JP2010129784A - Method and apparatus for measuring film thickness, and method of manufacturing photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of highly accurately measuring the film thickness of a second cell layer, a film thickness measuring apparatus, and to provide a method of manufacturing a photoelectric conversion device for forming the second cell layer so as to uniformize the film thickness within a substrate surface using the film thickness measuring method. <P>SOLUTION: The film thickness measuring method includes a process of calculating the film thickness of the second cell layer on the basis of transmissivity at an optional position within the substrate surface where a transparent electrode layer and a photoelectric conversion layer are formed and a transparent electrode layer haze ratio and a first cell layer film thickness measured beforehand. The film thickness measuring apparatus includes a second cell layer film thickness calculation unit for calculating the film thickness of the second cell layer by the film thickness measuring method. The method of manufacturing the photoelectric conversion device includes a process of calculating the film thickness of the second cell layer at the optional position within the substrate surface on the basis of the film thickness measuring method and a process of adjusting a second cell layer film forming condition when the film thickness of the second cell layer is out of an allowable film thickness range. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for measuring a film thickness of a photoelectric conversion layer, a film thickness measuring device, and a method for manufacturing a photoelectric conversion device to which the film thickness measuring method is applied.

  Solar cells that convert sunlight energy into electrical energy include thin films of p-type silicon-based semiconductor (p-layer), i-type silicon-based semiconductor (i-layer), and n-type silicon-based semiconductor (n-layer) on a transparent substrate. A thin film silicon solar cell including a photoelectric conversion layer formed by forming a film by plasma CVD or the like is known. In order to increase the conversion efficiency of thin-film silicon solar cells, that is, the power generation output, a photoelectric conversion layer with two layers of power generation cell layers with different absorption wavelength bands is used to efficiently absorb incident light and generate high power. Tandem solar cells have been proposed to obtain efficiency. In a super straight type tandem solar cell in which sunlight enters from the transparent substrate side, for example, a first cell layer made of amorphous silicon and a second cell layer made of crystalline silicon are formed in this order from the substrate side. The

  In the production of tandem solar cells, there has been a problem that variations and fluctuations in power generation output occur. As one of the factors of variation and fluctuation of the generated power, the film thickness of each layer of the photoelectric conversion layer varies for each film-forming batch. In particular, the influence of film thickness variation of the crystalline silicon i layer, which is a thick film, is large. FIG. 9 shows the relationship between the i-layer thickness of the second cell layer and the module output. In the figure, the horizontal axis represents the i-layer thickness of the second cell layer, and the vertical axis represents the normalized module output. Thus, there is a strong correlation between the i-layer thickness of the second cell layer and the module output. When the i-layer thickness of the second cell layer varies from batch to batch, the module output varies. Therefore, in order to improve and stabilize the performance, it is required to measure and manage the thickness of the crystalline silicon i layer.

The variation in the film thickness of the i layer is caused by fluctuations in the film forming conditions due to the deposition of a silicon film on the discharge electrode and the inner wall of the film forming, the deterioration of the power supply cable, and the like. In order to remove the deposited silicon film, a self-cleaning process using a fluorine-containing gas is carried out for each predetermined number of film-forming batches. However, the film thickness of the i layer varies due to the influence of residual fluorine after self-cleaning. To do.
In Patent Document 1, the thickness of a photoelectric conversion layer (i-layer film) is measured with a transmission film thickness meter for a solar cell on which one photoelectric conversion layer made of an amorphous silicon thin film is formed, and the measured photoelectric conversion layer A thin film manufacturing method and a thin film manufacturing system are disclosed in which the high-frequency power and the power-on time are controlled in accordance with the number of batches after self-cleaning so that the film thickness is constant at the reference film thickness.
JP 2008-56949 A

  In the production of a tandem solar cell, when a transmission film thickness meter is applied to the measurement of the second cell layer thickness, the number of layers is increased as compared with a single solar cell, so that it has been required to further improve measurement accuracy.

  By measuring the film thickness of the second cell layer with high accuracy and feeding it back to monitoring of film forming condition fluctuations and film thickness control, it is possible to suppress variations in power generation output between batches. In a tandem solar cell using a large-area substrate, a film thickness distribution in the substrate surface is likely to occur due to the distribution of power supply density, the distribution of supply gas and residual fluorine in the vicinity of the substrate, and the like. Therefore, in the large-area substrate solar cell, it is necessary to grasp the thickness distribution of the second cell layer, mainly the thickness of the i layer, and adjust the film forming conditions so that the thickness of the i layer is uniform in the plane. there were.

  The present invention provides a film thickness measuring method and a film thickness measuring apparatus capable of measuring the film thickness of a second cell layer in a tandem solar cell with higher accuracy. In addition, a method of manufacturing a photoelectric conversion device that forms a film by controlling the film thickness of the second cell layer, particularly the i layer of the second cell layer, to be uniform within the substrate surface using the film thickness measurement method. I will provide a.

  The present invention provides a film thickness measurement of a photoelectric conversion layer in a photoelectric conversion device comprising a transparent electrode layer and a photoelectric conversion layer composed of a first cell layer and a second cell layer in this order from the transparent electrode layer side. A method of measuring a transmittance at an arbitrary position in the substrate surface on which the transparent electrode layer and the photoelectric conversion layer are formed, the measured transmittance, and the transparent electrode measured in advance Calculating the film thickness of the second cell layer based on the haze ratio of the layer and the film thickness of the first cell layer measured in advance.

