JP2008288363A - Method of adjusting laser beam output, method of manufacturing semiconductor device, method of manufacturing display device, and apparatus for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce intensity deviation in each laser output without being affected by a difference, such as a difference in the depth of focus in each laser beam irradiation optical system, in parallel irradiation of a plurality of laser beams. <P>SOLUTION: Prior to parallel irradiation of laser beams to a body to be irradiated with laser beams by a plurality of laser irradiation optical units, optical characteristics are measured in the body to be irradiated with laser beams after irradiation with laser beams by respective laser irradiation optical units. Based on the measured results, laser beam output from each laser irradiation optical unit is adjusted so that the difference in the optical characteristics for each laser irradiation optical unit is within a prescribed range. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a laser light output adjustment method, a semiconductor device manufacturing method, a display device manufacturing method, and a semiconductor device manufacturing apparatus.

  Crystalline silicon is used to construct an active matrix liquid crystal display device or an organic electroluminescent display device (hereinafter referred to as “organic EL display”) using an organic electroluminescent device (hereinafter referred to as “organic EL device”). It is common to use a thin film transistor (hereinafter abbreviated as “TFT”) substrate. A TFT substrate is formed by forming an amorphous or polycrystalline semiconductor film with a relatively small grain size on the substrate, irradiating the semiconductor film with laser light, and then annealing it, and then forming a TFT as a drive element. It is.

Conventionally, an annealing process for forming a TFT substrate often uses an excimer laser having a high absorption rate of a semiconductor film and a large pulsed light output as a light source. However, since the excimer laser is a gas laser, the output intensity varies from pulse to pulse. Therefore, in recent years, it has been proposed to use a semiconductor laser with high output stability as a light source of a laser annealing apparatus for the purpose of avoiding image quality degradation due to pulse variations (see, for example, Patent Document 1).
However, when a semiconductor laser is used as a light source, the light output obtained from one light source is much smaller than that of an excimer laser or the like, and the beam spot size to be annealed is also small. For this reason, the processing time per unit area of the TFT substrate increases, leading to a decrease in productivity, an increase in manufacturing cost, and the like. Therefore, in order to increase the throughput of the annealing process, a plurality of semiconductor lasers are arranged close to each other, and a plurality of laser beams are irradiated in parallel to a plurality of portions of the amorphous semiconductor film, thereby shortening the scanning time. It has also been proposed to increase productivity (see, for example, Patent Document 2).

By the way, when performing parallel irradiation of a plurality of laser beams, if the laser output varies among the irradiation optical systems, a difference in crystal grain size for each irradiation region in the semiconductor film after annealing treatment is caused, and each irradiation This causes a difference in the characteristics of TFTs formed in the region. Therefore, in a display device configured using such a TFT substrate, there is a possibility that a difference occurs in the luminance of each irradiation region, and the boundary line is visually recognized as display unevenness.
From this, when performing parallel irradiation of a plurality of laser beams, the power intensity of each irradiation beam is monitored by a measuring instrument such as a power meter and calibrated so that all laser outputs are uniform. It has been proposed to perform the measurement using a single intensity measurement unit in order to eliminate power errors caused by individual differences between measuring instruments and calibration differences (see, for example, Patent Document 3).

JP 2003-332235 A JP 2004-153150 A JP-A-2005-101202

  However, when using a plurality of laser beams, due to individual differences in the divergence angle of the emitted light possessed by each laser light source, and due to adjustment errors, etc. when a uniform irradiation optical system for correcting this individual difference is used. A difference occurs in the size and intensity of the laser light irradiated to the irradiated object. In other words, if only the power of each light source of a plurality of laser beams is monitored, a subtle difference in power density on the surface of the irradiated object due to differences in focal position and aberrations of each irradiation optical system can be obtained. It is difficult to monitor. This difference in power density appears as a difference in the effect of annealing treatment on the object to be irradiated, and the characteristics of the formed TFTs differ for each laser beam. As a result, display on a display device equipped with TFTs It becomes a factor causing unevenness.

  Therefore, the present invention reduces the intensity deviation of each laser output as much as possible without being affected by the measurement error of the intensity measuring instrument and the difference in optical characteristics such as the difference in depth of focus in each laser light irradiation optical system. Laser light output adjustment method, semiconductor device manufacturing method, display device manufacturing method, and semiconductor device manufacturing apparatus capable of realizing in-plane uniform polycrystallization and improving display quality in the display device The purpose is to provide.

  The present invention is a laser light output adjustment method devised to achieve the above object, and outputs the laser light prior to the parallel irradiation of the laser light to the laser light irradiated body by a plurality of laser irradiation optical units. A laser light output adjusting method for adjusting, wherein each laser irradiation optical unit measures the optical characteristics of the laser light irradiated object after the laser light is irradiated, and based on the measurement result, an optical for each laser irradiation optical unit is measured. The laser light output from each laser irradiation optical unit is adjusted so that the difference in characteristics falls within a predetermined range.

