JP2005235874A - Heating unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a light irradiation heat treatment unit provided, in place of a conventional soaking plate, with a heat transmitting plate excellent in mechanical strength which does not deform significantly and exhibits a temperature variation quickly depending on a variation in lamp output. <P>SOLUTION: In the heating unit for irradiating a heat transmitting plate 4 with light from a light source 1 and heating a workpiece 6 with heat transmitted from the heat transmitting plate 4, the heat transmitting plate 4 comprises light transmitting holders 21, 22 and 23, and a heat transmitting layer 3 formed on the surface of the holder 22 and generating heat by absorbing the light irradiated from the light source 1 and transmitted through the holders 21, 22 and 23 wherein the holders 21, 22 and 23 have an air gap 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light irradiation type heating unit that heat-treats a substrate such as a wafer or a display panel.

Conventionally, in a process for processing a semiconductor wafer, various heat treatments such as annealing, film formation, and sputtering are performed. In addition to wafer processing, heat treatment is also performed in a glass substrate processing process for manufacturing a display panel.
As a heating unit of an apparatus for performing such a heat treatment, one using a sheath heater or a carbon heater as a heating means is known. In addition, there is a light irradiation type heating unit that uses a halogen lamp that efficiently emits infrared rays as a heating means.

  As a heating device that heats a glass substrate and uses a lamp as a heating means, one disclosed in JP-A-6-260422 is known. When a lamp is used as the heating means, there is an advantage that the temperature of the wafer or glass substrate can be controlled in a short time by changing the output of the lamp.

When heating a wafer or a glass substrate (hereinafter referred to as a workpiece together), it must be heated so that the temperature distribution on the workpiece surface is uniform. The reason for this is that when the film forming process is performed, if the temperature distribution is non-uniform, the formed film thickness also becomes non-uniform accordingly and causes a defect.
As a countermeasure, a member called a soaking plate is generally provided between the workpiece and the heating means (a lamp in the case of a light irradiation type heating unit). The soaking plate transmits the heat transferred from the heating means so that the heat soaking plate has a uniform distribution, and when the workpiece is heated, the temperature distribution of the workpiece is made uniform. As the soaking plate, a metal or carbon plate having good thermal conductivity is well known. Japanese Patent Application Laid-Open No. 7-172996 discloses using a stainless steel plate as a soaking plate.

JP-A-6-260422 Japanese Patent Laid-Open No. 7-172996

In general, soaking plates should have high thermal conductivity, large size and thickness, and large heat capacity in order to make them less susceptible to disturbances during heating. If the heat capacity of the heat equalizing plate is increased, the response time of the temperature change of the heat equalizing plate with respect to the output change of the lamp as the heating means becomes longer, and it is difficult to control the temperature of the work in a short time. Therefore, when a workpiece at room temperature is brought into the processing device for heating and heated, the soaking plate has a small heat capacity and changes the output of the lamp in order to raise it to the desired set temperature as quickly as possible. Accordingly, it is desired that the temperature changes following a short period of time.
Therefore, as the soaking plate used in the heating unit, it is desirable that the heat capacity is small as long as the temperature distribution of the work is not affected. However, in order to reduce the heat capacity of the soaking plate, the area is smaller than the work area. However, there is no way other than to make it thinner.

Conventionally, metal or carbon graphite is known as a soaking plate, and it is possible to manufacture and use a thin soaking plate having a thickness of 3 mm, for example, as follows. Problems arise.
When a metal plate is used as the soaking plate, warping (deformation) occurs during use. This is because the surface temperature on the heating means (lamp) side is likely to be higher than the surface temperature on the workpiece side during heating, and thermal distortion occurs, and this thermal distortion force is thin and can not withstand it. it is conceivable that.

When a carbon plate is used as the soaking plate, if it is left for a while after processing and molding, warping (deformation) of about 1 mm may occur with respect to the length of 300 mm. This is considered to be caused by gradually releasing the residual strain at the time of processing as the carbon plate, which was at a high temperature at the time of processing, is cooled.
When the soaking plate is warped or deformed in this way, the distance between the soaking plate and the workpiece is not uniform. For example, in the case of a warp of about 1 mm with respect to the length of 300 mm of the carbon plate, a gap difference of 1 mm is generated at both ends in the diameter direction with respect to a φ300 mm wafer. If the distance between the soaking plate and the work is not constant, the amount of heat transferred from the soaking plate to the work varies depending on the location, and the work cannot be heated with a uniform temperature distribution.