  When measuring the film thickness of the second cell layer based on the amount of transmitted light, the measurement light is irradiated to the substrate on which the transparent electrode layer and the photoelectric conversion layer (first cell layer and second cell layer) are formed. The light transmittance is measured. In the present invention, in consideration of correction by the haze ratio of the transparent electrode layer and the film thickness of the first cell layer, the transmittance of measurement light at an arbitrary position within the substrate surface on which the transparent electrode layer and the photoelectric conversion layer are formed. From the above, the film thickness of the second cell layer is calculated. As described above, the second cell layer is measured by taking into consideration the influence of light scattering caused by the surface shape of the transparent electrode layer and light absorption in the first cell layer in the film thickness measurement of the second cell layer based on the amount of transmitted light. The film thickness measurement accuracy can be improved.

  In the above invention, the haze ratio and the film thickness of the first cell layer are preferably the same as the position where the transmittance is measured in the substrate plane.

  As described above, the measurement accuracy of the second cell layer thickness is further improved by correcting using the haze rate and the first cell layer thickness at the same in-plane position as the position where the transmittance is measured. .

  In the above invention, it is preferable to calculate the film thickness of the second cell layer at an arbitrary plurality of positions in the substrate surface. Thereby, it is possible to obtain a more accurate in-plane film thickness distribution of the second cell layer particularly for a large-area substrate in which the film forming conditions are likely to vary within the substrate plane.

  In the present invention, an irradiation unit that irradiates measurement light of a predetermined wavelength to a substrate on which a transparent electrode layer and a photoelectric conversion layer composed of a first cell layer and a second cell layer are formed, and the substrate is transmitted. Measured by the transmittance measuring unit including a detection unit that receives the transmitted light of the measurement light, a transmittance calculating unit that calculates the transmittance from the intensity of the measurement light and the intensity of the transmitted light, and the transmittance measuring unit. A film thickness calculating unit that calculates the film thickness of the second cell layer based on the measured transmittance, the haze ratio of the transparent electrode layer measured in advance, and the film thickness of the first cell layer measured in advance. A film thickness measuring device is provided.

  In the film thickness measuring apparatus of the present invention, the second cell layer film thickness calculation unit calculates the second cell layer film thickness in consideration of light scattering by the transparent electrode layer and light absorption in the first cell layer. Therefore, if the film thickness measuring device of the present invention is used, the film thickness of the second cell layer formed on the transparent electrode layer and the first cell layer can be measured with high accuracy.

  Moreover, this invention is a manufacturing method of a photoelectric conversion apparatus provided on a board | substrate with a transparent electrode layer and the photoelectric converting layer comprised in order from this transparent electrode layer side by a 1st cell layer and a 2nd cell layer, Measuring the transmittance at an arbitrary position within the substrate surface on which the transparent electrode layer and the photoelectric conversion layer are formed; the measured transmittance; and the haze ratio of the transparent electrode layer measured in advance. Calculating the film thickness of the second cell layer at an arbitrary position in the substrate surface based on the film thickness of the first cell layer measured in advance, and the calculated film thickness of the second cell layer Comparing the film forming conditions of the second cell layer when the film thickness of the second cell layer deviates from the allowable film thickness range, A manufacturing method is provided for a photoelectric conversion device including:

  In the manufacture of a photoelectric conversion device including two power generation cell layers, the present invention uses the film thickness value of the second cell layer corrected in advance by the haze ratio of the transparent electrode layer and the film thickness of the first cell layer. Compared with the set allowable film thickness range, the second cell layer deposition condition is adjusted based on the comparison result. The film forming conditions to be adjusted are, for example, the high frequency power density input to the discharge electrode, the raw material gas pressure, the raw material gas flow rate, and the film forming time. Alternatively, the film forming conditions may be adjusted by adjusting devices such as a high-frequency power source and a gas flow meter. By performing correction in consideration of the surface shape of the transparent electrode layer and the absorption in the first cell layer, the film thickness measurement accuracy of the second cell layer is increased. Since the second cell layer deposition conditions are adjusted based on the film thickness measured with high accuracy, the film thickness control accuracy is improved. For this reason, the fluctuation | variation between batches of a 2nd cell layer film thickness can be suppressed. As a result, variation in output between batches is suppressed, and a constant output photoelectric conversion device can be stably produced.

  In the above invention, in the step of measuring the transmittance, the transmittance at any plurality of positions in the substrate surface is measured, and in the step of calculating the film thickness of the second cell layer, at the plurality of arbitrary positions. And calculating the film thickness of the second cell layer at any of a plurality of positions in the substrate surface based on the transmittance of the transparent electrode layer, the haze ratio of the transparent electrode layer, and the film thickness of the first cell layer. When the film thickness of the second cell layer at the position deviates from the allowable film thickness range, it is preferable to adjust the film forming conditions of the second cell layer.

