid.

The semiconductor wafer 10 constructed as described above
According to the cleaning method and the cleaning apparatus, the water vapor and the gas are supplied from the water vapor and gas jetting part 13 by adjusting the H ₂ O concentration in the cleaning liquid to be constant, for example.
A flow of fresh cleaning liquid is generated on the surface of the semiconductor wafer 10 immersed in the cleaning liquid, and physical force due to water vapor and gas acts on the surface of the semiconductor wafer 10, so that foreign substances on the wafer surface can be uniformly removed. In addition, even when a hydrolysis reaction occurs, the uniformity within the wafer surface can be improved. Therefore, uniformity of the cleaning efficiency in the wafer surface can be ensured, and the yield in manufacturing semiconductor devices can be improved.

Second Embodiment A semiconductor wafer cleaning method and a cleaning apparatus according to a second embodiment of the present invention will be described with reference to FIG. This embodiment relates to a wet batch immersion type APM cleaning apparatus. In FIG. 2, 2
0 is a semiconductor wafer, 21 is a cleaning tank composed of an outer tank and an inner tank, and 22 is a wafer carrier. 23 is a return part in the tank of the cleaning liquid circulation line, 24 is a circulation pump, 25
Denotes a filter, and 26 denotes an inline heater, which circulates a cleaning liquid in the cleaning tank 21 and filters particles with the filter 25. 27 is a buffer tank, 28 is an ultrasonic oscillator, and 29 is an ultrasonic oscillator for supplying a signal to the ultrasonic oscillator 28. Furthermore, 30 is the semiconductor wafer 20
Cleaning tank 2 so that water vapor and gas can be ejected to the surface of
Reference numeral 31 denotes a water vapor and gas supply unit connected to the water vapor and gas discharge unit 30, which is provided at a plurality of locations on the bottom of the unit 1 and is formed of a cylinder or a sphere made of a perforated plate.

The operation of the wet batch immersion type APM cleaning apparatus configured as described above will be described below. First, a predetermined cleaning solution volume ratio, for example, 29% NH ₄ OH
And 31% H ₂ O ₂ and H ₂ O in a volume ratio of 1: 1: 8 to 1:
An APM cleaning solution having a predetermined volume ratio up to 1:50 is applied to the cleaning tank 2.
Put in 1. Then, the circulating pump 24 and the in-line heater 26 are operated to circulate the cleaning liquid and stabilize the cleaning liquid at a predetermined temperature, for example, a temperature of 50 to 70 ° C. After that, the semiconductor wafer 20 is put into the cleaning tank 21, the ultrasonic oscillator 29 is operated, and the semiconductor wafer 20 is irradiated with ultrasonic waves from the ultrasonic vibrator 28.

At this time, water vapor or an inert gas containing an inert gas such as N _{2 is} supplied from the water vapor and gas supply device 31 to the water vapor and gas ejection section 30, and the water or the inert gas is continuously supplied into the cleaning tank 21. Alternatively, the semiconductor wafer 20 is cleaned by intermittently introducing water vapor and gas. The bubbles ejected from the water vapor and gas ejecting section 30 move upward between the semiconductor wafers 20 loaded in the wafer carrier 22, so that a cleaning liquid flows upward between the semiconductor wafers 20, and the surface of the semiconductor wafer 20 always flows. The physical force of the fresh cleaning solution and air bubbles acts on the surface. Thus, the efficiency of removing particles, metal contaminants, and the like attached to the surface of the semiconductor wafer 20 can be improved. In addition, since the components in the cleaning liquid evaporate or the cleaning liquid decreases when the semiconductor wafer 20 is taken out, the cleaning liquid may be additionally supplied periodically. Further, the water vapor and the water vapor supplied from the gas jetting section 30 have been sufficiently considered so as not to affect the etching rates of the oxide film and silicon.

The semiconductor wafer 20 constructed as described above
According to the cleaning method and the cleaning apparatus, the semiconductor wafer 2 is continuously or intermittently jetted into the cleaning liquid composed of ammonia, hydrogen peroxide water and water.
A fresh flow of the cleaning solution is generated on the surface of the semiconductor wafer 20, and physical force due to water vapor and gas acts on the surface of the semiconductor wafer 20, so that particles and metal contaminants attached to the wafer surface can be uniformly removed. Therefore, uniformity of the cleaning efficiency in the wafer surface can be ensured, and the yield in manufacturing semiconductor devices can be improved.

Third Embodiment A semiconductor wafer cleaning method and apparatus according to a third embodiment of the present invention will be described with reference to FIG. This embodiment relates to a wet batch immersion type phosphoric acid cleaning apparatus. In FIG.
40 is a semiconductor wafer, 41 is a cleaning tank composed of an outer tank and an inner tank, and 42 is a wafer carrier. Also, 43
Is a return portion in the tank of the cleaning liquid circulation line, 44 is a circulation pump, 45 is a filter, and 46 is an in-line heater. The cleaning liquid in the cleaning tank 41 is circulated and the filter 45 filters particles. Further, reference numeral 47 denotes a water vapor and gas ejecting portion formed of a perforated box-shaped body provided at the bottom of the cleaning tank 41 so as to eject water vapor and gas onto the surface of the semiconductor wafer 40, and 48 denotes a steam and gas ejecting portion. 4
7 is a water vapor and gas supply device.