  In view of the above problems, the object of the present invention is to provide a light irradiation type heat treatment unit, in place of a conventional heat equalizing plate, with little deformation and a rapid temperature change in response to a change in lamp output, An object of the present invention is to provide a heating unit including a heat transfer plate having excellent mechanical strength.

In order to eliminate the “warping” of the soaking plate, in the research process of the present inventors, instead of the soaking plate, a heating unit in which a thin carbon vapor deposition film is formed on a light-transmitting thick glass plate Was invented. According to this heating unit, the heat capacity can be reduced by thinly forming a vapor deposition film that contributes to heat transfer, and the workpiece can be heated with a uniform temperature distribution because it does not warp unlike a soaking plate. Was expected.
This heating unit needs to have a certain thickness because the glass plate for forming the vapor deposition film on the surface may be bent or damaged in the worst case. However, when the thickness of the glass plate is increased, the heat absorbed by the vapor deposition film due to heating is also transmitted to the glass plate side, and heat transfer to the work is reduced, so that the desired set temperature may not be reached quickly. It was done.
Therefore, the inventors pay attention to suppressing the heat absorbed by the vapor deposition film from being transmitted to the glass plate even when the thickness of the glass plate is increased in order to ensure the mechanical strength of the glass plate. Thus, the present invention has been completed. Specifically, the following means were adopted.

  A first means is a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate, wherein the heat transfer plate has a light transmitting property. And a heat transfer layer that is provided on the surface of the holding body and generates heat by absorbing light transmitted through the holding body from the light source, and the holding body has a gap. Is a unit.

  The second means is the first means, wherein the holding body is a first holding body located on the light source side, a second holding body provided with the heat transfer layer on the surface, and the first holding body. A heating unit comprising a holding body and a gap interposed between the second holding body, wherein the gap is formed between the first holding body and the second holding body.

  A third means is the first means or the first means, wherein the heat transfer layer comprises diamond-like carbon, metal oxide such as chromium oxide, nitride such as aluminum nitride or boron nitride, silicon carbide, silver or A heating unit comprising one of a metal such as gold paste and a silicide such as molybdenum silicide.

  The fourth means is a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate, wherein the heat transfer plate has a light transmitting property. And a gap provided on the holder, and a light provided on the gap, which passes through the holder from the light source, and further absorbs light transmitted through the gap and the gap between the gaps. And a heat transfer unit that generates heat.

  A fifth means is a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate. The heat transfer plate penetrates in a direction in which light is transmitted. A holding body having a gap formed of a round shape or a polygonal shape, and a heat transfer body that is provided on the holding body and generates heat by absorbing light transmitted through the holding body from the light source. This is a heating unit.

  A sixth means is the heating unit according to the fifth means, wherein the holding body is made of ceramics.

  A seventh means is any one of the fourth means to the sixth means, wherein the heat transfer body is made of quartz glass containing niobium or molybdenum, a nitride such as aluminum nitride or boron nitride, or silicon carbide. It is a heating unit comprising any one of them.

  According to the present invention, it is possible to solve the problem that heating cannot be performed with a uniform temperature distribution due to warpage that has occurred in a conventional heat equalizing plate, and it is accumulated in a heat transfer layer or a heat transfer body by a gap. Therefore, it is possible to reliably suppress the transfer of the heat to the holding body side, to efficiently perform the heat transfer of the object to be heated, and to raise the temperature of the object to be heated in a short time.