  Alternatively, in the above invention, the method further includes a step of obtaining a film thickness distribution of the second cell layer from the calculated film thickness of the second cell layer at the plurality of positions, wherein the second cell layer at the at least one position is obtained. When the film thickness is out of the allowable film thickness range, it is preferable to adjust the formation condition of the second cell layer based on the film thickness distribution.

  When a large-area substrate is used, the second cell layer film thickness is likely to vary within the substrate surface due to gas distribution within the substrate surface, high-frequency power density distribution, residual fluorine during self-cleaning, and the like. Thus, the film thickness of the second cell layer at a plurality of positions in the large-area substrate surface is calculated, and the second cell layer film thickness or the second cell layer film thickness distribution at the plurality of positions is determined as the second cell layer deposition condition. If this is reflected in the adjustment, the second cell layer can be uniformly formed with a film thickness that provides a high output. As a result, the output of the photoelectric conversion device can be improved.

  In the above invention, based on the transmittance, the haze ratio at the same position as the position where the transmittance was measured, and the film thickness of the first cell layer at the same position as the position where the transmittance was measured, It is preferable to calculate the film thickness of the second cell layer at an arbitrary position in the substrate plane. Thereby, the second cell layer thickness can be measured with high accuracy, and the control accuracy of the second cell layer thickness is further improved.

According to the film thickness measuring method and film thickness measuring apparatus of the present invention, the second cell layer film thickness can be measured in consideration of the influence of the transparent electrode layer and the first cell layer, and therefore the second cell layer can be accurately measured. The film thickness can be measured.
If the film thickness measurement method of the present invention is used to measure the film thickness of the second cell layer, and the result of comparing the measured value with the allowable film thickness range is reflected in the adjustment of the film formation conditions of the second cell layer, the second Variation in cell layer thickness between batches can be suppressed. As a result, variation in output between batches is suppressed, and a constant output photoelectric conversion device can be stably produced.
In particular, in the manufacture of a photoelectric conversion device using a large-area substrate, the film thickness measurement method of the present invention is used to measure the second cell layer film thickness at a plurality of positions, and the measurement result is determined as the second cell layer film formation condition. By reflecting this adjustment, the thickness of the second cell layer can be made uniform in the substrate plane. For this reason, a high output photoelectric conversion device can be manufactured.

  FIG. 1 is a schematic diagram illustrating a configuration of a photoelectric conversion device of the present invention. The photoelectric conversion device 100 is a tandem silicon solar cell, and includes a substrate 1, a transparent electrode layer 2, a first cell layer 91 (amorphous silicon system) and a second cell layer 92 ( Crystalline silicon) and back electrode layer 4 are provided. Here, the silicon-based is a generic name including silicon (Si), silicon carbide (SiC), and silicon germanium (SiGe). Further, the crystalline silicon system means a silicon system other than the amorphous silicon system, and includes microcrystalline silicon and polycrystalline silicon.

<First Embodiment>
A method for manufacturing a photoelectric conversion device according to the first embodiment will be described by taking a process for manufacturing a solar cell panel as an example. 2 to 5 are schematic views showing a method for manufacturing the solar cell panel of the present embodiment.

(1) FIG. 2 (a):
A soda float glass substrate (for example, 1.4 m × 1.1 m × plate thickness: 3.5 mm to 4.5 mm) having an area of 1 m ² or more or 1 m square or more is used as the substrate 1. The end face of the substrate is preferably subjected to corner chamfering or R chamfering to prevent damage due to thermal stress or impact.

(2) FIG. 2 (b):
As the transparent electrode layer 2, a transparent conductive film having a thickness of about 500 nm to 800 nm and having tin oxide (SnO ₂ ) as a main component is formed at about 500 ° C. with a thermal CVD apparatus. At this time, a texture with appropriate irregularities is formed on the surface of the transparent electrode film. As the transparent electrode layer 2, an alkali barrier film (not shown) may be formed between the substrate 1 and the transparent electrode film in addition to the transparent electrode film. As the alkali barrier film, a silicon oxide film (SiO ₂ ) is formed at a temperature of about 500 ° C. in a thermal CVD apparatus at 50 nm to 150 nm.

  After the formation of the transparent electrode layer 2, the haze ratio H on the surface of the transparent electrode layer 2 at an arbitrary position within the substrate surface (for example, 8 points × 8 points, a total of 64 points) is measured. Known methods can be applied to the method for measuring the haze ratio. The measured haze ratio H at each measurement position is stored in the film thickness calculation unit of the second cell layer film thickness measurement apparatus described later.

(3) FIG. 2 (c):
Thereafter, the substrate 1 is placed on an XY table, and the first harmonic (1064 nm) of the YAG laser is irradiated from the film surface side of the transparent electrode film as indicated by an arrow in the figure. The laser power is adjusted to be appropriate for the processing speed, and the transparent electrode film is moved relative to the direction perpendicular to the series connection direction of the power generation cells so that the substrate 1 and the laser beam are moved relative to each other to form the groove 10 And laser etching into a strip shape having a predetermined width of about 6 mm to 15 mm.

