JPH01146388A - Production device for semiconductor - Google Patents

Abstract

PURPOSE:To compensate for the aberration of laser beams having a plurality of wavelengths, to prevent the change of optical length due to the absorption of laser beams and to obtain a device capable of positively treating a semiconductor, etc., by laser beams stably by using a lens displaying the properties of two kinds or more of athermal having different Abbe's number as an optical system lens. CONSTITUTION:In a semiconductor production device irradiating the surface to be treated of a substrate to be treated 2 with laser beams guided by an optical system and treating the surface, lenses displaying the properties of two kinds or more of athermal having different Abbe's number are employed as lenses 10a, 10b, 17 for said optical system. The lenses 10a, 10b such as beam expanders 10a, 10b install ed onto the optical path of a laser annealing device synthesizing two laser beams and conducting annealing are composed of a negative lens 25 having the quality of the material of FK01, a positive lens 26 having the quality of, the material of ATF4, a negative lens 27 having the quality of the material of ATF4 and a positive lens 28 having the quality of the material of FK01. The ftheta lens 17 for condensing is constituted of positive lenses 40, 42 having the quality of the material of ATF4, a negative lens 41 having the quality of the material of FK01, negative lenses 43, 44, 46 having the quality of the material of ATF4, and positive lenses 45, 47 having the quality of the material of FK01.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a semiconductor manufacturing apparatus using laser light.

(Prior art) Energy beam irradiation technology that can locally supply high-density power in a short period of time has been researched and developed as an alternative to semiconductor manufacturing equipment that uses electric furnaces, etc.
Research has even progressed into devices aimed at creating three-dimensional integrated circuits. This energy beam irradiation technology includes methods that use laser beams and methods that use electron beams. In particular, laser beams are used for processing various semiconductors because they cause less damage and thermal distortion to semiconductor wafers. There is.

Processing using this laser beam involves irradiation damage caused by ion implantation, activation of implanted impurities, and recrystallization of polycrystalline silicon to produce single crystal silicon.
OI (Silicon on In5ulator)
There is annealing processing equipment such as technology,
No. 32 and Japanese Patent Application Laid-open No. 61-289617.

Also.

There is a CVD processing apparatus that selectively forms a film on a semiconductor substrate using a laser beam, and is disclosed in Japanese Patent Laid-Open No. 60-53017 and the like.

(Problems to be Solved by the Invention) However, conventional laser optical systems such as the above device do not correct aberrations for monochromatic light, and do not correct aberrations for laser light including multiple wavelengths, such as Ar laser, over the entire wavelength range. Since no corrections were made for chromatic aberrations, there were differences in the focal length for each wavelength, making it impossible to ideally focus and collimate light, resulting in the laser light output not being used effectively and resulting in a large loss of laser light output. Ta.

In addition, the lens of the laser optical system can be used as a normal optical lens, such as optical glass, which is the most commonly used lens.

BK7 and F are the most stable optical glasses produced in large quantities.
2, etc., when the laser light output is large, the optical path length changes due to thermal expansion of the lens due to absorption of the laser light, etc., and when the laser output is changed.

The focal length changed, which affected the beam spot diameter.

Therefore, due to the above-mentioned problems of aberration correction and optical path length change, when processing using a laser beam, the beam spot diameter becomes large, resulting in large laser light loss and the desired laser beam output and power density on the surface to be processed. If you increase the laser light output after adjusting the beam spot diameter, etc., the beam spot diameter etc. will change, making it impossible to create a laser beam of the desired size and output, and the laser beam may also become unstable. There was a problem.

The present invention has been made in response to the above-mentioned problems, and makes it possible to correct aberrations of laser beams having multiple wavelengths, prevent changes in optical path length due to absorption of laser beams, and ensure processing of semiconductors, etc. with laser beams. It is an object of the present invention to provide a semiconductor manufacturing apparatus that can stably perform semiconductor manufacturing.

[Structure of the invention]

(Means for Solving the Problems) The present invention is characterized in that two or more types of lenses exhibiting athermal properties having different Atbe numbers are used as the lenses of the optical system.

(Function) Abbe the lens of the optical system of L/-+F' light.
By using two or more different materials, it is possible to correct aberrations, such as chromatic aberration, of laser beams having a plurality of wavelengths, such as Ar laser. The material of this lens is athermal glass.
), it is possible to prevent thermal changes in the lens due to absorption of laser light, it is possible to prevent changes in optical path length due to changes in laser light output, and it is possible to achieve desired optical performance.