  In the laser light output adjustment method of the above procedure, prior to the parallel irradiation of a plurality of laser beams, the optical characteristics of the laser beam irradiated object after the laser beam irradiation are measured, and the difference in the optical characteristics of each laser irradiation optical unit is found. Fit within a predetermined range. Here, as an optical characteristic, the light transmittance or light reflectance of a laser beam irradiation body is mentioned, for example. Such optical characteristics are specified while being influenced by the laser light irradiation mode (for example, specific modes such as irradiation light intensity and focal position). This uniquely corresponds to the polycrystallized state, that is, the effect of annealing treatment by laser light irradiation. Therefore, if the optical characteristics of each laser irradiation optical unit are substantially the same, the effects of the annealing treatment by the laser light irradiation from each laser irradiation optical unit are also substantially the same.

  According to the present invention, the optical characteristics of the laser light irradiated object uniquely corresponding to the effect of the annealing treatment by the laser light irradiation are measured, and the difference in the optical characteristics for each laser irradiation optical unit is determined based on the measurement result. Since the laser beam output from each laser irradiation optical unit is adjusted so as to fall within the range, the effect of the annealing process by the laser beam irradiation from each laser irradiation optical unit becomes substantially the same after the adjustment. Therefore, it is possible to reduce the intensity deviation of each laser output as much as possible without being affected by the measurement error of the intensity measuring instrument or the difference in depth of focus in each laser light irradiation optical system, and a plurality of laser irradiation optical units. Differences in the annealing results resulting from individual differences can be prevented in advance. For example, if a display device is configured with TFTs formed through the annealing, uniform in-plane polycrystallization is achieved. This can be realized to improve the display quality in the display device. In other words, there is a subtle difference in the focal position of each laser irradiation optical unit, a subtle difference in beam diameter due to a difference in divergence angle, or a difference in power density on the irradiated object resulting from subtle aberrations in the optical system. However, unlike the conventional case where only the individual powers of a plurality of laser beams are monitored, it is possible to detect the difference in power density and correct the difference so as to achieve uniformity. It can be done.

  Hereinafter, a laser light output adjusting method, a semiconductor device manufacturing method, a display device manufacturing method, and a semiconductor device manufacturing apparatus according to the present invention will be described with reference to the drawings.

First, a semiconductor device and a display device will be briefly described.
The semiconductor device described here is a modification of an amorphous silicon film (amorphous silicon, hereinafter referred to as “a-Si”) from an amorphous state to a polycrystalline state, that is, a-Si to a polycrystalline silicon film ( It is obtained through modification to polysilicon (hereinafter referred to as “p-Si”). Specifically, a TFT which is a thin film semiconductor device is given as an example.
The display device described here refers to a display device that includes a TFT. Specifically, an organic EL display using an organic EL element as a light-emitting element can be given as an example. Here, an organic EL display is taken as an example, but the display device may be any device provided with a TFT, and may be a liquid crystal display, for example.

FIG. 1 is an explanatory diagram showing a configuration example of an organic EL display having TFTs.
The organic EL display 1 having the configuration shown in the figure is manufactured by the procedure described below.
First, a gate film 12 made of, for example, a Mo film is patterned on a substrate 11 made of a glass substrate, and then covered with a gate insulating film 13 made of, for example, a SiO / SiN film. Then, a semiconductor layer 14 made of an a-Si film is formed on the gate insulating film 13. The semiconductor layer 14 is subjected to a laser annealing process and is modified from an a-Si film to a p-Si film by crystallization. Next, the semiconductor layer 14 is patterned into an island shape covering the gate film 12. Thereafter, an insulating pattern (not shown) is formed at the position overlapping the gate film 12 of the semiconductor layer 14 by backside exposure from the substrate 11 side, and the semiconductor layer 14 is subjected to ion implantation and activation annealing treatment using the insulating pattern as a mask. A source / drain is formed on the substrate. As described above, the so-called bottom gate type TFT 10 in which the gate film 12, the gate insulating film 13, and the semiconductor layer 14 are sequentially laminated on the substrate 11 is formed. Here, a bottom gate type is taken as an example, but a top gate type TFT may be used.
Thereafter, the TFT 10 is covered with an interlayer insulating film 21, and a pixel circuit is formed by providing a wiring 22 connected to the TFT 10 through a connection hole formed in the interlayer insulating film 21. As described above, a so-called TFT substrate 20 is formed.
After the formation of the TFT substrate 20, the TFT substrate 20 is covered with the planarization insulating film 31 and a connection hole 31 a reaching the wiring 22 is formed in the planarization insulating film 31. Then, the pixel electrode 32 connected to the wiring 22 through the connection hole 31 a is formed on the planarization insulating film 31 as an anode, for example, and an insulating film pattern 33 having a shape covering the periphery of the pixel electrode 32 is formed. Further, the organic EL material layer 34 is laminated and formed on the exposed surface of the pixel electrode 32 so as to cover it. Further, the counter electrode 35 is formed in a state where the insulating property is maintained with respect to the pixel electrode 32. The counter electrode 35 is formed as a cathode made of a transparent conductive material, for example, and is formed in a solid film shape common to all pixels. In this manner, an organic EL element is configured in which an organic EL material layer 34 such as an organic hole transport layer or an organic light emitting layer is disposed between the pixel electrode 32 as an anode and the counter electrode 35 as a cathode. It is. Here, the top emission method is taken as an example, but in the case of the bottom emission method, the pixel electrode 32 may be formed of a conductive transparent film, and the counter electrode 35 may be formed of a highly reflective metal film. . It is also conceivable to employ a microcavity structure in which light is resonated by using a half mirror for the counter electrode 35 or the pixel electrode 32.
Thereafter, a transparent substrate 37 is bonded onto the counter electrode 35 via a light-transmitting adhesive layer 36 to complete the organic EL display 1.

