JP2006093725A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress decomposition of organic molecules constituting an electronic device. <P>SOLUTION: The electronic device is configured to include components of the organic molecules 305, and the outer periphery of the organic molecules 305 has water repellency. In the electron device, for example, a gate insulating film 302 is formed on an integrated circuit substrate 300, and the source electrode 303 and the drain electrode 304 are formed on the gate insulating film 302 so as to face each other via the upper side of a gate electrode 301, while the organic molecule 305 is provided so as to connect the source electrode 303 to the drain electrode 304. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic device such as a field effect transistor having organic molecules.

  In recent years, with the progress of higher integration of electronic integrated circuits using semiconductors, the size of transistors has been reduced, and at present, the operation of transistors having a gate length of 10 nm has been confirmed.

  However, in an electronic integrated circuit having a transistor having a gate length of 10 nm or less, an accuracy of 1 nm or less is required as a gate dimension, and thus it is difficult to finely process the transistor.

  Thus, in order to overcome the problem of miniaturization of transistors, transistors using organic molecules have been proposed. For example, according to a paper “Self-assembled monolayer organic field-effect transistors” described on page 713 of Nature Vol. 413, a transistor having an organic molecule as a constituent element as shown in FIG. 7 is proposed.

  As shown in FIG. 7, a gate insulating film 11 made of a silicon oxide film is formed on a silicon substrate 10 having a step portion so as to cover the step portion. A source electrode 12 is formed on the lower surface of the stepped portion on the gate insulating film 11, and an organic molecular film 13 is formed on the source electrode 12. A drain electrode 14 is formed from the upper surface of the organic molecular film 13 to the upper surface of the stepped portion on the gate insulating film 11 through the stepped portion.

  In this transistor, if no gate voltage is applied to the silicon substrate 10, no current flows through the organic molecular film 13, so the transistor is turned off. On the other hand, when a gate voltage is applied to the silicon substrate 10, the source electrode 12 Since a current flows through the organic molecular film 13 to the drain electrode 14, the transistor is turned on, and thus operates as a transistor. In this transistor, the gate length corresponds to the length of the organic molecule, that is, the thickness of the organic molecular film 13, and it is easy to control the length of the organic molecule to 10 nm or less.

  By the way, the aforementioned organic molecular transistor has a problem in the stability of the organic molecule. More specifically, the organic molecules constituting the electronic device are easily decomposed by the influence of water, oxygen, or active oxygen present in the vicinity thereof. For this reason, it is difficult to obtain stable transistor performance over a long period of time. This problem is particularly important when organic molecular transistors are integrated in a package and finally packaged as a chip.

  In view of the above, an object of the present invention is to enable organic molecules constituting an electronic device to maintain insulating properties for a long period of time.

  In order to achieve the above object, the first electronic device according to the present invention is directed to an electronic device having an organic molecule as a component, and the outer peripheral portion of the organic molecule is water-repellent.

  According to the first electronic device of the present invention, since the outer peripheral portion of the organic molecule is water repellent, water that tries to adhere to the organic molecule is repelled, so that the oxidation of the organic molecule can be prevented. However, the insulating property can be maintained for a long time.

  In the first electronic device, the organic molecule preferably has a water-repellent group on the outer periphery thereof.

  In this way, the water that tries to adhere to the organic molecules is surely repelled.

  In this case, the water-repellent group is preferably a group containing fluorine.

  If it does in this way, the outer peripheral part of an organic molecule can exhibit strong water repellency.

  The first electronic device is particularly effective when at least one end of the organic molecule is bonded to an electrode formed on the surface of the substrate. That is, when the organic molecule is exposed on the surface of the substrate, the organic molecule can be reliably prevented from being oxidized by making the outer periphery of the organic molecule water repellent.

  In the case where at least one end of the organic molecule is bonded to the electrode, the substrate preferably has a wiring that is connected to the electrode and inputs or outputs an electric signal to the organic molecule.

  In order to achieve the above object, a second electronic device according to the present invention is directed to an electronic device having an organic molecule as a component, and the outer peripheral portion of the organic molecule is electrically insulating.

