KR20120048562A - Materials and systems for advanced substrate cleaning - Google Patents

Abstract

Embodiments of the present invention provide improved materials, apparatuses, and methods for cleaning wafer surfaces, particularly surfaces of patterned wafers (or substrates). The cleaning materials, apparatuses, and methods discussed have advantages in cleaning patterned substrates with fine features without substantially damaging the features. The cleaning material comprises polymers of one or more polymerizable compounds. Cleaning materials can be used with a wide range of viscosities and pH to clean different kinds of surfaces. The cleaning materials are liquid and deformed around the device features to capture contaminants on the surface. Polymers prevent entrapment of contaminants and return to the substrate surface. The cleaning apparatus is designed to spray and rinse cleaning materials having a range of viscosities.

Description

MATERIALS AND SYSTEMS FOR ADVANCED SUBSTRATE CLEANING

In the fabrication of semiconductor devices such as integrated circuits, memory cells, and the like, a series of fabrication operations are performed to define features on semiconductor wafers (“wafers”). Wafers (or substrates) include integrated circuit devices in the form of multi-level structures defined on a silicon substrate. At the substrate level, transistor devices with diffusion regions are formed. At subsequent levels, interconnect metallization lines and vias are patterned and electrically connected to transistor devices to define the desired integrated circuit device. In addition, the patterned conductive layers are insulated from other conductive layers by dielectric materials.

During a series of manufacturing operations, the wafer surface is exposed to various types of contaminants. Basically, any material present during the manufacturing operation is a potential source of contamination. For example, contaminants may include process gases, chemicals, deposition materials, and liquids. Various contaminants may be deposited in particulate form on the wafer surface. If particulate contaminants are not removed, devices near contamination may not be able to operate as desired. For advanced technology nodes with fine feature sizes, on the wafer, because the size of particulate contamination causing the failure of the devices is on the order of (or more) the critical dimension size of the features fabricated on the wafer. It can be very difficult to remove small particulate contamination without damaging the features.

Conventional wafer cleaning methods have relied heavily on mechanical forces to remove particulate contamination from the wafer surface. As feature sizes continue to become smaller and more prone to damage, the likelihood of feature damage by applying mechanical forces on the wafer surface increases. For example, fine features with a high aspect ratio are susceptible to toppling or breaking when impacted by sufficient mechanical force. Further complicating the cleaning problem is that movement to the reduced feature size also causes a reduction in the acceptable size of particulate contamination. Particle contamination of sufficiently small size can enter areas on the wafer surface that are difficult to reach, such as in trenches surrounded by high aspect ratio features. Thus, efficient and intact contaminant removal during modern semiconductor fabrication represents a continuing challenge to be met by advanced wafer cleaning technologies. It should also be understood that manufacturing operations of flat panel displays suffer from the same disadvantages of integrated circuit fabrication described above.

In this respect, there is a need for cleaning materials, apparatuses and methods of patterned wafers that are effective in removing contaminants without damaging the features on the patterned wafers.

Embodiments of the present invention provide improved materials, apparatuses, and methods for cleaning wafer surfaces, particularly surfaces of patterned wafers (or substrates). The cleaning materials, apparatuses, and methods described above have advantages in cleaning patterned substrates having fine features without substantially damaging the features. The cleaning material comprises polymers of one or more polymerizable compounds dissolved in a solvent. The cleaning materials are in liquid phase and deformed around the device features; The cleaning materials nonetheless do not substantially damage the device features. Polymers of cleaning materials capture contaminants on the substrate. In addition, the polymers entrap the contaminants and prevent them from returning to the substrate surface. Cleaning materials can be used to clean different types of substrate surfaces, including hydrophilic, hydrophobic, and mixed hydrophobic and hydrophilic surfaces. The composition window and process window for the cleaning materials are widened, allowing formulated cleaning materials to be used to clean different types of substrate surfaces. The cleaning apparatuses can be designed to spray and rinse cleaning materials having a predetermined viscosity range.

The polymers can be crosslinked. However, the degree of crosslinking is relatively limited in order to avoid the polymers becoming too hard or too hard so that the polymers do not dissolve in solvent and do not deform around device features on the substrate surface.

It is to be understood that the present invention can be implemented in a number of ways, including as a system, a method, and a chamber. Several inventive embodiments of the present invention are described below.

In one embodiment, a cleaning material is provided that is supplied on a surface of a patterned substrate for defining integrated circuit devices to remove contaminants from the surface. The cleaning material includes a solvent and one or more polymerizable compounds. One or more polymerizable compounds are dissolved in a solvent. Solubilized polymers have long polymer chains that capture and entrap at least some of the contaminants from the surface of the patterned substrate for defining integrated circuit devices. The cleaning material is defined as a liquid phase. The viscosity of the cleaning material measured at a reference shear rate of less than about 100 / s is from about 100 cP to about 10,000 cP. The cleaning material is deformed around the device features on the surface of the patterned substrate when a force is applied on the cleaning material covering the patterned substrate.

In another embodiment, a cleaning material is provided that is supplied on a surface of a patterned substrate for defining integrated circuit devices to remove contaminants from the surface. The cleaning material comprises a solvent and a buffer for changing the potential of hydrogen (PH) value of the cleaning material, the buffer and the solvent forming a cleaning solution. The cleaning agent also includes polymers of one or more polymerizable compounds dissolved in the cleaning solution. The cleaning material has a pH of about 7 to about 12. Solubilized polymers have long polymer chains that capture and entrap at least some of the contaminants from the surface of the patterned substrate for defining integrated circuit devices. The cleaning material is defined as a liquid phase. The viscosity of the cleaning material measured at the reference shear rate is about 100 cP to about 10,000 cP. The cleaning material is deformed around the device features on the surface of the patterned substrate when a force is applied on the cleaning material covering the patterned substrate. The cleaning material also includes a surfactant to help disperse the polymers in the cleaning material and to help wetting the surface of the patterned substrate. The cleaning material also includes an ion-providing compound that is ionized in the cleaning solution to adjust the viscosity of the cleaning material.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals represent like structural elements.
1 illustrates defects and device features on a substrate, in accordance with an embodiment of the present invention.
2A shows a diagram of three response curves associated with supplying a cleaning material onto a patterned substrate, in accordance with an embodiment of the present invention.
2B shows a diagram of three response curves associated with supplying cleaning material onto a patterned substrate.
2C shows a diagram of three damage curves for different technology nodes and a force intensity curve of the cleaning material, according to one embodiment of the invention.
3A illustrates a cleaning material containing polymers of high molecular weight polymeric compound dissolved in a cleaning solution, in accordance with one embodiment of the present invention.
FIG. 3B illustrates the cleaning material of FIG. 3A entrapping contaminants, in accordance with an embodiment of the present invention. FIG.
3C illustrates the cleaning material of FIG. 3A sprayed onto a patterned wafer to clean contaminants from a substrate surface, in accordance with an embodiment of the present invention.
3D illustrates the cleaning material of FIG. 3A sprayed onto a patterned wafer to clean contaminants from a substrate surface, in accordance with an embodiment of the present invention.
3E illustrates the cleaning material of FIG. 3A sprayed onto a patterned wafer having trenches and vias to clean contaminants from the substrate surface, in accordance with an embodiment of the present invention.
3F illustrates a cleaning material having gel-type polymer droplets emulsified in the cleaning solution, according to one embodiment of the present invention.
3G illustrates a cleaning material having gel-like polymer globs suspended in the cleaning solution, according to one embodiment of the invention.
3H shows a foam cleaning material, according to one embodiment of the invention.
4A shows particle removal efficiency (PRE) as a function of molecular weight for hydroxyethyl cellulose (HEC) and polyacrylic acid (PAA), according to one embodiment of the invention.
4B shows PRE as a function of molecular weight for polyacrylamide (PAM), according to one embodiment of the invention.
4C shows the results of experiments using ammonium chloride to reduce the viscosity of a cleaning material made of polyacrylamide (PAM) polymers, according to one embodiment of the invention.
4D shows viscosity data of cleaning materials having different pH values and different ionic strengths, according to one embodiment of the invention.
5A illustrates a system for cleaning contaminants from a substrate, in accordance with an embodiment of the present invention.
5B shows a vertical cross sectional view of a chamber having a substrate carrier positioned below the upper processing head and above the lower processing head, in accordance with an embodiment of the present invention.
5C illustrates an upper processing head disposed above the substrate and a lower processing head disposed below the substrate opposite the upper processing head, according to one embodiment of the invention.
5D illustrates a substrate cleaning system, in accordance with an embodiment of the present invention.
6A shows a cleaning apparatus using a cleaning material containing polymers of high molecular weight polymerizable compounds and a rinsing apparatus for rinsing the cleaning material, in accordance with one embodiment of the present invention.
FIG. 6B illustrates a cleaning and rinsing apparatus using a cleaning material containing polymers of high molecular weight polymeric compounds to clean substrates, according to one embodiment of the invention.
7A shows a process flow for preparing a cleaning material containing polymers of one or more polymerizable compounds of high molecular weight, according to one embodiment of the invention.
7B shows a process flow using a cleaning material containing polymers of one or more polymerizable compounds of high molecular weight to clean patterned substrates, according to one embodiment of the invention.