FIG. 2 is an explanatory diagram illustrating an example of a pixel circuit configuration of the organic EL display. Here, an active matrix type organic EL display 1 using an organic EL element as a light emitting element is taken as an example.
As shown in FIG. 2A, on the substrate 40 of the organic EL display 1, a display area 40a and a peripheral area 40b are set. The display area 40a is configured as a pixel array section in which a plurality of scanning lines 41 and a plurality of signal lines 42 are wired vertically and horizontally, and one pixel a is provided corresponding to each intersection. Each pixel a is provided with an organic EL element. In the peripheral area 40b, a scanning line driving circuit 43 that scans and drives the scanning lines 41 and a signal line driving circuit 44 that supplies a video signal (that is, an input signal) corresponding to the luminance information to the signal line 42 are arranged. Yes.
In the display area 40a, organic EL elements corresponding to R, G, and B color components are mixed in order to perform full-color image display, and these are arranged in a matrix pattern according to a predetermined rule. It shall be. Although it is conceivable that the number of installed organic EL elements and the formation area thereof are the same for each color component, for example, they may be made different according to the energy component for each color component.
As shown in FIG. 2B, the pixel circuit provided in each pixel a includes, for example, an organic EL element 45, a driving transistor Tr1, a writing transistor (sampling transistor) Tr2, and a storage capacitor Cs. Then, the video signal written from the signal line 42 via the write transistor Tr2 is held in the holding capacitor Cs by driving by the scanning line driving circuit 43, and a current corresponding to the held signal amount is supplied to the organic EL element 45. Then, the organic EL element 45 emits light with a luminance corresponding to the current value.
Note that the configuration of the pixel circuit as described above is merely an example, and a capacitor element may be provided in the pixel circuit as necessary, or a plurality of transistors may be provided to configure the pixel circuit. In addition, a necessary drive circuit is added to the peripheral region 40b according to the change of the pixel circuit.

The display device represented by the organic EL display 1 described above includes various electronic devices shown in FIGS. 3 to 7, such as a digital camera, a notebook personal computer, a mobile terminal device such as a mobile phone, a video camera, etc. It is used as a display device for electronic devices in various fields that display video signals input to electronic devices or video signals generated in electronic devices as images or videos. Hereinafter, specific examples of electronic devices in which the display device is used will be described.
Note that the display device includes a module having a sealed configuration. For example, a display module formed by being attached to a facing portion such as transparent glass on the pixel array portion corresponds to this. The transparent facing portion may be provided with a color filter, a protective film, and the like, and further the above-described light shielding film. Further, the display module may be provided with a circuit unit for inputting / outputting a signal to the pixel array unit from the outside, an FPC (flexible printed circuit), and the like.

  FIG. 3 is a perspective view illustrating a television which is a specific example of the electronic apparatus. The television shown in the figure includes a video display screen unit 101 including a front panel 102, a filter glass 103, and the like, and is manufactured by using a display device as the video display screen unit 101.

  4A and 4B are perspective views illustrating a digital camera which is a specific example of the electronic device, in which FIG. 4A is a perspective view seen from the front side, and FIG. 4B is a perspective view seen from the back side. The digital camera of the illustrated example includes a light emitting unit 111 for flash, a display unit 112, a menu switch 113, a shutter button 114, and the like, and is manufactured by using a display device as the display unit 112.

  FIG. 5 is a perspective view illustrating a notebook personal computer which is a specific example of the electronic apparatus. The notebook personal computer of the illustrated example includes a keyboard 122 that is operated when characters and the like are input, a display unit 123 that displays an image, and the like. The display unit 123 is used as the display unit 123. .

