TWI582833B - Producing method and producing device of crystalline semiconductor film - Google Patents

Description

Method and apparatus for manufacturing crystalline semiconductor film

The present invention relates to a crystalline semiconductor film in which a pulsed laser having a rectangular cross section is irradiated a plurality of times on a semiconductor film (overlapped) and moved to perform crystallization of an amorphous film or modification of a crystalline film. Manufacturing method and manufacturing apparatus.

A thin film transistor used for a general television (TV) or a personal computer (PC) display is composed of amorphous (non-crystalline) germanium (hereinafter referred to as a-矽), but the germanium is crystallized by any means (below) By using p-矽), it is possible to significantly improve the performance as a thin film transistor (TFT). The excimer laser annealing technology has been put into practical use as a Si crystallization process at a low temperature, and is also frequently used for small-sized display applications such as smart phones, and has been put into practical use for large-screen displays and the like.

This laser annealing method is a process in which a non-crystalline semiconductor film is irradiated with a quasi-molecular laser having a high pulse energy, whereby a semiconductor that absorbs light energy is brought into a molten or semi-molten state, and then crystallized at the time of cooling and solidification. At this time, in order to For a large area, a pulse laser that is adjusted to a line beam shape is relatively scanned and illuminated in the short axis direction. The scanning stage provided with the amorphous semiconductor film is usually moved to perform scanning of a pulsed laser.

In the scanning of the pulsed laser, the pulsed laser is moved at a predetermined pitch in the scanning direction so that the pulsed laser is irradiated a plurality of times (overlapped irradiation) at the same position of the amorphous semiconductor film. Thereby, the laser annealing treatment of the semiconductor film of a large size can be performed.

Further, in the laser annealing process using the conventional linear beam, the beam width in the scanning direction of the laser pulse is fixed to, for example, about 0.35 mm to 0.4 mm, and the substrate transfer amount per pulse is set to 3% of the beam width. About 8% or so, in ensuring the uniformity of the performance of a plurality of thin film transistors, it is considered that it is necessary to increase the number of times of laser irradiation as much as possible.

For example, in a semiconductor film for a liquid crystal display (LCD), the overlap ratio is set to 92% to 95% (when the number of irradiations is 12 to 20 times, and the beam width is 0.4 mm, the scanning pitch is 32 μm to 20 μm). In the semiconductor film for an organic light-emitting diode (Organic Light-Emitting Diode), the overlap ratio is set to 93.8% to 97% (16 times to 33 times of irradiation, and the beam width is 0.4 mm, the scanning pitch is 25 μm) ~12μm).

In such a laser annealing process, the intensity distribution of the beam profile is generally set to a flat shape, thereby achieving uniformity of processing in the short axis direction and the long axis direction. On the other hand, Patent Document 1 proposes a method of generating a crystallization defect region due to uneven laser energy, and after sufficient crystallization treatment, by lower energy When the laser beam is irradiated, the portion which is sufficiently crystallized or activated is maintained, and the recrystallization or reactivation of the portion where the film quality is deteriorated due to the unevenness in energy intensity is performed.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-12548

The unevenness of the laser energy that is a problem in Patent Document 1 is caused by the uneven output of the laser light source. The output unevenness of the laser light source can be remarkably improved by the improvement of the oscillation circuit or the improvement of the laser light source itself, and the problem of crystallization due to uneven output is gradually reduced. In addition, since the irradiation is repeated a plurality of times in the same irradiation surface, the crystallization defect region generated by the unevenness of the output is remelted and crystallized, thereby realizing a defective region. Lifted.

However, according to the careful observation by the inventors of the present invention, it is understood that the irradiation unevenness can be recognized in the crystallized semiconductor even by the irradiation of the pulsed laser, and the unevenness of the irradiation causes the device to be formed. It has an impact on performance.

According to the study by the inventors of the present invention, it is considered that the above-described irradiation is not the cause of the formation of the polycrystalline germanium film on the end portion (the scanning direction rear end side) in the scanning direction (usually the short-axis direction) of the in-line type light beam. This portion corresponds to the boundary between the molten portion of the semiconductor film generated by the laser irradiation and the portion where the solid is not irradiated by the laser. This bulge is considered to be large in proportion to the intensity of the irradiation energy. In other words, as the irradiation energy increases, the melting proceeds in the film thickness direction of the semiconductor film, and after the entire film is melted, the temperature of the liquid semiconductor film layer also increases. Consider the liquid phase as a function of temperature When the crystallization is lowered, the solid-liquid interface at which the temperature starts to decrease earlier, that is, the liquid on the short-axis end of the linear beam is adsorbed on one side and solidified on one side, thereby causing bulging. In addition, it is considered that the energy fluctuation of the laser, the change in the shape of the short-axis of the linear beam, the positional confusion of the semiconductor film that relatively moves with respect to the light beam, and the like, and the unevenness of the height or the interval of the "raised portion".

Therefore, as long as the irradiation energy density is lowered and the pulse laser is irradiated, the above-described irradiation unevenness can be reduced. However, it is necessary to irradiate the laser with a larger number of irradiation times on the same irradiation surface, and the production efficiency is deteriorated. Further, when the irradiation pulse energy density is too low, there is a problem that the crystal grain size cannot be sufficiently increased.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a method and a manufacturing apparatus for a crystalline semiconductor film which can release the scanning direction end portion of a pulsed laser after suppressing a decrease in productivity as much as possible. Irradiation unevenness on the produced semiconductor film.