A first embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a front sectional view showing a configuration of a heating unit according to the invention of the present embodiment.
In this figure, this heating unit emits light having a wavelength that passes through the holder 2, for example, an incandescent lamp such as a halogen lamp, a discharge lamp such as a xenon lamp or a ceramic metal halide lamp, and a holder. 2 and a heat transfer plate 4 comprising a heat transfer layer 3 formed on the surface of the holding body 2 on the heated object 6 side, and a heating unit main body 5 for supporting the light source 1 and the heat transfer plate 4. The The heat transfer plate 4 generates heat when the light radiated from the light source 1 and transmitted through the holding body 2 is received by the heat transfer layer 3, and heats the object 6 to be heated, such as a wafer or a glass substrate. .

FIG. 2 is an enlarged cross-sectional view of the heat transfer plate 4 shown in FIG.
In the figure, the holding body 2 includes a plate-like first holding body 21 disposed on the light source 1 side, a spherical gap 23 welded to the first holding body 21, and a weld to the gap 23. It is comprised from the plate-shaped 2nd holding body 22 made. As shown in the figure, a gap 23 is interposed between the first holding body 21 and the second holding body 22, so that a gap 7 is formed between the first holding body 21 and the second holding body 22. Is formed.
The first holding body 21, the second holding body 22, and the gap 23 each have optical transparency, for example, glass such as quartz glass, borosilicate glass, sintered quartz glass, soda quartz glass, glass ceramic, It is composed of either alumina or sapphire. These materials have a smaller coefficient of thermal expansion than metals and carbon graphite, are not prone to deformation, are chemically robust and have excellent heat resistance, and mainly transmit light from the ultraviolet to the infrared range. There is little fever.

  An example of the dimension regarding the holding body 2 is given below. The thickness of the 1st holding body 21 is selected from the range of 2-10 mm, for example, is 5 mm. Moreover, the thickness of the 2nd holding body 22 is selected from the range of 0.2-0.6 mm, for example, is 0.3 mm. The outer diameter of the gap 23 is selected from a range of 0.5 mm to 2 mm, for example, 1 mm, and the interval between the gaps 23 is selected from a range of 10 to 50 mm, for example, 30 mm.

Next, an example of a method for attaching the gap 23 to the first holding body 21 and the second holding body 22 will be described.
Although not shown in FIG. 2, the first holding body 21 and the surface of the second holding body 22 on the side in contact with the gap 23 have recesses or holes so as to conform to the shape of the gap 23. Is provided. First, the gap 23 is arranged in the concave portion of the first holding body 21 and the periphery of the portion where both abut with each other is joined with an inorganic adhesive (in the case of 250 ° C. or less, a resin-based organic adhesive is also possible). To do. Thereafter, the second holding body 22 and the periphery of the gap 23 are bonded in the same manner as described above with the concave portion or hole of the second holding body 22 in contact with the upper portion of the gap 23 (upward in the drawing). Join with agent.

  In addition, when the holders 21 and 22 and the gap 23 are both glass, fusing by heating using frit glass is possible. Further, when the gap 23 is formed on the first holding body 21, it can be formed by cutting in addition to a mechanical fixing method using screws or pins.

  The heat transfer layer 3 formed on the surface of the second holding body 22 includes diamond-like carbon (DLC), metal oxide such as chromium oxide, nitride such as aluminum nitride and boron nitride, silicon carbide, silver and gold paste. Or the like, or a silicide such as molybdenum silicide. These materials are chemically robust and excellent in heat resistance, and generate heat by blocking light from the ultraviolet region to the visible region, and are excellent in heat transfer rate.

  The coating of the heat transfer layer 3 on the second holding body 22 is performed by CVD in the case of diamond-like carbon (DLC), metal oxides such as chromium oxide, nitrides such as aluminum nitride and boron nitride, silicon carbide In the case of sputtering, metal such as silver or gold paste is formed by screen printing, and silicide such as molybdenum silicide is formed by CVD, sputtering or heating after vapor deposition. If CVD, sputtering, vapor deposition, or printing is used, the thickness of the heat transfer layer 3 can be controlled to a desired thickness even when the surface of the second holding body 22 has some unevenness. . Specifically, the thickness of the heat transfer layer 3 is selected from the range of 40 to 100 μm, for example, 100 μm.

