JP3154685B2 - Ultrasonic cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic cleaning apparatus for ultrasonically cleaning an object to be cleaned such as a semiconductor substrate such as a wafer or a glass substrate, and more particularly to a high-frequency ultrasonic vibrator for a single-wafer ultrasonic cleaning apparatus. Not 800KHz
The present invention relates to an ultrasonic cleaning apparatus capable of reducing the amount of cleaning liquid to be used by using the following low-frequency ultrasonic vibrator to greatly reduce the amount of cleaning liquid used.

[0002]

2. Description of the Related Art As a conventional ultrasonic cleaning apparatus, for example, one described in Japanese Patent Application Laid-Open No. 6-461 is known.
This conventional ultrasonic cleaning apparatus will be described with reference to FIGS.

FIG. 7 is a cross-sectional view of a conventional ultrasonic cleaning apparatus as viewed from the front, FIG. 8 is a bottom view of the conventional ultrasonic cleaning apparatus viewed from the bottom, including a partially enlarged portion, and FIG. 9 is viewed from the side of FIG. FIG. 6 is a view showing a state of a flow of a cleaning liquid.

As shown in FIG. 7, this ultrasonic cleaning apparatus comprises a case 111 made of stainless steel or the like having a substantially concave cross section and a box shape in the longitudinal direction, and an ultrasonic wave arranged in the concave portion of the case 111. It has a vibrator 115 and an ultrasonic oscillator 116 for driving the ultrasonic vibrator 115 with an ultrasonic signal of, for example, 950 KHz. Therefore, the apparatus is a high-megasonic compatible apparatus that performs cleaning using a high-frequency ultrasonic vibrator.

[0005] The case 111 has an upper case including the vibration plate 111a of the ultrasonic vibrator 115 disposed in the concave portion and a surface of the ultrasonic vibrator 115 provided opposite to the vibration plate 111a. And a lower case including a reflecting plate 111b provided at an angle θ (0 <θ <10 °).

The upper case and the lower case are provided with bolts 1
21 and a nut 122 are fastened and fixed via a packing 119. On the side surface of the lower case, three cleaning liquid supply ports 112, two overflow discharge ports 114 provided on the opposite side surface of the cleaning liquid supply port 112, and a longitudinally extending central part of the lower reflector 111b. And a slit 125 formed at the center of the cleaning liquid lead-out portion 126.

A rectifying plate 118 having a substantially L-shaped cross section is attached to one side of the packing 119, and a plurality of slits 120 are formed in a lower portion of the rectifying plate 118 to perform rectifying action.

Next, the operation of the ultrasonic cleaning apparatus having the above configuration will be described.

As shown in FIG. 7, when the cleaning liquid 124 is supplied into the case 111 from the cleaning liquid supply port 112, the cleaning liquid 124 is rectified by the slits 20 of the rectifying plate 118 and flows in the case 111 as a laminar flow. The cleaning liquid has a uniform shape along the cleaning liquid outlet 113 and is ejected from the cleaning liquid outlet 113 onto the object to be cleaned 117. At this time, the ultrasonic vibrator 11
5 is a reflection plate 111b which is a bottom surface of the case 111 and is driven by an ultrasonic signal to transmit ultrasonic waves through the diaphragm 111a.
Reflects toward. The reflection plate 111b is set at a predetermined angle θ.
The ultrasonic waves 123a and 123b reflected by the reflector 111b repeatedly converge at the cleaning liquid jet port 113 while being repeatedly reflected, are guided to the ultrasonic wave deriving unit 126, and are guided from the slit 125 onto the object 117 to be cleaned. Irradiate with strong ultrasonic cleaning solution.

[0010]

As shown in FIGS. 7 to 9, the conventional ultrasonic cleaning apparatus has the following problems. That is,

The conventional ultrasonic cleaning apparatus is a single-wafer cleaning apparatus for cleaning objects to be cleaned such as wafers and glass substrates one by one. Are focused and become strong, but as shown in FIG. 7, since the area to be irradiated on the object to be cleaned 117 is very small, usually a plurality of ultrasonic cleaning apparatuses are used in order to obtain a sufficient cleaning effect. It is necessary to use them together, and a large amount of cleaning liquid is required. Moreover,
The cleaning liquid 124 applied to the object to be cleaned 117 is discharged without being collected.

