JP5358929B2 - Cleaning device and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent Cu ion concentration in chemical of a chemical circulation type substrate cleaning treatment apparatus from increasing. <P>SOLUTION: In the cleaning treatment apparatus having a treatment chamber 1 for cleaning a substrate to be treated using the chemical 4 and a circulation mechanism for circulating the chemical 4, a metal plate 5 coming into contact with the chemical 4 and made of aluminum or aluminum alloy is detachably installed in the circulation mechanism or the treatment chamber. Cu ions in the chemical 4 are exchanged with Al of the metal plate 5 and Cu is deposited on a surface of the metal plate 5, so that the Cu ions in the chemical are removed. The metal plate 5 produces no dust and is inexpensive and easy to attach and detach, so the manufacturing cost is reducible. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a cleaning apparatus for cleaning using a chemical that circulates a substrate to be processed, and a method for manufacturing a semiconductor device having such a cleaning process. In particular, Cu ions and other harmful ions dissolved in the chemical can be removed. The present invention relates to a cleaning processing apparatus and a method for manufacturing a semiconductor device.

  In a manufacturing process of a semiconductor device typified by an integrated circuit, a cleaning process using an alkaline or acid chemical is frequently performed. For example, in a wiring patterning process using plasma etching with a halogen-based gas or an insulating film etching process using a hydrofluoric acid chemical solution, a reaction product containing Cl or F adheres to the upper surface or side surface of the wiring formed on the substrate. To do. When this substrate is left in the atmosphere, these reaction products react with moisture in the atmosphere to generate hydrochloric acid or hydrofluoric acid, causing corrosion of the wiring, that is, corrosion of the Al wiring. In order to prevent the corrosion of the wiring due to such a reaction product, a cleaning process for removing the reaction product using a chemical (for example, a stripping chemical) is required.

  Since the chemical solution used in the reaction product washing step is expensive, the chemical solution is usually circulated and used repeatedly. Hereinafter, a conventional cleaning apparatus having a circulation mechanism for circulating such a chemical solution will be described.

  FIG. 5 is a configuration diagram of a conventional cleaning processing apparatus, and shows a main apparatus configuration of a chemical circulation type cleaning processing apparatus.

  Referring to FIG. 5, the conventional cleaning processing apparatus includes a processing chamber 1 and a circulation mechanism that circulates and re-supplys the chemical solution 4 discharged from the processing chamber 1. The processing chamber 1 accommodates a substrate to be processed (not shown) therein, sprays the chemical solution 4 in a shower shape, and peels and cleans the reaction products attached to the substrate to be processed.

  The circulation mechanism includes a pump 2, a chemical solution tank 3, and a filter 6, and these devices 2, 3, 6 and the processing chamber 1 are connected by a pipe 11. The chemical solution 4 used for cleaning in the processing chamber 1 is sent from the processing chamber 1 to the chemical solution tank 3 by a pump. Furthermore, the chemical solution 4 in the chemical solution tank 3 is purified by passing through a filter 6 that filters fine particles, and is sent to the processing chamber 1 again. In the circulation-type cleaning processing apparatus that uses the chemical solution 4 while being circulated, the expensive chemical solution 4 can be used repeatedly, so that the cost of purchasing and discarding the chemical solution 4 can be greatly reduced.

  However, such a circulation type cleaning apparatus has a problem that metal ions harmful to the manufacture of the semiconductor device, particularly Cu ions, accumulate, and the reliability of the semiconductor device is impaired.

  That is, Al wiring is usually used for wiring of the semiconductor device. This Al wiring uses an Al—Cu alloy in order to prevent electromigration. Alternatively, a Cu wiring may be used for the wiring that is likely to undergo electromigration, and the remainder may be an Al wiring. The reaction product generated by patterning the wiring containing Cu includes a large amount of Cu. For this reason, Cu contained in the reaction product is dissolved in the chemical solution 4 used for peeling and washing the reaction product, and is dissolved as Cu ions in the chemical solution 4.

