JP4855232B2 - Cleaning device and cleaning method - Google Patents

Description

  The present invention relates to a cleaning apparatus and a cleaning method, and more particularly to a cleaning apparatus and a cleaning method for cleaning a substrate immersed in a cleaning liquid by conducting ultrasonic waves through the cleaning liquid.

  Conventionally, an ultrasonic cleaning technique is one of industrial cleaning techniques for cleaning semiconductor substrates and the like. An ultrasonic cleaning apparatus using this technique is important in a semiconductor manufacturing process, and is used, for example, in a cleaning process such as solution processing, rinsing, and lift-off for a semiconductor substrate in the semiconductor manufacturing process.

  The ultrasonic cleaning apparatus is provided in contact with the cleaning tank, the ultrasonic oscillator that transmits a frequency signal to the vibrator, and the cleaning tank, and receives the frequency signal from the oscillator and vibrates. It is mainly composed of an oscillator (vibrator).

Next, the principle of cleaning using such an ultrasonic cleaning apparatus will be described with reference to the drawings.
FIG. 11 is a schematic cross-sectional view of a semiconductor substrate cleaned by a conventional ultrasonic cleaning apparatus, and FIG. 12 is a schematic cross-sectional view of a semiconductor substrate cleaned by a conventional ultrasonic cleaning apparatus.

  The semiconductor substrate 100 will be described as an example of the object to be cleaned. As shown in FIG. 11, in the semiconductor substrate 100, a reverse pattern is formed on the semiconductor substrate 100 with a resist film 100a, and the pattern film 100b is formed in the reverse pattern.

  In an ultrasonic cleaning device, a vibrator that receives a frequency signal from an ultrasonic oscillator vibrates the cleaning tank, and countless counts of microbubbles such as dissolved oxygen are formed in the cleaning liquid in the cleaning tank. A microcavity close to a vacuum (hereinafter referred to as “cavitation 101”) is generated.

  Then, as shown in FIG. 12, the resist film 100a and the pattern film 100b on the semiconductor substrate 100 immersed in the cleaning liquid in the cleaning tank can be removed by a shock wave when the cavitation 101 bursts.

  Generally, in an ultrasonic cleaning apparatus, as the frequency of cavitation increases, the energy released by individual bubbles decreases, so ultrasonic cleaning using a low frequency (from about 20 kHz to about 40 kHz) is performed.

  However, as the ultrasonic wave becomes lower in frequency, the cavitation energy increases, but the wavelength increases. For this reason, since the interval of the standing wave synthesized by the outgoing wave and the reflected wave of the ultrasonic wave also becomes large, depending on the location in the washing tank, the cleaning power (standing wave antinodes and nodes) has a large distribution As a result, there was a problem that reliable substrate cleaning could not be performed.

  On the other hand, methods for reducing the cleaning force distribution such as swinging of an object to be cleaned such as a substrate, stirring of a cleaning liquid, and movement of an optimal cleaning position due to frequency fluctuation have been proposed (for example, see Patent Documents 1 and 2). ).

In addition, attempts have been made to eliminate positions with relatively weak cleaning power by arranging a plurality of diaphragms in two or three directions and simultaneously emitting ultrasonic waves (see, for example, Patent Documents 3 and 4). .)
Japanese Patent Laid-Open No. 08-229525 JP 2003-001205 A Japanese Patent No. 3326310 JP 2003-209086 A

However, in Patent Documents 1 and 2, although the cleaning power distribution is reduced, there is a problem that the cleaning time cannot be significantly shortened because the cleaning power itself is also dispersed and reduced accordingly.
Further, in Patent Documents 3 and 4, since the output (voltage) is dispersed into two or three, there is a problem that the cleaning time cannot be significantly reduced as in Patent Documents 1 and 2.