(4) FIG. 2 (d):
As the first cell layer 91, a p layer, an i layer, and an n layer made of an amorphous silicon thin film are formed by a plasma CVD apparatus. Using SiH ₄ gas and H ₂ gas as main raw materials, the amorphous silicon p layer 31 from the side on which sunlight is incident on the transparent electrode layer 2 at a reduced pressure atmosphere: 30 Pa to 1000 Pa and a substrate temperature: about 200 ° C. Then, an amorphous silicon i layer 32 and an amorphous silicon n layer 33 are formed in this order. The amorphous silicon p layer 31 is mainly made of amorphous B-doped silicon and has a thickness of 10 nm to 30 nm. The amorphous silicon i layer 32 has a thickness of 200 nm to 350 nm. The amorphous silicon n layer 33 is mainly P-doped silicon containing microcrystalline silicon in amorphous silicon, and has a thickness of 30 nm to 50 nm. A buffer layer may be provided between the amorphous silicon p layer 31 and the amorphous silicon i layer 32 in order to improve interface characteristics.

After the first cell layer 91 is formed, the thickness of the first cell layer 91 at an arbitrary position within the substrate surface is measured using a transmission film thickness meter. The measurement position is preferably the same position as the position where the haze ratio of the transparent electrode layer 2 is measured.
Specifically, measurement light of a predetermined wavelength (for example, light having a wavelength of 625 nm) is irradiated from the first cell layer 91 side to each measurement position of the substrate 1 on which the transparent electrode layer 2 and the first cell layer 91 are formed. The The transmitted light that has passed through the substrate 1 is detected by a detection element arranged on the substrate side. Based on a graph that associates the transmitted light intensity and the film thickness of the first cell layer 91 that are created in advance, the film thickness D ₁ of the first cell layer 91 at each measurement position is calculated from the detected transmission intensity at each measurement position. Calculated. The first cell layer thickness D ₁ of the in each measurement position is measured is stored in the film thickness calculating unit of the second cell layer thickness measuring apparatus described later.

  Next, a crystalline silicon p layer 41, a crystalline silicon i layer 42, and a crystalline silicon n layer 43 as the second cell layer 92 are sequentially formed on the first cell layer 91.

FIG. 6 is a partial perspective view showing a part of the configuration of the plasma CVD thin film manufacturing apparatus used for forming the second cell layer. XYZ directions are indicated by arrows in the figure.
In a large area substrate deposition apparatus, a plurality of discharge electrodes are generally arranged. In the present embodiment, the discharge electrode 103 includes eight discharge electrodes 103a to 103h, each of which is disposed between the two horizontal electrodes 120 extending in the X direction substantially parallel to each other and the two horizontal electrodes 120. And a plurality of rod-like vertical electrodes 121 extending in the Y direction substantially parallel to each other. Matching units 113at to 113ht, high-frequency power supply transmission lines 112a and 114a, a heat medium supply pipe 115a, and a raw material gas pipe 116a are provided on the power supply point 153 side with respect to each of the discharge electrodes 103a to 103h. Matching units 113ab to 113hb (113hb is not shown), high-frequency power supply transmission lines 112b and 114b, a heat medium supply pipe 115b, and a raw material gas pipe 116b are provided on the power supply point 154 side. In FIG. 6, only the matching units 113 at, 113 ab, and 113 ht are displayed for easy understanding of the drawing, and the other matching units are not shown.
Each of the discharge electrodes 103a to 103h is supplied with source gas from source gas pipes 116a and 116b connected in the vicinity of the feeding point 153 and the feeding point 154, and this source gas is supplied in the direction indicated by the arrow in the figure (counter electrode). To the side). High-frequency power is supplied from a high-frequency power source (not shown) to the feeding point 153 of the discharge electrodes 103a to 103h, and high-frequency power is supplied to the feeding point 154 from another high-frequency power source (not shown).
However, the number of discharge electrodes is not necessarily eight, and there are cases where the number of discharge electrodes is larger or smaller, and is not particularly limited. It is also possible to supply power to the discharge electrodes 103a to 103h by a combination of more than eight or less than eight matching units 113a and 113b and high-frequency power transmission lines 114a and 114b. Moreover, you may supply electric power from each separate high frequency power supply part (not shown). In these cases, the grouping is preferably performed by adjusting the discharge electrodes 103a to 103h so as to correspond to the number of the groups.

  In forming the i-layer film mainly composed of microcrystalline silicon by the plasma CVD method, the distance between the plasma discharge electrode and the surface of the substrate 1 is preferably 3 mm or more and 10 mm or less. When it is smaller than 3 mm, it is difficult to keep the distance constant from the accuracy of each component device in the film forming chamber corresponding to the large substrate, and there is a possibility that the discharge becomes unstable because it is too close. When it is larger than 10 mm, it is difficult to obtain a sufficient film forming speed (1 nm / s or more), and the uniformity of the plasma is lowered and the film quality is lowered by ion bombardment.

  Using the thin film manufacturing apparatus shown in FIG. 6, in a reduced pressure atmosphere: 3000 Pa or less, a substrate temperature: about 200 ° C., a plasma generation frequency: 40 MHz to 100 MHz, a crystalline silicon p layer 41, a crystalline silicon i layer 42, and a crystalline material in this order. A silicon n layer 43 is formed, and a second cell layer 92 is formed. The crystalline silicon p layer 41 is mainly made of B-doped microcrystalline silicon and has a thickness of 10 nm to 50 nm. The crystalline silicon i layer 42 is mainly made of microcrystalline silicon and has a film thickness of 1.2 μm or more and 3.0 μm or less. The crystalline silicon n layer 43 is mainly made of P-doped microcrystalline silicon and has a thickness of 20 nm to 50 nm.