The operation of the wet batch immersion type phosphoric acid cleaning apparatus configured as described above will be described below. First, 85% phosphoric acid containing water is put into the cleaning tank 41. The circulation pump 44 and the in-line heater 46
Is operated to circulate the cleaning liquid and stabilize the cleaning liquid at a predetermined temperature, for example, 150 to 160 ° C. At this time, since the cleaning liquid is circulated through the filter 45, particles introduced into the cleaning tank 41 for each wafer processing are removed by the filter 45. Then, the steam and gas supply unit 48 adjusts the steam replenishment amount so that the boiling point of the phosphoric acid becomes the target temperature, supplies H ₂ O to the cleaning liquid from the steam and gas ejection unit 47, and keeps the phosphoric acid at a constant temperature in a boiling state. To keep. This is to stabilize the etching rate of the silicon nitride film. Thereafter, the semiconductor wafer 40 is put into the cleaning tank 41, and steam and gas are continuously or intermittently supplied from the water vapor and gas supply device 48 to the water vapor and gas ejecting section 47, so that the silicon nitride film and the silicon nitride An oxide film is removed. At this time, the water vapor and gas ejection part 47 is porous, and supplies the water vapor to at least the area of the cleaning tank 41 in which the semiconductor wafer 40 is loaded.

The semiconductor wafer 40 thus configured
According to the cleaning method and the cleaning apparatus thereof, by continuously or intermittently ejecting water vapor and gas into the cleaning liquid composed of phosphoric acid, a flow of a fresh cleaning liquid is generated on the surface of the semiconductor wafer 40 and the cleaning of the semiconductor wafer 40 is performed. A physical force due to water vapor and gas acts on the surface, and the silicon nitride film and silicon nitride oxide film in the wafer surface can be uniformly removed. Therefore, uniformity of the cleaning efficiency in the wafer surface can be ensured, and the yield in manufacturing semiconductor devices can be improved.

Further, since the steam and gas jetting portion 47 is porous, the steam is uniformly supplied from the porous jetting portion 47 into the cleaning liquid, and rapid generation of bubbles by high-temperature steam can be prevented. Damage due to misalignment of the wafer 40 can be prevented. In the above-described embodiment, the APM cleaning device of the wet batch immersion type and the phosphoric acid cleaning device of the wet batch immersion type have been exemplified. However, the present invention is not limited to these, and can be applied to all wet immersion type cleaning devices.

Further, the water vapor and gas jetting part is not limited to a porous box, cylinder, or sphere, and the installation location is not limited to the bottom in the cleaning tanks 11, 21, 41. , 20 and 40 as long as they can eject water vapor and gas.

[0028]

According to the method for cleaning a semiconductor wafer according to the first aspect of the present invention, water vapor and gas are jetted onto the surface of the semiconductor wafer immersed in the cleaning liquid, whereby a fresh cleaning liquid flows on the semiconductor wafer surface, Physical force due to water vapor and gas acts on the surface of the semiconductor wafer, foreign substances in the wafer surface can be uniformly removed, and the yield in manufacturing semiconductor devices can be improved.

According to the semiconductor wafer cleaning method of the present invention, water vapor and gas are continuously or intermittently jetted onto the surface of the semiconductor wafer immersed in a cleaning solution comprising ammonia, hydrogen peroxide solution and water, A flow of a fresh cleaning solution is generated on the surface of the semiconductor wafer, and a physical force of water vapor and gas acts on the surface of the semiconductor wafer, whereby particles and metal contaminants attached to the wafer surface can be uniformly removed, thereby manufacturing a semiconductor device. The above yield can be improved.

According to the method for cleaning a semiconductor wafer according to the third aspect, water vapor and gas are continuously or intermittently jetted onto the surface of the semiconductor wafer immersed in a cleaning solution comprising phosphoric acid, so that the surface of the semiconductor wafer can be freshly cleaned. With the flow of the cleaning liquid, the physical force of water vapor and gas acts on the surface of the semiconductor wafer, and the silicon nitride film and silicon nitride oxide film on the wafer surface can be uniformly removed, thereby improving the yield in semiconductor device manufacturing. be able to.

According to the semiconductor wafer cleaning apparatus of the fourth aspect, the flow of the fresh cleaning liquid is applied to the surface of the semiconductor wafer immersed in the cleaning liquid by jetting water vapor and gas onto the surface of the semiconductor wafer immersed in the cleaning liquid. At the same time, physical force due to water vapor and gas acts on the surface of the semiconductor wafer, foreign substances in the wafer surface can be uniformly removed, and the yield in manufacturing semiconductor devices can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor wafer cleaning apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a semiconductor wafer cleaning apparatus according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a semiconductor wafer cleaning apparatus according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional wet batch immersion type APM cleaning apparatus.

FIG. 5 is a configuration diagram of a conventional wet batch immersion type phosphoric acid cleaning apparatus.

[Explanation of symbols]

 10, 20, 40 Semiconductor wafer 11, 21, 41 Cleaning tank 13, 30, 47 Steam and gas ejection section

Claims (4)

[Claims] 1. A method for cleaning a semiconductor wafer, comprising: a step of immersing a semiconductor wafer in a cleaning liquid; and a step of ejecting water vapor and gas onto a surface of the semiconductor wafer to remove foreign substances on the semiconductor wafer. 2. A step of immersing a semiconductor wafer in a cleaning solution comprising ammonia, a hydrogen peroxide solution and water, and a step of continuously or intermittently jetting water vapor and gas onto the surface of the semiconductor wafer to cause foreign matter on the semiconductor wafer. And a step of removing the semiconductor wafer. 3. A step of immersing a semiconductor wafer on which a silicon nitride film and a silicon oxynitride film are formed in a cleaning solution made of phosphoric acid, and continuously or intermittently ejecting water vapor and gas onto the surface of the semiconductor wafer. Removing the silicon nitride film and the silicon oxynitride film on the semiconductor wafer. 4. A semiconductor wafer provided with a cleaning tank filled with a cleaning liquid having a capacity for immersing a semiconductor wafer therein, and a water vapor and gas jetting section provided in the cleaning tank and jetting water vapor and gas onto the surface of the semiconductor wafer. Cleaning equipment.