Embodiments of materials, apparatuses, and methods are provided for cleaning wafer surfaces, particularly surfaces of patterned wafers (or substrates). The cleaning materials, apparatuses, and methods described above have advantages in cleaning patterned substrates having fine features without substantially damaging the features. In one embodiment, the cleaning material comprises polymers of one or more polymerizable compounds dissolved in a solvent. The cleaning materials are liquid and deform around the device features; The cleaning materials do not substantially damage the device features or reduce all of the damage together. Polymers of cleaning materials capture contaminants on the substrate. In addition, polymers prevent the entrapment of contaminants and return to the substrate surface. Cleaning materials can be used to clean different types of substrate surfaces, including hydrophilic and hydrophobic surfaces. The composition window and process window for the cleaning materials are widened to allow formulated cleaning materials to be used to clean different types of substrate surfaces. The cleaning apparatuses can be designed to spray and rinse cleaning materials having a predetermined viscosity range. The polymers form long polymer chains, which can also be crosslinked to form a network (or polymerizable network). Long polymer chains and / or polymer networks exhibit superior abilities to capture and entrap contaminants as compared to conventional cleaning materials.

In another embodiment, the cleaning material also contains a buffer for changing the pH of the cleaning material. The cleaning material also contains a surfactant to assist in the dispersion of the polymers in the solvent and to wet the surface of the patterned substrate. The cleaning material also contains an ion-providing compound that changes the viscosity of the cleaning material.

However, it will be apparent to one skilled in the art that the present invention may be practiced without some or all of these specific details. Moreover, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.

Embodiments described herein provide cleaning materials and cleaning methods that are effective at removing contaminants and do not damage features on a patterned wafer, some of which may include high aspect ratio features. Although embodiments provide specific examples of semiconductor cleaning applications, these cleaning applications may be extended to any technology that requires removing contaminants from a substrate.

1 shows a substrate 100 having a substrate body 101, according to one embodiment of the invention. On the substrate 101, there is a device structure 102 and a particle 103 near the surface 105. The particle 103 has an approximate diameter 107, which diameter may be about the same size as the width 104 of the device structure 102.

For advanced technologies such as 65 nm, 45 nm, 32 nm, 22 nm, and 16 nm technology nodes, the width 104 of the device structure 102 is no greater than 65 nm. The widths of the device structures, such as the width 104 of the device structure 102, are continuously scaled down using each technology node to equip more devices on the limited surface area of the chips. In general, the heights of the device structures, such as the height 106 of the device structure 102, do not scale down in proportion to the width of the device features due to high resistivity concerns. In conductive structures such as polysilicon lines and metal interconnects, narrowing the widths and heights of the structures increases the resistivity too much, causing significant RC delay and generating too much heat for the conductive structures. As a result, device structures such as structure 102 have a high aspect ratio that is susceptible to damage to the structure by the force 111 applied to the structure. In one embodiment, the aspect ratio of the device structure may be in the range of about 2 or more. Force 112 is applied on particle 103 to help remove particle 103. Forces 111 and 112 are applied by a cleaning material (not shown) on the substrate surface near the device structure 102 to remove surface particulates, such as particles 103. In one embodiment, the forces 111 and 112 are very close in size because they are in the vicinity of each other. The forces 111 and 112 exerted on the substrate surface may be due to any relative motion between the cleaning material and the substrate surface. For example, the force may be by spraying the cleaning material or by rinsing the cleaning material.

The reduced width 104 of the device structure 102 and the relatively high aspect ratio of the device structure 102 cause the device structure 102 to break below the force 111 applied or to the force 111 applied to it. Energy accumulation below. Damaged device structure 102 becomes a particle source to reduce yield. In addition, the damaged device structure 102 may become inoperable due to damage.

2A shows a diagram of three response curves associated with supplying a cleaning material onto a patterned substrate, in accordance with an embodiment of the present invention. Curve 201 represents the energy versus intensity exerted (as a result of the force) exerted by the cleaning material on the substrate surface. The intensity of the cleaning energy exerted by the cleaning material peaks at E _P. Curve 202 represents particle removal efficiency as a function of energy applied on the substrate by the cleaning material. The particle removal rate peaks near E _R. When the energy exerted by the cleaning material reaches E _R , the cleaning material is most efficient at removing particles from the substrate surface. Curve 203 represents the amount of damage of device structures caused by the cleaning material as a function of energy applied on the substrate surface by the cleaning material. The device structures are damaged at E _{S which} is higher than the upper limit E _N of the energy exerted by the cleaning material on the substrate. Since the device structure damage curve 203 is outside the energy distribution 201 of the cleaning material exerted on the pattern substrate, the device structures on the pattern substrate are not damaged. The particle removal curve 202 indicates that the cleaning material can remove particles (or contaminants) from the substrate surface without damaging the structures on the substrate.

2B shows a diagram of three response curves associated with supplying cleaning material onto a patterned substrate. Curve 201 'represents the energy versus intensity exerted by the cleaning material on the patterned substrate. The intensity exerted by the cleaning material peaks at E _P ′. Curve 202 'represents the particle removal rate relative to the energy applied on the substrate. The particle removal rate peaks near E _R ′. When the energy exerted by the cleaning material reaches E _R ′, the cleaning material is most efficient at removing particles from the substrate surface. Curve 203 'represents the amount of damage of device structures caused by the cleaning material as a function of the energy applied on the substrate surface by the cleaning material. Device structures on the substrate are damaged at E _S 'which is lower than the upper limit E _N ' of the energy distribution of energy exerted by the cleaning material. Since the device structure damage curve 203 'is within the energy distribution 201' of the cleaning material exerted on the patterned substrate, the device structures on the patterned substrate are damaged by the cleaning material to add particles (or defects). .

As mentioned above, damage to device structures during the cleaning process may render the device inoperable, and the damaged device structures may remain on the substrate surface to reduce device yield. Therefore, the relationship between the cleaning curve 201 'and the damage curve 203' of FIG. 2B is undesirable. In contrast, the relationship between the cleaning curve 201 and the damage curve 203 of FIG. 2A is desirable.

Conventional substrate cleaning apparatuses and methods include brushes and pads that utilize mechanical forces in removing particulates from the substrate surface. In advanced technologies that use device structures with narrow widths and high aspect ratios, the mechanical force exerted by the brushes and pads can damage the device structures. Rough brushes and pads may also cause scratches on the substrate surface. Cleaning techniques, such as megasonic cleaning and ultrasonic cleaning, which clean the substrate using cavitation bubbles and acoustic streaming, can also damage fragile structures. Cleaning techniques using jets and sprays can cause erosion of the films and can also damage fragile structures.