After the second cell layer 92 is formed, the film thickness of the second cell layer 92 at an arbitrary position within the substrate surface is measured. The measurement position is preferably the same position as the position where the haze ratio of the transparent electrode layer 2 is measured.
The film thickness measuring device used for measuring the film thickness of the second cell layer is a transmission film thickness meter. The second cell layer film thickness measurement apparatus includes a transmittance measurement unit and a film thickness calculation unit. The transmittance measuring unit includes an irradiating unit, a detecting unit, and a transmittance calculating unit.

The irradiation unit irradiates each measurement position of the substrate 1 on which the transparent electrode layer 2 and the photoelectric conversion layer 3 are formed with measurement light having a predetermined wavelength (for example, light having a wavelength of 625 nm) from the second cell layer 92 side. The transmitted light that has passed through the substrate 1 is detected by a detector disposed on the substrate side.
The transmittance calculation unit calculates the transmittance T from Equation (1) from the measured light intensity I ₀ irradiated from the irradiation unit and the transmitted light intensity I detected by the detection unit.
Transmittance T = I / I ₀ × 100 (%) (1)

In general, the transmitted light intensity I is expressed by Equation (2) from Beer's law.
I = I ₀ (1-R) exp (−αD) (2)
However, R: reflectance, α: absorption coefficient, D: film thickness. Therefore, the film thickness D is represented by the formula (3).
D = A + BT (3)
However, A and B are constants.

In the present embodiment, based on the formula (3), a formula for calculating the second cell layer thickness considering the physical properties of the transparent electrode layer, the first cell layer, and the second cell layer was derived.
The transparent electrode layer needs to have high transmittance in order to allow measurement light (incident light) to reach the photoelectric conversion layer. On the other hand, light scattering caused by the surface shape of the transparent electrode layer affects the transmittance and absorption of the transparent electrode layer. Therefore, in deriving the formula for calculating the second cell layer thickness, the influence of the thickness of the transparent electrode layer is ignored in consideration of the haze ratio of the transparent electrode layer.
The first cell layer absorbs measurement light (incident light) transmitted through the transparent electrode layer. That is, the transmittance of the measurement light varies depending on the film thickness of the first cell layer. The film quality of the first cell layer does not affect the measurement light transmittance. Therefore, in the derivation of the second cell layer thickness calculation formula, the thickness of the first cell layer is taken into consideration.
The second cell layer absorbs measurement light transmitted through the first cell layer. The transmittance of the measurement light varies depending on the film thickness of the second cell layer, but the influence of the film quality (crystallinity) of the second cell layer is sufficiently small compared with the influence of the film thickness, and thus does not become an important factor. . Therefore, in the derivation of the second cell layer thickness calculation formula, the thickness of the second cell layer is taken into consideration.

The formula (4) for calculating the second cell layer thickness is obtained by incorporating the haze ratio H of the transparent electrode layer, the first cell layer thickness D ₁ , and the second cell layer thickness D ₂ into the formula (3). It is.
D ₂ = a + bH + c (logT) + d (logT) ² + eH (logT) + fD ₁ + gD ₁ H + hD ₁ (logT) (4)
In the formula (4), a to h are calibration curve constants derived by fitting from the measurement results of samples with known second cell layer thicknesses. The second term bH and the fifth term eH (logT) in Equation (4) correspond to a correction coefficient related to the haze ratio. The fourth term d (logT) ² is a term added to improve the fitting accuracy. The sixth term fD ₁ and the eighth term hD ₁ (logT) correspond to a correction coefficient related to the first cell layer thickness. The seventh term gD ₁ H corresponds to a correction coefficient related to the haze ratio and the first cell layer thickness.

The transmittance T at each measurement position in the substrate surface calculated by the transmittance calculator is output to the film thickness calculator. Formula (4) is stored in the film thickness calculation unit of the film thickness measuring apparatus. The film thickness calculation unit substitutes the output transmittance T, the stored haze ratio H at each measurement position, and the first cell layer film thickness D ₁ into Equation (4), and the second film thickness at each measurement position. calculating the thickness D ₂ of the cell layer.
The film thickness calculating unit, based on the second cell layer thickness D ₂ at each measurement position may create diagram representing the second cell layer film substrate in-plane distribution of the thickness.

The second cell layer thickness D ₂ at each measurement position is compared with preset allowable thickness range. If the second cell layer thickness D ₂ is within an allowable film thickness range, the film condition is not changed, the formation of the second cell layer is continued. If the second cell layer thickness D ₂ is out of the allowable film thickness range, the adjustment of the deposition conditions is performed.