  According to the second electronic device of the present invention, since the outer peripheral portion of the organic molecule is electrically insulative, the organic molecule is not affected from the outside by static electricity or an ionic substance. Electrical characteristics are stable over a long period of time.

  In the second electronic device, the organic molecule preferably has an insulating group on the outer periphery thereof.

  In this way, it is possible to reliably prevent the situation where the organic molecules are affected by static electricity or ionic substances.

  In this case, the insulating group is preferably a group containing an alkyl chain.

  If it does in this way, the outer peripheral part of an organic molecule can exhibit strong insulation.

  The second electronic device is particularly effective when at least one end of the organic molecule is bonded to an electrode formed on the surface of the substrate. That is, when the organic molecule is exposed on the surface of the substrate, if the outer periphery of the organic molecule is made insulative, the influence of static electricity or an ionic substance on the organic molecule can be surely prevented.

  In the case where at least one end of the organic molecule is bonded to the electrode, the substrate preferably has a wiring that is connected to the electrode and inputs or outputs an electric signal to the organic molecule.

  According to the first electronic device of the present invention, since the outer peripheral portion of the organic molecule is water repellent, water that adheres to the organic molecule is repelled, so that the organic molecule can be prevented from being oxidized. Insulating properties can be maintained.

  According to the second electronic device of the present invention, since the outer peripheral portion of the organic molecule is electrically insulative, the organic molecule is not affected from the outside by static electricity or an ionic substance. Electrical characteristics are stable over a long period of time.

(First embodiment)
Hereinafter, an electronic device according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 shows a cross-sectional structure of the electronic device according to the first embodiment, and FIG. 2 shows an enlarged cross-sectional structure of a main part in FIG.

  As shown in FIGS. 1 and 2, a gate electrode 101 made of a polysilicon film is formed on a surface portion of an integrated circuit substrate 100 in which a multilayer metal wiring is formed inside the substrate, and the integrated circuit substrate 100 A gate insulating film 102 made of a zirconium oxide film and having a thickness of 3 nm is formed so as to cover the gate electrode 101.

  A source electrode 103 and a drain electrode 104 are formed on the gate insulating film 102 so as to face each other with an upper portion of the gate electrode 101 interposed therebetween, and an organic material is connected so as to connect the source electrode 103 and the drain electrode 104. A molecule 105 is provided, and the source electrode 103, the drain electrode 104, and the organic molecule 105 constitute a field effect transistor 106 that is an electronic element having an organic molecule as a component. The organic molecules 105 are arranged side by side in the front and back direction of the paper.

  The gate electrode 101, the source electrode 103, and the drain electrode 104 are each connected to a metal wiring formed inside the integrated circuit substrate 100, and from the metal wiring to the gate electrode 101, the source electrode 103, and the drain electrode 104. On the other hand, an input signal or an output signal is input / output.

  When no voltage is applied to the gate electrode 101, no current flows through the organic molecules 105, so that the field effect transistor 106 is in an off state, whereas when a voltage is applied to the gate electrode 101, Since current flows through the molecule 105 to the drain electrode 104, the field-effect transistor 106 is turned on.

  The field effect transistor 106 is covered with a protective member 108 containing an inert gas such as nitrogen gas 107 together with the integrated circuit substrate 100. In this case, in the atmosphere of an inert gas such as nitrogen gas 107, water, oxygen and ionic substances are substantially not contained.

  Thus, since the organic molecule 105 exists in the nitrogen gas 107 in which impurities such as water, oxygen, and ionic substances do not exist, it is not affected by the ionic substances, and thus is maintained in a good insulating state. In addition, malfunction of the transistor does not occur, and the organic molecule 105 does not undergo oxidative decomposition due to water or oxygen.

  The integrated circuit substrate 100 and the field effect transistor 106 held on the integrated circuit substrate 100 in an atmosphere of nitrogen gas 107 are sealed in a package 109. An end portion on the inner side of the lead terminal 110 penetrating the package 109 is connected to a bonding terminal 111 formed on the surface portion of the integrated circuit substrate 100 via a bonding wire 112.

  In order to manufacture the electronic device according to the first embodiment, a plurality of field effect transistors 106 held on the integrated circuit substrate 100 are covered with a protection member 108 and then protected from the integrated circuit substrate 100. A space formed by the member 108 is purged with nitrogen gas 107.