Furthermore, the heat transfer effect | action to the to-be-heated material 6 of the heating unit which concerns on invention of this embodiment is demonstrated using FIG.
The light emitted from the light source 1 is applied to the heat transfer plate 4, and the irradiated light passes through the first holding body 21, passes through the gap 23 and the gap 7 between the gaps 23, and then the second The heat transfer layer 3 is irradiated through the holder 22. When the heat transfer layer 3 is irradiated with light, the heat transfer layer 3 generates heat and is transferred to the heated object 6 such as a wafer or a glass substrate, and the heated object 6 is uniformly heated.

  According to the heat equalizing plate 4 of the present invention, it is possible to solve the problem that heating cannot be performed with a uniform temperature distribution due to warpage that has occurred in conventional heat equalizing plates made of metal or carbon. The second holding body 22 provided with the heat transfer layer 3 is as thin as 0.3 mm as described above. However, since the second holding body 22 is supported by a plurality of gaps 23, there is a problem such as bending. Does not occur.

Further, according to the heating unit of the present invention, the first holding body 21 and the second holding body 22 are provided by interposing the gap 23 between the first holding body 21 and the second holding body 22. Since the space | gap 7 is formed in between, it can suppress reliably that the heat | fever accumulate | stored in the heat-transfer layer 3 is transmitted to the 1st holding body 21 side.
That is, since the gap 7 is formed by interposing the gap 23 between the first holding body 21 and the second holding body 22, the gap 7 is normally filled with air. In the gap 7, the thermal conductivity is lower than that of the material constituting the first holding body 21 and the second holding body 22. Therefore, in a thick holding body structure that does not have a gap as previously proposed, heat accumulated in the heat transfer layer is easily transferred to the holding body side, but according to the holding body structure of the present invention, heat transfer Since the heat accumulated in the layer 3 passes through the gap 7 having a lower thermal conductivity than the material constituting the holding bodies 21 and 22, it is possible to suppress the heat transfer to the first holding body 21 side.
Therefore, by arranging the object to be heated 6 close to the heat transfer layer 3, the object to be heated 6 can be efficiently transferred, and the object to be heated 6 can be raised in a short time.

  In addition, although the case where air is used as the gas filled in the gap 7 has been described, the present invention is not limited to this, and the holding body 2 is sealed so that the inside is in a vacuum state, or nitrogen gas or rare heat with low heat conduction is used. It is also possible to fill a gas such as a gas. As a result, the above effect can be further improved.

FIG. 4 is an enlarged cross-sectional view of a modification of the heat transfer plate 4 shown in FIG.
As shown in the figure, in this modification, a plurality of angular gaps 24 are provided on the surface of the first holding body 21 on the heated object 6 side. Other configurations correspond to the configurations of the same reference numerals shown in FIG.
A gap 7 is formed between the first holding body 21 and the second holding body 22 by attaching the second holding body 22 to the gap 24 with, for example, an adhesive. For example, the gap 24 is formed on a plate to be the first holding body 21 by a method such as machining or adhesion.
Also in this modification, the same operation and effect as in the case of the heat transfer plate 4 shown in FIG. 2 can be achieved.

Next, a second embodiment according to the present invention will be described with reference to FIGS.
FIG. 5 is an enlarged cross-sectional view of the heat transfer plate 10 constituting the heating unit according to the invention of the present embodiment.
Compared to the heat transfer plate 4 of the first embodiment, the heat transfer plate 10 of the present embodiment is coated with the heat transfer layer 3 on the surface of the second holding body 22 in the heat transfer plate 4 of the first embodiment. In contrast, the heat transfer plate 10 of the present embodiment has the heat transfer body 9 in which the holding body and the heat transfer layer are integrally formed, and the holding body 8 is spherical with the first holding body 81. It is different in that it is composed of a gap element 82.

The heat transfer body 9 is made of any one of quartz glass containing niobium or molybdenum, nitrides such as aluminum nitride and boron nitride, and silicon carbide. The thickness of the heat transfer body 9 is selected from the range of 0.1 to 0.8 mm, for example, 0.4 mm.
In this heating unit, when the light transmitted through the first holding body 81 is irradiated onto the heat transfer body 9, the heat transfer body 9 generates heat and is transferred to a heated object such as a wafer or a glass substrate. Things are heated uniformly. The heat transfer plate 10 of this embodiment can also exhibit the same effects as the heat transfer plate 4 of the first embodiment.