Figure 2C shows a cleaning curve 201 "for a conventional cleaning material supplied by a conventional method, such as megasonic cleaning, according to one embodiment of the invention. Three technology nodes, 90 nm, 65 nm. There are damage curves 203 _I , 203 _II , and 203 _III for, and 45 nm, respectively .. Initiation of damage in curve 203 _I for patterned wafers of 90 nm technology node begins at energy E _{S I.} E _{S I} is greater than the upper limit E _N "of the energy distribution of the cleaning material on the patterned substrate. Thus, there is no damage to the device structures. Since the onset of damage starts at E _{S II} higher than E _N ", the conventional cleaning material of Figure 2C is still valid at the 65 nm technology node. As the technology moves to a narrower width, the onset of damage is Start at a lower energy level. When the technology node is 45 nm or less, the conventional cleaning material and method of curve 201 " will cause damage to device structures. The onset of damage at the 45 nm technology node, E _{S III} is lower than E _N ". FIG. 2C shows that although some cleaning materials and methods are valid for conventional technologies, advanced features with narrower feature widths are possible. There is a need to find a cleaning mechanism that utilizes a cleaning material that is softer for device structures and effective for removing particles from the substrate surface.

3A shows a liquid cleaning material 300 containing polymers 310 having high molecular weight (s) dissolved in the cleaning solution 305, according to one embodiment of the invention. In one embodiment, the liquid cleaning material 300 is a gel. In another embodiment, the liquid cleaning material 300 is a sol. In yet another embodiment, the liquid cleaning material 300 is a liquid solution. The liquid cleaning material 300 can remove particles on the substrate surface when supplied onto the substrate having particles on the substrate surface. In one embodiment, the removed particles 320 are attached to the polymers 310 as shown in FIG. 3B. Polymers have a high molecular weight (s). In one embodiment, the molecular weight (s) of the polymers is greater than about 10,000 g / mol. The polymers form long polymer chains that capture and trap the removed particles, preventing particles from returning back to the substrate surface. In one embodiment, the polymer chains form a polymerizable network. In one embodiment, the polymers 310 are acidic or basic. When the polymer 310 is dissolved in water, the polymer 310 provides a solution having a lower or higher hydrogen ion activity (pH), that is, a pH above or below 7.0, than in pure water. In another embodiment, the cleaning material 300 also contains a buffer to help adjust and maintain the pH of the cleaning material.

The polymers dissolved in the solvent may be soft gels or gel-like droplets suspended in the solvent. In one embodiment, contaminants on the substrate surface adhere to the solvated polymers by ionic force, van der Waals force, electrostatic force, hydrophobic interaction, steric interaction, or chemical bonding when the polymer molecules are in the vicinity of the contaminants. do. Polymers capture and entrap contaminants.

As described above, the polymers may form a network in solvent 305. The polymers are dispersed in liquid solvent 305. Liquid cleaning material 300 is soft to device structures on the substrate during the cleaning process. As shown in the cleaning volume 330 of FIG. 3C, the polymers 310 in the cleaning material 300 are around device structures, such as the structure 302, without a strong impact on the device structure 302. Can slide In contrast, the above-mentioned rigid brushes and pads contact the device structures without flexibility and damage the device structures. Forces (or energy) generated by cavitation in megasonic cleaning and high velocity impact by liquid during jet spraying can also damage the structure. Alternatively, two or more kinds of polymers may be dissolved in a solvent to constitute the cleaning material. For example, the polymers in the cleaning material may include "A" polymeric compounds and "B" polymeric compounds.

Polymers of one or more polymerizable compounds of high molecular weight form long chains of polymers, with or without crosslinking, to form a polymerizable network. As discussed above, the polymers may be crosslinked. However, the degree of crosslinking is relatively limited in order for the polymers to be too hard or too hard to prevent the polymers from dissolving in the solvent and deforming around device features on the substrate surface.

As shown in FIG. 3C, the polymers 310 come into contact with contaminants such as contaminants 3 O ₁ , 32 O _II , 320 _III , 320 _IV on the patterned (or unpatterned) substrate surface, and the contaminants Capture it. After the contaminants are captured by the polymers, the contaminants are attached to the polymers and suspended in the cleaning material. 3C shows contaminants 320 _III and 320 _IV attached to polymer chain (s) 311 _I and 311 _II , respectively. Contaminants 32O _I , 32O _II are attached to other polymer chains. Alternatively, contaminants 32O _I , 32O _II , 320 _III , and 320 _IV may each be attached to a plurality of polymer chains, or may be attached to a polymerizable network. When the polymers in the cleaning material 300 are removed from the substrate surface, for example by rinsing, contaminants attached to these polymer chains are removed from the substrate surface along with the polymer chains.

The embodiment shown in FIG. 3C shows only one device structure 302. In accordance with one embodiment of the present invention, as shown in FIG. 3D, a plurality of device structures, such as 302 _I , 302 _II , 302 _III , and 302 _IV , are clustered on a substrate such as substrate 301. ) Can be next to each other. Similar to FIG. 3C, the liquid cleaning material 300 in the cleaning volume 330 ′ is soft to the device structure on the substrate during the cleaning process. The polymers 310 in the cleaning material 300 slide around the device structures 302 _I , 302 _II , 302 _III , and 302 _IV without giving a strong impact on the device structures. Similar to the contaminants (32O _I , 32O _II , 320 _III , and 320 _IV ) of FIG. 3C attached to the polymer chains, the contaminants 325 _I , 325 _II , 325 _III , and 325 _IV also have polymer chains. Is attached to.

3C and 3D, in addition to the cleaning substrate with wiring features, substrates with other patterned features may also be cleaned by the materials and methods described herein. 3E illustrates a substrate 301 'having structures 302' forming vias 315 and trenches 316 in accordance with one embodiment of the present invention. Contaminants 326 _I , 326 _II , 326 _III , and 326 _IV may also be removed by the cleaning material 300 by the mechanisms discussed in FIGS. 3C and 3D above.

As mentioned above, polymers of one or more polymerizable compounds having high molecular weight are dispersed in a solvent. Examples of high molecular weight polymerizable compounds include, but are not limited to, polyacrylamide (PAM), polyacrylic acid (PAA) such as Carbopol 940 ™ and Carbopol 941 ™, poly- (N, N-dimethyl-acrylamide) Acrylic polymers such as (PDMAAm), poly- (N-isopropyl-acrylamide) (PIPAAm), polymethacrylic acid (PMAA), polymethacrylamide (PMAAm); Polyimines and oxides such as polyethylene imine (PEI), polyethylene oxide (PEO), polypropylene oxide (PPO), and the like; Vinyl polymers such as polyvinyl alcohol (PVA), polyethylene sulfonic acid (PESA), polyvinylamine (PVAm), polyvinyl-pyrrolidone (PVP), poly-4-vinyl pyridine (P4VP) and the like; Cellulose derivatives such as methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC) and the like; Acacia (arabic gum), agar and polysaccharides such as agarose, heparin, guar gum, xanthan gum and the like, and proteins such as albumin, collagen, gluten and the like. To illustrate some examples of polymer structures, polyacrylamide is an acrylate polymer (-CH ₂ CHCONH _2- ) n formed from acrylamide subunits. Polyvinyl alcohol is a polymer (-CH ₂ CHOH-) m formed from vinyl alcohol subunits. Polyacrylic acid is a polymer (-CH ₂ = CH-COOH-) o formed from acrylic acid subunits. "n", "m", and "o" are integers. Polymers of one or more polymerizable compounds of high molecular weight are soluble or highly absorbent in aqueous solutions, forming soft gels in aqueous solutions. As mentioned above, in one embodiment, the molecular weight of the one or more polymerizable compounds is greater than 10,000 g / mol. In another embodiment, the molecular weight of the one or more polymerizable compounds is greater than 100,000 g / mol. In yet another embodiment, the molecular weight of the one or more polymerizable compounds is from about 0.01 M g / mol to about 1 OOM g / mol. In yet another embodiment, the molecular weight of the one or more polymerizable compounds is about 0.1 M g / mol to about 50 M g / mol. In yet another embodiment, the molecular weight of the one or more polymerizable compounds is about 1 M g / mol to about 2 OM g / mol. In yet another embodiment, the molecular weight of the one or more polymerizable compounds is about 15 M g / mol to about 2 OM g / mol. The weight percentage of the polymers in the cleaning material is, in one embodiment, from about 0.001% to about 20%. In another embodiment, the weight percent is about 0.001% to about 10%. In yet another embodiment, the weight percent is about 0.01% to about 10%. In yet another embodiment, the weight percent is about 0.05% to about 5%. The polymers may be dissolved in the solvent, completely dispersed in the solvent, may form (emulsified) droplets in the solvent, or may form lumps (clumps) in the solvent.