(Example) Hereinafter, an example in which the apparatus of the present invention is applied to a laser annealing apparatus that performs annealing by combining two laser beams in a semiconductor manufacturing process will be described with reference to the drawings.

An airtight AQ chamber (■) that can be opened and closed by an opening/closing mechanism (not shown) is provided in this chamber (ω), and by pressing the edge of a substrate to be processed, such as a semiconductor wafer (■), the semiconductor wafer (■) can be placed with the surface to be processed facing downward. A plurality of IR lamps (infrared lamps) equipped with an installation stand (2) to hold the semiconductor wafer (3) at a temperature of approximately 500°C, and a reflector (4) to preheat the semiconductor wafer
A red ray lamp (5) is provided.

Further, a window 0 made of a material that transmits laser light, such as quartz glass, is provided below the semiconductor wafer 1 in the chamber ω.

Two laser oscillators (7a, 7b), for example, 18 WAr ion lasers, are provided to output high-output laser light. On each optical path of this output laser light, a blocking section (8a,
8b) For example, a galvano scanner is provided as a mirror rotating shutter, and a cooling section (9a, 9b), for example, made of black alumite, absorbs the laser beam reflected by the mirror of this blocking section and cools it by water cooling, forced air cooling, or natural air cooling. Processed AQ
A WJ heat sink is provided. The laser light that has passed through without being blocked by the blocking part can be converted to a beam diameter during processing and narrowed down to a beam diameter suitable for annealing processing, such as the minimum.
two or more types of athermal (athe) with different numbers
Beam expanders (10a, 10b) using lenses exhibiting properties of
) is installed on the optical path.

From there, a total reflection type mirror (lla) and a polarizing prism (1
2) A prism made of, for example, BK7A is provided.

In addition, in order to adjust the beam profile of the combined laser beam, two reflective optical attenuators (13a, 13b) are provided, which can be switched between, for example, 100% reflection and 1% reflection. Then, a total reflection type mirror (11b to 11f) that can transmit the laser beam to the bottom of the chamber ■
is installed.

The laser beam transmitted to the bottom of this chamber 1 can be scanned onto the semiconductor wafer 2 through the window 0.

A scanning section (14) is provided. In the scanning section (14),
An X-direction scanning mechanism (15), for example, a galvano scanner, which is a chain-link type scanning mechanism, is installed on a Y-direction scanning mechanism (16), for example, a 1-axis precision stage using a ball screw capable of fine-feeding with high precision. There is. Then, the X direction scanning mechanism (
An f-theta lens (15) is constructed using two or more types of lenses exhibiting athermal properties with different Atbe numbers, so that the scanning speed is constant at the center and periphery of the lens during scanning with the laser beam scanned in (15). ) is also provided on the Y-direction scanning mechanism (16).

The operation and settings of the laser annealing apparatus having the above configuration are controlled by a control section (not shown).

Next, a method of annealing semiconductor wafer (1) using the above-mentioned laser annealing apparatus will be explained.

Chamber (2) is opened by an opening/closing mechanism (not shown).

A hand arm (not shown) carries the semiconductor wafer (2) into the chamber (ω). Here, the center alignment and orientation flat alignment of the semiconductor wafer (2) have been performed in advance by, for example, detecting and calculating the edges of the wafer (2) at three or more points using photodiodes or the like. and.

Load the wafer ■ into the chamber ω with the surface to be processed facing downward, and place 5 ml of the edge of the wafer ■ on the installation stand ■ in the chamber ω.
Hold it facing down on the installation stand (■). At this time, if the semiconductor wafer (2) is preheated, damage to the wafer (2) due to thermal expansion can be prevented.

Then, the chamber is closed by an opening/closing mechanism (not shown).

Then, the semiconductor wafer ■ with the reflector (a) and the IR lamp ■
After heating to a temperature of about 500° C., annealing treatment using laser light is performed. Uniform heating by the IR lamp (2) can prevent thermal distortion caused by local heat generation from the laser beam. Further, during the annealing process, temperature uniformity can be further improved if a gas purge of, for example, N2 is performed in the chamber ω.

