Patent Application
20130084400
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2011-214831, filed Sep. 29, 2011, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a substrate processing method.
In manufacturing, for example, a semiconductor device, a method is performed, in which insulating films and interconnect films are filled in fine pattern trenches, thereby forming insulating film patterns and interconnect layer patterns. In the shallow trench isolation (STI) step performed to isolate elements by, for example, photolithography and reactive ion etching (RIE) are first performed, thereby forming a trench pattern in the surface of a silicon substrate, and chemical vapor deposition (CVD), for example, is then performed, thereby forming an SiO2 film. Thereafter, those parts of the SiO2 film, which exist outside the trenches, are removed by chemical mechanical planarization (CMP). An insulating layer pattern, i.e., SiO2 films in the trenches, is thereby obtained.
Any method of this type is, however, disadvantageous in that both a film forming step and a CMP step must be performed and much time is inevitably required. Further, as the design rule advances, accomplishing miniaturization of elements, it is demanded that an air gap structure should be formed in insulating film in order to enhance the device characteristic. However, it is difficult to make the air gap structure by processing that forms the film.
In general, according to one embodiment, a substrate processing method is provided, in which a solvent is supplied to a surface of a substrate having trenches made in the surface, a solvent holding member made of elastic material is set in contact with the surface of the substrate, and the substrate is rotated, making the solvent holding member slide on the surface of the substrate.
Embodiments will be explained in detail, with reference to the accompanying drawings.
In
The surface plate 21 can be rotated by a drive mechanism (not shown), on its axis at a rate of, for example, 10 to 100 rpm. The holder 30 has a smaller diameter than the surface plate 21 and can be rotated by a drive mechanism (not shown), on its axis at a rate of, for example, 10 to 200 rpm.
The axis of rotation of the holder 30 is not aligned with the axis of rotation of the surface plate 21, and is displaced from the center of the surface plate 21 in the radial direction. That is, the axis of rotation of the surface plate 21 and the axis of rotation of the holder 30 are parallel and spaced apart. Note that the axis of rotation of the substrate 10 and the axis of rotation of the holder 30 need not be aligned with each other. Therefore, the substrate 10 is rotated around an axis that is perpendicular to the substrate 10.
It is desired that the solvent holding member 22 should be made of material that has fine pores in the surface. Foamed rubber such as polyvinyl alcohol (PVA), foamed polyurethane, unwoven cloth, or epoxy resin pad, for example, can be used as material of the solvent holding member 22. If the solvent 42 has, for example, high viscosity and may likely remain on the surface of the solvent holding member 22, the solvent holding member 22 need not have fine pores at all. The solvent holding member 22, however, must be elastic enough not to damage the substrate 10 even if it is pressed onto the substrate 10. Hence, the solvent holding member 22 should better be made of elastic material.
To acquire plasticity high enough not to damage the substrate 10, the solvent holding member 22 must have hardness equal to or smaller than the hardness of the film on the substrate in which the trench pattern is made. If the solvent holding member 22 has such hardness, it can be a nylon brush.
The solvent supplying nozzle 41 has a port for supplying the solvent 42, which is positioned near the center of the surface plate 21. The solvent 42 can drip from the port of the solvent supplying nozzle 41.
A method of filling the trenches with the solvent by using the apparatus described above will be explained below.
First, the substrate 10 having a trench pattern on the surface is placed on the holder 30, with the surface turned downwards. Then, the surface plate 21 and the holder 30 are rotated together, while the solvent 42 is being supplied from the solvent supplying nozzle 41 to the solvent holding member 22. That is, the rotation of the substrate 10 and solvent holding member 22 and the supplying of the solvent 42 are performed at the same time. Further, the surface of the substrate 10 is brought into contact with the solvent holding member 22.
Since the solvent holding member 22 has a structure having fine pores, the solvent 42 accumulates on the solvent holding member 22 as it is supplied to the solvent holding member 22. Further, as the solvent holding member 22 is rotated, the surface of the substrate 10 and the solvent holding member 22 slide relative to each other. The solvent 42 can thereby be supplied to the surface of the substrate. At this point, not only the solvent holding member 22, but also the substrate 10 is rotated. The solvent holding member 22 can therefore slide on the surface of the substrate 10, more uniformly than otherwise. The solvent 42 can therefore be filled only in the trenches made in the substrate 10, both efficiently and uniformly.
In this case, the solvent 42 fills the trenches only. A CMP process need not be performed as a post process as in the case where the film has been formed by CVD. If the solvent 42 is SOG, polysilazane or the like, insulating film will be formed in the trenches. The solvent 42 can then serve to form STI. Further, since the solvent holding member 22 possesses plasticity, it would not damage the substrate 10.
This embodiment thus uses such a filling apparatus as shown in
The apparatus shown in
In order to form a spaced structure to the insulating layer provided in each trench, it is useful to use fine particles in the process of filling the trenches. To form this structure, it suffices to contain hollow fine particles in the solvent 42.