  In the lift-off process using ultrasonic waves, since the foreign matter (for example, resist film) to be removed from the object to be cleaned is not directly in contact with the cleaning liquid, the surface of the pattern film formed on the entire surface of the object to be cleaned is cracked. Until the cleaning liquid penetrates into the object to be cleaned, the resist dissolving effect by the cleaning liquid cannot be expected. Furthermore, due to recent miniaturization, the pattern is difficult to crack, and there is a problem that the cleaning power is insufficient only by the effect of cavitation of the conventional ultrasonic cleaning technology.

  This invention is made | formed in view of such a point, and it aims at providing the washing | cleaning apparatus and washing | cleaning method which can perform ultrasonic cleaning with high cleaning efficiency.

In the present invention, in order to solve the above-described problem, in the cleaning apparatus 10 that cleans the substrate 1 immersed in the cleaning liquid 11 by conducting ultrasonic waves to the cleaning liquid 11, the cleaning liquid 11 is placed as shown in FIG. The cleaning tank 12, the holding unit 13 that is installed in the cleaning tank 12 and holds the substrate 1 to which the removal target is attached, the ultrasonic oscillator 15 that generates a signal of the natural frequency of the substrate 1, and the cleaning tank 12 There is provided a cleaning apparatus having an oscillator that is installed, receives a signal, vibrates at a natural frequency, and generates an ultrasonic wave to vibrate the cleaning tank.

  According to such a cleaning apparatus, an ultrasonic wave corresponding to the natural frequency of the substrate is generated by the vibration of the vibrator to which the signal corresponding to the natural frequency of the substrate is input from the ultrasonic oscillator by the control unit. The ultrasonic wave having the natural frequency of the substrate is conducted to the cleaning liquid in the cleaning tank.

Further, in the present invention, in order to solve the above problems, in a cleaning method for cleaning a substrate immersed in the cleaning liquid by conducting ultrasonic waves in the cleaning liquid, a cleaning tank in which the cleaning liquid is put by an ultrasonic oscillator holder installed is kept in the steps of generating a natural frequency of the signal substrate removal target is attached, by the installed transducer to the cleaning tank, by receiving the signal, the unique And a step of vibrating the cleaning tank by generating the ultrasonic wave at a vibration frequency.

  According to such a cleaning method, the ultrasonic wave corresponding to the natural frequency of the substrate is generated by the vibration of the vibrator to which the signal corresponding to the natural frequency of the substrate is input from the ultrasonic oscillator by the control unit. The ultrasonic wave having the natural frequency of the substrate is conducted to the cleaning liquid in the cleaning tank.

In the present invention, the vibrator inputs a signal corresponding to the natural frequency of the substrate to which the object to be removed is attached from the ultrasonic oscillator, and generates an ultrasonic wave by vibrating to be removed to the cleaning liquid in the cleaning tank. Ultrasonic waves with the natural frequency of the substrate to which the object is attached are conducted. Thereby, the substrate immersed in the cleaning liquid resonates by the ultrasonic wave generated from the vibrator , and the removal target can be removed from the substrate .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The outline of the present invention will be described first, and the embodiments of the present invention will be described. However, the technical scope of the present invention is not limited to these embodiments, but extends to the matters described in the claims and equivalents thereof.

FIG. 1 is a schematic view of a cleaning apparatus according to the present invention, and FIG. 2 is a schematic cross-sectional view of a main part of a substrate.
As shown in FIG. 1, in the cleaning apparatus 10, a holding unit 13 is installed in a cleaning tank 12 in which a cleaning liquid 11 is placed, and the substrate 1 is arranged in the holding unit 13. The vibrator 16 installed at the bottom of the cleaning tank 12 receives a frequency signal from the ultrasonic oscillator 15. Further, the holding unit 13 and the ultrasonic oscillator 15 are controlled by the control unit 14.

  The cleaning liquid 11 is placed in the cleaning tank 12. The cleaning liquid 11 conducts ultrasonic vibration from the vibrator 16 through the cleaning tank 12 to the immersed substrate 1. Moreover, the cleaning effect can be improved by using various chemicals for the cleaning liquid 11 according to the object to be cleaned.