At this time, the two laser oscillators (7a, 7b) are stabilized in a high output state, and the laser beam is reflected by the reflecting mirror (20) of the blocking part (8) as shown in Figure 2, and the laser beam is cooled. Section (9) For example, the heat of the laser beam is absorbed by a heat sink and is cooled by natural cooling. During the laser beam annealing process, the reflecting mirror (20) rotates parallel to the laser beam and irradiates the laser beam from the hole (21).

This rotation mechanism is a galvano scanner, which is a mirror rotating shutter, and it takes 10 degrees to rotate an angle of about 20 degrees.
Since it is a high-speed shutter of about +++ seconds, it can be annealed on semiconductor wafers.

It will not have any negative impact on. Additionally, as shown in Figure 3, if an emergency cut-off mirror (22) is installed so that it rises to block the laser beam when the power is turned off, accidents caused by the laser beam can be prevented even in the event of a power outage. be able to. By providing the cutoff section (8) and the cooling section ■, it is possible to reliably convert the laser output between 0% and 100% at high speed while keeping the output of the laser oscillators (7a, 7b) at high output. It is possible to prevent the adverse effects of heat on the surrounding area, and it is possible to turn on and off a high-power laser at low cost.

Then, the laser light that has passed through the blocking parts (8a, 8b) for annealing is transferred to a beam expander (10a, 8b).
, 10b), the beam diameter is once expanded to about three times. This is done in order to further narrow down the beam onto the semiconductor wafer (1) to obtain a beam diameter suitable for annealing treatment, thereby making it possible to anneal the wafer (2) at a higher temperature, for example, 1000° C. or higher. These beam expanders (10a, 10b) are as shown in FIG.
For example, a negative lens (25) with material FKOI, material AT
It consists of a positive lens (26) with F4, a negative lens (27) with material ATF4, and a positive lens (28) with material FKOI. This FKOI is a crown glass type, and has a refractive index nd = 1.49700, which indicates the degree of refraction of an object, an Atsube number v @ = 81.6, which indicates the degree of dispersion, and a linear expansion coefficient a = 127 x 10''. refractive index temperature coefficient dn
/dT = -5,4X 10-', optical path length temperature coefficient ds
/dT=o, 91×10-'. Here, the optical path length temperature coefficient ds/dT is determined by n hammer = (nd-1) α10T, and the refractive index temperature coefficient is determined by Lorentz −Lorentz
It is derived from the renz formula. In addition, ATF4 is a flint glass type, and has a refractive index nd = 1.65376, an Atsube number Vd = 44.7, and a linear expansion coefficient α = 117
10″'7, refractive index temperature coefficient dn/dT=-6,5X1
0-', optical path length temperature coefficient ds/dT = 1.15 X
10'''! Since athermal glass has a refractive index temperature coefficient dn/dT<O, the optical path length temperature coefficient ds
A glass material with a /dT of approximately O has the effect that in an optical system that involves temperature changes, the optical path and length do not change with temperature, and the focal length does not change. Therefore, the above FKOI and AT
F4 is an athermal glass exhibiting this athermal property. By the way, B 7, which is the most used optical glass, has ds/dT = 6.62X 10-' and F
2 is ds/dT=8.79X10-'. In addition, since it is composed of two or more types of lenses (25 to 28) with different numbers of lenses, laser beams with multiple wavelengths, such as Ar
It is possible to correct chromatic aberration over the entire laser wavelength range of 457.4 to 514.5 nm. In other words, the aberrations of the optical system are corrected by combining the positive and negative lenses (25 to 28) made of athermal glass with which the optical path length change due to the change in laser light output is almost 0, and the materials with different Atsube numbers. Prevents loss of laser light output due to changes in beam spot due to changes in output or changes in focal length, enables stable desired processing laser beams, and ensures stable annealing of semiconductor wafers with laser light be able to.

Next, the two laser beams are connected to a mirror (lla) and a polarizing prism (
12) to create a desired beam profile, and send the laser beam to the scanning section (11) using a mirror (llb-11f).
4) Send to. At this time, when adjusting the beam profile etc., the laser light output is attenuated using optical attenuators (13a, 13b). Optical attenuator (13a, 13b)
As shown in Figure 5, the mechanism of 100% reflection fi (3
0) and a 1% reflecting mirror (31) that reflects 1% and transmits and absorbs 99% by parallel movement using a parallel movement mechanism using, for example, a linear guide (32) and an air cylinder (33). , the laser output is attenuated to 100% and 1%. Further, this switching may be performed by rotational movement. In this embodiment, two optical attenuators (13a
, 13b), 100%, 1%, 0
．． This enables laser output attenuation of 0.1%.