Alternatively, the polymers can be copolymers derived from two or more monomer species. For example, the copolymers may comprise 90% PAM and 10% PAA made from monomers of PAM and PAA. Copolymers of other concentrations of components are also possible. The polymers may also be mixtures of two or more polymers. For example, the polymers may be prepared by mixing two polymers such as 90% PAM and 10% PAA in a solvent. Using copolymers or mixtures of different polymers in the cleaning materials has the advantage of using different strengths of different polymers to achieve the best cleaning results.

In the embodiments shown in FIGS. 3A-3C, polymers of one or more polymerizable compounds of high molecular weight dissolve uniformly in a solvent. The solvent may be a nonpolar liquid such as terpentine, or a polar liquid such as water (H ₂ O). Other examples of solvents include isopropyl alcohol (IPA), dimethyl sulfoxide (DMSO), and dimethyl formamide (DMF). In one embodiment, the solvent is a mixture of two or more liquids. For polymers with polarity such as PAM, PAA, or PVA, a suitable solvent is a polar liquid such as water (H ₂ O).

The polymers used in the cleaning materials may be acidic or basic. For example, the polymers containing acrylic acid units are acidic and the mixture of PAA in water may have a pH value of about 3. Examples of basic polymers include polymers containing quaternary ammonium salts such as poly (diallyldimethylammonium chloride) or tertiary amines such as polyethyleneimine (PEI). The 50 wt% PEI and water mixture may have a pH value of approximately 12.

In order to adjust (or change) the properties of the cleaning material, additives may be mixed in the cleaning material. The additive (s) can be mixed with the solvent to become a cleaning solution before the polymers are added. For example, the additive may be a buffer, which may be a weak acid or a weak base to adjust the pH value of the cleaning material. One example of a weak acid used as a buffer is citric acid. One example of a weak base used as a buffer is ammonium hydroxide (NH ₄ OH).

The pH value of the cleaning materials can be about 1 to about 12. In one embodiment, in front-end applications (prior to deposition of copper and intermetallic insulators), the cleaning material is basic. In one embodiment, the pH value of the front-end applications is about 7 to about 12. In another embodiment, the pH value of the cleaning materials in front-end applications is about 7 to about 10. In one embodiment, for backend processing (after deposition of copper and intermetallic dielectrics), the cleaning solution is weak basic, neutral, or acidic. Copper in the backend interconnect is not compatible with cleaning materials containing ammonium hydroxide as a buffer. Ammonium hydroxide interacts with copper and dissolves copper. In one embodiment, the pH value of the backend applications is about 1 to about 7. In another embodiment, the pH value of the backend applications is about 1 to about 5. In yet another embodiment, the pH value of the backend applications is about 1 to about 2. However, if the buffer is not ammonium hydroxide, the pH range can be widened for backend applications. In one embodiment, the pH value is about 1 to about 12 for backend applications.

In another embodiment, the additives of the cleaning material include a surfactant such as ammonium dodecyl sulfate (ADS) to help disperse the polymers in the cleaning solution. In one embodiment, the surfactant also helps wet the cleaning material on the substrate surface. Wetting of the cleaning material on the substrate surface allows the cleaning material to adhere to the substrate surface and the particles on the substrate surface. Wetting improves cleaning efficiency. Other additives may also be added to improve surface wettability, viscosity, substrate cleaning, rinse, and other related properties.

Examples of buffered rinse solutions (or rinse solutions) include buffered ammonium hydroxide solution (BAS) comprising basic and acidic buffers such as 0.44 wt% NH ₄ OH and 0.4 wt% citric acid in the solution. It includes. Alternatively, a buffered solution, such as BAS, contains 1 wt% of an amount of surfactant, such as ADS, to help suspend and disperse the polymers in the cleaning solution. A solution containing 1 wt% ADS, 0.44 wt% NH ₃ , and 0.4 wt% citric acid is referred to as solution “100”. Both solution "100" and BAS have a pH value of about 10.

The embodiments shown in FIGS. 3A-3E provide a liquid cleaning material 300 having polymers 310 of high molecular weight uniformly dispersed (or dissolved) in the cleaning solution 305. As mentioned above, in this application the high molecular weight polymers are completely dissolved in the cleaning solution, which may be water soluble. The polymers are highly absorbent, forming soft gels in aqueous solution. 3F shows an embodiment of a liquid cleaning material 300 'with gel-like polymer droplets 340 emulsified in the cleaning solution 305'. The cleaning solution 305 ′ also contains a small independent polymer 306. Surfactants, such as ADS, may be added to the cleaning solution to help the gel-like polymer droplets 340 to be uniformly dispersed in the cleaning solution 305 '. In the embodiment shown in FIG. 3F, there is a boundary 341 between the cleaning solution 305 ′ and the gel-type polymer droplets 340. Gel-like polymer droplets 340 are soft and deformed around device features on the substrate surface. Because gel-like polymer droplets 340 are deformed around the device features, the droplets do not exert great energy (or force) on the device features to damage the features. In one embodiment, the diameter of the droplets is from about 0.1 μm to about 100 μm.

In another embodiment, polymers of one or more polymerizable compounds of high molecular weight are dissolved in the cleaning solution to form gel-like polymer masses (or cores) 350, which are cleaned as shown in FIG. 3G. No clear boundary is established with the solution 305 ". The cleaning solution 305" also contains small independent polymers 306. Gel-like polymer masses 350 are soft, deformed around device features on the substrate surface, and do not exert a large amount of energy (or force) that can damage the features on device features on the substrate surface. . In one embodiment, the diameter of the polymer masses is about 0.1 μm to about 100 μm.

The cleaning materials discussed above are all liquid. In another embodiment, cleaning material, such as the liquid cleaning materials 300, 300 ′, and 300 ″ discussed above, may be N ₂ to form the cleaning material into a foam, as shown in FIG. 3H. It may be stirred to add a gas, such as an inert gas, or a mixture of gases, such as air, In Figure 3H, the cleaning material 300 * has air bubbles 360 dispersed in the cleaning solution 305. The polymers 310 are also dispersed in the cleaning solution 305. In another embodiment, the polymers 310 of FIG. 3H are polymer droplets 340 or polymer chunks 350 described in FIGS. 3F and 3G. The cleaning material 300 * has a gaseous phase and a liquid phase.

The cleaning material described above can be sprayed onto the substrate surface by a number of mechanisms. As discussed above in FIGS. 2A and 2B, in order to prevent damage to device features on the patterned substrates, the energy applied by the cleaning material on the patterned surface is reduced to a minimum force (E) to prevent damage to the device features. _It needs to be less than _S or E _S '). Cleaning materials, such as the cleaning materials 300, 300 ', 300 ", and 300 * discussed above, are liquid or gaseous / liquid. Liquid and foam can flow on the substrate surface and surround device features on the substrate surface. Can be deformed (or flowed) in. Thus, the cleaning material can be supplied onto the patterned substrate without exerting great energy on device features on the substrate surface.