In the method for producing a crystalline semiconductor film of the present invention, the first invention is a method for producing a crystalline semiconductor film which is crystallization by superimposing a pulsed laser while scanning a pulsed laser in a short-axis direction on a non-single-crystal semiconductor film. According to a method of manufacturing a crystalline semiconductor film, the method includes a first step of lowering an energy density of an irradiation pulse which is microcrystallized on the non-single-crystal semiconductor film by irradiation with the pulsed laser. And the irradiation pulse energy density suitable for crystallization by irradiation a plurality of times is set to E0, and the same irradiation pulse energy density as the above-mentioned irradiation pulse energy density E0 E1 is irradiated with the pulsed laser; and the second step is irradiated by an irradiation pulse energy density E2 which is lower than the irradiation energy density E1 required for recrystallization of the crystal, and is lower than the irradiation pulse energy density E1. In the above-described pulsed laser, the total number of irradiations of the first step and the second step on the same irradiation surface is N or more.

According to a second aspect of the invention, in the first aspect of the invention, the irradiation pulse energy density suitable for crystallization is an irradiation pulse energy in which crystal grain size is saturated by irradiation a plurality of times. Density E, and in the range of E × 0.98 ~ E × 1.03.

In the first or second aspect of the invention, the irradiation pulse energy density E2 is E1 × 0.95 or more.

In the method of producing a crystalline semiconductor film according to the fourth aspect of the invention, the total number of times of irradiation is N × 1.5 or less.

In a method of producing a crystalline semiconductor film according to the first aspect of the present invention, the method of the present invention, characterized in that, in the first step, the pulsed laser is scanned while facing the same illumination surface. Performing a plurality of times of N1 times of irradiation, and then scanning the pulsed laser by the second step, sequentially performing N2 times of multiple irradiations on the same irradiation surface, and setting N1+N2 to N times or more. The total number of irradiations is taken as the above.

In the fifth aspect of the invention, the method of producing the crystalline semiconductor film according to the invention of the present invention is characterized in that the N1 is the number of times N2 or more.

In a method of producing a crystalline semiconductor film according to a seventh aspect of the present invention, the pulsed laser beam is scanned toward a rear end in a scanning direction in a beam profile intensity distribution in a scanning direction. The rear side of the direction has a lower intensity than the front side in the scanning direction, and the first step is performed on the front side in the scanning direction on the front side, and the second step is performed on the rear side in the scanning direction based on the intensity. Irradiation.

According to a seventh aspect of the invention, in the seventh aspect of the invention, the scanning direction width of the front side in the scanning direction is equal to or larger than the scanning direction width of the rear side in the scanning direction.

In the method of producing a crystalline semiconductor film according to the first to eighth aspects of the invention, the wavelength of the pulsed laser is 400 nm or less.

In the method of producing a crystalline semiconductor film according to the first aspect of the present invention, the pulsed laser has a half value width of 200 ns or less.

In a method of producing a crystalline semiconductor film according to any one of the first to tenth aspects of the present invention, the non-single-crystalline semiconductor film is a ruthenium.

A device for manufacturing a crystalline semiconductor film according to a twelfth aspect of the present invention, comprising: one or two or more laser light sources, and outputting a pulsed laser; An optical system that adjusts a shape of the pulsed laser to be introduced into a non-single-crystal semiconductor film; an energy adjustment unit that adjusts an irradiation energy density of the pulsed laser; and a scanning device that scans the pulsed laser for the non-single-crystal semiconductor film And a control unit that controls the laser light source, the energy adjustment unit, and the scanning device, wherein the control unit performs the first step of controlling the energy adjustment unit to adjust to an irradiation pulse energy density equal to an irradiation pulse energy density E0. E1, the irradiation pulse energy density E0 is lower than the irradiation pulse energy density which is microcrystallized on the non-single-crystal semiconductor film by irradiation with a pulsed laser, and is suitable for crystallization by irradiation for N times. And the control unit controls the scanning device to scan the pulsed laser energy by the irradiation pulse energy density E1 to sequentially perform N1 times (where N1 < N) multiple times on the non-single-crystal semiconductor film; In a second step, the control unit controls the energy in the semiconductor irradiated with the pulse laser by the first step The adjustment portion is adjusted to the irradiation pulse energy density E2, and the irradiation pulse energy density E2 is lower than the irradiation pulse energy density E1 and is equal to or higher than a necessary irradiation energy density for recrystallizing the crystal, and the control unit controls The scanning device scans the pulsed laser light by the irradiation pulse energy density E2 and sequentially performs N2 times (where N2 < N, N1 + N2 ≧ N) multiple times on the non-single-crystal semiconductor film.