Since the crystalline silicon i layer occupies most of the film thickness of the second cell layer, it is particularly important to adjust the thickness of the crystalline silicon i layer 42.
Specifically, the second cell layer thickness D ₂ may deviate from the allowable thickness range across the substrate, adjusts input power density at the crystalline silicon i-layer 42 made of film, film pressure, and the film period. When the second cell layer film thickness has a distribution in the substrate surface and D ₂ that deviates from the allowable film thickness range is locally generated, in the film formation of the crystalline silicon i layer 42, it is made to correspond to the distribution of D _2. Then, the input power density of the discharge electrode and the flow rate of the source gas (H ₂ gas, SiH ₄ gas) supplied from the source gas pipe are adjusted.
Based on the in-plane distribution of the second cell layer thickness D ₂ and D ₂ , the abnormality of each device of the thin film manufacturing apparatus such as a high frequency power source, a pressure gauge, and a flow meter is detected, and the film forming conditions are adjusted by adjusting the device You may adjust it.

A second cell layer is formed on the first cell layer on another substrate under the adjusted film forming conditions. For each measurement position on the different substrate, the second cell layer film thickness D ₂ ′ after film formation condition adjustment is measured using the above-described film thickness measurement apparatus. Film formation condition adjustment and film thickness measurement are repeated until the second cell layer (crystalline silicon i layer) film thickness D ₂ ′ after film formation condition adjustment at each measurement position satisfies the allowable film thickness range. When the second cell layer film thickness D ₂ ′ after the film formation condition adjustment is within the allowable film thickness range, the formation of the second cell layer is continued under the finally adjusted film formation condition.

Incidentally, the allowable film thickness range, the film thickness calculating unit of the film thickness measuring apparatus, it is also possible to calculate and set the numerical value range on the basis of the first cell layer thickness D _1.

  By the above process, the film thickness of the second cell layer in the substrate surface becomes substantially constant at a value within a predetermined film thickness range, and the fluctuation range of the film thickness of the second cell layer between batches is suppressed.

  In the present embodiment, an intermediate contact layer serving as a semi-reflective film may be provided between the first cell layer 91 and the second cell layer 92 in order to improve the contact property and obtain current matching. As an intermediate contact layer, a GZO (Ga-doped ZnO) film having a thickness of 20 nm to 100 nm is formed by sputtering using a target: Ga-doped ZnO sintered body. Further, the intermediate contact layer 5 may not be provided.

(5) FIG. 2 (e):
The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is irradiated from the film surface side of the photoelectric conversion layer 3 as indicated by an arrow in the figure. Pulse oscillation: 10 kHz to 20 kHz, laser power is adjusted so as to be suitable for the processing speed, and laser etching is performed so that grooves 11 are formed on the lateral side of the laser etching line of the transparent electrode layer 2 from about 100 μm to 150 μm. To do. Further, this laser may be irradiated from the substrate 1 side. In this case, the photoelectric conversion layer is formed by utilizing a high vapor pressure generated by the energy absorbed in the amorphous silicon-based first cell layer of the photoelectric conversion layer 3. Since 3 can be etched, a more stable laser etching process can be performed. The position of the laser etching line is selected in consideration of positioning tolerances so as not to intersect with the etching line in the previous process.

(6) FIG. 3 (a):
An Ag film / Ti film is formed as the back electrode layer 4 by a sputtering apparatus at a reduced pressure atmosphere and at a film forming temperature of 150 ° C. to 200 ° C. In this embodiment, an Ag film: 150 nm or more and 500 nm or less, and a Ti film having a high anticorrosion effect: 10 nm or more and 20 nm or less are stacked in this order to protect them. Alternatively, the back electrode layer 4 may have a laminated structure of an Ag film having a thickness of 25 nm to 100 nm and an Al film having a thickness of 15 nm to 500 nm. For the purpose of reducing the contact resistance between the crystalline silicon n layer 43 and the back electrode layer 4 and improving the light reflection, a film thickness of 50 nm or more and 100 nm or less is formed between the photoelectric conversion layer 3 and the back electrode layer 4 by a sputtering apparatus. A GZO (Ga-doped ZnO) film may be formed and provided.

(7) FIG. 3 (b):
The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode-pumped YAG laser is irradiated from the substrate 1 side as indicated by the arrow in the figure. The laser light is absorbed by the photoelectric conversion layer 3, and the back electrode layer 4 is exploded and removed using the high gas vapor pressure generated at this time. Pulse oscillation: laser power is adjusted so as to be suitable for the processing speed from 1 kHz to 10 kHz, and laser etching is performed so that grooves 12 are formed on the lateral side of the laser etching line of the transparent electrode layer 2 from 250 μm to 400 μm. .

(8) FIG. 3 (c) and FIG. 3 (a):
The power generation region is divided to eliminate the influence that the serial connection portion due to laser etching is likely to be short-circuited at the film edge around the substrate edge. The substrate 1 is placed on an XY table, and the second harmonic (532 nm) of the laser diode pumped YAG laser is irradiated from the substrate 1 side. The laser light is absorbed by the transparent electrode layer 2 and the photoelectric conversion layer 3, and the back electrode layer 4 explodes using the high gas vapor pressure generated at this time, and the back electrode layer 4 / photoelectric conversion layer 3 / transparent electrode layer 2 is removed. Pulse oscillation: 1 kHz or more and 10 kHz or less, the laser power is adjusted so as to be suitable for the processing speed, and the position of 5 nm to 20 mm from the end of the substrate 1 is placed in the X-direction insulating groove as shown in FIG. Laser etching is performed to form 15. In addition, in FIG.3 (c), since it becomes X direction sectional drawing cut | disconnected in the direction in which the photoelectric converting layer 3 was connected in series, the back surface electrode layer 4 / photoelectric conversion is originally in the position of the insulating groove 15 A state (see FIG. 3A) where there is a peripheral film removal region 14 obtained by polishing and removing the layer 3 / transparent electrode layer 2 should appear, but for the convenience of explanation of processing to the end of the substrate 1, The insulating groove formed to represent the Y-direction cross section at the position will be described as the X-direction insulating groove 15. At this time, the Y-direction insulating groove does not need to be provided because the film surface polishing removal processing of the peripheral film removal region of the substrate 1 is performed in a later process.