  FIG. 6 is a perspective view showing a video camera which is a specific example of the electronic apparatus. The video camera of the illustrated example includes a main body 131, a lens 132 for photographing an object on a side facing forward, a start / stop switch 133 at the time of photographing, a display unit 134, and the like, and a display device is used as the display unit 134. It is produced by.

  7A and 7B are diagrams illustrating a mobile terminal device, for example, a mobile phone, which is a specific example of an electronic device, in which FIG. 7A is a front view in an open state, FIG. 7B is a side view thereof, and FIG. (D) is a left side view, (E) is a right side view, (F) is a top view, and (G) is a bottom view. The mobile phone according to this application example includes an upper housing 141, a lower housing 142, a connecting portion (here, a hinge portion) 143, a display 144, a sub display 145, a picture light 146, a camera 147, and the like. Alternatively, it is manufactured by using a display device as the sub display 145.

Next, features of the TFT 10 (semiconductor device) and the organic EL display 1 (display device) configured by including the TFT 10 in the present embodiment as described above will be described.
In this embodiment, the laser annealing process performed on the semiconductor layer 14 of the TFT 10 during the manufacturing process of the TFT 10 has a great feature.

FIG. 8 is an explanatory view showing a configuration example of a laser annealing apparatus that performs laser annealing, that is, a laser annealing apparatus that is one of manufacturing apparatuses used in the manufacturing process of the TFT 10.
The laser annealing apparatus shown in FIG. 1 includes a plurality of (for example, four) laser irradiation optical units each including a laser head 51 serving as a laser light source and a projection optical system including a mirror 55b and an objective lens (not shown). Each laser irradiation optical unit is configured to perform parallel irradiation of laser light onto the TFT substrate 20 that is a laser light irradiation object.
If the laser annealing process is performed using the laser annealing apparatus configured as described above, the laser annealing process can be simultaneously performed for the number of pixels corresponding to the number of the laser heads 51 arranged in parallel. The throughput of the laser annealing process can be improved as compared with the case where only one axis is irradiated instead of irradiation.

  In such a laser annealing apparatus, a gas laser or a solid-state laser can be used as a laser light source. In particular, when the laser light irradiated body is a Si film, it has an appropriate absorption performance for the Si film, and therefore, visible light having a wavelength of 330 to 800 nm is widely used as a laser light source. These laser light sources include Nd: YAG laser second harmonic or third harmonic, Nd: glass laser second harmonic or third harmonic, Nd: YVO4 laser second harmonic or third harmonic. Wave, second harmonic or third harmonic of Nd: YLF laser, Yb: second harmonic or third harmonic of YAG laser, Yb: second harmonic or third harmonic of glass laser, or Ti : Fundamental or second harmonic of Al2O3 laser can be used. In addition to the harmonics of the solid-state laser, the laser light source can be used for applications in which a plurality of gas lasers, for example, CO2 lasers are arranged to heat a wide surface area. Thus, the laser beam used for the laser annealing treatment is not particularly limited, and the layer structure in the TFT substrate 20 that is the laser beam irradiation object, particularly the characteristics of the gate film 12 and the semiconductor layer 14 constituting the TFT 10. It may be set accordingly.

  However, in the laser annealing apparatus described in the present embodiment, it is desirable to use a semiconductor laser whose medium is a semiconductor instead of gas or solid as the laser head 51 serving as a laser light source. Furthermore, the laser head 51 configured using a semiconductor laser emits CW (Continuous wave) laser light that continuously emits laser light, instead of pulse laser light that intermittently emits laser light. It shall be. This is because the CW laser beam is superior in controllability of the output intensity compared to the pulse laser beam, and the adjustment of the output intensity is easy and appropriate. Note that the CW laser light here includes quasi-CW laser light in which the laser light is pseudo-continuous.

  By the way, when performing parallel irradiation of a plurality of laser beams, there should be no difference in the effect of the laser annealing treatment by each laser beam. More specifically, not only individual differences among the laser heads 51 but also variations in the adjustment of the projection optical system corresponding to the laser heads 51 are not affected by this, and the laser annealing treatment effect by each laser beam is uniform. Should be promoted.

  Therefore, in the laser annealing apparatus described in the present embodiment, each laser irradiation is performed in the procedure described below prior to the execution of the laser annealing process, that is, prior to the parallel irradiation of the laser light by the plurality of laser irradiation optical units. Laser light output adjustment is performed on the laser head 51 in the optical unit.

Below, the output adjustment procedure of the laser beam in this embodiment is demonstrated.
9-15 is explanatory drawing which shows the outline | summary of the output adjustment procedure of the laser beam in this embodiment.