A device for manufacturing a crystalline semiconductor film according to a thirteenth aspect of the present invention is characterized in that Included: one or two or more laser light sources, outputting a pulsed laser; an optical system that adjusts the shape of the pulsed laser to be introduced into a non-single-crystal semiconductor film; and an intensity adjustment unit in the scanning direction of the pulsed laser In the beam profile intensity distribution, the intensity adjustment unit adjusts the intensity distribution such that the intensity toward the rear side in the scanning direction at the rear end in the scanning direction is lower than the intensity on the front side in the scanning direction, and the intensity from the rear side in the scanning direction is low. The energy density of the irradiation pulse generated is 0.95 times or more of the energy density of the irradiation pulse generated by the intensity of the front side in the scanning direction; the energy adjustment unit adjusts the irradiation energy density of the pulse laser; and the scanning device is opposite to the non-single crystal semiconductor film Scanning the pulsed laser; and a control unit that controls the laser light source, the energy adjustment unit, and the scanning device, wherein the control unit performs the step of controlling the energy adjustment unit to be in front of the scanning direction of the pulse laser The irradiation pulse energy density E1 which is the same as the irradiation pulse energy density E0 during irradiation, The irradiation pulse energy density E0 is lower than the energy density of the irradiation pulse which generates microcrystallization in the non-single-crystal semiconductor film, and is suitable for crystallization by irradiation for a plurality of times, in the scanning direction of the pulse laser. In the side irradiation, the irradiation pulse energy density E2 is adjusted, and the irradiation pulse energy density E2 is lower than the irradiation pulse energy density E1, and is used for The control unit further controls the scanning device to scan the pulsed laser to sequentially perform the plurality of irradiations of the non-single-crystal semiconductor film N times or more in order to control the scanning energy.

According to a thirteenth or thirteenth aspect of the present invention, in the fourth aspect of the present invention, the control unit illuminates the energy density of the irradiation pulse suitable for crystallization as a plurality of times of irradiation The irradiation pulse energy density E at which the particle diameter is saturated is set to be in the range of E × 0.98 to E × 1.03.

In the present invention, similarly to the case where the non-single-crystal semiconductor film is subjected to pulsed laser irradiation with an irradiation pulse energy density suitable for crystallization by N-time irradiation, the first step and the second step can be used to generate no micro-generation. In the manner of crystallization, the non-single crystal semiconductor film is well crystallized. Further, in the present invention, the height of the ridge portion on the semiconductor film caused by the end portion of the pulse laser can be lowered. Further, the crystallization may be such that the non-single crystal semiconductor film is a single crystal, and the amorphous semiconductor film may be a polycrystalline semiconductor film, or the amorphous semiconductor film may be a single crystal semiconductor film.

The irradiation pulse energy density is the pulse energy density on the semiconductor film, and in the first step, the irradiation pulse energy density can be irradiated with the same irradiation energy density suitable for crystallization by N-time irradiation. Thereby, microcrystallization can be avoided in the first step. Further, the energy density suitable for crystallization in the first step can be appropriately selected within the range in which crystallization is achieved. For example, it is possible to set the irradiation pulse energy density to the same level as the irradiation pulse energy density E in which the crystal grain size is saturated by the irradiation of N times. Specifically, it is desirable to have a range of E × 0.98 to E × 1.03. If step When the irradiation pulse energy density of the first step exceeds E × 1.03, unevenness due to coarsening of the crystal grain size or the like is likely to occur. On the other hand, when it is less than E*0.98, crystal grain growth is insufficient, and unevenness of crystal grain size is likely to occur.

In addition, in the second step, the irradiation pulse energy density E1 or less is set to be equal to or higher than the necessary irradiation energy density for remelting the crystal, and the end portion of the pulse laser generated in the first step can be reduced. The height of the ridges on the semiconductor film is caused, and good crystallinity can be maintained. Here, the irradiation pulse energy density E2 of the second step must satisfy the above conditions, but it is more preferable that E1 × 0.95 or more. Thereby, the crystal grain size after the pulsed laser irradiation in the first step and the second step can be made uniform and the crystal can be sufficiently grown. When the energy density of the irradiation pulse in the second step is too low, if the melting energy density region is not reached, the bulging cannot be alleviated, and even if the melting energy density region is reached, sufficient crystal growth cannot be obtained even if the swelling effect is obtained. The crystal grain size becomes small.

Further, the irradiation pulse energy density E2 is desirably set to be smaller than E1 × 0.98. When the irradiation pulse energy density E2 is the same as the irradiation pulse energy density E1, the same ridge is formed again on the semiconductor film, and the relaxation effect of the ridge cannot be obtained.

In addition, by setting the total number of irradiations to N or more, the crystal grain size can be sufficiently grown. In addition, the numerical value of N is not particularly limited, and from the viewpoint of preventing a decrease in film quality due to uneven output, it is preferable to set the number of times to a certain degree, for example, 8 or more times.

Further, it is preferable that the total number of irradiations is N × 1.5 or less. If the number of full irradiations is large, productivity is lowered. In terms of productivity, the most ideal total The number of times of irradiation is N times, but it can be selected in consideration of the state of crystallization.

Further, the number of times of irradiation N1 in the first step is desirably the same as or larger than the number of times of irradiation N2 in the second step. Thereby, the total number of irradiations can be reduced as much as possible.

Further, in the present invention, the wavelength of the pulsed laser is not particularly limited, but may be, for example, a wavelength of 400 nm or less.