To fill the fine particles efficiently in any trench made in the substrate, it is desirable to select fine particles having an average diameter that is equal to or smaller than the width of the trench made in the substrate. To fill solvent containing fine particles in only any trench that has a width equal to or larger than a desirable width, it suffices to use solvent that contains fine particles having a diameter equal to or larger than a designated trench width. Since the fine particles cannot enter any trench that is narrower than the diameter of the fine particles, the solvent containing the fine particles can be selectively filled in only the trenches broader than the designated width. Only the solvent is filled in any trench narrower.
The fine particles may not be spherical. In this case, the size of the fine particles may be based on the minor-axis diameter. The shape of the fine particles contained in the solvent is not limited to spherical or quasi-spherical. The fine particles may be shaped like hollow fibers or may have any irregular shape.
If the fine particles are made of material that attracts the material of the substrate having the trenches, the solvent containing the fine particles can be more efficiently filled than otherwise in the trenches. For example, the zeta potential at the trenches made in the substrate and the zeta potential at the surfaces of the fine particles may be set to opposite polarities. Then, the fine particles can be readily adsorbed and filled in the trenches. Alternatively, if the zeta potential at the trenches or the surfaces of the fine particles is almost zero, the fine particles can be also readily filled in the trenches. Not only the electrical attraction, but also magnetic attraction can be utilized. For example, fine particles having ferromagnetism may be used, and a magnetic force may be applied from behind the substrate. Then, the fine particles can be readily adsorbed and filled in the trenches.
In the embodiment described above, it may be difficult to disperse the fine particles uniformly in the solvent 42. In this case, the fine particles may be contained in other solvent, in which the fine particles are well dispersed. The other solvent containing the fine particles is supplied into each trench, not filling up the trench. Thereafter, the solvent containing no particles is supplied into the trench, filling the trench completely.
The step of supplying the solvent 42 need not be performed at the same the step of filling the trenches is performed. The trenches may be filled with the solvent after the step of supplying the solvent. Alternatively, a part of the step of supplying the solvent and a part of the step filling the trenches may proceed simultaneously or alternately. Moreover, the solvent holding member 22 may rub the surface of the substrate, while applying remover, after the solvent has been supplied, filling the trenches to efficiently, thereby to remove the solvent from outside the trenches.
It may be necessary to remove the solvent, partly or entirely, after filling the trenches. In this case, the solvent may be so removed by means of heating or washing. Further, the solvent and the fine particles need not be filled in each trench to the brim. They may instead fill the trench to a level below the brim. Moreover, the trench pattern need not be composed of trenches. Rather, it may be shaped like holes or spaces of irregular shape, as well.
As described above, the solvent contains fine particles, and the fine particles are made of selected material, having specific electrical conductivity, thermal conductivity and optical characteristic. Thus, the filler in the trenches can be controlled to acquire desirable characteristics. If hollow fine particles, for example, are used, the dielectric constant of the filler can be decreased. The method according to this embodiment may be used in, for example, the STIT step in manufacturing an LSI. Then, can enhance the electrical characteristics of the semiconductor device. Moreover, if electrically conductive fine particles are used, the filler can be used to form interconnects.
If fine particles are contained in the solvent that will change to transparent resin, and if this solvent is filled in pattern trenches, the filler can be controlled in terms of reflectivity, refractive index and transmittance. This is useful if the solvent is used to form optical waveguides. Further, if fibrous fine particles are, the mechanical strength of the filler can be greatly increased.
A substrate 10 having a trench pattern on the surface is placed on a holder (not shown), with the surface turned upwards. The substrate 10 can be rotated with a driving force applied from the holder. A pillar-shaped solvent holding member 23 the length of which is slightly greater than the diameter of the substrate 10 is arranged above the substrate 10. The solvent holding member 23 can be rotated with a driving force applied from a drive unit (not shown). The axis of rotation of the substrate 10 and the axis of rotation of the solvent holding member 23 are orthogonal to each other. Further, a solvent supplying nozzle 41 is positioned above the solvent holding member 23.
The solvent holding member 23 should better be a roll-type or a small-type. It is desired that the solvent holding member 23 should be made of material that has fine pores in the surface in most cases, as in the first embodiment. A pillar of foamed rubber can be used as the solvent holding member 23. If the solvent 42 is of the type that tends to remain on the surface of the substrate 10, the solvent holding member 23 need not have fine pores at all. The solvent holding member 23 only needs to be elastic enough not to damage the substrate 10 even if it is pressed onto the substrate 10.
The apparatus shown in
As a result, insulating films and interconnect films can be easily formed in the trenches, in the same way as in the first embodiment. This can shorten the manufacturing time and reduce the manufacturing cost. If fine particles (not shown) are contained in the solvent 42, the trenches made in the substrate can be filled with the solvent containing the fine particles.