Table 1 compares the viscosity, rinse time, and particle removal efficiency (PRE) of different weight percents of Carbopol 941 ™ PAA in BAS. The viscosity of the liquid cleaning materials can be measured in the range of shear rates such as about 1 × 10 ⁻⁶ / s to about 1 × 10 ⁵ / s. In one embodiment, the viscosity of the liquid cleaning material may be measured at a reference shear rate of less than about 100 / s. In other embodiments, the viscosity can be measured at a reference shear rate of less than about 10 / s. In yet another embodiment, the viscosity can be measured at a reference shear rate of less than about 1 / s. The viscosity data in Table 1 is 500 s ^- is measured with a strain rate of ¹ (strain rate). Rinse time measures the time taken to rinse the cleaning material at the surface of the substrate. PRE is measured by using particle monitor substrates that are intentionally deposited with silicon nitride particles of varying sizes. In this study, only particle sizes of 90 nm to 1 μm are measured. PRE is calculated by the formula (1) described below:

PRE = (Pre-clean count-Post-clean count) / Pre-clean count × 100 ....... (1)

Comparison of Cleaning Materials with Different Concentrations of Carbopol 941 ™ PAA Polymers density
(wt%) Polymer molecular weight
(g / mol) Viscosity @
500 s ^-1 (cP) Rinse time
(second) PRE 0.2% 1.25 M 26

5

5 74% 0.5% 1.25 M 198 5-10 89% One % 1.25 M 560 8-10 87%

The cleaning materials in Table 1 were prepared by mixing the BAS described above with commercially available Carbopol 941 ™ PAA. The Carbopol 941 ™ PAA used has a molecular weight of 1,250,000 (or 1.25M) g / mol. The results in Table 1 show that PRE increases until about 0.5% depending on the weight percent of Carbopol 941 ™ PAA. Polymers between 0.5% and 1% have no significant difference in PRE. The results also show that the viscosity of the cleaning material increases with the weight percent of the polymers. In addition, the rinse time taken to rinse the cleaning material increases with the viscosity of the cleaning material. Water is used to rinse the substrates.

Table 2 compares the capabilities of different cleaning materials in trapping or suspending particles in the cleaning materials. Silicon nitride particles are intentionally added to the cleaning materials. After silicon nitride particles are added, cleaning materials are sprayed onto the cleaning substrates. Next, cleaning materials are rinsed from the substrate, and then the number of particles (silicon nitride) remaining on the surface is measured.

Comparison of Particle Counts Using Different Cleaning Materials Added Silicon Nitride Particles Cleaning material
w / 1X SiN Particles After rinse
Particle count Cleaning material
w / 50X SiN particles After rinse
Particle count DIW saturation DIW saturation DIW + Ammonium Hydroxide
(pH> 10) 6002 DIW + Ammonium Hydroxide
(pH> 10) saturation "100" 4238 "100" saturation 0.2% Carbopol 940 ^TM in "100" 1137 0.2% Carbopol 940 ^TM in "100" 15689 0.5% PAM in "100" 53 0.5% PAM in "100" 104

In the study of Table 2 five cleaning materials (solvent or solutions) are used. The first cleaning material, "DIW", is only deionized water. The second cleaning material is DIW with ammonium hydroxide added to adjust the pH value above 10. The third cleaning material is solution "100" which is BAS with 1 wt% of ADS added. As mentioned above, the pH value of the solution "100" is 10. The fourth cleaning material is 0.2 wt% Carbopol 940 ™ PAA dissolved in a “100” solution. Carbopol 940 ™ PAA has a molecular weight of 4M (or 4 million) g / mol. The fifth type is 0.5 wt% PAM dissolved in solution “100”. The molecular weight of PAM is 18 M g / mol. The pH value of the fifth cleaning material is about 10. The five cleaning materials are mixed with two amounts of silicon nitride particles, 1X and 5OX. The number of silicon nitride particles of 50X is 50 times the number of particles of 1X. 1X nitride particles indicate that the nitride particle weight percentage is 0.00048%, while 50X nitride particles indicate the nitride particle weight percentage is 0.024%.

The results indicate that DIW is not very good at suspending silicon nitride particles. Large amounts of (saturated) silicon nitride particles remain on the substrate surface. The description of "saturation" used in Table 2 describes a particle (or defects) count of greater than 75,000. In contrast, 0.2% Carbopol 940 ™ PAA in "100" and 0.5% PAM in "100" are much better for suspending silicon nitride particles in the cleaning material. 0.5% PAM in "100" is particularly good at trapping or suspending silicon nitride particles added to the cleaning material. Among the silicon nitride (or Si ₃ N ₄ ) particles in the cleaning material, there are only a few, 53 and 50X silicon nitride particles left on the substrate surface.

The molecular weight of the polymers used in the cleaning material can affect the particle removal efficiency (PRE). 4A shows 1% (% by weight) of PAA and 1% (% by weight) of hydroxyethyl cellulose (HEC) in "100" as a function of the molecular weight of two polymers (PAA and HEC) A graph of PRE of more than 90 nm silicon nitride particles on a substrate with cleaning materials having is shown. The data in FIG. 4A shows that PRE increases with HEC molecular weight from 100,000 g / mol to 1M (or 1,000,000) g / mol. The data in FIG. 4A also shows that PRE increases with a PAA molecular weight of 500,000 g / mol to 1 M g / mol. However, at 1 M g / mol to 1.25 M g / mol of PAA, PRE does not change much. 4B shows a PRE graph of more than 90 nm silicon nitride particles on a substrate with cleaning materials having a PAM of 1% (% by weight) of “100” as a function of molecular weight of PAM. The data in FIG. 4B shows that the increase in PRE increases with the molecular weight of PAM from 500,000 g / mol to 18 M g / mol. The data in both graphs show the effect of molecular weight on PRE.

As mentioned above, the viscosity of the cleaning material affects the rinse time for removing the cleaning material from the substrate surface. 4C shows the results of adding ammonium chloride (NH ₄ Cl) to a cleaning material having 0.2 wt% -1 wt% PAM dissolved in deionized (DI) water. PAM has a molecular weight of 18 M g / mol. The ammonium chloride added is ionized in the cleaning solution, providing additional ions that increase the ionic strength of the cleaning material. Increased ionic strength reduces the viscosity of the cleaning material. For example, 1.5 wt% ammonium chloride can reduce the viscosity from about 100 cP (centipoises) to 60 cP for a cleaning material with 1 wt% PAM. 1.5 wt% ammonium chloride can also reduce the viscosity for cleaning materials with 0.5 wt% PAM from about 50 cP to about 25 cP. These viscosities are measured at a shear rate of 500 / s. Lowering the viscosity can lower the amount of time it takes to rinse the cleaning material from the substrate surface.

In addition to affecting the rinse time of the cleaning materials, the viscosity also affects how the cleaning materials are dispersed on the substrate surface. Cleaning materials with higher viscosity need to be sprayed to have larger openings compared to cleaning materials with lower viscosity. Rinse times of higher viscosity cleaning materials may also be reduced by coarser rinse.

Table 3 compares PRE, pH values, and ionic strength for the four compositions of cleaning materials. Polymers in all four cleaning materials are copolymers of acrylamide and acrylic acid. The copolymers are mixed in solution "100". Ammonium hydroxide is used to adjust the pH value of cleaning materials. Citric acid is used to alter the ionic strength of cleaning materials. In addition to buffers (ammonium hydroxide) and ionic strength modifiers (citric acid), the cleaning materials in Table 3 also include small amounts of surfactants, ammonium dodecyl sulfate, to improve solubility of the polymers in the cleaning solution and to the substrate surface. Improve the wettability of cleaning materials. The weight percentage of acrylic acid in the copolymers is less than about 50%.

Data comparison of PRE, pH, and ionic strength for four compositions of cleaning materials Furtherance PRE pH Ionic strength #One 97% 7 1X #2 98% 10 1X # 3 95% 7 0.15X #4 91% 10 0.15X

The data in Table 3 show that all four different cleaning materials have very good PRE. The pH values of the cleaning materials in Table 3 vary from about 7 to about 10. The ionic strength of the cleaning materials varies from about 0.15X to about 1X, where X is the set point. The viscosity of cleaning materials with an ionic strength of 0.15X exceeds 5 times the viscosity of cleaning materials with an ionic strength of 1X. Viscosity data of the cleaning materials in Table 3 are presented and discussed in FIG. 4D below. Cleaning materials provide very good cleaning efficiencies over a wide range of pH values, ionic strengths and viscosities. This wide process window is important because the substrate surfaces may be very different and may require wide process conditions during different process steps of device fabrication. For example, the wafers used in the study in Table 3 are made of silicon covered with a thin layer of natural oxide. The surface of these wafers is hydrophilic. For hydrophilic substrate surfaces, cleaning materials have large compositional (or process) windows. However, when these wafers are treated with HF solution, the surfaces become hydrophobic. Table 4 shows the data of particle adders for hydrophobic wafer surfaces after the wafers have been treated with three different compositions of cleaning materials. The chemical compounds (or components) used in formulating the cleaning materials of Table 4 are the same as those used in Table 3. The wafers in the study of Table 4 are exposed to the compositions, and additional particle defects resulting from the exposure are measured by commercial light scattering tools and classified into adders. The fewer particle defects added, the better the process. In Table 4, 95% CI represents a 95% confidence interval. Multiple wafers are processed to obtain data with 95% CI.