FIG. 6 is an enlarged cross-sectional view of a modification of the heat transfer plate 10 shown in FIG.
As shown in the figure, in this modification, a plurality of angular gaps 83 are provided on the surface of the first holding body 81 on the heated object 6 side. Other configurations correspond to the configurations of the same reference numerals shown in FIG.
Also in this modification, the same effect as the case of the heat exchanger plate 10 shown in FIG. 5 can be exhibited.

Next, a third embodiment according to the present invention will be described with reference to FIGS.
FIG. 7 is an enlarged cross-sectional view of the heat transfer plate 12 constituting the heating unit according to the invention of the present embodiment.
Compared with the heat transfer plate 10 of the second embodiment, the heat transfer plate 12 of the present embodiment is provided with gaps 82 and 83 on the first holding body 81 in the heat transfer plate 10 of the second embodiment. In contrast to the above, the heat transfer plate 12 of the present embodiment is different in that it has a holding body 11 having a through hole in a light transmitting direction. Other configurations correspond to configurations of the same reference numerals shown in FIGS.

  Here, the holding body 11 penetrates in the light-transmitting direction as shown in FIG. 8B, or the round gap 7 penetrating in the light-transmitting direction, as shown in FIG. 8A. As shown in FIG. 8D, the honeycomb-shaped voids 7 and the lattice-shaped voids 7 penetrating in the light transmitting direction are provided. 8C is a cross-sectional view taken along AB in FIG. 8A or CD in FIG. 8B, and FIG. 8E shows E in FIG. 8D. It is sectional drawing seen from -F.

  In the heat transfer plate 12 of the present embodiment, the gap 7 that is a through hole provided in the holding body 11 exhibits the same function as the gap 7 in the first embodiment and the second embodiment. As shown in FIGS. 8A to 8E, the shape of the gap 7 that is a through hole can be various shapes, but is not limited to the through hole and may be a bottomed hole. The thickness of the holding body 11 is selected from a range of 2 to 20 mm, for example, 10 mm, and the diameter of the gap 7 that is a through hole is selected from a range of 3 to 15 mm, for example, 5 mm. The void area ratio in the portion of the heat transfer body 9 is, for example, 70%.

The material of the holding body 11 is any one of glass such as quartz glass, borosilicate glass, sintered quartz glass, and soda quartz glass, glass ceramic, alumina, sapphire, and the like, but is not limited thereto and transmits light. Ceramics such as alumina and zirconia that do not have properties may be used.
The heat transfer plate 12 of this embodiment can also exhibit the same effects as the heat transfer plate 4 of the first embodiment and the heat transfer plate 10 of the second embodiment.

Next, experiments that demonstrate the effects of the present invention and the invention proposed in the research process (hereinafter referred to as comparative examples) will be described. A numerical example of the heating unit manufactured for the experiment is as follows. In addition, the thing of the structure shown in FIG. 2 is employ | adopted for the heat exchanger plate 4 integrated in the heating unit of the invention example shown below.
(Invention example)
Light source 1: Halogen lamp with power consumption of 55 W Spacing (pitch) between light sources 1: 56 mm
Distance between light source 1 (filament center) and heat transfer plate 4: 50 mm
Number of light sources 1: 5 Dimensions of heat transfer plate 4: length 70mm, width 260mm
Structure of heat transfer plate 4: In the holding body 2 having a structure in which a gap 23 is interposed between the first holding body 21 and the second holding body 22, a heat transfer layer is formed on the surface of the second holding body 22. 3 (see FIG. 2)
Dimensions of holding body 2: thickness of first holding body 21 5 mm, thickness of second holding body 22 0.3 mm, outer diameter of gap 23 1 mm
Material of the holder 2: All of the first holder 21, the second holder 22 and the gap 23 are quartz glass. Heat transfer layer 3: Diamond-like carbon having a thickness of 100 μm (comparative example)
Heat transfer plate structure: heat transfer layer 3 is formed on the surface of a single plate holder. Dimensions of holder: thickness 1 mm
Material of holding body: quartz glass Other structures are the same as the above-described invention example.
(Conventional example)
Heat transfer plate structure: carbon graphite having a thickness of 1 mm There is no carrier and heat transfer layer, and the other structures are the same as those of the above-described invention example.
In the experiment, the halogen lamp in each heating unit of the invention example, the comparative example, and the conventional example was turned on, and the temperature rise characteristic in the range of the central portion φ50 of the heat transfer plate was measured.