In adjusting the output of the laser beam, first, a test substrate having the same configuration as that of the TFT substrate 20 which is a laser beam irradiated body is prepared. Then, the test substrate is irradiated with laser light from each laser irradiation optical unit under the same processing conditions as in the case where laser annealing processing is performed on the TFT substrate 20. That is, the laser light emitted from each laser head 51 is made to reach the test substrate through the projection optical system corresponding to each laser head 51, and the test substrate is irradiated.
At this time, as shown in FIG. 9, on the test substrate, for each laser irradiation optical unit, an irradiation unit 61 that is an area irradiated with laser light, and an unirradiated unit 62 that is an area not irradiated with the laser light, , Ensure the presence of.

  Thereafter, the optical characteristics of the test substrate after the laser beam irradiation are measured. Examples of the optical characteristics include light transmittance and light reflectance. It is conceivable to measure such optical characteristics through detection of transmitted light intensity or reflected light intensity on the test substrate.

  For example, in the case of measuring the light transmittance, as shown in FIG. 10, the emitted light from the same light source is applied to the irradiation unit 61 and the non-irradiation unit 62 on the test substrate after being irradiated with the laser beam. , And the intensity of light transmitted through each of the irradiation unit 61 and the non-irradiation unit 62 is detected. Each detection result is differentially amplified.

  Further, for example, in the case of measuring the light reflectance, as shown in FIG. 11, the irradiation unit 61 and the non-irradiation unit 62 on the test substrate after being irradiated with the laser beam are irradiated from the same light source. The emitted light is irradiated, and the intensity of the light reflected by each of the irradiation unit 61 and the non-irradiation unit 62 is detected. Each detection result is differentially amplified.

More specifically, as shown in FIG. 12 or FIG. 13, the emitted light is irradiated to each of the irradiation unit 61 and the non-irradiation unit 62, and the resulting light intensity is detected.
FIG. 12 shows a specific example in the case where the transmitted light intensity is detected. FIG. 12A shows a bottom gate type film configuration in which a gate film 12, a gate insulating film 13, and a semiconductor layer 14 are sequentially stacked on a substrate 11. On the other hand, a specific example of transmitted light intensity detection corresponding to the case of performing laser annealing processing by the so-called indirect heating method using the light absorption layer 63 covering the semiconductor layer 14, (b) is for the bottom gate type film configuration Thus, a specific example of transmitted light intensity detection corresponding to the case where the laser annealing treatment by the so-called direct heating method without the light absorption layer 63 is performed, or the case where the light absorption layer 63 is peeled after the laser annealing treatment by the indirect heating method is performed. (C) is an indirect heating method using a light absorption layer 63 for a top gate type film structure in which a semiconductor layer 14 and a gate insulating film 13 are sequentially laminated on a substrate 11. Specific example of transmitted light intensity detection corresponding to the case where laser annealing treatment is performed, (d) is a case where laser annealing treatment is performed by a direct heating method without using the light absorption layer 63 for the top gate type film configuration This is a specific example of transmitted light intensity detection corresponding to the case where the light absorption layer 63 is peeled after the laser annealing treatment by the indirect heating method.
FIG. 13 shows a specific example in the case where the reflected overlight intensity is detected. FIG. 13A is a specific example of reflected light intensity detection corresponding to the case where laser annealing is performed by the indirect heating method using the light absorption layer 63 for the bottom gate type film configuration. Corresponds to the case where the bottom gate type film structure is subjected to the laser annealing process by the direct heating method without using the light absorption layer 63, or the case where the light absorption layer 63 is peeled after the laser annealing process by the indirect heating method. It is a specific example of reflected light intensity detection. In the example of FIG. 13B, the crystallinity of the semiconductor layer 14 on the gate film 12 can be evaluated. FIG. 13C is a specific example of reflected light intensity detection corresponding to the case where the laser annealing process by the indirect heating method using the light absorption layer 63 is performed on the top gate type film configuration.
In the light intensity detection as described above, a green light source is used when detecting the transmitted light intensity shown in FIG. 12, and a blue light source is used when detecting the reflected light intensity shown in FIG. It is possible to perform measurement with good S / N.

  Such detection of transmitted light intensity or reflected light intensity may be performed using a known technique. For example, it is conceivable that the test substrate after being irradiated with the laser light is transferred from the laser annealing apparatus to a detection apparatus such as an electron microscope capable of detecting the light intensity, and the light intensity is detected using the detection apparatus. In addition, since the light intensity detection in the said detection apparatus should just be implement | achieved using a well-known method, the detailed description is abbreviate | omitted here.