This achieves the desired attenuation rate required for each adjustment. Furthermore, since the 1% reflecting mirror (31) transmits and absorbs 99% of the laser light, a heat sink (not shown) for cooling is provided on the back surface to prevent heat influence on the surrounding area. and,
By using the reflective optical attenuator (13a, 13b) using the 100% reflective mirror (30) and the 1% reflective mirror (31), interference of laser light that occurs in a transmission type optical attenuation mechanism, etc. Optical path misalignment, laser beam diffusion, wavefront disturbance, etc. can be prevented. In addition, when performing optical attenuation in two or more stages as in this example, in the transmission type optical attenuation, it is necessary to create a parallel plane plate that is precise and parallel and can transmit the laser beam. -Although adjustment was difficult and required optical path correction using, for example, an optical path correction plate, the above-mentioned problems were solved by adopting a reflective type, and a highly accurate optical attenuation mechanism could be easily realized.

Then, the laser beam whose beam profile and optical axis have been adjusted is sent to the scanning unit (14) using mirrors (11b to 11f).
Send light to. Here, the laser beam is transmitted by the X-direction scanning mechanism (15)
For example, a galvanometer scanner and an fθ cylinder 17) are used to obtain a desired constant speed, and the semiconductor wafer (2) is scanned in the X direction through the window (1), and similarly, by an X direction scanning mechanism (16), for example, a single-axis precision stage.

The semiconductor wafer (2) is scanned in the Y direction by a desired continuous scan or step scan. And fθ cylinder 17)
The focused laser beam is placed on a semiconductor wafer with a diameter of 60μ.
The beam diameter is approximately 300 μm, and the semiconductor wafer ■
The temperature of the surface to be processed becomes, for example, more than 0.degree. This heat performs an annealing process on the wafer (2), and the X-direction scanning mechanism (15) and the X-direction scanning mechanism (16)
The annealing process is completed by scanning a desired portion or the entire surface of the substrate.

Here, as shown in FIG. 6, the fθ cylinder 17) that focuses the laser beam onto the semiconductor wafer
Positive lens (40) at F4, negative lens (41) at material FKOI, positive lens (42) at material ATF4, material A
Consists of a negative lens (43) with TF4, a negative lens (44) with material ATF4, a positive lens (45) with material FKOI, a negative lens (46) with material ATF4, and a positive lens (47) with material FKOI. be done.

This fθ cylinder 17) is also a beam expander (10a
.

10b), a lens (40 to 4
7) is a combination of materials with different Atsube numbers.

Next, after the laser beam is blocked by the blocking portions (8a, 8b), the chamber (2) is opened by an opening/closing mechanism (not shown), and the semiconductor wafer (2) is carried out of the chamber (ω) by a hand arm (not shown), and the processing is completed.

The blocking portions (8a, 8b) of the above embodiment are I! I explained using a galvano scanner as a rotating shutter, but
It is sufficient if the optical path can be blocked by a mirror, the mirror may be attached to a rotary cylinder or rotary solenoid, or the optical path can also be blocked by moving a mirror at high speed in a straight line.
0. Modulator, E, 0. Needless to say, a modulator or the like may be used.

Furthermore, the cooling parts (9a, 9b) in the above embodiment were explained using an air-cooled black alumite-treated aluminum heat sink, but if the cooling part (9a, 9b) could be cooled by absorbing the laser light reflected from the blocking part (8a, 8b), Any method may be used, such as a water cooling method using cooling water or forced air cooling using a fan, and is not limited to the above embodiments.

In the above embodiment, the beam expander (loa
, 1Ob) - once the beam diameter is expanded and fθ cylinder 1
7), but as long as the desired beam diameter and beam output can be obtained on the semiconductor wafer ■, the laser oscillator (7a
, 7b) may be used as is and focused onto the wafer (2) using a lens.

In addition, in the above embodiment, parallel displacement switching type optical attenuators (13a, 13b) for 100% reflection and 1% reflection were set at two locations, but the reflectance, switching method, and number of settings are the same as in the above embodiment. Needless to say, it is not limited.