Data comparison of particle adders, pH, and ionic strength for three compositions of cleaning materials Furtherance > 65nm Adders (95% CI) > 50nm adders (95% CI) pH Ionic strength A 271 ± 61 695 ± 125 10 1X B 90 ± 39 177 ± 53 10 0.15X C 24 ± 6 51 ± 14 7 0.15X

The data in Table 4 show that for hydrophobic surfaces, cleaning materials with lower ionic strength and lower pH show better particle add results. The results in Tables 3 and 4 indicate that different substrate surfaces may require cleaning materials of different compositions. The results also indicate that for some applications, low ionic strength may be required to achieve good cleaning results. These applications may include processes where hydrophobic surfaces encounter photoresist, polysilicon, low-k dielectrics or porous low-k dielectrics, and the like. Since lower ionic strength increases the viscosity of the cleaning materials, it may be necessary to have a cleaning system and method effective for the above-described cleaning materials having higher viscosity. 4D shows viscosity data of the aforementioned cleaning materials that differ in pH value and differ in ionic strength, according to one embodiment of the invention. The data indicate that lower ionic strengths lead to higher viscosities. The viscosity of the cleaning materials is measured at 0.1 / s shear rate. For example, a viscosity measured at less than about 1 / s (<1 / s) is believed to be measured at low shear rates. At normal ionic strength 1X, the viscosity increases with the pH value of the cleaning material. However, at low ionic strength (0.15X), the viscosity decreases with pH value.

In one embodiment, the low shear viscosity of the cleaning materials with polymers ranges from 10 cP to about 100,000 cP. In another embodiment, the low shear viscosity of the cleaning materials ranges from about 100 cP to about 100,000 cP. As mentioned above, the process window of viscosity of cleaning materials can be widened by varying equipment design and process conditions. For example, the spray openings of the cleaning materials can be made larger so that the cleaning materials are supplied (or sprayed) at reasonable rates on the substrates. In addition, the apparatus for delivering and removing rinse liquids can be designed to allow for coarser rinsing, thereby shortening the rinse time of higher viscosity cleaning materials.

5A illustrates a system for cleaning contaminants from a substrate, in accordance with an embodiment of the present invention. The system includes a chamber 500 defined by enclosing walls 501. Chamber 500 includes an input module 519, a processing module 521, and an output module 523. Substrate carrier 503 and the corresponding drive device move linear movement of substrate 502 from input module 519, through processing module 521, to output module 523, as indicated by arrow 507. It is defined to provide. The drive rail 505A and guide rail 505B are defined to provide controlled linear movement of the substrate carrier 503 so that the substrate 502 is a linear path defined by the drive rail 505A and the guide rail 505B. Along the substantially horizontal direction.

The input module 519 includes a door assembly 513, through which the substrate 502 can be inserted into the chamber 500 by the substrate-handling device. The input module 519 is also defined as a substrate lifter defined to move vertically through the opening area of the substrate carrier 503 when the substrate carrier 503 is centered above the substrate lifter 509 in the input module 519. 509. When the substrate 502 is inserted into the chamber 500 through the door assembly 513, the substrate lifter 509 can be raised to receive the substrate 502. Substrate lifter 509 can then be lowered to position substrate 502 on substrate carrier 503.

The processing module 521 is an upper processing head 517 disposed to process the upper surface of the substrate 502 when the substrate carrier 503 on which the substrate 502 is disposed moves below the upper processing head 517. ) The processing module 521 also includes a lower processing head 518 (see FIG. 5B) disposed below the linear transport path of the substrate carrier 503 opposite the upper processing head 517. The bottom processing head 518 is defined and arranged to process the bottom surface of the substrate 502 as the substrate carrier 503 passes through the processing module 521. Each of the upper and lower processing heads 517 and 518 has a leading edge 541 and a trailing edge 543, during which the substrate carrier 503 has a trailing edge from the leading edge 541 during the processing operation. The substrate 502 is moved along the linear path to the side 543. As discussed in more detail below, in connection with the present invention, each of the top and bottom processing heads 517 and 518 is defined to perform a multi-step cleaning process on each of the top and bottom surfaces of the substrate 502.

In some embodiments, one or more additional processing heads may be used with the upper processing head 517 over the linear transport path of the substrate carrier 503, and / or one or more additional processing heads of the substrate carrier 503 It should be understood that it can be used with the bottom processing head 518 under the linear transport path. For example, processing heads defined to perform a drying process on substrate 502 may be disposed behind trailing edges of each of upper and lower processing heads 517 and 518.

Once the substrate carrier 503 moves through the processing module 521, the substrate carrier 503 arrives at the output module 523. The output module 523 is a substrate lifter defined to move vertically through the opening area of the substrate carrier 503 when the substrate carrier 503 is centered above the substrate lifter 511 in the output module 523. 511). The substrate lifter 511 is raised to lift the substrate 502 from the substrate carrier 503 to the seat for recovery from the chamber 500. The output module 523 also includes a door assembly 515, through which the substrate 502 can be retrieved from the chamber 500 by the substrate-handling device.

5B shows a vertical cross-sectional view of a chamber 500 having a substrate carrier 503 positioned below the upper processing head 517 and above the lower processing head 518, in accordance with an embodiment of the present invention. The upper processing head 517 is mounted on both the drive rail 505A and the guide rail 505B so that the vertical position of the upper processing head 517 is the vertical position of the drive rail 505A and the vertical position of the guide rail 505B. Indexed to all, thereby indexing the vertical position of the substrate carrier 503 and the substrate 502 held thereon.

The upper processing head 517 is defined to perform a cleaning process on the upper surface of the substrate 502 when the substrate carrier 503 moves the substrate 502 thereunder. Similarly, the lower processing head 518 is defined to perform a rinse process on the bottom surface of the substrate 502 when the substrate carrier 503 moves the substrate 502 thereon. In various embodiments, each of the upper and lower processing heads 517 and 518 in the processing module 521 can be defined to perform one or multiple substrate processing operations on the substrate 502. In addition, in one embodiment, the upper and lower processing heads 517 and 518 in the processing module 521 are defined to span the diameter of the substrate 502, resulting in upper / lower processing heads 517/518. The entirety of the top / bottom surface of the substrate 102 is processed in one pass of the substrate carrier 503 at the bottom / top.

5C illustrates an upper processing head 517 disposed above the substrate 502 and a lower processing head 518 disposed below the substrate 502 opposite the upper processing head 517, according to one embodiment of the invention. Shows a cross-sectional view. Upper processing head 517 includes a first upper side module 517A operative to supply cleaning material 561A through cleaning material injection port 529A to substrate 502. The upper processing head 517 also includes a second upper side module 517A operative to supply the cleaning material 561B to the substrate 502 through the cleaning material injection port 529B. The chemical components of the cleaning material 561A may be the same as or different from the cleaning material 561B. In one embodiment, the cleaning material spray ports 529A and 529B are long slits along the length of the upper processing head 517.

In each of the first and second upper side modules 517A / 517B, the rinse material injection port 541A / 541B supplies the rinse material at the trailing side of the rinse meniscus, while the first row of vacuum ports ( 547A / 547B remove fluid at the leading side of the rinse meniscus. Since the vacuum ports 547A / 547B in the first row are provided on the leading side of the rinse meniscus, unlike those provided on both the leading and trailing sides, the ports in the fluid supply ports 541A / 541B are located in the first row. Angled downward toward the vacuum ports 547A / 547B.