Further, in recent years, the size of a cleaning apparatus has been required to be increased as the size of a substrate such as a glass substrate is increased. However, in this ultrasonic cleaning device, as shown in FIG. 8, since the cleaning liquid outlet 126 is usually manufactured by welding or the like, it is very difficult to manufacture the central slit 125 with a uniform width and a long length. In addition, since the width of the slit 125 depends on the wavelength of the frequency of the ultrasonic waves, if the width is reduced, the ultrasonic waves are attenuated and cannot be transmitted sufficiently. Therefore, there is a limit in reducing this width, and there is a limit in reducing the amount of water used.

That is, for example, assuming that the sound velocity in water is 1500 m / sec at f ₀ = 1 MHz, λ = 1.5 mm. Therefore, when the width of the slit 125 is d under such conditions, d is used as d ≧ 1.5 mm. If the slit has a length of, for example, 660 mm, a flow rate of 40 l (liter) / min or more is required.

Also, as shown in FIG.
When 5 is not formed with a uniform width, the tip of the cleaning liquid 124 has a slightly wavy shape as shown by a two-dot chain line in FIG. 9 (illustrated as 127a). in this case,
When the amount of the cleaning liquid is large, the cleaning liquid has a so-called water curtain shape and a nearly uniform flow.
As shown by 27b, a so-called liquid crack occurs, and ultrasonic waves cannot be transmitted uniformly to the object to be cleaned 117, and a problem occurs that a sufficient cleaning effect cannot be obtained. In addition, in this ultrasonic cleaning device, it is necessary to provide an ultrasonic flow meter or the like separately and always monitor the flow rate in order to prevent the above-mentioned liquid shortage.

Further, the ultrasonic cleaning apparatus includes a reflector 1
11b is formed at a predetermined angle.
11b is for reflecting ultrasonic waves and converging them with equal strength, so that they must be formed at equal left and right angles as shown in FIG. However, since the reflection plate 111b is usually processed by welding or the like, thermal expansion or the like occurs, and as shown in FIG.

The above-mentioned items are mainly of the conventional ultrasonic cleaning apparatus which is of a single-wafer type and has a slit structure. In recent years, however, particles such as large dust (approximately 1 It is necessary to use low-frequency and powerful ultrasonic waves in order to obtain a diameter of 0.0 μm or more.

However, in the conventional apparatus as shown in FIGS.
When a frequency of about KHz is used, the width of the slit 125 is 7.
5 mm, which is considerably wider than the 1.5 mm in the case of f ₀ = 1 MHz and requires a large amount of cleaning liquid, and it is difficult to always supply an appropriate amount of cleaning liquid to form a uniform water curtain.

Accordingly, the present invention has been made in view of the above-mentioned disadvantages of the prior art, and is particularly directed to an ultrasonic cleaning apparatus for ultrasonically cleaning an object to be cleaned such as a semiconductor substrate such as a wafer or a glass substrate. In a leaf type ultrasonic cleaning apparatus, not a high frequency ultrasonic vibrator but a low frequency ultrasonic vibrator of 800 KHz or less is used to irradiate powerful ultrasonic waves, and a cleaning liquid to be used is greatly reduced, and liquid saving is possible. It is an object to provide an ultrasonic cleaning device.

[0019]

According to the present invention, there is provided an ultrasonic cleaning apparatus comprising: a case comprising a rectangular upper case having a thin plate shape, and a longitudinal intermediate case disposed on both lower sides of the upper case; An intermediate plate having a substantially concave cross-section and a long shape interposed between the upper case and the intermediate case, and an ultrasonic vibrator driven at a low frequency of 800 KHz or less disposed in the concave portion of the intermediate plate, A vibration plate having a substantially concave cross section formed by fixing a bent portion to a lower side portion of the intermediate case so as to face the ultrasonic vibrator, wherein the bent portion of the vibration plate is separated from an object to be cleaned. distance is set within a range of an integral multiple of the vibration resonant length lambda / 2, the vibration
A liquid film is supplied by supplying a cleaning liquid between the plate and the object to be cleaned.
Forming ultrasonic waves from the vibrating plate to be cleaned
It communicates things.