The cleaning tank 12 is provided with a cleaning liquid 11, and is provided with a holding part 13 inside a side part and a vibrator 16 at the bottom part.
The holding unit 13 is configured by connecting an arm 13b to a driving unit 13a provided on a side wall of the cleaning tank 12, and connecting a support frame 13c to a tip of the arm 13b.

  The drive unit 13 a is controlled by the control unit 14, adjusts the substrate 1 to a predetermined position from the bottom surface of the cleaning tank 12 via the arm 13 b and the support frame 13 c, and swings in the horizontal direction with respect to the vibrator 16. Move.

  The arm 13b has an L-shape and is connected to the drive unit 13a. A part of the arm 13b is immersed in the cleaning liquid 11 and a support frame 13c is installed at the tip. Note that the length of the arm 13b can be freely adjusted by the drive unit 13a, and the positions of the support frame 13c and the bottom surface of the cleaning tank 12 can be freely adjusted.

The support frame 13c is installed at the tip of the arm 13b so as to face the vibrator 16, and the substrate 1 is installed inside.
The control unit 14 controls the swing of the holding unit 13, the position of the substrate 1 in the cleaning tank 12, and the frequency signal output from the ultrasonic oscillator 15.

The ultrasonic oscillator 15 is controlled by the control unit 14 and outputs a frequency signal to the vibrator 16.
The vibrator 16 vibrates according to the input frequency signal and generates ultrasonic waves in the cleaning liquid 11 via the cleaning tank 12.

As shown in FIG. 2, the substrate 1 has a reverse pattern formed on the substrate 1 by a resist film 1a, and a pattern film 1b is formed on the entire surface including the reverse pattern.
The cleaning of the substrate 1 by the cleaning apparatus 10 having such a configuration will be described below.

The substrate 1 to be cleaned is placed on the support frame 13 c of the holding unit 13. The natural frequency of the substrate 1 is analyzed in advance.
The control unit 14 outputs a frequency signal for the natural frequency of the substrate 1 analyzed in advance from the ultrasonic oscillator 15 and swings the substrate 1 in the horizontal direction with the bottom surface of the cleaning tank 12 via the drive unit 13a. Let

The vibrator 16 receiving the frequency signal from the ultrasonic oscillator 15 vibrates and conducts ultrasonic waves to the cleaning liquid 11 through the cleaning tank 12.
At this time, as shown in FIG. 2, the substrate 1 is resonated, so that the resist film 1a and the pattern film 1b on the resist film 1a are removed, and only the pattern film 1b not on the resist film 1a is placed on the substrate 1. Can be left in.

  In the cleaning such as the lift-off process using the natural frequency of the object to be cleaned, the adhesion between the substrate 1 and the pattern film 1b is such that the adhesion between the substrate 1 and the resist film 1a and the resist film 1a and the pattern film 1b An effect can be obtained when it is larger than the adhesive strength of.

Further, when the substrate 1 is positioned at the antinode of the standing wave of the ultrasonic wave generated by the vibrator 16, the cleaning efficiency for the substrate 1 can be improved at the position of the antinode of the standing wave having a large amplitude.
As described above, in the cleaning apparatus of the present invention, when cleaning is performed using ultrasonic waves according to the natural frequency of the semiconductor substrate that is the object to be cleaned, resonance occurs in the object to be cleaned, and the object to be cleaned is efficiently and Ultrasonic waves can be applied uniformly, and the cleaning efficiency by the lift-off process and the like, the reliability and stability of cleaning can be greatly improved.

Next, an embodiment using the present invention will be described.
FIG. 3 is a schematic cross-sectional view of the cleaning device according to the embodiment.
In the cleaning apparatus 20, a holding unit 23 is installed in a cleaning tank 22 in which a cleaning liquid 21 is placed, and an alumina-titanium carbide (AlTiC) substrate 2 that is a ceramic substrate is disposed on the holding unit 23. The vibrator 26 installed at the bottom of the cleaning tank 22 receives a frequency signal from the ultrasonic oscillator 25. Further, the holding unit 23 and the ultrasonic oscillator 25 are controlled by the control unit 24.