  According to the first embodiment, since the insulating property of the organic molecule 105 can be maintained without depositing an insulating film on the field effect transistor 106, that is, the organic molecule 106 has its own weight or heat during film formation. Therefore, the electronic device can be stably operated over a long period of time.

  In addition, since the field effect transistor 106 having the organic molecule 105 is held in an atmosphere of nitrogen gas 107 that does not contain impurities such as water, oxygen, and ionic substances, oxidative decomposition of the organic molecule 105 by water or oxygen occurs. In addition, there is no malfunction of the electronic device due to the ionic material, and good insulation can be obtained.

  In addition, since the organic molecule 105 is covered with the protective member 108 in which the nitrogen gas 107 is confined, a situation in which the impurity enters from the outside is prevented, so that deterioration of electrical characteristics due to the impurity can be prevented.

  In the first embodiment, a molecule indicating a semiconductor such as polythiophene is used as the organic molecule 105. Instead, a porphyrin, a phenyl base polymer, a polymer having another thiophene unit, carbon, and the like are used. A semiconductor or a conductive organic molecule such as a nanotube or fullerene can be used.

  Further, in the first embodiment, the nitrogen gas 107 is used as the inert gas, but argon gas, helium gas, neon gas, or the like can be used instead.

  In the first embodiment, a field effect transistor having an organic molecule is used as the electronic element. However, the electronic element is not limited to this, and is an organic molecular electronic element having other functions such as a diode or an optical switch. In addition, the structure of the electronic element is not limited to that of the first embodiment.

  In the first embodiment, the field effect transistor 106 is covered with the protective member 108 confining the nitrogen gas 107. Instead, the field effect transistor 106 is replaced with the protective member 108. You may hold | maintain in the atmosphere of the nitrogen gas with which it filled in the package 109, without covering.

(Modification of the first embodiment)
Hereinafter, an electronic device according to a modification of the first embodiment will be described with reference to FIG.

  A gate electrode 152 made of a polysilicon film is formed on an integrated circuit substrate 150 in which a multilayer metal wiring is formed inside the substrate via a gate insulating film 151 made of a silicon oxide film. A source region 153 and a drain region 154 are formed on the surface portion of the integrated circuit substrate 150 so as to face each other with a lower portion of the gate electrode 152 interposed therebetween. The gate electrode 152, the source region 153, and the drain region 154 A MOS field effect transistor, which is an electronic element, is configured.

  The MOS field effect transistor is covered with a protective member (not shown) that confines an inert gas such as nitrogen gas 155 together with the integrated circuit substrate 150. In this case, in an atmosphere of an inert gas such as nitrogen gas 155, water, oxygen and ionic substances are substantially not contained.

  According to the modification of the first embodiment, the insulating property of the gate electrode 152 can be maintained without depositing an insulating film on the gate electrode 152. Therefore, even when the gate electrode 152 becomes extremely fine and cannot withstand the dead weight of the insulating film or the heat generated when the film is deposited, the insulating property can be maintained. For this reason, an electronic device can be operated stably over a long period of time.

(Second Embodiment)
Hereinafter, an electronic device according to a second embodiment of the present invention will be described with reference to FIG.

  As in the first embodiment, a gate electrode made of a polysilicon film is formed on the surface portion of the integrated circuit substrate 200 in which a multilayer metal wiring is formed inside the substrate, and on the integrated circuit substrate. Is formed of a zirconium oxide film having a thickness of 3 nm so as to cover the gate electrode. A source electrode and a drain electrode are formed on the gate insulating film so as to face each other with an upper portion of the gate electrode interposed therebetween, and organic molecules are provided so as to connect the source electrode and the drain electrode. These source electrode, drain electrode and organic molecules constitute a field effect transistor which is an electronic element having organic molecules as components.

  The gate electrode, the source electrode, and the drain electrode are each connected to a metal wiring formed inside the integrated circuit substrate, and an input signal or an output from the metal wiring to the gate electrode, the source electrode, and the drain electrode. Signals are input and output.