The result of the temperature increase rate obtained by the above experiment is shown in FIG. In the figure, the horizontal axis represents the time from the start of lamp lighting, and the vertical axis represents the rising temperature of the heat transfer plate.
As shown in FIG. 9, the heating unit of the invention requires 11 seconds to reach a predetermined temperature, whereas the comparative and conventional heating units require 13 seconds and 22 seconds, respectively. doing. As is clear from this, it can be seen that the heating rate is greatly improved in the invention example and the comparative example as compared with the conventional example. In addition, it can be seen that the invention example is further excellent in the heating rate compared to the comparative example. That is, it can be seen that the heat transfer plate of the present invention can change the temperature quickly by changing the output of the lamp and can raise the temperature of the object to be heated in a short time.

It is front sectional drawing which shows the structure of the heating unit which concerns on invention of 1st Embodiment. It is an expanded sectional view of the heat exchanger plate 4 shown in FIG. It is a figure for demonstrating the heat transfer effect | action to the to-be-heated material 6 of the heating unit which concerns on invention of 1st Embodiment. It is an expanded sectional view of the modification of the heat exchanger plate 4 shown in FIG. It is an expanded sectional view of the heat exchanger plate 10 which comprises the heating unit which concerns on invention of 2nd Embodiment. It is an expanded sectional view of the modification of the heat exchanger plate 10 shown in FIG. It is an expanded sectional view of the heat exchanger plate 12 which comprises the heating unit which concerns on invention of 3rd Embodiment. It is a figure which shows the shape of the holding body 11 shown in FIG. It is a figure which shows the result of the temperature increase rate obtained by experiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Holding body 21 1st holding body 22 2nd holding bodies 23 and 24 Spacer 3 Heat transfer layer 4 Heat transfer plate 5 Heating unit main body 6 Heated object 7 Space | gap
8 Holder 81 First Holder 82, 83 Gap 9 Heat Transfer Body 10 Heat Transfer Plate 11 Holder 12 Heat Transfer Plate

Claims (7)

In a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate,
The heat transfer plate is composed of a holder having light permeability, and a heat transfer layer that is provided on the surface of the holder and absorbs light transmitted through the holder from the light source to generate heat. The heating unit, wherein the holding body has a gap.   The holding body is interposed between the first holding body positioned on the light source side, the second holding body having the heat transfer layer provided on the surface thereof, and the first holding body and the second holding body. 2. The heating unit according to claim 1, wherein the heating unit includes a gap element, and the gap is formed between the first holding body and the second holding body.   The heat transfer layer is made of any one of metal oxides such as diamond-like carbon and chromium oxide, nitrides such as aluminum nitride and boron nitride, metals such as silicon carbide, silver and gold paste, and silicides such as molybdenum silicide. The heating unit according to claim 1 or 2, characterized by comprising: In a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate,
The heat transfer plate includes a light-transmissive holder, a gap provided on the holder, the gap provided on the gap, and passes through the holder from the light source, and further includes the gap and A heating unit comprising: a heat transfer body that absorbs light transmitted through the gap between the gaps and generates heat. In a heating unit that irradiates a heat transfer plate with a light source and heats an object to be heated by heat transfer from the irradiated heat transfer plate,
The heat transfer plate is provided with a holding body having a gap in which a shape penetrating in a light transmitting direction is a round shape or a polygonal shape, and light transmitted through the holding body from the light source. A heating unit comprising a heat transfer body that absorbs heat and generates heat.   The heating unit according to claim 5, wherein the holding body is made of ceramics.   The heat transfer body is made of any one of quartz glass containing niobium or molybdenum, nitrides such as aluminum nitride and boron nitride, and silicon carbide. The heating unit according to claim.

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