  The cleaning liquid 21 is placed in the cleaning tank 22. The cleaning liquid 21 conducts ultrasonic vibration from the vibrator 26 through the cleaning tank 22 to the immersed AlTiC substrate 2. Moreover, the cleaning effect can be improved by using various chemicals for the cleaning liquid 21 according to the object to be cleaned.

The cleaning tank 22 is provided with a cleaning liquid 21 and is provided with a holding part 23 inside a side part and a vibrator 26 at the bottom part.
The holding unit 23 is configured by connecting an arm 23b to a driving unit 23a provided on a side wall of the cleaning tank 22 and connecting a support frame 23c to a tip of the arm 23b.

  The drive unit 23 a is controlled by the control unit 24, and adjusts the AlTiC substrate 2 to a predetermined position from the bottom and side walls of the cleaning tank 22 via the arm 23 b and the support frame 23 c, and is horizontal with respect to the vibrator 26. Swing in the direction.

  The arm 23b is L-shaped and connected to the drive unit 23a. A part of the arm 23b is immersed in the cleaning liquid 21, and a support frame 23c is installed at the tip. The length of the arm 23b can be freely adjusted by the drive unit 23a, and the positions of the support frame 23c and the bottom surface of the cleaning tank 22 can be freely adjusted.

The support frame 23 c is installed at the tip of the arm 23 b so as to face the vibrator 26, and the AlTiC substrate 2 inside the support frame 23 c is installed so as to be perpendicular to the vibrator 26.
The control unit 24 controls the swing of the holding unit 23, the position of the AlTiC substrate 2 in the cleaning tank 22 and the frequency signal output from the ultrasonic oscillator 25.

The ultrasonic oscillator 25 is controlled by the control unit 24 and outputs a frequency signal to the vibrator 26.
The vibrator 26 vibrates according to the input frequency signal and generates ultrasonic waves in the cleaning liquid 21 through the cleaning tank 22.

Next, a semiconductor substrate that is an object to be cleaned will be described.
FIG. 4 is a schematic cross-sectional view of an essential part of a semiconductor substrate in the embodiment.
A reverse pattern is formed by a resist film 2a on an AlTiC substrate 2 that is a ceramic substrate, and an alumina (Al ₂ O ₃ ) film 2b is formed in the reverse pattern.

  The resist film 2a is formed on the AlTiC substrate 2 (thickness: 6 μm), and is a pattern (minimum pattern: about 9 μm × about 3 μm, maximum pattern) by photolithography (manufactured by Clariant Japan, i-line resist and developer). About 300 μm × about 200 μm).

The Al ₂ O ₃ film 2b was formed on the resist film 2a by sputtering using Al ₂ O ₃ (thickness: 5000 nm), and used as a test pattern for the lift-off process.
The cleaning of the AlTiC substrate 2 by the cleaning apparatus 20 having such a configuration will be described below.

The AlTiC substrate 2 that is the object to be cleaned is placed on the support frame 23 c of the holding unit 23. Then, the natural frequency of the AlTiC substrate 2 is analyzed.
The analysis of the natural frequency of the AlTiC substrate 2 will be described below.

  To analyze the natural frequency of the AlTiC substrate 2 in the three-dimensional shell element 3 shell, create a model of the object to be cleaned, perform eigenvalue analysis of the created model, and analyze the response of each model to the natural vibration mode To do. In the analysis, the model has a two-dimensional uniform structure in order to improve calculation efficiency. Further, for analysis of the natural frequency of the AlTiC substrate 2, a two-dimensional model is created from the substrate physical properties and constraint conditions of the AlTiC substrate 2 using PATRAN (ver. 2005), and an input file is output. Then, analysis is performed from this input file using ABAQUS (ver 6.4) as a solver.

  PATRAN is widely used in the development of vehicles, ships, engines, precision machinery, construction, structural analysis in the field of aerospace, etc., and directly accesses the shape model created by the CAD system to model various analyzes. This is a general-purpose preprocessor that can perform everything from result processing to result processing with a unified user interface.