Further, the half value width of the pulse laser in the present invention is not particularly limited, but may be, for example, a half value width of 200 ns or less.

Further, in the irradiation of the pulsed laser in the first step and the second step, the non-single crystal semiconductor film is irradiated with different pulse lasers depending on the time, but the first step may be performed by one pulse laser. Pulsed laser irradiation with the second step. The pulsed laser can simulate a synthesizer by irradiating two or more pulsed lasers simultaneously to a non-single-crystal semiconductor film.

In other words, in the beam profile intensity distribution in the scanning direction, the pulse laser has a lower intensity toward the front side in the scanning direction toward the rear side in the scanning direction, and the intensity is lower on the front side in the scanning direction. In the irradiation in the first step, the irradiation in the second step is performed in accordance with the intensity in the rear side in the scanning direction.

As described above, according to the present invention, the pulsed laser irradiation in the first step and the second step has an effect of allowing the crystal to be sufficiently grown to obtain a favorable crystalline semiconductor film having less unevenness in irradiation.

1‧‧‧ Crystalline semiconductor film manufacturing apparatus

2‧‧‧Processing room

3‧‧‧Scanning device

5‧‧‧ platform

6‧‧‧Introduction window

8‧‧‧Control Department

10‧‧‧pulse laser oscillation device

11‧‧‧Attenuator

12‧‧‧Optical system

12a‧‧‧Mirror

12b‧‧‧ collecting lens

15‧‧‧pulse laser

100‧‧‧矽膜

E1, E2‧‧‧ illumination pulse energy density

L1, L2‧‧‧ length

FIG. 1 is a view showing an apparatus for manufacturing a crystalline semiconductor film according to an embodiment of the present invention.

Fig. 2 is a view similarly showing a beam profile intensity distribution in which the beam intensity has a level in the beam profile intensity distribution in the scanning direction.

3(a) and FIG. 3(b) are diagrams showing an optical system in which the beam intensity has a level and the shape of the pulse laser is adjusted in the beam profile intensity distribution in the scanning direction.

4(a) and FIG. 4(b) are diagrams showing the synthesis of a pulse laser having a beam intensity in a beam profile intensity distribution in the scanning direction in the same manner.

Fig. 5 (a) and Fig. 5 (b) are views similarly showing the state of the surface of the semiconductor film in the examples.

Fig. 6 is a view similarly showing the results of the unevenness evaluation in the examples.

Hereinafter, a manufacturing apparatus and a manufacturing method of a crystalline semiconductor film according to an embodiment of the present invention will be described.

The crystalline semiconductor film manufacturing apparatus 1 includes a processing chamber 2, and a scanning device 3 that is movable in the X-Y direction is provided in the processing chamber 2, and the scanning device 3 is provided with a stage 5. At the time of the treatment, an amorphous tantalum film 100 or the like is provided on the stage 5 as a non-single-crystal semiconductor film, and the environment in the processing chamber 2 is adjusted as needed. The ruthenium film 100 is formed on a substrate (not shown) with a thickness of, for example, 40 nm to 100 nm. Further, the present invention does not particularly limit the thickness of the non-single crystal semiconductor film. Non-single crystallization by ordinary methods In the formation of the semiconductor film, the method of forming the semiconductor film is not particularly limited in the present invention. Further, the semiconductor film to be processed is preferably an amorphous semiconductor film. However, the present invention is not limited to an amorphous semiconductor film, and may be a semiconductor film which is not a single crystal or a semiconductor film which partially contains a crystal. In these, the device can be applied as a modification of crystallization.

Further, the scanner device 3 is driven by a motor or the like (not shown), and the motor is controlled by the control unit 8 to be described later, thereby setting the scanning speed of the scanner device 3. Further, the processing chamber 2 is provided with an introduction window 6 for introducing a pulsed laser from the outside.

A pulsed laser oscillating device 10 is disposed outside the processing chamber 2. The pulsed laser oscillation device 10 is composed of a pseudo-molecular laser oscillation device. The pulsed laser oscillation device 10 is connected to a control unit 8 that can be controlled. The pulse laser oscillation device 10 outputs a pulse laser at a predetermined output in accordance with an instruction from the control unit 8. Further, the present invention does not limit the type of the oscillating device or the oscillating medium as long as the desired pulsed laser can be irradiated onto the semiconductor film.

In the pulse laser oscillation device 10, the pulse laser 15 that is pulse-oscillated and output is, for example, having a wavelength of 400 nm or less and a pulse half-value width of 200 ns or less. However, the present invention is not limited to these.

The pulsed laser 15 adjusts the pulse energy density by means of an attenuator 11. The attenuator 11 is connected to the controller 8 that can be controlled, and is set to a predetermined attenuation rate in accordance with an instruction from the control unit 8. The control unit 8 adjusts the attenuation rate such that a predetermined irradiation pulse energy density is obtained on the irradiation surface of the semiconductor film. It is preferable that the irradiation surface of the ruthenium film 100 can be adjusted so that the energy density becomes 100 mJ/cm ² to 500 mJ/cm ² .