When the transmitted light intensity or the reflected light intensity is detected, the transmission contrast or the reflection contrast between the irradiation unit 61 and the non-irradiation unit 62 is obtained from the detection results of the irradiation unit 61 and the non-irradiation unit 62.
The transmission contrast corresponds to the comparison result of the transmitted light intensity between the irradiation unit 61 and the non-irradiated unit 62, and “transmission contrast = (irradiated unit transmitted light intensity−unirradiated unit transmitted light intensity) / (irradiated unit). Transmitted light intensity + unirradiated portion transmitted light intensity) ”.
The reflection contrast corresponds to the comparison result of the reflected light intensity between the irradiation unit 61 and the non-irradiated unit 62, and “reflection contrast = (irradiated part reflected light intensity−unirradiated part reflected light intensity) / ( (Irradiated portion reflected light intensity + unirradiated portion reflected light intensity) ”.

  The transmission contrast or the reflection contrast differs depending on the influence of the irradiation mode of the laser beam to the irradiation unit 61 (for example, specific modes such as irradiation light intensity and focal position). In other words, the result is specified while receiving the laser light irradiation mode. Therefore, it is considered that the transmission contrast or the reflection contrast uniquely corresponds to the polycrystallized state of the irradiation unit 61 after the laser beam irradiation, that is, the effect of the annealing process in the irradiation unit 61 by the laser beam irradiation.

This can also be verified by the following matters.
For example, it is known from experimental results that the relationship shown in FIG. 14 is established when the transistor characteristic variation of adjacent TFTs 10 is as small as about 3% or less. That is, 1) The fluence of the laser beam and the transmission contrast have a unique and linear correspondence. Here, the fluence means the energy density (J / cm 2) obtained by dividing the output energy of the laser beam by the irradiation cross-sectional area. 2) It can be assumed that the transmission contrast and the electrical characteristics of the TFT 10 have a unique and substantially linear correspondence. Furthermore, 3) If the output energy of the laser beam is controlled so that the transmission contrast always has a specific value, the electrical characteristics of the TFT 10 also become constant.

  Among these, for example, the correspondence shown in 2) is shown in FIG. In the illustrated example, a specific example of the correspondence relationship between the value of the transmission contrast and the device characteristic current value in the TFT 10 is shown.

  Such a correspondence is exactly the same for reflection contrast.

  Generally, in a display device, it is said that if the luminance difference between adjacent pixels is 3% or less, the luminance difference cannot be visually recognized. That is, if the difference in the device characteristic current value in the TFT 10 is 3% or less, the difference is not visually recognized. This is because the corresponding curve of 2) above is created in advance, its derivative is obtained, and the difference in transmission contrast between each laser irradiation optical unit is within the range of 0.03 / derivative based on the result. In other words, even when parallel irradiation of laser light is performed using a plurality of laser irradiation optical units, it means that there is no visible difference between the laser light irradiation regions.

  Therefore, after obtaining the transmission contrast or reflection contrast for each laser irradiation optical unit, based on the respective transmission contrast or reflection contrast, the difference in transmission contrast or reflection contrast for each laser irradiation optical unit is within a predetermined range ( The laser light output from each laser irradiation optical unit is adjusted so as to be within a range set in advance as an allowable range. Specifically, among the laser irradiation optical units, a unit serving as a reference is determined, and other units are set so that the transmission contrast or reflection contrast value in the unit matches or the difference falls within a predetermined range. The laser light output at is adjusted to match the value of transmission contrast or reflection contrast by the other unit. It is conceivable that the amount of adjustment at this time is specified with reference to the corresponding curve in 2) above, for example.

In this way, for each of the laser irradiation optical units, after the laser light output is adjusted so as to make the transmission contrast or the reflection contrast uniform, the laser annealing process for the TFT substrate 20 is performed. After the adjustment, the effect of the annealing process by the laser light irradiation from each laser irradiation optical unit becomes substantially the same. That is, even when laser beams are irradiated in parallel by a plurality of laser irradiation optical units, it is possible to perform the annealing process with each laser beam with the same intensity.
Therefore, it is possible to reduce the intensity deviation of each laser output as much as possible without being affected by the measurement error of the intensity measuring instrument or the difference in depth of focus in each laser light irradiation optical system, and a plurality of laser irradiation optical units. It is possible to prevent the occurrence of differences in the results of laser annealing caused by individual differences. Further, in the case where the organic EL display 1 is configured by including the TFT 10 formed through the laser annealing process, uniform in-plane polycrystallization is realized and display quality in the organic EL display 1 is improved. Can do. In other words, there is a subtle difference in the focal position of each laser irradiation optical unit, a subtle difference in beam diameter due to a difference in divergence angle, or a difference in power density on the irradiated object resulting from subtle aberrations in the optical system. However, unlike the conventional case where only the individual powers of a plurality of laser beams are monitored, it is possible to detect the difference in power density and correct the difference so as to achieve uniformity. It can be done.
Moreover, it is very preferable in that it is a non-contact and non-destructive inspection, and it is expected that the processing efficiency can be improved and the processing speed can be improved as compared with the conventional method.