  This is because the shape of the CAD system can be directly accessed by the unique direct shape access function, and integration with various analysis programs can be realized by the analysis function.

  In addition, once a finite element model is created in PATRAN, not only can it be freely converted into data corresponding to many finite element method solvers, but each solver can be executed from PATRAN and the results can be evaluated. it can. The solver is a program that solves a large-scale simultaneous linear equation for performing numerical analysis such as a finite element method or a boundary element method.

  In the finite element method, ABAQUS is a PATRAN solver and is a general-purpose finite element method analysis program that enables simulation of structural problems. In particular, it is possible to deal with problems including intense nonlinearity such as contact and material destruction by specializing in nonlinear analysis. A rich library of elements, materials and analysis functions are available for modeling.

First, in order to create a model of an object to be cleaned, the characteristics of the AlTiC substrate 2, the characteristics of the beam (substrate restraining portion), and restraint conditions are set as follows.
FIG. 5 is an example of an input file card for model formation.

  FIG. 5A shows the characteristics of the AlTiC substrate 2, FIG. 5B shows an example of a beam (substrate restraint section) characteristic, and FIG. 5C shows an example of a card of an input file of restraint conditions.

In the input file card of the characteristics of the AlTiC substrate 2 (FIG. 5A), the code 31a represents an elastic modulus of 420 GPa and a Poisson's ratio of 0.24, respectively, and the code 32a has a density of 4.32e (-9) kg. / mm ³ represents the code 33a represents respectively the elements of the AlTiC substrate 2 is a two-dimensional 4-node shell element.

  In the input file card of the beam characteristics (FIG. 5B), the code 31b indicates that the beam elastic modulus is 1 GPa and the Poisson's ratio is 0.3, and the code 32b indicates that the beam element is a two-dimensional three-contact. The beam element represents a beam element, and the code 33b represents that the direction component of the beam is 5 mm in length in the negative z-axis direction and 1 mm in diameter.

  In the input file card (FIG. 5C) of the beam constraint condition, the code 31c constrains the beam lower end node (nodes constituting various elements), and in this embodiment, the orientation flat part edge is two points. Represents.

FIG. 6 shows a two-dimensional shell model of the substrate.
As the two-dimensional shell model 35 of the AlTiC substrate 2, the substrate dimension diameter of the AlTiC substrate 2 is 125 mm, the thickness is 2 mm, and the length of the perpendicular from the substrate center to the orientation flat 35a is 59.05 mm (the orientation flat length is 40.05 mm). 96 mm). Then, the number of nodes is set to 3517 and the number of elements is set to 3352, and the beam is fixed at the two restraint points 35b with a beam. In addition, for example, one axis (x-axis) is parallel to the orientation flat 35a, two axes (y-axis) define the thickness (plane strain element), and three axes (z-axis) are The direction is perpendicular to the orientation flat 35a.

Next, eigenvalue analysis of the AlTiC substrate 2 is performed.
An AlTiC substrate in the range of the peripheral frequency (about ± 10 kHz, but ± 20 kHz for 100 kHz) of each frequency (28 kHz, 38 kHz, 100 kHz, 200 kHz, 430 kHz, 950 kHz) of the cleaning device 20 (made by Kaijo) in the present embodiment. 2's natural frequency is obtained.

FIG. 7 is an example of an input file card for eigenvalue analysis.
In order to obtain the natural frequency of the AlTiC substrate 2, the center of the AlTiC substrate 2 is constrained in the y direction (substrate thickness direction), and for example, the eigenvalue analysis of the AlTiC substrate 2 is performed at a peripheral frequency of 100 kHz between 80 kHz and 120 kHz. When attaching the card, a card as shown in FIG. 7 is attached to the input file shown in FIG.

  Each code in FIG. 7 will be described. Code 41 solves each mode of natural frequency, geometric nonlinear analysis, maximum number of steps, and code 42 uses the LANCZOS eigenvalue solver to extract 500 natural vibration modes in the frequency range from 80 kHz to 120 kHz. The code 43 represents the application of vibration in the biaxial (y-axis) direction of the node 715 (substrate center), and the code 44 represents the pasting of the analysis result (Mises stress and substrate deformation) to be extracted last.