The pulse laser 15 that has passed through the attenuator 11 adjusts the shape of the light beam by the optical system 12, and the optical system 12 is constituted by a lens, a mirror, a homogenizer, or the like, and is introduced through the processing chamber 2. The pulse laser 15 is introduced into the window 6 to illuminate the ruthenium film 100 in the processing chamber 2. In the figure, a mirror 12a and a collecting lens 12b are illustrated as one optical system 12. The invention does not particularly limit the type or number of optical members contained in the optical system.

The shape of the irradiation surface at the time of irradiation is a cross-sectional angular shape, and a linear shape is included in the angular shape.

Next, a method of manufacturing the crystalline semiconductor film using the above-described crystalline semiconductor film production apparatus 1 will be described.

The above-described ruthenium film 100 is used as a target to determine an irradiation pulse energy density E0 which is low in energy density due to irradiation of the pulsed laser 15 and which is suitable for crystallization by irradiation for a plurality of times N times. . As the irradiation pulse energy density E0 suitable for crystallization, the irradiation pulse energy density which is the same as the irradiation pulse energy density E in which the crystal grain size is saturated by the N irradiation can be selected. As the same irradiation pulse energy density, E × 0.98 to E × 1.03 can be exemplified. In this embodiment, the same crystallization is obtained when the pulsed laser is irradiated with the irradiation pulse energy density E0 by the overlapping irradiation of the number of times of N times.

The irradiation pulse energy density E0 is determined as the irradiation pulse energy density E1 of the first step. In addition, the irradiation pulse energy density E2 in the second step is determined to be lower than the irradiation pulse energy density E1, and the irradiation pulse energy density E2 equal to or higher than the necessary irradiation energy density for recrystallizing the crystal is set by the control unit 8. These. In addition, The irradiation pulse energy density E2 is desirably set to E1 × 0.95 or more.

The above E0, E1, E2 can be used to obtain data by experience.

Next, the number of times of irradiation N1 in which the overlap is performed in the first step and the number of times of irradiation N2 in the second step are determined, and are set in the control unit 8. The sum of N1 and N2 is set to N or more. Further, it is desirable that N1≧N2, and more desirably, N1+N2≦1.5N. The number of times N1 and N2 can be determined empirically.

According to the above setting, the pulse laser 15 is output from the pulse laser oscillation device 10 by the scanning device 3 while moving the diaphragm 100 in one direction under the condition of the first step, and passes through the optical system 12 and the introduction window 6. On the other hand, the pulse laser 15 is superimposed and irradiated onto the ruthenium film 100 in the processing chamber 2 to perform processing. Further, the number of overlaps is determined by the scanning speed of the scanning device 3 and the repetition frequency of the pulse laser and the width in the short-axis direction of the pulse. Therefore, the control unit 8 determines the scanning speed of the scanning device 3 so as to overlap N1 times on the premise of the repetition frequency of the pulse laser. The scanning speed can be selected, for example, in the range of 6 mm/s to 16 mm/s. Further, the present invention is not particularly limited to the scanning speed, and can be selected, for example, in the range of 1 mm/s to 100 mm/s. Further, the attenuation rate of the attenuator 11 is adjusted by the control unit 8 so that the irradiation pulse energy density E1 on the diaphragm 100 becomes a set value. This adjustment can be performed based on the relationship between the attenuation rate and the irradiation pulse energy density in advance. Further, the pulse energy density of the pulse laser 15 is measured by a measuring device (not shown), and the attenuator 11 can be controlled such that the pulse energy density becomes a predetermined value.

Next, when the processing of the predetermined region of the ruthenium film 100 is completed, the scanning device 3 is moved in the reverse direction to perform the overlap of the second step. Irradiation. The control unit 8 determines the scanning speed of the scanning device 3 so as to overlap N2 times on the premise of the repetition frequency of the pulse laser. The scanning speed can be selected, for example, in the range of 6 mm/s to 16 mm/s. Further, the present invention is not particularly limited to the scanning speed, and can be selected, for example, in the range of 1 mm/s to 100 mm/s. Further, the attenuation rate of the attenuator 11 is adjusted by the control unit 8 so that the irradiation pulse energy density E2 of the diaphragm 100 becomes a set value. This adjustment can be performed in the same manner as in the first step. Further, it is also possible to change the number of times of overlap by using a pulse laser having a different pulse width in the second step, and it is also possible to obtain a desired number of overlaps in combination with a scanning speed or the like.

The pulsed laser irradiation in the first step and the predetermined region of the ruthenium film 100 in the pulsed laser irradiation in the second step are crystallized with a good degree in the same manner as in the case where the irradiation is performed N times by the irradiation pulse energy density E0. Further, in the present embodiment, by performing the irradiation in the first step and the irradiation in the second step, the height of the raised portion on the semiconductor film due to the end portion of the pulse laser can be reduced, and the unevenness of the irradiation can be eliminated. Provided in a more compact semiconductor device.

Further, in the above-described embodiment, after the scanning irradiation in the first step is performed in a predetermined region, the scanning irradiation in the second step is performed in the above-described region. However, the first step can be performed using two pulse lasers. Immediately after the irradiation, the irradiation in the second step is performed. In this case, the two pulse lasers can be output by two pulsed laser light sources, or the pulse laser output by one pulse laser light source can be divided to perform energy adjustment or delay adjustment, etc., thereby obtaining 2 Pulse laser.