Further, the ultrasonic cleaning apparatus according to the present invention comprises a case comprising an upper case having a thin rectangular shape and an intermediate case having a substantially U-shaped cross section and being disposed on both lower sides of the upper case. An intermediate plate having a substantially concave cross section and a longitudinal shape interposed between the upper case and the intermediate case; and 800 KHz disposed in the concave portion of the intermediate plate.
An ultrasonic vibrator driven at a low frequency below, a vibrating plate having a substantially concave cross section formed by fixing a bent portion on the lower side of the intermediate case opposite to the ultrasonic vibrator, A liquid supply member provided at a lower portion of one side surface of the intermediate case so as to face the lower surface of the vibration plate; and the other side surface of the intermediate case such that a front end faces the liquid supply member and faces the lower surface of the vibration plate. and a suction member provided in a lower portion, bent portion of the vibration plate, it was set in the range distance is an integral multiple of the vibration resonant length lambda / 2 of the object to be cleaned
Between the vibrating plate and the object to be cleaned.
Ultrasonic wave from the vibrating plate by supplying and forming a liquid film
Is transmitted to the object to be cleaned .

Further, the vibrating plate of the present invention is made of a material such as quartz, stainless steel, aluminum, and tantalum.

Further, the ultrasonic vibrator of the present invention has an
It is driven at a frequency of 00 KHz or less.

Further, the liquid supply member and the suction member of the present invention are formed integrally with the intermediate case.

Further, the vibration plate of the present invention is provided with a liquid amount adjusting means.

Further, one side surface of the intermediate case of the present invention is provided with a detecting means for detecting the amount of liquid inside.

Further, the liquid sucked by the suction member of the present invention is returned to the liquid supply member.

Further, the bent portion of the vibrating plate of the present invention is provided with adjusting means for adjusting the length.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ultrasonic cleaning apparatus according to the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an ultrasonic cleaning apparatus according to a first embodiment of the present invention. 1 is a sectional view of the ultrasonic cleaning apparatus according to the present invention as viewed from the front, FIG. 2 is a bottom view of FIG. 1, and FIG. 3 is a perspective view showing a state of use of the ultrasonic cleaning apparatus shown in FIGS. It is.

As shown in FIGS. 1 and 2, this ultrasonic cleaning apparatus comprises an upper case 1a made of a thin rectangular stainless steel, and a long intermediate case provided on both lower sides of the upper case 1a. 1b consisting of
An intermediate plate 2 having a substantially concave cross section and a longitudinal shape disposed between the upper case 1a and the intermediate case 1b with a packing 9 interposed therebetween, and an ultrasonic vibrator 4 disposed in a concave portion of the intermediate plate 2; The vibrating plate 3 and the like have a substantially concave cross section and are formed in a longitudinal shape and are opposed to the ultrasonic vibrator 4 and fixed to both lower sides of the intermediate case 1b.

As shown in FIG. 2, the intermediate plate 2 disposed at the lower end of the upper case 1a of the case 1 is sealed in the intermediate case 1b via a packing 9 by a plurality of bolts 10 and nuts 11. It is fastened and fixed. Further, on both lower sides of the intermediate case 1b, bent portions 3a of the vibration plate 3 are fixed in a sealed state so that the liquid 15 does not leak.

As shown in FIG. 2, two liquid supply ports 16 are provided on one side surface of the intermediate case 1b. Then, the liquid 15 such as city water is supplied from the liquid supply port in the direction of the arrow X. Therefore, in the first embodiment, it is not necessary to use pure water or the like, and since city water can be used, there is no need to perform a special surface treatment or the like on the inside filled with the liquid 15, and the assembling process is simplified. It is a simple and inexpensive device.

The transmission of ultrasonic waves can be further improved by using degassed water in addition to city water.

The concave portion of the intermediate plate 2 is made of stainless steel or the like and acts as a diaphragm 2a.
An ultrasonic vibrator 4 is provided at a portion corresponding to a.
The ultrasonic transducer 4 is driven at a frequency of about 800 KHz or less.