  As shown in FIG. 4, the field effect transistor 206 is covered with a protective member 208 that holds the interior of the integrated circuit substrate 200 in a vacuum state 207. In this case, the atmosphere in the vacuum state 207 is substantially free of water, oxygen, and ionic substances.

  The integrated circuit substrate 200 and the field effect transistor 206 held on the integrated circuit substrate 200 in an atmosphere in a vacuum state 207 are sealed in a package 209. An end portion on the inner side of the lead terminal 210 passing through the package 209 is connected to a bonding terminal 211 formed on the surface portion of the integrated circuit substrate 200 via a bonding wire 212.

  In order to manufacture an electronic device according to the second embodiment, a plurality of field effect transistors 206 held on the integrated circuit substrate 200 are covered with a protection member 208, and then the integrated circuit substrate 200 and the protection are protected. The space formed by the member 208 is depressurized to a vacuum state.

  According to the second embodiment, the insulating properties of organic molecules can be maintained without depositing an insulating film on the field effect transistor 206. That is, the organic molecules are damaged by the dead weight of the insulating film or by heat during film formation. Therefore, the electronic device can be stably operated over a long period of time.

  In addition, since the field effect transistor 206 having organic molecules is held in an atmosphere of a vacuum state 207 that does not contain impurities such as water, oxygen, and ionic substances, the organic molecules are not oxidatively decomposed by water or oxygen. The electronic device does not malfunction due to the ionic substance, and good insulation can be obtained.

  In addition, since the organic molecules are held in an atmosphere in a vacuum state 207, collision with other molecules that cause fluctuations in the potential of the organic molecules hardly occurs, so that highly reliable electrical characteristics can be obtained.

  In the second embodiment, as the organic molecule, a molecule indicating a semiconductor such as polythiophene is used. Instead, a porphyrin, a phenyl base polymer, a polymer having another thiophene unit, a carbon nanotube Alternatively, a semiconductor or a conductive organic molecule such as fullerene can be used.

  In the second embodiment, a field effect transistor having an organic molecule is used as the electronic element. However, the present invention is not limited to this, and the electronic element is an organic molecular electronic element having other functions such as a diode or an optical switch. In addition, the structure of the electronic element is not limited to that of the second embodiment.

  In the second embodiment, the field effect transistor 206 is covered with the protective member 208 that holds the vacuum state 207. Instead, the field effect transistor 206 is replaced with the protective member 208. It may hold | maintain inside the package 209 hold | maintained in the vacuum state, without covering by.

(Third embodiment)
Hereinafter, an electronic device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 shows an enlarged cross-sectional structure of the main part of the electronic device according to the third embodiment.

  As shown in FIG. 5, a gate electrode 301 made of a polysilicon film is formed on the surface portion of the integrated circuit substrate 300 in which a multilayer metal wiring is formed inside the substrate, and on the integrated circuit substrate 300. A gate insulating film 302 made of a zirconium oxide film and having a thickness of 3 nm is formed so as to cover the gate electrode 301.

  A source electrode 303 and a drain electrode 304 are formed on the gate insulating film 302 so as to face each other with an upper portion of the gate electrode 301 interposed therebetween, and an organic so as to connect the source electrode 303 and the drain electrode 304. A molecule 305 is provided, and the field effect transistor 306 is configured by the source electrode 303, the drain electrode 304, and the organic molecule 305. The organic molecules 305 are arranged side by side in the front and back direction of the paper.

  The gate electrode 301, the source electrode 303, and the drain electrode 304 are each connected to a metal wiring formed inside the integrated circuit substrate 300, and the gate electrode 301, the source electrode 303, and the drain electrode 304 are connected from the metal wiring. On the other hand, an input signal or an output signal is input / output.

  When no voltage is applied to the gate electrode 301, no current flows through the organic molecules 305, so that the field effect transistor 306 is in an off state, while when a voltage is applied to the gate electrode 301, Since current flows through the molecule 305 to the drain electrode 304, the field-effect transistor 306 is turned on.

  The organic molecule 305 is a polymer having a semiconductor structure of polythiophene as a skeleton. When the thiophene is modified with, for example, a trifluoroalkyl chain, the outer peripheral portion of the polymer is water-repellent.

  A structure in which a plurality of field effect transistors 306 are integrated on an integrated circuit substrate 300 is housed in a package (not shown) filled with argon gas 307 inside.