In addition, pulsed lasers can also be used to combine multiple pulsed lasers to adjust the pulse width.

Further, in the above-described embodiment, after the ruthenium film of the predetermined region is processed by one pulse laser in the first step, the pulse processing is performed by the other pulse laser in the second step, but one may be used. The pulse is performed while the first step and the second step are performed simultaneously. In addition, as one pulse, one may be called a simulation.

In other words, in the beam profile intensity distribution in the short-axis direction, the pulse laser has a lower intensity toward the front side in the scanning direction toward the rear side in the scanning direction, and the intensity is lower on the front side in the scanning direction. In the irradiation in the first step, the irradiation in the second step is performed on the rear side in the scanning direction in accordance with the intensity.

The beam profile intensity distribution in the scanning direction of the pulse laser used in this embodiment is shown in Fig. 2 . The beam profile has a beam intensity of a hierarchy having a height of the irradiation pulse energy density E1 on the front side in the scanning direction and a height of the irradiation pulse energy density E2 toward the rear end in the scanning direction rear side. In this form, N1 pulse laser irradiation is performed in the same region of the ruthenium film 100 by the pulse portion having the height of the irradiation pulse energy density E1, by the pulse portion having the height of the irradiation pulse energy density E2 in the ruthenium film The same area of 100 was subjected to N2 pulsed laser irradiation. The number of times of N1 and N2 is determined by the partial length L1 of the scanning direction having the height of the irradiation pulse energy density E1, the partial length L2 of the scanning direction having the height of the irradiation pulse energy density E1, and the pitch of each pulse. For example, if set to L1= L2 (for example, 200 μm), basically N1 and N2 are the same number of times.

That is, by making the length L1 relatively long, the number of times of N1 can be increased. Therefore, it is desirable to set it to L1≧L2. Therefore, N1 and N2 depend on the length L1 and the length L2, and further depend on the scanning speed and the repetition frequency of the pulse laser as in the above embodiment. With these settings, N1 and N2 in this form can be determined.

The pulse laser having the beam profile intensity distribution in the scanning direction of the above shape can be obtained by various methods.

For example, as shown in FIG. 3(a), a part of the laser beam or a member for suppressing transmission is shielded on the optical path of the optical system by the upstream side or the downstream side of the optical member, thereby as shown in FIG. 3(b). It is shown that the beam intensity in the scanning direction is partially lowered, and a pulse laser having a beam intensity distribution which becomes a layer is obtained.

Further, as shown in FIG. 4(a), by combining or simulating two pulses, as shown in FIG. 4(b), the beam intensity can be made hierarchical (scanning direction width L1, scanning direction width L2). The beam profile intensity distribution of the pulse c. For example, the time difference between the pulse a and the pulse b having different beam intensities can be combined in the optical system to irradiate the synthesized pulse onto the non-single-crystal semiconductor film. Further, by irradiating the pulse a and the pulse b having different beam intensities at the same time and shifting the position to the non-single-crystal semiconductor film, one pulse of the simulation can be used.

[Example 1]

Next, using a pulsed laser light source (product number LSX540C), the amorphous ruthenium film having a thickness of 50 nm was irradiated with a wavelength of 308 nm, a pulse width of 70 nm, a repetition frequency of 300 Hz, and a long axis length of 465 mm in the beam profile × a short axis length of 400 mm. The linear beam-shaped excimer pulsed laser is annealed.

As a conventional example, an irradiation pulse energy density E0 (Optinum energy density) suitable for crystallization is obtained by an overlap ratio of 95% (overlap irradiation 20 times); in this example, 370 mJ/cm ² is set. At this time, the scanning speed and the repetition frequency of the pulse laser were set so as to have a pitch of 20 μm. The irradiation pulse energy density E0 does not generate microcrystals, and is equal to the irradiation pulse energy density E at which the crystal grain size is saturated by the above overlapping irradiation.

Further, as an invention example and a reference example, in the first step, the irradiation pulse energy density E1 (370 mJ/cm ² ) which is the same as the irradiation pulse energy density E0 is set by the overlap ratio of 90% (overlap irradiation 10 times). At this time, the scanning speed was set so as to have a pitch of 40 μm.

Further, as an example of the invention, in the second step, the irradiation pulse energy density E2 (352 mJ/cm ² ) which is -5% of the irradiation pulse energy density E1 is set by the overlap ratio of 90% (10 times of overlapping irradiation). At this time, the scanning speed was set so as to have a pitch of 40 μm.

Further, as a reference example, in the second step, the irradiation pulse energy density of -10%, -15%, or -20% of the irradiation pulse energy density E1 is set by the overlap ratio of 90% (10 times of overlapping irradiation). At this time, the scanning speed and the repetition frequency of the pulse laser were set so as to have a pitch of 40 μm.

Among the above conditions, a pulsed laser was superimposed on the amorphous ruthenium film, and the unevenness of irradiation and crystallinity of the crystal ruthenium film after the treatment were evaluated. Further, regarding the conventional example and the invention example, observation by an atomic force microscope (AFM) The surface of the ruthenium film is uneven.