  A considerable portion of fine particles such as reaction product fragments and organic matter is removed by a filter 6 provided in the circulation mechanism. However, since the filter 6 does not capture metal ions, metal ions that dissolve in the chemical solution 4 accumulate in each cleaning step, and the metal ion concentration in the chemical solution 4 increases in accordance with the number of cleaning steps.

  When the metal ion concentration in the chemical solution 4, for example, the Cu ion concentration becomes high, when the chemical solution 4 comes into contact with the Al wiring made of Al or Al alloy having a larger ionization tendency than the metal during cleaning, the Al in the Al wiring is It dissolves in the chemical solution 4, and Cu ions in the chemical solution 4 are deposited on the Al wiring instead. Thus, when Cu having a lower ionization tendency than Al is deposited on the Al wiring, a local battery is formed between the Al wiring and the deposited Cu, further elution of the Al wiring proceeds, and the Al wiring is corroded. So-called Al corrosion occurs. As a result, a narrowed portion is formed in the Al wiring, and the reliability of the semiconductor device is impaired. This situation is the same when metal ions having a smaller ionization tendency than Al, such as Cu, are dissolved in the chemical solution, such as noble metal ions and rare earth metal ions. Similarly, these metals are deposited on the Al wiring. A local battery is formed, and corrosion of the Al wiring proceeds. (For example, refer to Patent Document 1).

  In order to prevent the corrosion of the Al wiring due to the increase of the Cu ion concentration in the chemical solution 4 described above, a Cu trap for reducing the Cu ion concentration in the chemical solution 4 used for cleaning is provided in the circulation mechanism. A treatment cleaning apparatus has been devised that removes Cu ions dissolved in the substrate and suppresses an increase in Cu ion concentration. (For example, refer to Patent Document 2).

  FIG. 6 is a configuration diagram of a conventional cleaning processing apparatus having a Cu trap, and shows a main apparatus configuration of a cleaning processing apparatus including a column for trapping Cu in a chemical solution circulation mechanism.

  Referring to FIG. 6, the conventional cleaning apparatus having a Cu trap includes a column 7 filled with silicon particles 7a in place of the filter 6 of the conventional cleaning apparatus described with reference to FIG. The chemical solution 4 containing Cu ions that have passed through the column 7 comes into contact with the silicon particles 7a to elute silicon from the silicon particles 7a, and at the same time, Cu is deposited on the surface of the silicon particles 7a, so that the Cu ion concentration in the chemical solution 4 is reduced. Reduce. Therefore, even if the chemical solution 4 is circulated, the Cu ion concentration in the chemical solution 4 does not increase, so that the deposition of Cu on the Al wiring is prevented and the progress of corrosion of the Al wiring is prevented.

  This conventional cleaning apparatus having a Cu trap uses silicon particles 7a as the Cu trap. As a result, the Si ion concentration in the chemical solution 4 increases. However, since the Si ions in the chemical solution 4 do not precipitate on the semiconductor device, for example, on the Al wiring, and the Si ions do not adversely affect the characteristics of the semiconductor device, the increase in the Si ion concentration is not a problem.

However, the silicon particles 7a are brittle and easily broken, and may rub against each other in the column 7 to generate fine silicon fragments. There is a possibility that this silicon fragment mixes in the chemical solution 4 and adheres to the surface of the substrate to be cleaned to cause a defect in the semiconductor device. Further, when the filter 6 for removing fine particles is used in combination, the silicon debris promotes clogging of the filter for removing fine particles and accelerates the replacement time of the filter, so that the manufacturing cost increases.
JP 2002-110616 A Japanese Patent Laid-Open No. 06-279005

  As described above, in a cleaning processing apparatus for cleaning a substrate to be processed by circulating a cleaning chemical through a filter that removes fine particles, metal ions such as Cu ions are dissolved and accumulated in the chemical by the cleaning. The metal ion concentration in the chemical increases. As a result, there is a problem that a metal, for example, Cu is deposited on the Al wiring of the substrate to be processed which comes into contact with the chemical solution, and a local battery is formed between the metal and the Al wiring to cause corrosion of the Al wiring.