The ultrasonic vibrator 4 is connected via a cable 6 to a connector 5 provided on the upper case 1a, and this connector 5 is connected via a cable 7 to an ultrasonic oscillator 8. The ultrasonic oscillator 8 includes the ultrasonic vibrator 4
Is driven by an ultrasonic signal.

In this embodiment, the ultrasonic vibrator 4 has approximately 2
Those having a frequency of about 0 KHz to 100 KHz are used. For example, when f ₀ = 100 KHz and the sound velocity C of the material is about 5000 m / sec, λ / 2 = 7.5.
mm.

Therefore, as shown in FIG. 1, if the length L of the bent portion 3a of the vibration plate 3 is set to 5 mm and the gap g between the substrate 20 and the bent portion 3a is set to 2.5 mm,
A resonance length of λ / 2 = 7.5 mm can be formed, and ultrasonic waves can be transmitted.

As described above, the length of the bent portion 3a is set to λ
It is set appropriately within a range of a resonance length that is an integral multiple of / 2.

The length of the bent portion 3a is λ /
Although it is within a range of a resonance length of an integral multiple of 2, the cleaning liquid 23 may be a medium for transmitting ultrasonic waves without leaking to the outside. And adjusting means for adjusting the length appropriately to set an optimum value. As this adjusting means, for example, a configuration in which the bent portion 3a slides as a double structure may be used.

The vibrating plate 3 includes an ultrasonic vibrator 4
And has a function of transmitting vibration by resonating with ultrasonic waves 17 generated from the material. The vibration plate 3 is made of a material such as quartz, stainless steel, aluminum, or tantalum, and the thickness of the vibration plate 3 is an integral multiple of the vibration resonance length λ / 2. It is composed of

Next, the operation of the ultrasonic cleaning apparatus shown in FIG. 1 will be described.

First, for example, about 10
When an ultrasonic signal of 0 KHz is applied to the ultrasonic vibrator 4, the ultrasonic wave 17 indicated by an arrow is generated by the liquid 15 through the diaphragm 2a.
And transmitted to the vibration plate 3. At this time, the ultrasonic waves 17 are evenly transmitted to the vibration plate 3 over the entire width of the ultrasonic vibrator 4 as indicated by arrows.

A case of cleaning an object to be cleaned using the ultrasonic cleaning apparatus according to the first embodiment will be described with reference to FIG.

In the ultrasonic cleaning apparatus shown in FIGS. 1 and 2, a cleaning liquid 23 such as pure water as a medium is not supplied to the lower part of the vibration plate 3 of the ultrasonic cleaning apparatus. Although no ultrasonic wave is transmitted, as shown in FIG. 3, the distance between the substrate 20 and the tip of the bent portion 3a of the vibrating plate 3, that is, the separation distance is about 2.5 mm,
Is passed along a transport direction indicated by an arrow Xb in FIG. 3 by a plurality of rollers 27 as a transport unit, and a cleaning liquid 23 such as pure water is supplied between the substrate 20 and the vibration plate 3 from the liquid supply member 21 in the arrow direction. , A liquid film is formed between the substrate 20 and the vibration plate 3 by the action of surface tension, and ultrasonic waves from the vibration plate 3 are transmitted to the substrate 20 via the liquid film. Therefore, the substrate 20 can be cleaned by the action of the liquid film. Moreover, since this liquid film has a surface tension, it is difficult for the liquid film to leak except between the substrate 20 and the vibration plate 3, and the amount of the cleaning liquid 23 used can be suppressed.

Further, as shown in FIG.
Is disposed on one side of the vibration plate 3, and the liquid supply member 21 is disposed on the other side of the vibrating plate 3, and the bent portion 3 a,
The cleaning liquid 23 is sufficiently filled between the suction member 22 and the liquid supply member 21 so that the cleaning liquid 23 is sufficiently filled between the suction member 22 and the liquid supply member 21. Further, the liquid supply member 21,
The suction member 22 may be integrally formed on the lower side surface of the intermediate case 1b of the case 1.

Further, the cleaning liquid 23 sucked by the suction member 22 may be discarded as it is. However, in this embodiment, the cleaning liquid 23 is suctioned by the pump 24, then cleaned by the filter 25, and then returned to the liquid supply member 21. ing. Therefore,
The use amount of the cleaning liquid 23 can be significantly reduced by this reflux circuit.