5(a) and 5(b) are schematic views showing a surface cross section of a crystalline ruthenium film. In the conventional example, as shown in FIG. 5(b), a relatively large ridge is formed corresponding to the end portion of the final irradiation of the pulsed laser. On the other hand, in the invention example, as shown in FIG. 5(a), it is recognized that the above-described ridges are low and gentle, and it is understood that the ridges are alleviated by the irradiation of the first step and the second step.

The unevenness of the irradiation of the crystallization film was evaluated by the following method.

In each of the examples, the inspection light is applied to the five locations of the crystallization film, and the reflected light is received to obtain a color image, and the color component of the color image is detected, and the color image is monochrome based on the detected color component. Chemical. Next, the data of the monochromated image is convolved to obtain image data in which the image is emphasized. The image data of the image shading is emphasized by projective transformation, and the surface unevenness is evaluated based on the image data transformed by the projection. Monochromization can be performed using the main color component of the detected color component, and the main color component can be set to a color component having a relatively large light distribution compared to other color components.

The monochromated image data can be represented by row and column data. The above-mentioned row data is set to the column direction of the laser beam, and the scanning direction of the laser is set to a row, and the convolution is obtained by multiplying the row and the column of the specified coefficient. This is done in a matrix of monochromated image data.

The order of the predetermined coefficients is the one that emphasizes the direction of the beam and the direction in which the scanning direction is emphasized, thereby respectively obtaining image data of the image in which the beam direction is emphasized and image data of the image in which the scanning direction is emphasized.

Specifically, the following convolution is performed. In addition, the ranks of the specified coefficients are not limited. It is set as follows.

The image data in which the image is emphasized is emphasized by the state in which the stripes integrated in the scanning direction and the emission direction appear, thereby obtaining projections in the respective directions.

Specifically, projection conversion is performed in the emission direction and the scanning direction, respectively, by the expression shown below.

Direction of emission = (Max(Σf(x)/Nx)-Min(Σf(x)/Nx))/average

Scanning direction = (Max(Σf(y)/Ny)-Min(Σf(y)/Ny))/average

Where x represents the position of the image in the emission direction, y represents the position of the image in the scanning direction, f(x) represents the image data at the x position, f(y) represents the image data at the y position, and Nx represents The number of images in the emission direction, Ny represents the number of images in the scanning direction.

The unevenness score of FIG. 6 is a score indicating that the unevenness of the scanning direction is numerically represented. The higher the value, the greater the unevenness.

As can be seen from Fig. 6, in the conventional example, the unevenness score is 0.2 to 0.3, and the unevenness is large. As mentioned above, this situation can be considered as the surface bulge caused by the end of the pulsed laser. ring.

On the other hand, in the inventive example, the unevenness after the first step is as large as the conventional example, but the unevenness score after the second step is 0.06 to 0.13, and the unevenness is alleviated. Further, the irradiation in the second step is performed by the irradiation pulse energy density of -10%E0, -15%E0, and -20%E0. Although the unevenness is smaller than the conventional example, it is not uniform in terms of reducing unevenness. full.

Next, the crystallinity of the crystalline ruthenium film of the conventional example, the inventive example, and the reference example was observed by a photograph of a scanning electron microscope (Scanning Electron Microscope).

As a result, in the conventional example and the inventive example, uniform crystal grains were formed in the same manner. On the other hand, in the reference examples of -15% E0 and -20% E0, sufficient crystal growth was not performed, and the crystal grain size was small. -10% E0 is not the extent of -15% E0, -20% E0, but the crystal grain size is still slightly smaller.

As described above, according to the example of the present invention, good crystal grain growth can be obtained, and the ridges generated at the ends of the pulsed laser can be made small to reduce unevenness. In addition, processing can be performed with almost no reduction in productivity as compared with the prior art.

The present invention has been described above with reference to the embodiments and examples. However, the invention is not limited thereto, and may be appropriately modified without departing from the scope of the invention.

Claims (14)