  In order to perform eigenvalue analysis of the AlTiC substrate 2 in this manner, the frequency range, the number of vibration modes, and the center of the substrate are constrained in the y direction, and the eigenvalue analysis of the AlTiC substrate 2 is defined in the range of 80 kHz to 120 kHz. Then, an ABAQUS input file is created by attaching the card thus defined to the input file card shown in FIG. Then, it is analyzed by ABAQUS, and a natural vibration mode in the range of 80 kHz to 120 kHz of the AlTiC substrate 2 is obtained. And it analyzes similarly about the peripheral frequency (± 10 kHz) of 28 kHz, 38 kHz, 200 kHz, 430 kHz, and 950 kHz.

  According to this result (not shown), the vibration of the AlTiC substrate 2 of the present embodiment has a different distribution depending on the inherent vibration mode of the AlTiC substrate 2, and a large vibration was obtained particularly in the vicinity of a frequency of 100 kHz. .

Finally, frequency response analysis of the AlTiC substrate 2 is performed.
The response when an arbitrary frequency is applied to the AlTiC substrate 2 having the inherent vibration mode obtained by performing the eigenvalue analysis is analyzed.

FIG. 8 shows an example of an input file card for frequency response analysis.
In order to perform the frequency response analysis of the AlTiC substrate 2, for example, when performing a frequency response around 100 kHz where a large vibration is obtained from the result of the eigenvalue analysis, a card as shown in FIG. ABAQUS input file is created by attaching it to the input file card shown in FIGS. And it analyzes using ABAQUS.

  Each code in FIG. 8 will be described. Code 51 represents natural frequency and geometric nonlinear analysis, code 52 represents frequency response analysis at 100 kHz, code 53 represents application of a sin wave with an amplitude of 1 mm in a frequency range of 1 kHz to 100 kHz, and code 54 represents modal. Definition of basic excitation in analysis, application of wave defined by AMP, application of displacement, biaxial (y-axis) direction, excitation to CENTER part defined by “BOUNDARY” of eigenvalue analysis, code 55 A data line specifying modal damping represents 2.5% attenuation in 1 to 500 modes, code 56 represents a data line specifying the natural vibration mode to use, and all uses of 1 to 500 natural vibration modes, A code 57 represents the pasting of the analysis result (Mises stress).

9 and 10 are examples of diagrams of frequency response analysis results.
9 and 10 show the stress distribution when each frequency (28 kHz, 38 kHz, 100 kHz, 200 kHz, 430 kHz, 950 kHz) of the cleaning device 20 is applied to the AlTiC substrate 2 from the analysis result by ABAQUS.

According to this result, when the frequency of the cleaning device 20 is 28 kHz (FIG. 9A), 38 kHz (FIG. 9B), 430 kHz (FIG. 10B), 950 kHz (FIG. 10C), The Mises stress in the ± z direction from the center of the AlTiC substrate 2 or from the center is in the range of 3.333 × 10 ³ Pa to 1.000 × 10 ⁴ Pa, and outward from the center of the AlTiC substrate 2. The Mises stress was in the range of 0.000 Pa to 6.667 × 10 ³ Pa.

On the other hand, when the frequency of the cleaning device 20 is 100 kHz (FIG. 9C) and 200 kHz (FIG. 10A), the Mises stress at the center of the AlTiC substrate 2 is 2.667 × 10 ⁴ Pa to 4.0000. × a 10 ⁴ Pa, outward from the center of the AlTiC substrate 2, Mises stress is ^{1.667 × 10 4 Pa~2.667 × 10 4} Pa, especially when the frequency is 100kHz, high Mises stress was obtained over a wide range.

From the above, it can be seen that the largest frequency response was obtained when a frequency of 100 kHz was applied to the AlTiC substrate 2.
As a result of the analysis, it was found that the frequency that can be output from the cleaning device 20 and that is closest to the natural frequency of the AlTiC substrate 2 is 100 kHz.