According to the ultrasonic cleaning apparatus of the first embodiment, a liquid such as city water other than pure water can be used as the liquid 15 inside the apparatus, and the ultrasonic wave is applied over the entire width of the ultrasonic vibrator 4. Can be transmitted to perform cleaning.

Further, in the ultrasonic cleaning apparatus according to the first embodiment, the ultrasonic waves themselves are powerful without focusing the ultrasonic waves as in the conventional ultrasonic cleaning apparatus as shown in FIG. In addition, an excellent cleaning effect can be obtained because the ultrasonic wave is uniformly distributed to the object to be cleaned, and if the liquid amount is sufficient to form a surface tension between the vibration plate 3 and the object to be cleaned. Therefore, the amount of liquid used for cleaning can be greatly reduced as a whole as compared with the amount of liquid used conventionally.

[0049]

Next, a second embodiment of the ultrasonic cleaning apparatus according to the present invention will be described with reference to FIGS. However,
Parts having the same structure and function as those of the first embodiment will not be described because they are duplicated, and only the main parts will be described. In the following drawings, parts having the same structures and functions as those of the ultrasonic cleaning apparatus shown in FIGS. 1 to 3 are denoted by the same reference numerals.

The second embodiment is characterized in that a plurality of small holes 32 are formed in the vibration plate 3 of the first embodiment. Therefore, as shown in FIGS. 5 and 6, the liquid supplied from the liquid supply port 16 of the ultrasonic cleaning device is a cleaning liquid 23 such as pure water.
2 and a liquid film is formed between the substrate and the substrate 20.

The second embodiment also has a bent portion of about 5 mm,
The separation distance between the substrate 20 and the bent portion 3a of the vibrating plate 3 is set to about 2.5 mm, and the substrate 20 passes along the transport direction indicated by arrow Xb by a plurality of rollers 27 as transport means. Thus, a liquid film is formed between the substrate 20 and the vibration plate 3 by the action of surface tension, and ultrasonic waves from the vibration plate 3 are transmitted to the substrate 20 via the liquid film.

The ultrasonic cleaning apparatus according to the second embodiment has the first
As a different point from the embodiment, a flow meter 28 as a detecting means as shown in FIG. 5 is provided. This is because the flow meter 28 needs to always fill the inside of the case 1 with the cleaning liquid 23 in order to prevent the ultrasonic vibrator 4 from being damaged by empty heating. Therefore, a flow meter 28 as a detecting means as shown in FIG. 5 is mounted on one side surface of the intermediate case 1b of the case 1 with one end facing the cleaning liquid 23.
Is detected by measuring the distance from the liquid surface with an optical sensor.

The inside of the case 1 of the ultrasonic cleaning apparatus is subjected to a surface treatment or the like in order to be filled with a cleaning liquid such as pure water.

The vibration plate 3 resonates and transmits vibrations.
It is not for transmitting the ultrasonic waves 17 from the apparatus, but has an operation as a liquid amount adjusting means for adjusting the liquid amount of the cleaning liquid 23. Therefore, the plurality of small holes 32 shown in FIG. 4 are aligned in the vertical direction and the horizontal direction, but are not limited thereto, and may be provided to appropriately adjust the liquid amount. The cleaning liquid from the small holes 32 flows vertically downward like a shower when there is no substrate 20.

In short, the small holes 32 need only have a liquid amount capable of forming a liquid film between the small holes 32 and the substrate 20. Such a liquid film may be formed. The small holes 32 are
Since the amount of liquid can be adjusted by its size, shape, number, and the like, liquid saving can be achieved as compared with a conventional ultrasonic cleaning apparatus. This small hole 32
Although it is formed in a circular shape, it is not limited to this shape, and an optimum one may be selected as appropriate.

In the second embodiment, it is not necessary to provide the liquid supply member 21 and the suction member 22 shown in FIG. 3 described as the first embodiment. Therefore, the bent portion 3a of the vibration plate 3 is configured to surround the periphery like a so-called lunch box.

[0057]

As described above, the ultrasonic cleaning apparatus according to the present invention uniformly cleans an object to be cleaned by irradiating it with powerful ultrasonic waves, and greatly reduces the amount of cleaning liquid to be used. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an ultrasonic cleaning apparatus viewed from the front as a first embodiment of the present invention.