  The insulating groove 15 exhibits an effective effect in suppressing external moisture intrusion into the solar cell module 6 from the end of the solar cell panel by terminating the etching at a position of 5 nm to 15 mm from the end of the substrate 1. Therefore, it is preferable.

  In addition, although the laser beam in the above process is made into a YAG laser, there exists what can use a YVO4 laser, a fiber laser, etc. similarly.

(9) FIG. 4 (a: view seen from solar cell film surface side, b: view seen from substrate side of light receiving surface):
Since the laminated film around the substrate 1 (peripheral film removal region 14) has a step and is easy to peel off in order to ensure a sound adhesion / seal surface with the back sheet 24 via EVA or the like in a later process, The film is removed to form a peripheral film removal region 14. In removing the film over the entire circumference of the substrate 1 at 5 to 20 mm from the end of the substrate 1, the X direction is closer to the substrate end than the insulating groove 15 provided in the step of FIG. The back electrode layer 4 / photoelectric conversion layer 3 / transparent electrode layer 2 are removed by using grinding stone polishing, blast polishing, or the like on the substrate end side with respect to the groove 10 near the side portion.
Polishing debris and abrasive grains were removed by cleaning the substrate 1.

(10) FIGS. 5A and 5B:
An attachment portion of the terminal box 23 is provided with an opening through window in the back sheet 24 to take out the current collector plate. Insulating materials are installed in a plurality of layers in the opening through window portion to suppress intrusion of moisture and the like from the outside.
Processing so that power can be taken out from the terminal box 23 on the back side of the solar battery panel by collecting copper foil from one end of the photovoltaic power generation cells arranged in series and the other end of the solar power generation cell. To do. In order to prevent a short circuit with each part, the copper foil arranges an insulating sheet wider than the copper foil width.
After the current collecting copper foil or the like is disposed at a predetermined position, an adhesive filler sheet made of EVA (ethylene vinyl acetate copolymer) or the like is disposed so as to cover the entire solar cell module 6 and not protrude from the substrate 1. .
A back sheet 24 having a high waterproof effect is installed on the EVA. In this embodiment, the back sheet 24 has a three-layer structure of PET sheet / Al foil / PET sheet so that the waterproof and moisture-proof effect is high.
The EVA sheet is placed in a predetermined position until the back sheet 24 is deaerated with a laminator in a reduced pressure atmosphere and pressed at about 150 to 160 ° C., and EVA is crosslinked and brought into close contact.

(11) FIG. 5 (a):
The terminal box 23 is attached to the back side of the solar cell module 6 with an adhesive.
(12) FIG. 5 (b):
The copper foil and the output cable of the terminal box 23 are connected by solder or the like, and the inside of the terminal box 23 is filled with a sealing agent (potting agent) and sealed. Thus, the solar cell panel 50 is completed.
(13) FIG. 5 (c):
A power generation inspection and a predetermined performance test are performed on the solar cell panel 50 formed in the steps up to FIG. The power generation inspection is performed using a solar simulator of AM1.5 and solar radiation standard sunlight (1000 W / m ² ).
(14) FIG. 5 (d):
Before and after the power generation inspection (FIG. 5C), a predetermined performance inspection is performed including an appearance inspection.

In FIG. 7, the crystalline silicon i layer thickness of the second cell layer calculated in consideration of the haze ratio of the transparent electrode layer and the first cell layer thickness in the formula (4), and the output of the tandem solar cell module The relationship is shown. FIG. 8 shows the relationship between the crystalline silicon i layer thickness of the second cell layer calculated in consideration of only the first cell layer thickness in Equation (4) and the output of the tandem solar cell module. 7 and 8, the horizontal axis represents the crystalline silicon i-layer thickness of the second cell layer, and the vertical axis represents the normalized module output.
In FIG. 7, it can be seen that the measurement error of the film thickness of the crystalline silicon i layer of the second cell layer is suppressed. In FIG. 8, since the influence of the haze ratio of the transparent electrode layer is not taken into account, the measurement error of the crystalline silicon i layer film thickness of the second cell layer becomes large, and the film thickness measurement value varies.
As described above, if the crystalline silicon i layer thickness of the second cell layer is corrected using the haze ratio of the transparent electrode layer and the first cell layer thickness, the crystalline silicon i layer film of the second cell layer is corrected. Thickness measurement error can be suppressed.