Hereinafter, a case where cleaning is performed by actually using the frequency obtained by analysis will be described.
In the cleaning apparatus 20, as shown in FIG. 3, the AlTiC substrate 2 was placed vertically in the cleaning tank 22 in which the cleaning liquid 21 was placed, held by the holding unit 23. And it wash | cleaned by each frequency (38 kHz, 100 kHz, 200 kHz, 430 kHz, 950 kHz) of the washing | cleaning apparatus 20 for 20 minutes with the output of 600W. When cleaning was not completed in 20 minutes, the remaining rate of the Al ₂ O ₃ film 2b per one AlTiC substrate 2 was evaluated.

When a frequency of 38 kHz was applied, all the Al ₂ O ₃ films 2b could not be removed by the treatment for 20 minutes, and the remaining rate at that time was 45%.
When 100 kHz, which is the resonance frequency according to the analysis result, was applied, all of the Al ₂ O ₃ film 2b could be removed in 4 minutes.

As a result of analysis, when 200 kHz, which is the frequency that was the second largest stress, was applied, all of the Al ₂ O ₃ film 2b could be removed in 8 minutes.
When a frequency of 430 kHz was applied, all the Al ₂ O ₃ films 2b could not be removed by the treatment for 20 minutes, and the remaining rate at that time was 72%.

When a frequency of 950 kHz was applied, all the Al ₂ O ₃ films 2b could not be removed by the treatment for 20 minutes, and the remaining rate at that time was 98%.
As described above, when cleaning is performed using ultrasonic waves according to the natural frequency of the semiconductor substrate that is the object to be cleaned, as in the cleaning apparatus of the present invention, resonance occurs in the object to be cleaned, and the object to be cleaned is efficiently and uniformly applied. Therefore, the cleaning efficiency by the lift-off process and the like, and the reliability and stability of the cleaning can be greatly improved.

(Additional remark 1) In the washing | cleaning apparatus which conducts an ultrasonic wave to a washing | cleaning liquid and wash | cleans the board | substrate immersed in the said washing | cleaning liquid,
A cleaning tank containing the cleaning liquid;
A holding unit that is installed in the cleaning tank and holds the substrate;
An ultrasonic oscillator for generating a signal of the natural frequency of the substrate;
A vibrator that is installed in the cleaning tank, receives the signal, vibrates at the natural frequency, generates the ultrasonic wave, and vibrates the cleaning tank;
A cleaning apparatus comprising:

(Additional remark 2) The said signal respond | corresponds to the said natural frequency with the highest response of the said board | substrate by the vibration of the said ultrasonic wave, The cleaning apparatus of Additional remark 1 characterized by the above-mentioned.
(Supplementary Note 3) The cleaning apparatus according to Supplementary Note 1 or 2, wherein the natural frequency is analyzed on the substrate using a finite element method.

  (Supplementary Note 4) The first adhesion force between the substrate and the resist film formed on the substrate and the second adhesion force between the resist film and the pattern film forming the pattern formed on the substrate are the substrate 4. The cleaning apparatus according to any one of appendices 1 to 3, wherein the cleaning apparatus has a smaller adhesion force than a third adhesion force between the pattern film and the pattern film.

(Supplementary note 5) The cleaning apparatus according to any one of supplementary notes 1 to 4, wherein a position where the substrate is held by the holding unit is an antinode of standing waves by the ultrasonic waves.
(Additional remark 6) The said holding | maintenance part has an arm which moves the position with a strong cleaning power which exists in the said washing tank, and the relative position of the said board | substrate, Any one of Additional remark 1 thru | or 5 characterized by the above-mentioned. The cleaning apparatus according to 1.