A substrate 10 having a trench pattern on the surface is placed, with the surface turned upwards, as in the second embodiment. The substrate 10 can be rotated with a driving force applied from a holder (not shown). An arm 25 that can rotate by a prescribed angle is arranged, with its distal end positioned above the substrate 10. A pillar-shaped solvent holding member 24 having a smaller diameter than the substrate 10 is secured to the distal end of the arm 25. The solvent holding member 24 can be rotated with a driving force applied from a drive unit (not shown). The axis of rotation of the substrate 10 and the axis of rotation of the solvent holding member 24 are parallel to each other. Further, a solvent supplying nozzle 41 configured to supply the solvent 42 directly to the surface of the substrate 10 is arranged above the solvent holding member 23.
It is desired that the solvent holding member 24 should be made of material that has fine pores in the surface in most cases, as in the first embodiment. A pillar of foamed rubber can be used as the solvent holding member 24. If the solvent 42 may likely remain on the surface of the substrate 10, the solvent holding member 24 need not have fine pores at all. The solvent holding member 24 only needs to be elastic enough not to damage the substrate 10 even if it is pressed onto the substrate 10.
The apparatus shown in
As a result, insulating films and interconnect films can be easily formed in the trenches in the same way as in the first embodiment and the second embodiment. This can shorten the manufacturing time and reduce the manufacturing cost.
A semiconductor device manufacturing processing method performed by using the apparatus shown in any one of
First, as shown in
The material to fill the trenches 11 and trench 12 will form insulating layers. The solvent 42 used is therefore SOG containing, for example, hollow Si fine particles 44. The fine particles 44 have a diameter of, for example, 50 nm or less. Al2O3 fine particles or SiN-based fine particles may be used as hollow particles, in place of Si fine particles. To form interconnect layers, not insulating layers, fine particles of metal oxide or C-based fine particles may be used.
Next, the apparatus shown in
At this point, the solvent 42 can be filled in the trenches 11 and 12 at high efficiency if the fine particles 44 have a diameter much smaller than the width of the trenches 11 and the width of the trench 12. In this case, almost no solvent 42 remains outside the trenches 11 and 12. Therefore, a post process, such as CMP process, need not be performed.
A conventional method of filling a trench pattern provided on the surface of a substrate with insulating layers will be explained with reference to
Thus, both a step of forming films and a step of performing CMP must be performed in the conventional method. The conventional method is inevitably complex. Further, it desired that spaces should be made to provide an air gap structure in order to enhance the device characteristics. If the spaces are made by forming films, however, it is difficult to control the air gap structure. Still further, the contamination of the slurry components will cause the degradation of the device characteristics.
By contrast, in this embodiment, the solvent 42 containing hollow fine particles 44 is supplied to the substrate 10 and the solvent holding member 22 is rotated while pressed onto the surface of the substrate. The solvent 42 containing fine particles 44 can thereby be filled in only the trenches 11 and 12. Since the fine particles 44 have a space in each, they serve as buried insulating films in the same way as in an air gap structure, and can therefore decrease the dielectric. In addition, the air gap structure can be well controlled only if the size of the spaces in the fine particles 44 is set to a specific value. This is because the air gap structure depends on the size of these spaces in the fine particles.
In this embodiment, the supplying of the solvent 42 containing hollow fine particles 44 and the filling of the trenches by using the solvent holding member 22 can thus be performed at the same time. The step of forming buried insulating films can therefore be simplified. Further, the air gap structure can be controlled at the buried insulating films. Still further, the embodiment is advantageous in that the device characteristics are prevented from being degraded due to slurry component contamination.
As shown in
In this embodiment, an ethanol-based solvent containing, for example, fine particles 54 of metal oxide is used as solvent 52 that will form interconnect layers in trenches 51.
Next, the apparatus shown in
Then, the product is annealed in hydrogen, performing a reduction process. The solvent 52 is thereby evaporated and, at the same time, the fine particles are combined to one another as shown in
Thus, the solvent 52 containing fine particles 54 of metal oxide or the like can be filled in the trenches 51 in this embodiment, by virtue of the rotation of the substrate 10 and solvent holding member 22. Therefore, the buried interconnect layers 55 can be formed in the trenches 51 made in the substrate surface, without performing a process such as CMP. That is, the same apparatus can form films in the trenches 51 and remove the solvent from outside the trenches 51. This can shorten the manufacturing time and reduce the manufacturing cost.
This invention is not limited to the embodiments described above.
The solvent filling apparatuses shown in
In any embodiment described above, the solvent holding member is rotated along with the substrate. Nonetheless, the solvent holding member need not be rotated by all means.
For example, in an apparatus similar in configuration to the apparatus of
Moreover, as shown in
In any embodiment described above, the fine particles used are made of Si or metal oxide. Nonetheless, the material of the fine particles can be changed, as needed, in accordance with the specification of the semiconductor device to manufacture. Further, the solvent, which will form an optical component, can contain fine particles that maintain desirable characteristics such as refractive index and transmittance and strength. Still further, the solvent is not limited to one containing fine particles. The trenches may, of course, be filled with solvent containing no file particles.
The embodiments described above are methods applied to the manufacture of semiconductor devices. Nevertheless, this invention can be applied not only to the manufacture of semiconductor devices, in which the trenches of a substrate must be filled with material other than that of the substrate.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-214831 | Sep 2011 | JP | national |