By the way, in the series of laser light output adjustment procedures described above, transmission contrast or reflection contrast is obtained as the optical characteristics of the test substrate. That is, the transmitted light intensity or the reflected light intensity is detected for each of the irradiation unit 61 and the non-irradiation unit 62, and the transmission contrast or reflection contrast between the irradiation unit 61 and the non-irradiation unit 62 is detected from each detection result. Have gained. Therefore, in measuring the optical characteristics on the test board, it is possible to eliminate the influence of the characteristics of the light intensity detector of the detection device (for example, the γ characteristics of the imaging camera) and the light amount of the irradiation light source, and the accuracy of the measurement. Improvement can be achieved.
Note that it is conceivable that the transmission contrast or the reflection contrast is not used as long as the light amount of the irradiation light source can be managed. That is, for example, when the electrical characteristics of each laser head 51 can be predicted to some extent or when it is not necessary to predict, the light intensity detection result for the irradiation unit 61 without performing the light intensity detection for the unirradiated unit 62. The output adjustment of each laser head 51 may be performed based only on the above.

  Further, in the above-described series of laser light output adjustment procedures, a detection device that is a device different from the laser annealing device is used to measure the optical characteristics of the test substrate, and the irradiation light from the light source included in the detection device. Is used to obtain transmission contrast or reflection contrast for the test substrate. In that case, the light source included in the detection device is preferably a monochromatic light source. This is because light of various wavelengths is mixed in a general white light source, but a monochromatic light source can be measured and evaluated with higher accuracy without being affected by the spectral distribution of light. As the monochromatic light source used at this time, it is conceivable to use light having a wavelength that varies greatly depending on the state of crystallization by laser annealing.

However, it is conceivable that the optical characteristics of the test substrate are measured by the laser annealing apparatus, not by a detection apparatus different from the laser annealing apparatus.
FIG. 16 is an explanatory diagram showing an example of a configuration of a main part of a laser annealing apparatus having an optical characteristic measurement function.
For example, in the case of detecting the transmitted light intensity on the test board for measuring the optical characteristics of the test board, as shown in FIG. 16A, a detector 73 is placed on a stage 72 on which the test board 71 is set. Try to embed. In the laser annealing apparatus having such a configuration, it is possible to detect the transmitted light intensity at the location where the detector 73 is embedded in the test substrate 71 set on the stage 72.
Further, for example, in the case of detecting the reflected light intensity on the test substrate for measuring the optical characteristics of the test substrate, as shown in FIG. 16B, the irradiation of the test substrate 71 set on the stage 72 is performed. A detector 73 and a beam splitter 74 that guides reflected light to the detector 73 are arranged on the light emission side. In the laser annealing apparatus having such a configuration, since the detector 73 is not integrated with the stage 72, it is possible to detect the reflected light intensity at any location on the test substrate 71.
In any case, the detector 73 is not particularly limited as long as it can detect the light intensity, and may be any detector realized using a known technique.

  In this way, if the laser annealing apparatus is provided with the detector 73 for detecting the transmitted light intensity or the reflected light intensity so that the function as the laser annealing apparatus and the function as the detection apparatus are integrated, a test between the apparatuses is possible. There is no need to move the substrate, and the processing can be accelerated accordingly.

Furthermore, when integrating the laser annealing treatment function and the optical characteristic measurement function, a light source of irradiation light for detecting the optical characteristics may be prepared separately from the laser light source for the laser annealing treatment. However, it is also conceivable to detect optical characteristics using laser light irradiation from the laser light source. That is, while irradiating the TFT substrate 20 with laser light for laser annealing, the transmitted light intensity or reflected light intensity of the laser light on the TFT substrate 20 is detected, and the TFT substrate 20 is detected based on the detection result. The laser light output is adjusted.
As described above, if the laser light irradiated by the laser irradiation optical unit is used as a light source and the optical characteristics of the TFT substrate 20 irradiated with the laser light are measured together with the laser light irradiation, the laser annealing process is executed. However, the optical characteristics of the TFT substrate 20 can be measured substantially in real time, and the feedback control of the laser light output based on the measurement result can be performed, so that the processing can be speeded up and the production efficiency can be improved. It becomes very suitable.

  In the above-described embodiment, the preferred specific example of the present invention has been described. However, the present invention is not limited to the content, and can be appropriately changed without departing from the gist thereof. For example, in the present embodiment, the laser annealing process in the manufacturing process of the organic EL display 1 configured to include the TFT 10 has been described as an example. However, this is only a specific example, and the annealing process is performed on other semiconductor films. Even so, it is possible to apply the present invention in exactly the same manner.