In one embodiment, each of the first and second upper side modules 517A / 517B has a second row of vacuum ports 549A / 549B defined along the trailing side of the first row of vacuum ports 547A / 547B. ) The second row of vacuum ports 549A / 549B are defined to provide multi-phase suction of the cleaning material and the rinse material from the substrate when the substrate is below. The second row of vacuum ports 549A / 549B may be controlled independently from the first row of vacuum ports 547A / 547B. The ports of the second row of vacuum ports 549A / 549B are defined as single phase liquid return ports and are configured to prevent interference of rinse fluid meniscus stability.

The first upper side module 517A carries the upper side rinse meniscus in a substantially uni-directional manner toward the cleaning material 561A and opposite the direction of movement 560 of the substrate 502. 563A). The flow rate of the rinse material through the upper side rinse meniscus 563A is set to prevent the cleaning material from leaking past the upper side rinse meniscus 563A. The first upper side module 517A leaves a uniform thin rinse material 565 on the substrate 502.

The second upper side module 517B of the upper processing head 517 operates to supply the cleaning material 561B to the substrate 502, and then exposes the substrate 502 to the upper side rinse meniscus 563B. . The second upper side module 517B flows the rinse material through the upper side rinse meniscus 563B in a substantially unidirectional manner towards the cleaning material 561B and opposite the direction of movement 560 of the substrate 502. To make it work. The flow rate of the rinse material through the upper side rinse meniscus 563B is set to prevent the cleaning material from leaking past the upper side rinse meniscus 563B. The second upper side module 517B leaves a uniform thin film of rinse material 567 on the substrate 502.

The first bottom side module 518A of the lower processing head 518 operates to supply the bottom side rinse meniscus 569A to the substrate 502, thereby allowing the substrate 502 by the top side rinse meniscus 563A. Balancing the force on). The first bottom side module 518A operates to flow the rinse material through the bottom rinse meniscus 569A in a substantially unidirectional manner opposite the direction of movement 560 of the substrate 502. The first bottom side module 518A leaves a uniform thin film of rinse material 571 on the substrate 502.

The second bottom module 518B of the lower processing head 518 operates to supply the bottom rinse meniscus 569B to the substrate 502, thereby allowing the substrate 502 to be fed by the top rinse meniscus 563B. Balancing the force on). The second bottom module 518B operates to flow the rinse material through the bottom rinse meniscus 569B in a substantially unidirectional manner opposite the direction of movement 560 of the substrate 502. The second bottom module 518B leaves a uniform thin film of rinse material 573 on the substrate 502.

Each of the first and second bottom side modules 518A / 518B includes a respective row of rinse material injection ports 551A / 551B defined within respective rinse meniscus regions 569A / 569B. Each row of rinse material spray ports 551A / 551B is defined to spray the rinse material upward onto the substrate when a substrate is present thereon.

In one embodiment, the rinse material is deionized water (DIW). However, in other embodiments, the rinse material may be one of many different materials in the liquid state, such as easily miscible with dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), dimethyl acetate (DMAC), DIW Possible polar solvents, atomized liquids such as atomized polar solvents (eg, DIW), or any combination thereof. It is to be understood that the rinse materials defined above are provided as examples and do not represent a comprehensive set of rinse materials.

5D illustrates a cleaning system 550 having a substrate cleaning chamber 500 ', in accordance with one embodiment of the present invention. The substrate cleaning chamber 500 'is similar to the chamber 500 described above. In the chamber 500 ', there is a substrate 502' held by a substrate carrier 503 '. The substrate cleaning chamber 500 'has an upper processing head 517' and a lower processing head 518 '. In one embodiment, the upper processing head 517 'is held by the arm 581 and the lower processing head 518' is held by the arm 581 '. The cleaning material with the polymers is supplied to the upper processing head 517 via the supply line 595. Rinse material, such as deionized water (DIW), is supplied to the upper processing head via supply line 597. Cleaning waste is removed from the substrate 502 ′ via waste line 596. The rinse material is supplied to the lower processing head 518 ′ via the supply line 599. Rinse waste is removed via waste line 598. Supply lines 595, 597, 599, and waste lines 596, 598 are coupled to proximity head manifold 583. Proximity head manifold 583 is also coupled to container 584 of rinse material, container 585 of cleaning material, and waste container 586. Waste container 586 is also coupled to vacuum pump 587.

Proximity head manifold 583 is coupled to proximity head controller 588, which is then controlled by computer 590. The operator can make control commands via the computer 590. In one embodiment, the proximity head controller 588 is connected to the computer 590 via the internet 589. The perimeter of the substrate cleaning chamber 500 'may also be controlled. One or more gases may be supplied to the chamber 500 '. For example, a gas tank 593 can be coupled to the chamber 500 '. The pressure in the chamber 500 'may also be maintained through the vacuum pump 594. The flow of gas from the gas tank 593 and the evacuation of the chamber 500 ′ can be controlled by the chamber manifold 592, which is coupled to the peripheral controller 591. Peripheral controller 591 may also be coupled to computer 590.

Further details of the above-described cleaning apparatus are filed on April 28, 2009, and are entitled US Patent Application 12 / 431,731 (Representative Document No. LAM2P660), entitled “Apparatus and System for Cleaning Substrate,” and June 2008. Filed on Feb. 2, the invention may be found in US Patent Application 12 / 131,667 (Representative Document No. LAM2P628G) entitled "Apparatus for Particle Removal by Single-Phase and Two-Phase Media". Each disclosure of the related applications mentioned above is incorporated herein by reference.

The above-described embodiments are merely examples. Other embodiments of cleaning heads for spraying the cleaning material onto the substrate surface and removing the cleaning material from the substrate surface are also possible. 6A shows a cleaning tank 680 containing a cleaning material 681 and a rinse tank 690 containing a rinse liquid 691, according to one embodiment of the invention. The substrate 620 ′, held by the substrate carrier 623, first dips into the cleaning material 481 of the tank 680, causing the cleaning material to contact the contaminants on the substrate surface. The substrate 620 'is lowered into the cleaning material 681 and raised out of the cleaning material 681 in the cleaning tank 680 by a mechanical mechanism (not shown). Thereafter, the substrate 620 'held by the substrate carrier 626 is dipped into the rinse liquid 691 of the cleaning tank 690 to rinse the cleaning material. A mechanical mechanism (not shown) is used to lower the substrate to the rinse tank 690 and to lift it out of the rinse tank 690. In the rinse tank (or rinse tank) 690, when cleaning material remains on the surface of the substrate 620 ′, contaminants are removed from the substrate surface along with the cleaning material. In the rinse tank 690, the substrate 620 ′ is lowered into the rinse liquid 691 by a mechanical mechanism (not shown). Although the direction of the substrate shown in FIG. 6A is vertical, other directions are also possible. For example, the substrate may be submerged in the horizontal direction in the cleaning tank and / or the rinse tank.

6B shows another embodiment of a cleaning apparatus 699 for cleaning contaminants from the surface of the substrates. The cleaning apparatus has a cleaning tank 685 having a substrate support 683. A substrate 620 * is disposed on the substrate support 683, and the substrate support 683 rotates during the cleaning process. The cleaning apparatus 699 has a cleaning material spray head 697, and the cleaning material spray head 697 sprays the cleaning material on the surface of the substrate 620 *. The cleaning material spray head 697 (or spray nozzle) is coupled to the storage tank 670 of cleaning material. The cleaning apparatus 699 also has a rinse liquid jet head 698 (or spray nozzle), which rinse liquid rinse liquid onto the surface of the substrate 620 ″. 698 is coupled to a storage tank of rinse liquid 696. A rotating substrate 620 * allows the cleaning material and the rinse liquid to cover the entire substrate surface by spraying the rinse liquid to remove the cleaning material from the substrate surface. Prior to doing so, a cleaning material is sprayed onto the substrate surface.

After rinsing the cleaning material from the surface of the patterned substrate, the patterned substrate is dried by spinning (or rotating) the substrate at a relatively high speed. During spinning, although not shown in FIG. 6B, the substrate is secured by the device (or mechanism). In one embodiment, a surface tension reducing gas is supplied to the surface of the patterned substrate to help remove rinse and possibly remove remaining cleaning material. In one embodiment, the surface tension reducing gas comprises a mixture of isopropyl alcohol (IPA) and nitrogen (N ₂ ). Other surface tension reducing gases can also be used.