  According to the third embodiment, in the electronic device having the organic molecule 305, the insulating property can be maintained without destroying the organic molecule 305, so that the electronic device can stably operate for a long period of time. Become.

  In particular, since the outer peripheral portion of the organic molecule 305 has water repellency, the organic molecule 305 repels water even if a slight amount of water is present in the atmosphere of the argon gas 307. Therefore, the organic molecule 305 is oxidatively decomposed by water. Absent. Moreover, since the water repellent group in the outer peripheral portion of the organic molecule 305 contains an alkyl chain, high insulation can be obtained.

  In the third embodiment, a polymer having a polythiophene skeleton as the organic molecule 305 is used as a molecule having a water-repellent group modified, but a polymer having a phenyl base polymer as a skeleton or a molecule such as a carbon nanotube. A water-repellent group may be modified and used on the outer peripheral portion.

  Further, as the water-repellent group, a trifluoroalkyl chain is used, but instead, a group containing another fluorine atom may be used.

  In the third embodiment, the field effect transistor 306 having the organic molecules 305 is held in an argon gas atmosphere. Instead of the argon gas, an inert gas such as nitrogen gas, helium gas, or neon gas is used. May be used. In addition, as in the first or second embodiment, it is preferable to cover the field effect transistor 306 with a protective member that maintains an inert gas atmosphere together with the integrated circuit substrate 300. However, the field effect transistor 306 is not necessarily covered with the protective member. Good.

  In the third embodiment, the field effect transistor 306 having the organic molecule 305 is used as the electronic element. However, an electronic element having a function such as a diode or an optical switch element may be used instead. In addition, the structure of the electronic element is not limited to that of the third embodiment.

(Fourth embodiment)
Hereinafter, an electronic device according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 shows an enlarged cross-sectional structure of the main part of the electronic device according to the fourth embodiment.

  As shown in FIG. 6, a gate electrode 401 made of a polysilicon film is formed on the surface portion of the integrated circuit substrate 400 in which a multilayer metal wiring is formed inside the substrate, and on the integrated circuit substrate 400. A gate insulating film 402 made of a zirconium oxide film and having a thickness of 3 nm is formed so as to cover the gate electrode 401.

  A source electrode 403 and a drain electrode 404 are formed on the gate insulating film 402 so as to face each other with an upper portion of the gate electrode 401 interposed therebetween, and the source electrode 403 and the drain electrode 404 are connected to each other. An organic molecule 405 is provided, and the field effect transistor 406 is configured by the source electrode 403, the drain electrode 404, and the organic molecule 405. The organic molecules 405 are arranged side by side in the front and back direction of the paper.

  The gate electrode 401, the source electrode 403, and the drain electrode 404 are each connected to a metal wiring formed inside the integrated circuit substrate 400, and the gate electrode 401, the source electrode 403, and the drain electrode 404 are connected from the metal wiring. On the other hand, an input signal or an output signal is input / output.

  When no voltage is applied to the gate electrode 401, no current flows through the organic molecules 405, so that the field-effect transistor 406 is in an off state, whereas when a voltage is applied to the gate electrode 401, Since a current flows through the molecule 405 to the drain electrode 404, the field effect transistor 406 is turned on.

  The organic molecule 405 is a polymer having a semiconductor structure of polythiophene as a skeleton. When the thiophene is modified with, for example, an alkyl chain having a dendrid structure, the outer periphery of the polymer has an electrical insulating property. Yes.

  A structure in which a plurality of field effect transistors 406 are integrated on an integrated circuit substrate 400 is housed in a package (not shown) filled with a dry atmosphere 407 that does not contain moisture. ing.

  According to the fourth embodiment, in the electronic device having the organic molecule 405, the insulating property can be maintained without destroying the organic molecule 405, so that the electronic device can stably operate for a long period of time. Become.

  In particular, since the outer peripheral portion of the organic molecule 405 includes an alkyl chain, high insulation can be obtained. Even if an ionic substance is contained in the dry atmosphere 407, the outer peripheral part of the organic molecule 405 is protected by an alkyl chain, so that the ionic substance cannot enter the polymer skeleton having semiconductor properties. Therefore, the electronic element operates stably without causing malfunction.