(Supplementary Note 7) In a cleaning method for cleaning a substrate immersed in the cleaning liquid by conducting ultrasonic waves to the cleaning liquid,
A step of generating a signal of a natural frequency of the substrate held by a holding unit installed in a cleaning tank in which the cleaning liquid is placed by an ultrasonic oscillator;
Receiving the signal by a vibrator installed in the cleaning tank, oscillating at the natural frequency, and generating the ultrasonic wave to vibrate the cleaning tank;
A cleaning method characterized by comprising:

(Additional remark 8) The said signal respond | corresponds to the said natural frequency with the highest response of the said board | substrate by the vibration of the said ultrasonic wave, The cleaning method of Additional remark 7 characterized by the above-mentioned.
(Supplementary note 9) The cleaning method according to supplementary note 7 or 8, wherein the natural frequency is analyzed on the substrate using a finite element method.

  (Supplementary Note 10) The first adhesion force between the substrate and the resist film formed on the substrate and the second adhesion force between the resist film and the pattern film forming the pattern formed on the substrate are the substrate The cleaning method according to any one of appendices 7 to 9, wherein the cleaning force is smaller than a third adhesion between the pattern film and the pattern film.

(Supplementary note 11) The cleaning method according to any one of supplementary notes 7 to 10, wherein a position where the substrate is held by the holding portion is an antinode of a standing wave by the ultrasonic wave.
(Additional remark 12) The said holding | maintenance part has an arm which moves the relative position of the position with the strong cleaning power which exists in the said washing tank, and the said board | substrate, Any one of Additional remark 7 thru | or 11 characterized by the above-mentioned. The cleaning method according to 1.

It is a schematic diagram of the cleaning apparatus of the present invention. It is a principal part cross-sectional schematic diagram of a board | substrate. It is a cross-sectional schematic diagram of the washing | cleaning apparatus in embodiment. It is a principal part cross-sectional schematic diagram of the semiconductor substrate in embodiment. It is an example of the card of the input file of model formation. It is a figure showing the two-dimensional shell model of a board | substrate. It is an example of the card of the input file of eigenvalue analysis. It is an example of the card | curd of the input file of a frequency response analysis. It is an example (the 1) of the figure of a frequency response analysis result. It is an example (the 2) of the figure of a frequency response analysis result. It is a cross-sectional schematic diagram of the semiconductor substrate cleaned by the conventional ultrasonic cleaning apparatus. It is a cross-sectional schematic diagram of the semiconductor substrate cleaned by the conventional ultrasonic cleaning apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 10 Cleaning apparatus 11 Cleaning liquid 12 Cleaning tank 13 Holding part 13a Drive part 13b Arm 13c Support frame 14 Control unit 15 Ultrasonic oscillator 16 Vibrator

Claims (6)

In a cleaning apparatus for cleaning a substrate immersed in the cleaning liquid by conducting ultrasonic waves to the cleaning liquid,
A cleaning tank containing the cleaning liquid;
A holding unit that is installed in the cleaning tank and holds a substrate to which an object to be removed is attached ;
An ultrasonic oscillator for generating a signal of the natural frequency of the substrate;
A vibrator that is installed in the cleaning tank, receives the signal, vibrates at the natural frequency, generates the ultrasonic wave, and vibrates the cleaning tank;
A cleaning apparatus comprising: The cleaning apparatus according to claim 1, wherein the signal corresponds to the natural frequency at which the response of the substrate due to the vibration of the ultrasonic wave is maximized.   The cleaning apparatus according to claim 1, wherein the natural frequency is analyzed on the substrate using a finite element method.   The cleaning apparatus according to claim 1, wherein the object to be removed includes a resist film.   The said holding | maintenance part has an arm which moves the relative position of the position with the strong cleaning power which exists in the said washing tank, and the said board | substrate, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Cleaning device. In the cleaning method of cleaning the substrate immersed in the cleaning liquid by conducting ultrasonic waves to the cleaning liquid,
A step of generating a signal of the natural frequency of the substrate to which the object to be removed is attached, held by a holding unit installed in the cleaning tank in which the cleaning liquid is placed, by an ultrasonic oscillator;
By the installed transducer to the cleaning tank, by receiving the signal, the steps of the oscillating at the natural frequency, to vibrate the cleaning tank to generate the ultrasound,
A cleaning method characterized by comprising:

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