FIG. 2 is a bottom view of the ultrasonic cleaning apparatus shown in FIG.

FIG. 3 is a perspective view showing a state of use of the ultrasonic cleaning apparatus shown in FIG. 1;

FIG. 4 is a bottom view including a vibration plate of an ultrasonic cleaning apparatus according to a second embodiment of the present invention.

5 is a sectional view of an ultrasonic cleaning apparatus using the vibration plate of FIG.

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a sectional view of a conventional ultrasonic cleaning apparatus.

FIG. 8 is a bottom view including a partly enlarged view of the ultrasonic cleaning apparatus shown in FIG. 7;

FIG. 9 is a side view showing a state of a flow of a cleaning liquid in the ultrasonic cleaning apparatus shown in FIG. 7;

[Description of Signs] 1 Case 2 Intermediate Plate 3 Vibration Plate 4 Ultrasonic Vibrator 8 Ultrasonic Oscillator 15 Liquid 16 Liquid Supply Port 17 Ultrasonic 20 Substrate 21 Liquid Supply Member 22 Suction Member 23 Cleaning Liquid 24 Pump 25 Filter 27 Roller 28 Flow Rate Total

Claims (9)

(57) [Claims] 1. A case comprising a thin rectangular upper case, a longitudinal intermediate case disposed on both lower sides of the upper case, and a case interposed between the upper case and the intermediate case. An intermediate plate having a substantially concave cross section and a longitudinal shape; an ultrasonic vibrator disposed in a concave portion of the intermediate plate and driven at a low frequency of 800 KHz or less; and an ultrasonic vibrator facing the ultrasonic vibrator and the intermediate case. A vibration plate having a substantially concave cross section formed by fixing a bent portion to a lower side portion, wherein a distance between the bent portion of the vibration plate and an object to be cleaned is an integer multiple of a vibration resonance length λ / 2. be set in the inner, the cleaning liquid is supplied between the vibration plate and the object to be cleaned
To form a liquid film, and
An ultrasonic cleaning device for transmitting the cleaning object. 2. A case comprising: a thin rectangular upper case; and a middle case having a substantially U-shaped cross section and a longitudinal middle case disposed on both lower sides of the upper case; and the upper case and the middle case. An intermediate plate having a substantially concave cross section and a longitudinal shape interposed therebetween; an ultrasonic vibrator driven at a low frequency of 800 KHz or less provided in a concave portion of the intermediate plate; and the ultrasonic vibrator. A vibrating plate having a substantially concave cross-section and having a bent portion fixed to the lower side of the intermediate case, and a feeder provided at a lower portion of one side surface of the intermediate case so that a front end faces the lower surface of the vibrating plate. A liquid member; and a suction member provided at a lower portion of the other side surface of the intermediate case such that a front end faces the liquid supply member and faces a lower surface of the vibration plate. Separation from cleaning object During the distance is set within a range of an integral multiple of the vibration resonant length lambda / 2, the cleaning liquid is supplied between the vibration plate and the object to be cleaned
Before the ultrasonic waves from the previous SL vibrating plates to form a liquid film and
An ultrasonic cleaning device for transmitting the cleaning object. 3. The ultrasonic cleaning apparatus according to claim 1, wherein the vibration plate is made of a material such as quartz, stainless steel, aluminum, and tantalum. 4. The ultrasonic cleaning apparatus according to claim 1, wherein the ultrasonic vibrator is driven at a frequency of about 800 KHz or less. 5. The ultrasonic cleaning apparatus according to claim 2, wherein the liquid supply member and the suction member are formed integrally with the intermediate case. 6. The ultrasonic cleaning apparatus according to claim 2, wherein the vibration plate includes a liquid amount adjusting unit. 7. The ultrasonic cleaning according to claim 2, wherein a detection means for detecting an amount of liquid inside the intermediate case is provided on one side surface of the intermediate case. apparatus. 8. The ultrasonic cleaning apparatus according to claim 2, wherein the liquid sucked by the suction member is returned to the liquid supply member. 9. The bending portion of the vibrating plate includes adjusting means for adjusting a length.
Or the ultrasonic cleaning device according to claim 2.