  In a conventional cleaning apparatus having a Cu trap that removes metal ions such as Cu ions in a chemical solution by passing the chemical solution through a column filled with silicon particles, fine particles of silicon particles are likely to be mixed into the chemical solution. In the case of using a filter or causing a defect in the semiconductor device, there is a problem that the replacement time of the filter is advanced and the cost is increased. Further, since the silicon particles are exchanged for each column, the washing process must be interrupted or two columns must be used alternately, resulting in an increase in cost.

  According to the present invention, in a cleaning apparatus for a substrate to be processed that circulates and uses a chemical for cleaning, a low-cost apparatus is used to detect metal ions (for example, Cu ions) in the chemical that adversely affect the characteristics of the semiconductor device. It is an object of the present invention to provide a cleaning apparatus that can suppress an increase in concentration and can avoid the mixing of fine particles into a solution.

A first configuration of the present invention for solving the above-described problem includes a processing chamber for cleaning a substrate to be processed, on which an Al—Cu alloy wiring is formed , using a chemical solution, and a chemical solution circulation mechanism. In a cleaning processing apparatus, a metal plate made of aluminum or an aluminum alloy that comes into contact with a chemical solution is provided in a circulation mechanism or a processing chamber.
When using a some metal plate, it can be set as the structure where a metal plate is fixed to the shaft rod which penetrates a some metal plate so that the plate surface may become parallel with respect to the flow direction of the said chemical | medical solution. In this structure, a plurality of metal plates can be attached or detached simultaneously, and handling is easy.
Furthermore, in order to increase the surface area of the metal plate, a plate obtained by bending the metal plate, for example, a corrugated plate, or a plate that is embossed with protrusions and depressions in the vertical direction (front and back direction of the plate) can be used.

  In this 1st structure, the metal plate which consists of aluminum or aluminum alloy is provided, and this metal plate is contacting the chemical | medical solution which is circulating. For this reason, metal ions having a smaller ionization tendency than Al dissolved in the chemical solution are deposited on the surface of the metal plate, and an increase in the metal ion concentration in the solution is suppressed. Therefore, since the metal ion concentration in the chemical solution is always maintained at a low concentration, the deposition on the Al wiring of the metal having a smaller ionization tendency than that of Al is suppressed, and the substrate to be processed with high reliability, and further such a substrate to be processed. A highly reliable semiconductor device using a substrate is manufactured.

  Moreover, since a metal plate consists of Al or Al alloy, it can be manufactured cheaply. Further, by moving the metal plate up and down in the chemical solution, the metal plate can be easily replaced even during the cleaning process. Furthermore, since it is plate-shaped, fine fragments are not mixed in the solution unlike a column packed with particles. For this reason, compared with the case where the column packed with particle | grains is used, the exchange period of the filter which capture | acquires microparticles | fine-particles becomes long, and the maintenance cost of a washing | cleaning processing apparatus can be reduced. Note that Al ions melt from the metal plate into the chemical solution, and the concentration of Al ions in the chemical solution increases. However, since Al ions do not have a significant adverse effect on the characteristics of the semiconductor device, they can usually be ignored. In order to minimize the dissolution of impurities in the chemical solution, it is desirable that the metal plate be a pure Al plate that does not contain an additive element.

  By using the cleaning apparatus of the first configuration, metal ions having a smaller ionization tendency than Al causing corrosion of Al wiring, for example, Cu ions can be effectively removed from the chemical solution. In addition, rare earth elements and noble metal elements used for electrodes of semiconductor devices are also removed. For this reason, a highly reliable semiconductor device can be manufactured. Hereinafter, in this specification, “metal ion” is used to mean a metal ion of a metal having a smaller ionization tendency than Al.

  It is preferable to use a plurality of the metal plates from the viewpoint of increasing the area where the metal plate is in contact with the chemical solution and quickly removing metal ions in the chemical solution. Thus, when the surface area of a metal plate is enlarged, the advantage that the replacement period of a metal plate is extended also arises. That is, metal is deposited on the surface of the metal plate, and finally, a considerable area is covered with the deposited metal. When the coating area of the deposited metal is increased and the exposed area of the metal plate is decreased, the removal rate of metal ions is decreased, and the concentration of metal ions in the chemical solution is increased. Before that, the metal plate must be replaced with a new one. If the total surface area of the metal plate is large, even if a large amount of metal is deposited, the exposed area of the metal plate is still large, so the replacement time is greatly extended.