It is explanatory drawing which shows the structural example of the organic electroluminescent display provided with TFT. It is explanatory drawing which shows an example of the pixel circuit structure of an organic EL display. It is a perspective view which shows the television which is a specific example of an electronic device. It is a perspective view which shows the digital camera which is a specific example of an electronic device. It is a perspective view which shows the notebook type personal computer which is a specific example of an electronic device. It is a perspective view which shows the video camera which is a specific example of an electronic device. It is a figure which shows the portable terminal device which is a specific example of an electronic device, for example, a mobile telephone. It is explanatory drawing which shows the structural example of the laser annealing apparatus which is one of the manufacturing apparatuses used in the manufacture process of TFT. It is explanatory drawing (the 1) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure explaining the outline | summary of an irradiation part and an unirradiated part. It is explanatory drawing (the 2) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure explaining the outline | summary of transmitted light intensity detection. It is explanatory drawing (the 3) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure explaining the outline | summary of reflected light intensity detection. It is explanatory drawing (the 4) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure which shows the specific example of transmitted light intensity detection. It is explanatory drawing (the 5) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure which shows the specific example of reflected light intensity detection. It is explanatory drawing (the 6) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure explaining the outline | summary of the correspondence between the transistor characteristic of TFT, and a transmission contrast. It is explanatory drawing (the 7) which shows the outline | summary of the output adjustment procedure of the laser beam based on this invention, and is a figure which shows the specific example of the correspondence of the device characteristic current value of TFT and the value of transmission contrast. It is explanatory drawing which shows an example of a principal part structure of the laser annealing apparatus provided with the optical characteristic measurement function.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Organic EL display, 10 ... TFT, 11 ... Substrate, 12 ... Gate film, 13 ... Gate insulating film, 14 ... Semiconductor layer, 61 ... Irradiation part, 62 ... Non-irradiation part, 71 ... Test substrate, 72 ... Stage, 73 ... Detector, 74 ... Beam splitter

Claims (8)

A laser light output adjustment method for adjusting the output of the laser light prior to parallel irradiation of the laser light to the laser light irradiated object by a plurality of laser irradiation optical units,
Measure the optical characteristics of the laser light irradiated object after each laser irradiation optical unit irradiates laser light,
A laser light output adjustment method comprising adjusting a laser light output from each laser irradiation optical unit based on the measurement result so that a difference in optical characteristics of each laser irradiation optical unit is within a predetermined range.   2. The laser light output adjustment method according to claim 1, wherein the optical characteristic is light transmittance in the laser light irradiated body.   2. The laser light output adjustment method according to claim 1, wherein the optical characteristic is a light reflectance in the laser light irradiated body.   2. The laser light output adjustment method according to claim 1, wherein a semiconductor laser is used as a laser light source of the laser irradiation optical unit. A method of manufacturing a semiconductor device including an annealing step of modifying a semiconductor film in a laser light irradiated body by performing parallel irradiation of laser light on the laser light irradiated body by a plurality of laser irradiation optical units,
Prior to the annealing step, each laser irradiation optical unit measures the optical characteristics of the irradiated object after the laser beam is irradiated,
A method for manufacturing a semiconductor device, comprising: adjusting a laser beam output from each laser irradiation optical unit based on a result of the measurement so that a difference in optical characteristics of each laser irradiation optical unit is within a predetermined range. A method of manufacturing a display device including a thin film semiconductor device,
Through the annealing process of modifying the semiconductor film in the laser light irradiated body by performing parallel irradiation of the laser light on the laser light irradiated body by a plurality of laser irradiation optical units, the thin film semiconductor device is formed,
Prior to the annealing step, each laser irradiation optical unit measures the optical characteristics of the irradiated object after the laser beam is irradiated,
A method of manufacturing a display device, comprising: adjusting a laser beam output from each laser irradiation optical unit so that a difference in optical characteristics of each laser irradiation optical unit is within a predetermined range based on the measurement result. A semiconductor device manufacturing apparatus that performs parallel irradiation of laser light on a laser light irradiated body by a plurality of laser irradiation optical units and performs an annealing process for modifying a semiconductor film in the laser light irradiated body,
Measuring means for measuring the optical characteristics of the laser light irradiated body after each laser irradiation optical unit has irradiated the laser light,
Adjusting means for adjusting the laser light output from each laser irradiation optical unit so that the difference in optical characteristics of each laser irradiation optical unit falls within a predetermined range based on the measurement result by the measurement means, Semiconductor device manufacturing equipment. The measuring means measures, using the laser light emitted from the laser irradiation optical unit as a light source, the optical characteristics of the laser light irradiated object irradiated with the laser light together with the irradiation of the laser light. An apparatus for manufacturing a semiconductor device according to claim 7.

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