  In the fourth embodiment, as the organic molecule 405, a molecule in which an insulating group is modified to a polymer having a polythiophene skeleton is used. However, a molecule such as a polymer having a phenyl base polymer as a skeleton or a carbon nanotube is used. You may use the molecule | numerator by which the insulating group was modified in the outer peripheral part. In addition, as the insulating group, an alkyl chain having a dendride structure is used, but instead, a siloxane skeleton group or another insulating group may be used.

  In the fourth embodiment, the organic molecules 405 are held in an atmosphere of a dry atmosphere 407 that does not contain water, but instead, inert gases such as nitrogen gas, argon gas, helium gas, or neon gas are used. It is preferable to hold in a gas atmosphere. In this case, as in the first or second embodiment, it is preferable to cover the field effect transistor 406 having the organic molecules 405 with a protective member that holds an atmosphere of an inert gas together with the integrated circuit substrate 400. It does not have to be covered with a member.

  In the fourth embodiment, the field effect transistor 406 having the organic molecules 405 is used as the electronic element. However, instead of this, an electronic element having a function such as a diode or an optical switch element may be used. In addition, the structure of the electronic element is not limited to that of the fourth embodiment.

  The electronic device of the present invention has an organic molecule because the water that tries to adhere to the organic molecule as a constituent element is repelled so that the oxidation of the organic molecule is suppressed, and the organic molecule retains insulation for a long time. It is useful as an electronic device, for example, a field effect transistor.

FIG. 1 is a cross-sectional view of the electronic device according to the first embodiment. FIG. 2 is an enlarged cross-sectional view of a main part of the electronic device according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a main part of an electronic device according to a modification of the first embodiment. FIG. 4 is a cross-sectional view of the electronic device according to the second embodiment. FIG. 5 is an enlarged cross-sectional view of a main part of an electronic device according to the third embodiment. FIG. 6 is an enlarged cross-sectional view of a main part of an electronic device according to the fourth embodiment. FIG. 7 is a cross-sectional view of a conventional electronic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Integrated circuit board 101 Gate electrode 102 Gate insulating film 103 Source electrode 104 Drain electrode 105 Organic molecule 106 Field effect transistor 107 Nitrogen gas 108 Protection member 109 Package 110 Lead terminal 111 Bonding terminal 112 Bonding wire 150 Integrated circuit board 151 Gate insulating film 152 Gate electrode 153 Source region 154 Drain region 155 Nitrogen gas 200 Integrated circuit substrate 206 Field effect transistor 207 Vacuum state 208 Protection member 209 Package 210 Lead terminal 211 Bonding terminal 212 Bonding wire 300 Integrated circuit substrate 301 Gate electrode 302 Gate insulating film 303 Source electrode 304 Drain electrode 305 Organic molecule 306 Field effect transistor 307 Argon gas 400 integrated circuit substrate 401 gate electrode 402 gate insulating film 403 source electrode 404 drain electrode 405 organic molecules 406 field effect transistor 407 dry air

Claims (10)

  An electronic device having an organic molecule as a constituent element, wherein an outer peripheral portion of the organic molecule is water-repellent.   The electronic device according to claim 1, wherein the organic molecule has a water-repellent group on an outer peripheral portion thereof.   The electronic device according to claim 2, wherein the water repellent group is a group containing fluorine.   The electronic device according to claim 1, wherein at least one end of the organic molecule is bonded to an electrode formed on the surface of the substrate.   The electronic device according to claim 4, wherein the substrate has a wiring connected to the electrode and for inputting or outputting an electric signal to the organic molecule.   An electronic device having an organic molecule as a constituent element, wherein an outer peripheral portion of the organic molecule is electrically insulating.   The electronic device according to claim 6, wherein the organic molecule has an insulating group on an outer peripheral portion thereof.   The electronic device according to claim 7, wherein the insulating group is a group including an alkyl chain.   The electronic device according to claim 6, wherein at least one end of the organic molecule is bonded to an electrode formed on a surface of the substrate.   The electronic device according to claim 9, wherein the substrate has a wiring connected to the electrode and for inputting or outputting an electric signal to the organic molecule.

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