  The metal plate described above is held so as to be immersed in the chemical solution or poured into the chemical solution. For example, the metal plate is immersed in a chemical solution in a chemical solution tank that constitutes a chemical solution circulation mechanism. Or it is immersed in the chemical | medical solution in the chemical | medical solution reservoir in a washing | cleaning processing apparatus. The chemical solution may be poured in a shower form without being immersed. Further, the metal plate can be provided in a part of the chemical solution circulation mechanism, for example, in a pipe for circulating the chemical solution.

  It is preferable that the metal plate is detachably installed so that it can be easily replaced. When a plurality of metal plates form an integral structure, it is desirable to replace the entire integral structure so that the replacement work can be performed quickly and easily. When a plurality of metal plates are separately installed, any one metal plate can be exchanged. By exchanging one by one in this way, the exposed area of the metal plate can always be kept at a predetermined area or more, and the upper limit of the metal ion concentration in the chemical solution can be surely limited.

According to a second configuration of the present invention, there is provided a semiconductor device manufacturing method including a step of cleaning a substrate to be processed, on which an Al—Cu alloy wiring is formed , using a chemical solution while circulating the chemical solution. Alternatively, the method includes a step of contacting a metal plate made of an aluminum alloy.
When using a some metal plate, it can be set as the structure where a metal plate is fixed to the shaft rod which penetrates a some metal plate so that the plate surface may become parallel with respect to the flow direction of the said chemical | medical solution. In this structure, a plurality of metal plates can be attached or detached simultaneously, and handling is easy.
Furthermore, in order to increase the surface area of the metal plate, a plate obtained by bending the metal plate, for example, a corrugated plate, or a plate that is embossed with protrusions and depressions in the vertical direction (front and back direction of the plate) can be used.

  Similar to the first configuration described above, in the second configuration, a metal plate made of aluminum or an aluminum alloy is brought into contact with the chemical solution to be circulated. At this time, Al dissolves in the chemical solution from the metal plate, and at the same time, metal ions in the chemical solution, such as Cu ions, are deposited on the surface of the metal plate. As a result, the metal ion concentration in the chemical solution decreases, and the increase in the metal ion concentration in the chemical solution is suppressed. Therefore, metal deposition on the Al wiring formed on the substrate to be processed is suppressed, and a highly reliable semiconductor device is manufactured.

  According to the present invention, since the increase in the metal ion concentration, which is less ionized than Al in the chemical solution that is circulated and used for substrate cleaning, is suppressed, the metal is deposited on the Al wiring formed on the substrate. Thus, corrosion of the Al wiring can be avoided.

  1st Embodiment of this invention is related with the washing | cleaning processing apparatus using the integral several metal plate. The cleaning apparatus of the first embodiment is configured as a semiconductor device manufacturing apparatus.

  FIG. 1 is a configuration diagram of a cleaning processing apparatus according to a first embodiment of the present invention, and shows a main apparatus configuration of a cleaning processing apparatus that circulates and uses a chemical solution. FIG. 2 is a perspective view of a metal plate according to the first embodiment of the present invention, showing an integrated structure of a plurality of metal plates and a chemical tank that stores the metal plates.

  With reference to FIG. 1, the cleaning processing apparatus used in the first embodiment of the present invention accommodates a semiconductor substrate which is a substrate to be processed, and a processing chamber 1 for cleaning the substrate using a chemical solution 4, A circulation mechanism for circulating the chemical solution 4.

  The processing chamber 1 can wash the 25 semiconductor substrates simultaneously by pouring the chemical solution 4 into 25 semiconductor substrates (wafers) having a diameter of 8 inches accommodated in the processing chamber 1 in a shower shape. This semiconductor substrate is in the process of forming Al wiring (more precisely, Al-Cu wiring) constituting an integrated circuit, and an Al-Cu alloy thin film deposited on the surface is subjected to reactive ion etching using a Cl-containing gas. Immediately after patterning. By this reactive ion etching, reaction products adhere to the surface of the semiconductor substrate, particularly the upper surface and side surfaces of the Al wiring.