It is the schematic showing the structure of the photoelectric conversion apparatus manufactured by the manufacturing method of the photoelectric conversion apparatus of this invention. It is the schematic explaining one Embodiment which manufactures a solar cell panel using the manufacturing method of the photoelectric conversion apparatus of this invention. It is the schematic explaining one Embodiment which manufactures a solar cell panel using the manufacturing method of the photoelectric conversion apparatus of this invention. It is the schematic explaining one Embodiment which manufactures a solar cell panel using the manufacturing method of the photoelectric conversion apparatus of this invention. It is the schematic explaining one Embodiment which manufactures a solar cell panel using the manufacturing method of the photoelectric conversion apparatus of this invention. It is a fragmentary perspective view which shows a part of structure of the thin film manufacturing apparatus used for the manufacturing method of the photoelectric conversion apparatus of this embodiment. It is a graph which shows the relationship between the crystalline silicon i layer film thickness calculated in consideration of the haze rate of the transparent electrode layer, and the 1st cell layer film thickness, and the output of a tandem type solar cell module. It is a graph which shows the relationship between the crystalline silicon i layer film thickness calculated only considering the 1st cell layer film thickness, and the output of a tandem type solar cell module. It is a graph which shows the relationship between i layer thickness of a 2nd cell layer, and a module output.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Transparent electrode layer 3 Photoelectric conversion layer 4 Back electrode layer 6 Solar cell module 31 Amorphous silicon p layer 32 Amorphous silicon i layer 33 Amorphous silicon n layer 41 Crystalline silicon p layer 42 Crystalline silicon i Layer 43 Crystalline silicon n layer 91 1st cell layer 92 2nd cell layer 100 Photoelectric conversion device 103a to 103h Discharge electrode 113at, 113ht, 113ab Matching device 112a, 114a, 112b, 114b High-frequency power transmission path 115a, 115b Heat medium supply Pipe 116a, 116b Raw material gas pipe 153, 154 Feed point

Claims (8)

A method for measuring a film thickness of a photoelectric conversion layer in a photoelectric conversion device comprising a transparent electrode layer and a photoelectric conversion layer composed of a first cell layer and a second cell layer in order from the transparent electrode layer side on a substrate. ,
Measuring the transmittance at an arbitrary position in the substrate surface on which the transparent electrode layer and the photoelectric conversion layer are formed;
Calculating the thickness of the second cell layer based on the measured transmittance, the haze rate of the transparent electrode layer measured in advance, and the thickness of the first cell layer measured in advance; A film thickness measuring method including   The film thickness measuring method according to claim 1, wherein the haze ratio and the film thickness of the first cell layer are the same as the position where the transmittance is measured in the substrate surface.   The film thickness measurement method according to claim 1, wherein the film thickness of the second cell layer at any plurality of positions in the substrate surface is calculated. An irradiation unit for irradiating measurement light of a predetermined wavelength to a substrate on which a transparent electrode layer and a photoelectric conversion layer composed of a first cell layer and a second cell layer are formed; and the measurement light transmitted through the substrate A transmittance measuring unit comprising: a detecting unit that receives transmitted light; and a transmittance calculating unit that calculates the transmittance from the intensity of the measurement light and the intensity of the transmitted light;
Based on the transmittance measured by the transmittance measuring unit, the haze rate of the transparent electrode layer measured in advance, and the thickness of the first cell layer measured in advance, the thickness of the second cell layer A film thickness measurement device comprising: a film thickness calculation unit that calculates A method for producing a photoelectric conversion device comprising a transparent electrode layer and a photoelectric conversion layer composed of a first cell layer and a second cell layer in order from the transparent electrode layer side on a substrate,
Measuring the transmittance at an arbitrary position within the substrate surface on which the transparent electrode layer and the photoelectric conversion layer are formed;
Based on the measured transmittance, the haze rate of the transparent electrode layer measured in advance, and the thickness of the first cell layer measured in advance, the second cell layer at an arbitrary position in the substrate plane Calculating the film thickness of
Comparing the calculated thickness of the second cell layer with a preset allowable thickness range;
And adjusting the film forming conditions of the second cell layer when the film thickness of the second cell layer is out of the allowable film thickness range. In the step of measuring the transmittance, the transmittance at any of a plurality of positions in the substrate surface is measured,
In the step of calculating the film thickness of the second cell layer, based on the transmittance at the plurality of arbitrary positions, the haze ratio of the transparent electrode layer, and the film thickness of the first cell layer, The film thickness of the second cell layer at any of a plurality of positions is calculated,
The method for manufacturing a photoelectric conversion device according to claim 5, wherein the film forming condition of the second cell layer is adjusted when the film thickness of the second cell layer at at least one position is out of the allowable film thickness range. Further including obtaining a film thickness distribution of the second cell layer from the calculated film thickness of the second cell layer at the plurality of positions,
The formation condition of the second cell layer is adjusted based on the film thickness distribution when the film thickness of the second cell layer in at least one position is out of the allowable film thickness range. A method for manufacturing a photoelectric conversion device.   Based on the transmittance, the haze rate at the same position as the position where the transmittance was measured, and the film thickness of the first cell layer at the same position as the position where the transmittance was measured, The method for manufacturing a photoelectric conversion device according to claim 5, wherein the film thickness of the second cell layer at an arbitrary position is calculated.

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