Next, in the scanning section (14) of the above embodiment, the X-direction scanning mechanism (15) and the X-direction scanning mechanism (16) were explained using a galvano scanner and a 1-axis precision stage. Any method is fine as long as it is a rask scan method or a vector scan method, X-Y
A stage may be used, a polygon mirror and a uniaxial stage may be used in combination, two galvano scanners may be used, and the present invention is not limited to the above embodiments.

In the above embodiment, a laser annealing apparatus that performs annealing by combining two laser beams was used, but any semiconductor manufacturing apparatus that processes a substrate using laser beams may be used. The number of laser beams used may be one or more, and the processing may be CvD processing or mask repair processing, and it goes without saying that the present invention is not limited to the above embodiments.

Further, in the above embodiment, the lenses (40 to 47) constituting the fθ cylinder 17) of the optical system and the beam expander (
The materials of the lenses (25 to 28) constituting lenses 10a and 10b) have been explained using FKOI and ATF4, but they are glass that exhibits athermal properties in which the change in optical path length due to temperature change is almost 0, and two different materials with different Atsube numbers are used. It is sufficient that the material is made of a material of at least 100% or more, and may be used for lenses constituting an f-5inθ lens or an ordinary lens.

The present invention is not limited to the above embodiments.

As described above, according to this embodiment, the semiconductor wafer ■
is preheated in an airtight chamber ω with an IR lamp 0 and annealed using laser light through window 0. Then, a beam expander (1
0a, 10b) and the lenses (25 to 28, 40 to 47) constituting the fθ lens (17), are
By using a lens exhibiting athermal properties of more than 100%, it is possible to correct aberrations, prevent changes in optical path length, and obtain a desired stable laser beam during processing.

〔Effect of the invention〕

As explained above, according to the present invention, aberration correction of laser light having a plurality of wavelengths is realized by using two or more types of lenses exhibiting athermal properties with different Atbe numbers as the lenses of the optical system. It prevents loss of laser light output and changes in the beam spot diameter due to changes in optical path length caused by thermal expansion of the lens, making it possible to reliably process semiconductors, etc. with laser light under desired stable conditions. can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment in which the semiconductor manufacturing apparatus of the present invention is applied to annealing processing, FIG. 2 is a cross-sectional view illustrating the blocking section and cooling section of FIG. 1, and FIG. 4 is a configuration diagram of the beam expander of FIG. 1, FIG. 5 is a diagram explaining the optical attenuator of FIG. 1, and FIG. 6 is a diagram of the beam expander of FIG. 1.
FIG. 7 is a block diagram of the lens, and is a flow diagram briefly showing the annealing process shown in FIG. 1. In the figure, 1...chamber 2...semiconductor wafer 5...
・IR clamp 6...window 10a, 10b...
・Beam expander 14...scanning section 17
...Fθ lens 25-28. 40-47...Lens Fig. 2, Fig. 3 has a skin bulge Fig. 4, Fig. 6

Claims (8)

[Claims] (1) In semiconductor manufacturing equipment that performs processing by irradiating the surface of a substrate to be processed with laser light guided by an optical system, the lenses of the optical system exhibit two or more types of athermal properties with different Abbe numbers. A semiconductor manufacturing device characterized by using a lens. (2) The semiconductor manufacturing apparatus according to claim 1, wherein the laser light is an Ar laser. (3) The semiconductor manufacturing apparatus according to claim 1, wherein the lens is a lens that condenses laser light and a lens that magnifies laser light. (4) The lens for condensing the laser beam is a lens constituting an fθ lens whose scanning speed is constant between the center and the periphery of the lens when scanning the laser beam. Semiconductor manufacturing equipment. (5) The semiconductor manufacturing apparatus according to claim 3, wherein the lens that expands the laser beam is a lens that constitutes a beam expander that converts the beam diameter. (6) The semiconductor manufacturing apparatus according to claim 1, wherein the lens exhibiting athermal properties is constituted by a combination of a positive lens and a negative lens. (7) The semiconductor manufacturing apparatus according to claim 1, wherein the treatment is an annealing treatment. (8) The semiconductor manufacturing apparatus according to claim 1, wherein the substrate to be processed is a semiconductor wafer.