  The cleaning process in the processing chamber 1 is a well-known cleaning processing apparatus used for manufacturing a semiconductor device, and a reaction product adhering to the semiconductor substrate is removed by pouring a chemical solution such as a stripping solution in a shower shape. As the chemical solution for the cleaning treatment, a known alkaline stripping solution containing monoethanolamine and hydroxylamine (for example, Ashland-ACT, trade name of Ashland Specialty Chemical Co.) or a known acidic stripping solution was used.

  The processing chamber 1 is supplied with 4 liters (4 l / min) of the chemical solution 4 per minute, and the same amount of the chemical solution 4 is discharged from the processing chamber. In the processing chamber 1, for example, 15 liters of the chemical solution 4 is stopped. Of course, the amount of the chemical solution 4 retained can be reduced depending on the structure of the processing chamber.

  The circulation mechanism of the chemical solution 4 includes a pump 2, a chemical solution tank 3, a filter 6, and a pipe 11 that connects these devices. Both ends of the pipe 11 are connected to the processing chamber. The chemical solution 4 is supplied from one end into the processing chamber 1 and the chemical solution 4 discharged from the other end is collected.

  The chemical solution 4 used for the cleaning process is collected in a pipe 11 connected to the processing chamber 1 (a pipe 11 connected to the lower side of the paper of the processing chamber in FIG. 1) and sent to the chemical tank 3 by the pump 2.

  An Al plate 5 made of pure Al is disposed in the chemical liquid tank 3. The Al plate 5 is immersed in about 30 liters of the chemical solution 4 filled in the chemical solution tank 3. At this time, metal ions having a smaller ionization tendency than Al dissolved in the chemical solution 4, such as Cu ions, are deposited on the surface of the Al plate 5 and removed from the chemical solution 4. At the same time, Al melts into the chemical solution from the Al plate, so that the Al plate 5 is corroded and thinned.

  The chemical solution 4 from which the metal ions have been removed in the chemical solution tank 3 is sent to the filter 6 through the pipe 11. The filter 6 removes dust and other solid matters mixed in the chemical solution 4. For example, when a reaction product adhering to the surface of the semiconductor substrate by reactive ion etching is separated in the chemical treatment process and mixed into the chemical solution 4 to become dust, such dust (mostly containing organic matter) is filtered out. Is removed.

  On the other hand, since the metal ion concentration in the chemical liquid 4 delivered from the chemical liquid tank 3 is low, the chemical liquid 4 from which the solid matter is removed by the filter 6 has a low metal ion concentration and a small amount of solid matter (for example, organic matter).

  The chemical solution 4 that has passed through the filter 6 is sent to the processing chamber 1 through the pipe 11. Then, as described above, the substrate is washed in a shower-like manner. In this way, the chemical liquid circulates through the processing chamber 1, the pump 2, the chemical liquid tank 3 and the filter 6 and is returned to the processing chamber 1 again.

  FIG. 2 is a perspective view of the metal plate according to the first embodiment of the present invention, and shows the structure of the metal plate 5 immersed in the chemical tank 3.

  Referring to FIG. 2, six Al plates 5 (metal plates) are fixed to shaft rod 5a. The Al plate 5 is made of pure Al with few impurities, and is, for example, a square plate having a thickness of 1 mm and a side of 10 cm. Since the Al plate 5 is corroded and thinned during use, it is preferable to have a thickness that can maintain strength even at the end of the use period, for example, a thickness of 0.5 mm or more. If it is too thin, corrosion holes are formed, and fragments from the Al plate 5 may be mixed in the chemical solution 4. If it is too thick, the cost of the Al plate increases unnecessarily. For this reason, it is preferable to set it as the thickness of 0.5 mm-2 mm, and it is more desirable to set it as the thickness of 0.5-1 mm further. Since the amount of corrosion depends on the surface area of the Al plate, the thickness of the Al plate is also determined in consideration of the surface area.

  The shaft bar 5a is made of, for example, a pure Al cylinder having a diameter of 5 mm, and is fitted into a circular hole formed in the center of the Al plate 5 to fix the Al plate 5 vertically to the shaft bar 5a. Accordingly, the six Al plates 5 are fixed perpendicularly to the shaft bar 5a and held parallel to each other.