A method for producing a crystalline semiconductor film, which is a method for producing a crystalline semiconductor film in which a pulsed laser is relatively scanned in a short-axis direction while being irradiated with a pulsed laser in a short-axis direction, and the crystalline semiconductor film is produced. And characterized in that: in the first step, the energy density of the irradiation pulse which is microcrystallized on the non-single-crystal semiconductor film is lower than that by the irradiation of the pulsed laser, and is irradiated a plurality of times by N times. The irradiation pulse energy density suitable for crystallization is set to E0, and the pulse laser is irradiated by the same irradiation pulse energy density E1 as the irradiation pulse energy density E0; and the second step is performed by comparing the irradiation pulse energy The density E1 is low, and the pulsed laser energy density E2 equal to or higher than the required irradiation energy density for recrystallizing the crystal is used to illuminate the pulsed laser, and the total of the first step and the second step on the same irradiation surface The number of irradiations is N or more. The method for producing a crystalline semiconductor film according to claim 1, wherein the irradiation pulse energy density suitable for crystallization is an irradiation pulse energy density E at which crystal grain size is saturated by irradiation a plurality of times, and E × 0.98 ~ E × 1.03 range. The method for producing a crystalline semiconductor film according to the above aspect, wherein the irradiation pulse energy density E2 is E1 × 0.95 or more. The system for crystallizing a semiconductor film as described in claim 1 or 2 In the method, the total number of irradiations is N×1.5 or less. The method for producing a crystalline semiconductor film according to the first or second aspect of the invention, wherein the scanning of the pulsed laser by the first step is performed in sequence with the same irradiation surface for N1 times of multiple irradiations. Then, the pulse laser is scanned by the second step, and N2 times of the plurality of irradiations are sequentially performed on the same irradiation surface, and the N1+N2 is set to N times or more as the total number of irradiations. The method for producing a crystalline semiconductor film according to claim 5, wherein the above N1 is set to the number of times N2 or more. The method for producing a crystalline semiconductor film according to the first or second aspect of the invention, wherein the pulsed laser beam in the scanning direction has a beam profile intensity distribution, and the scanning direction toward the rear end in the scanning direction has a scanning side. The intensity on the front side is low, and the irradiation in the first step is performed on the front side in the scanning direction based on the intensity, and the irradiation in the second step is performed on the rear side in the scanning direction based on the intensity. The method for producing a crystalline semiconductor film according to the seventh aspect of the invention, wherein the scanning direction width on the front side in the scanning direction is equal to or larger than the scanning direction width on the rear side in the scanning direction. The method for producing a crystalline semiconductor film according to the first or second aspect of the invention, wherein the wavelength of the pulsed laser is 400 nm or less. The method for producing a crystalline semiconductor film according to the first or second aspect of the invention, wherein the pulse laser has a half-value width of 200 ns or less. The method for producing a crystalline semiconductor film according to the above aspect, wherein the non-single-crystal semiconductor film is germanium. A device for manufacturing a crystalline semiconductor film, comprising: one or two or more laser light sources for outputting a pulsed laser; and an optical system for adjusting a shape of the pulsed laser to be introduced into a non-single-crystal semiconductor film; energy adjustment a portion that adjusts an irradiation energy density of the pulsed laser; a scanning device that scans the pulse laser relative to the non-single crystal semiconductor film; and a control unit that controls the laser light source, the energy adjustment unit, and the scanning device The control unit performs the first step of controlling the energy adjustment unit to adjust the irradiation pulse energy density E1 equal to the irradiation pulse energy density E0, and the irradiation pulse energy density E0 is compared to the irradiation by the pulse laser. The irradiation pulse energy density which is microcrystallized on the non-single crystal semiconductor film is low, and is suitable for crystallization by irradiation a plurality of times, and the control unit controls the scanning device to scan by the irradiation pulse energy density E1. The above-mentioned pulsed laser is subjected to N1 times (where N1 < N) multiple times in the face of the above-mentioned non-single-crystal semiconductor film. In the second step, in the semiconductor irradiated with the pulsed laser by the first step, the control unit controls the energy adjustment unit to adjust the irradiation pulse energy density E2, and the irradiation pulse energy density E2 is compared with the above The irradiation pulse energy density E1 is low and is equal to or greater than the necessary irradiation energy density for remelting the crystal, and The control unit controls the scanning device to scan the pulsed laser light by the irradiation pulse energy density E2 to face the non-single-crystal semiconductor film N2 times (where N2<N, N1+N2≧N) Multiple exposures. A device for manufacturing a crystalline semiconductor film, comprising: one or two or more laser light sources for outputting a pulsed laser; an optical system for adjusting a shape of the pulsed laser to be introduced into a non-single-crystal semiconductor film; and intensity adjustment In the beam profile intensity distribution in the scanning direction of the pulsed laser, the intensity adjustment unit adjusts the intensity distribution as follows: the intensity toward the rear side in the scanning direction at the rear end in the scanning direction is stronger than the intensity in the front side in the scanning direction The energy density of the irradiation pulse generated by the intensity of the rear side in the scanning direction is 0.95 times or more of the energy density of the irradiation pulse generated by the intensity of the front side in the scanning direction; and the energy adjustment unit adjusts the irradiation energy density of the pulsed laser; a scanning device that scans the pulse laser relative to the non-single crystal semiconductor film; and a control unit that controls the laser light source, the energy adjustment unit, and the scanning device, wherein the control unit performs the following steps: controlling the energy adjustment unit In the illumination on the front side of the scanning direction of the pulsed laser described above Pulse energy density E0 same irradiation pulse energy density E1, the irradiation energy density E0 pulse compared to the non-single crystal semiconductor film of microcrystalline generated pulse energy density of the irradiation It is low and is suitable for crystallization by irradiation a plurality of times, and is adjusted to an irradiation pulse energy density E2 in the irradiation of the scanning laser to the rear side of the scanning direction, and the irradiation pulse energy density E2 is higher than the irradiation pulse energy. The density E1 is lower than the necessary irradiation energy density for remelting the crystal, and the control unit further controls the scanning device to scan the pulsed laser and sequentially face the non-single-crystal semiconductor film N times. Multiple exposures above. The apparatus for manufacturing a crystalline semiconductor film according to the above aspect, wherein the control unit saturates the crystal grain size by the irradiation pulse energy density suitable for crystallization as a plurality of times of N times of irradiation. The irradiation pulse energy density E is set to be in the range of E × 0.98 to E × 1.03.