  The chemical liquid tank 3 is a rectangular parallelepiped box whose inner surface has a lid on which an inner surface is processed with Teflon (registered trademark). 11a and the outlet port piping 11b which sends out a chemical | medical solution are connected. A support 3a for horizontally supporting the shaft rod 5a is attached to the inner surface of the side wall 3c that is orthogonal to and opposite to the side wall 3b to which the inlet port pipe 11a or the outlet port pipe 11b is connected.

  The Al plate 5 fixed to the shaft rod 5a is lowered into the chemical solution tank 3, and is held in the chemical solution tank 3 so that both ends of the shaft rod 5a are supported horizontally by the support 3a. At this time, the plate surface (front and back surfaces) of the Al plate 5 is orthogonal to the opposing side wall 3b to which the inlet port pipe 11a or the outlet port pipe 11b is connected. Therefore, the plate surface of the Al plate 5 is parallel to the water flow in the chemical tank 3 flowing from the inlet port 11a to the outlet port 11. For this reason, the disturbance of the water flow is reduced, and the opportunity for the chemical solution 4 passing through the chemical solution tank 3 to contact the Al plate is increased. As a result, circulation of the chemical solution 4 is facilitated and metal ions are sufficiently removed.

  In order to increase the contact area with the metal plate 5, it is desirable that the chemical solution 4 in the chemical solution tank 3 has a liquid amount that completely immerses the metal plate 5. Of course, one part may contact the chemical | medical solution 4.

  In order to increase the surface area of the Al plate 5, it is also possible to use a corrugated Al plate 5 or an Al plate 5 whose surface is embossed with irregularities. Furthermore, an Al plate 5 having a large surface area, for example, a cooling fin shape, may be used.

  FIG. 3 is a diagram for explaining the effect of the first embodiment of the present invention, and shows the relationship between the number of substrate cleaning processes and the Cu ion concentration in the chemical solution. The straight line 1 in the figure represents the change in Cu ion concentration in the first embodiment, and the straight line B compares the change in Cu ion concentration when using the conventional cleaning apparatus described with reference to FIG. It is shown as an example.

  Here, in the first embodiment, as described above, there are 30 liters and 15 liters of the chemical solution 4 in the chemical solution tank 3 and the processing chamber 1, respectively, and the chemical solution 4 in the pump 2, the column 7 and the piping is added thereto. And about 60 liters of chemical | medical solution 4 is used with the whole washing | cleaning processing apparatus, and it circulates at 4 liters / min / min. In addition, 25 substrates were simultaneously cleaned by one cleaning process. This washing process was performed for about 15 minutes each time.

  As a comparative example, the result of the conventional cleaning processing apparatus shown by a straight line B in FIG. 3 is that the cleaning processing apparatus is the processing chamber 1, the pump 2, the chemical tank 3, The filter 6 and the piping 11 are the same as those in the first embodiment, and further, the cleaning process of the semiconductor substrate is performed under the same conditions as in the first embodiment with respect to the amount of the used chemical solution 4 and the circulation speed of the chemical solution 4. is there.

  Referring to the straight line A in FIG. 3, in the first embodiment, even if the number of cleaning treatments reaches 130, the increase in the Cu ion concentration in the chemical solution 4 is not measured. In contrast, in the cleaning process of the comparative example using the conventional processing apparatus, the Cu ion concentration in the chemical solution 4 increases in proportion to the number of cleaning processes, and reaches nearly 100 ppm when the number of cleaning processes is 130.

  Next, in the comparative example using the first embodiment and the conventional cleaning apparatus, the presence or absence of Cu deposition on the Al wiring formed on the semiconductor substrate was observed. As a result, in the first embodiment, Cu deposition on the Al wiring was not observed even when the number of cleaning treatments exceeded 300. On the other hand, in the comparative example using the conventional cleaning processing apparatus, Cu deposition on the Al wiring was observed when the number of cleaning processing exceeded approximately 95 times. The Cu ion concentration in the chemical solution 4 when this Cu precipitation was observed was 70 ppm. This fact indicates that Cu deposition on the Al wiring occurs when the Cu ion concentration in the chemical solution 4 exceeds 70 ppm. Further, in the first embodiment, the increase in Cu concentration is strongly suppressed, suggesting that Cu deposition on the Al wiring is prevented.

  Thus, in order to prevent Cu deposition on the Al wiring, the metal ion concentration (for example, Cu ion concentration) in the chemical solution 4 must be controlled to be less than 70 ppm. Therefore, in order to prevent Cu deposition on the Al wiring, in the comparative example using the conventional cleaning processing apparatus, the number of cleaning processes is less than 95 times, and the chemical solution 4 can be used in about 60 times with a margin in the implementation. It is necessary to replace the whole with a new chemical solution 4.

  On the other hand, in the first embodiment, in a normal operation state, the cleaning process can be continued for 3 to 6 months without causing Cu deposition on the Al wiring.

  In the first embodiment, as the number of cleaning processes increases, the surface of the Al plate 5 (metal plate) is covered with deposited Cu, and the exposed surface area of the Al plate 5 gradually decreases. When the exposed surface area of the Al plate 5 becomes smaller than a certain value, the Cu ion deposition rate becomes slower than the Cu ion increase rate generated by the cleaning treatment, and as a result, the Cu ion concentration in the chemical solution 4 starts to increase. . Since the increase in the Cu ion concentration accelerates the further decrease in the surface area of the Al plate 5, the Cu ion concentration in the chemical solution 4 rapidly increases. Therefore, it is desirable to replace the Al plate 5 when or before the rapid increase of the Cu ion concentration begins. Such an exchange time can be known by observing the Cu ion concentration or observing the coating state of Cu deposited on the Al plate 5.

  The second embodiment of the present invention relates to a cleaning processing apparatus in which a plurality of Al plates can be replaced one by one. The Al plate 5 integrally fixed to the shaft rod 5a of the first embodiment described above was detachably mounted in the chemical liquid tank 3 by moving the shaft rod 5a up and down. In the second embodiment, the Al plate 5 is detachably mounted in the chemical tank 3 for each sheet.

  FIG. 2 is a structural view of a metal plate according to a second embodiment of the present invention, and shows a metal plate held detachably for each sheet.

  With reference to FIG. 2, in this 2nd Embodiment, several Al plate 5 (metal plate) is hold | maintained so that immersion of any one sheet and the chemical | medical solution 4 in the chemical | medical solution tank 3 is possible. Such a holding mechanism has a structure similar to, for example, a known wafer holder that holds a plurality of semiconductor substrates substantially vertically, and can be realized by using a holder 8 that holds the Al plate 5 in the same manner as the semiconductor substrate. it can. The chemical tank 3 and other configurations are the same as those in the first embodiment except for the Al plate 5 and the holder 8 described above.

  As such a holder 8, when the holder 8 is accommodated in the chemical tank 3, the holder 8 includes a pair of horizontal frames 8 a and 8 b that are horizontally held vertically, and the Al plate 5 is attached to the horizontal frames 8 a and 8 b. What is supported by the formed groove | channel can be used. At this time, the plurality of Al plates 5 are held substantially parallel to each other. In addition, the replacement of the Al plate 5 (detachment from the holder) is performed by taking out the single Al plate 5 selected by using tweezers while the Al plate 5 is immersed in the chemical solution 4 and placing the new Al plate 5 in the horizontal frame. Insert it into the grooves 8a and 8b. Since the Al plate 5 can be replaced while being immersed in the chemical solution 4 in this way, the cleaning process is not interrupted for replacement.

  The replacement of the Al plate 5 in the second embodiment is performed while the metal ion concentration in the chemical solution 4 starts to rise and then rises to a concentration deposited on the Al wiring, for example, 70 ppm for the Cu ion concentration. Even if the metal ion concentration starts to rise, the total surface area of the plurality of Al plates 5 is increased by replacing the Al plate 5, so that the rise of the metal ion concentration is suppressed or reduced.

  In the second embodiment, first, seven Al plates 5 having a thickness of 1 mm and a side length of 10 cm or a disc-shaped Al plate 5 having a thickness of 1 mm and a diameter of 10 cm are immersed in the chemical solution 4, and then 0 The Al plate 5 was replaced one by one every 5 months. By exchanging one by one in this way, avoiding a rapid increase in metal ion concentration caused by a rapid decrease in the exposed area of the plurality of Al plates 5 that occurs when all the plurality of Al plates 5 are replaced at once. Can do.

  Note that the number of Al plates to be replaced at the same time is not limited to one, but may be a plurality of, for example, two to three. In this case, the replacement time can be extended by 2 to 3 times, for example, compared to the replacement one by one.

As described above, the present invention disclosed in the following supplementary notes is disclosed in this specification.
(Supplementary note 1) In a cleaning processing apparatus having a processing chamber for cleaning a substrate to be processed using a chemical solution and a circulation mechanism for circulating the chemical solution,
A cleaning processing apparatus comprising a metal plate made of aluminum or an aluminum alloy in contact with the chemical solution in the circulation mechanism or the processing chamber.
(Additional remark 2) The washing | cleaning processing apparatus of Additional remark 1 characterized by the several said metal plate being fixed mutually parallel to the shaft rod which penetrates the said several metal plate.
(Additional remark 3) The said metal plate is made into the board bent in order to enlarge a surface area, The washing | cleaning processing apparatus of Additional remark 1 or 2 characterized by the above-mentioned.
(Additional remark 4) The said metal plate is detachably installed, The washing | cleaning processing apparatus of Additional remark 1, 2 or 3 characterized by the above-mentioned.
(Appendix 5) Having a plurality of the metal plates,
The cleaning processing apparatus according to appendix 1, wherein any metal plate is detachably installed. (Additional remark 6) In the manufacturing method of the semiconductor device which has the process of wash | cleaning a to-be-processed substrate using the said chemical | medical solution, circulating a chemical | medical solution,
A method for manufacturing a semiconductor device, comprising: bringing a metal plate made of aluminum or an aluminum alloy into contact with the chemical solution.

  By applying the present invention to a cleaning process of a semiconductor device having an Al wiring, a highly reliable semiconductor device with little corrosion of the Al wiring can be manufactured.

1 is a block diagram of a cleaning apparatus according to a first embodiment of the present invention. Metal plate perspective view of the first embodiment of the present invention 1st Embodiment effect explanatory drawing of this invention Second Embodiment Metal Plate Structure Diagram of the Present Invention Conventional cleaning equipment configuration diagram Configuration diagram of a conventional cleaning apparatus having a Cu trap

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Process chamber 2 Pump 3 Chemical solution tank 3a Support tool 3b, 3c Side wall 4 Chemical solution 5 Al plate (metal plate)
5a Shaft rod 6 Filter 7 Column 7a Silicon particles 8 Holder 8a, 8b Horizontal frame 11 Piping 11a Inlet port piping 11b Outlet port piping

Claims (4)

In a cleaning processing apparatus having a processing chamber for cleaning a substrate to be processed on which Al—Cu alloy wiring is formed using a chemical solution, and a circulation mechanism for circulating the chemical solution,
In the circulation mechanism or the processing chamber, a metal plate made of aluminum or aluminum alloy that comes into contact with the chemical solution,
A cleaning apparatus, wherein a plurality of the metal plates are fixed to a shaft bar penetrating the plurality of metal plates so that the plate surfaces thereof are parallel to a flow direction of the chemical solution.   The cleaning apparatus according to claim 1, wherein the metal plate is a plate bent to increase the surface area. The metal plate, the cleaning apparatus according to claim 1 or 2, characterized in that it is installed detachably. In a method for manufacturing a semiconductor device, the method includes a step of cleaning a substrate to be processed having an Al-Cu alloy wiring formed on a surface using the chemical solution while circulating the chemical solution.
A step of bringing a metal plate made of aluminum or an aluminum alloy into contact with the chemical solution;
A method of manufacturing a semiconductor device, wherein a plurality of the metal plates are fixed to a shaft bar penetrating the plurality of metal plates so that the plate surfaces thereof are parallel to a flow direction of the chemical solution. .

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