The cleaning tank 685 may receive waste of the cleaning process. Wastes of the cleaning process include cleaning material waste and rinse liquid waste. In one embodiment, the cleaning tank 685 has a drain hold 603, and the drain hold 603 is connected to the waste line 604. Waste line 604 is coupled to valve 605, which controls the drainage of cleaning waste from cleaning tank 685. The cleaning waste may be directed to recycling processor 606 or waste processor 607.

The cleaning materials described above have particular advantages in cleaning substrates having fine features (or topologies), such as polysilicon lines (with trenches and / or vias) or metal interconnects, on the substrate surface. . The minimum width (or critical dimension) of these fine features can be 45 nm, 32 nm, 22 nm, 16 nm or less.

7A shows a flow chart 700 for preparing a cleaning material containing one or more polymerizable compounds of high molecular weight, according to one embodiment of the invention. In operation 701, one or more polymerizable compounds are mixed with a solvent. In one embodiment, the one or more polymerizable compounds are in powder form and the amount is premeasured. Prior to the mixing process, the amount of one or more polymerizable compounds is calculated and weighed. Likewise, the amount of solvent used is also measured. In operation 702, the additives are mixed with the mixture prepared in operation 701 to adjust the properties of the prepared cleaning material. The additives may include a buffer for adjusting the pH value of the cleaning material. The additives may also include an ion-providing compound for adjusting the viscosity of the cleaning material. In addition, the additives may include surfactants that enhance the solubility of the polymerizable compounds and / or assist in wetting the surface of the patterned substrate with the cleaning material. Other kinds of additives may also be included to adjust the properties of the cleaning material.

By using the flow chart 700 for preparing the cleaning material, the cleaning material can have a target pH value, target viscosity, and other desired properties such as solubilized polymers and good wetting properties. As mentioned above, the operable pH range and viscosity range can be very wide. Alternatively, the mixing of surfactant, buffer, and ion-providing compound can occur in a variety of sequential steps. In other embodiments, the different components used to prepare the cleaning material may be mixed in one single process step.

7B shows a flow chart 750 of cleaning a patterned substrate using a cleaning material containing one or more polymerizable compounds of high molecular weight, according to one embodiment of the invention. Cleaning materials are described above. In step 751, the patterned substrate is placed in a cleaning apparatus. In step 752, cleaning material is sprayed onto the surface of the patterned substrate. In step 753, a rinse liquid is sprayed onto the surface of the patterned substrate to rinse the cleaning material. Rinse liquids are described above. In one embodiment, after the rinse liquid is supplied onto the substrate surface, the rinse liquid, cleaning material, and contaminants on the substrate surface may be removed from the surface of the patterned substrate by vacuum.

The cleaning materials, apparatuses, and methods discussed above have an advantage in cleaning patterned substrates having fine features without damaging the features. The cleaning materials are liquid or liquid / gas phase (foam) fluids, and deform around device features; Cleaning materials do not damage the device features. Liquid cleaning materials may be in liquid, sol, or gel form. Cleaning materials containing polymers of high molecular weight (s) capture contaminants on the substrate. In addition, cleaning materials entrap contaminants and prevent contaminants from returning to the substrate surface. The polymers form long polymer chains, and the long polymer chains can also be crosslinked to form a network of polymers. Long polymer chains and / or polymer networks exhibit excellent ability to capture and entrap contaminants as compared to conventional cleaning materials.

Prior to the cleaning material being supplied on the substrate surface to remove contaminants or particles from the substrate surface, the cleaning material is substantially free of particles (or coarse particles) that are not deformed. Unmodified particles are hard particles, such as particles in sand or slurry, and can damage fine device features on a patterned substrate. During the substrate cleaning process, the cleaning material collects contaminants or particles from the substrate surface. However, no undeformed particles are intentionally mixed with the cleaning material before the cleaning material is supplied onto the substrate surface for cleaning the substrate.

While the above embodiments describe materials, methods, and systems for cleaning patterned substrates, the materials, methods, and systems may also be used to clean unpatterned (or blank) substrates. have.

Although the discussion above centers on cleaning contaminants from patterned wafers, cleaning apparatuses and methods may also be used to clean contaminants from non-patterned wafers. Also, exemplary patterns on the patterned wafers discussed above are protruding lines such as polysilicon lines, metal lines, or dielectric lines. However, the concept of the present invention can be applied to a substrate having concave features. For example, concave trenches or vias after CMP can form a pattern on the wafer, and the most suitable design of the cleaning head can be used to achieve the best decontamination efficiency.

As an example used herein, substrates represent semiconductor wafers, hard drive disks, optical disks, glass substrates, and flat panel display surfaces, liquid crystal display surfaces, and the like, which may be contaminated during manufacturing or handling operations, without limitation. Depending on the actual substrate, the surface may be contaminated in different ways, and the acceptable level of contamination is defined in the particular industry in which the substrate is handled.

While some embodiments of the invention have been described in detail herein, it should be understood by those skilled in the art that the invention may be embodied in many other specific forms without departing from the spirit and scope of the invention. Accordingly, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details provided herein, but may be modified and practiced within the scope of the appended claims.

Claims (23)

A cleaning material supplied on a surface of a patterned substrate for defining integrated circuit devices to remove contaminants from the surface, the cleaning material comprising:
menstruum; And
Include polymers of one or more polymerizable compounds,
The one or more polymerizable compounds are dissolved in the solvent,
The solubilized polymers have long polymer chains that capture and entrap at least a portion of the contaminants from the surface of the patterned substrate for defining the integrated circuit devices,
The cleaning material is defined as a liquid phase,
The viscosity of the cleaning material measured at a reference shear rate of less than about 100 / s is from about 10 cP to about 100,000 cP,
And the cleaning material is deformed around device features on the surface of the patterned substrate when a force is applied on the cleaning material covering the patterned substrate. The method of claim 1,
The solvent is selected from the group consisting of water, isopropyl alcohol (IPA), dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), or a combination thereof. The method of claim 1,
The at least one polymerizable compound is polyacrylamide (PAM), polyacrylic acid (PAA) such as Carbopol 940 ™ and Carbopol 941 ™, copolymers of PAM and PAA, poly- (N, N-dimethyl-acrylamide (PDMAAm), poly- (N-isopropyl-acrylamide) (PIPAAm), acrylic polymers such as polymethacrylic acid (PMAA), polymethacrylamide (PMAAm), polyethylene imine (PEI), polyethylene oxide ( PEO), polyimines and oxides such as polypropylene oxide (PPO), polyvinyl alcohol (PVA), polyethylene sulfonic acid (PESA), polyvinylamine (PVAm), polyvinyl-pyrrolidone (PVP), poly- Vinyl polymers such as 4-vinyl pyridine (P4VP), cellulose derivatives such as methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), acacia, agar and agar Such as Ross, Heparin, Guar Gum, Xanthan Gum It is selected from the sugars, and albumin, collagen, and the group consisting of proteins such as gluten, the cleaning material. The method of claim 1,
The molecular weight of the at least one polymerizable compound is from about 0.01 M g / mol to about 1 OOM g / mol. The method of claim 1,
And the weight percentage of polymers in the cleaning material is from about 0.001% to about 10%. The method of claim 1,
Further comprising a buffer for changing the pH (potential of hydrogen) value of the cleaning material,
The buffer and the solvent form a cleaning solution. The method of claim 1,
And a surfactant to help disperse the polymers in the cleaning material and to help wetting the surface of the patterned substrate. The method of claim 7, wherein
And the surfactant is ammonium dodecyl sulfate (ADS). The method of claim 1,
The cleaning material is a fluid in the form of a liquid, sol, or gel. The method according to claim 6,
And the pH value of the cleaning material is about 1 to about 12 for front-end and backend applications. The method of claim 1,
Further comprising an ion-providing compound,
And the ion-providing compound is ionized in the cleaning solution to provide greater ionic strength to the cleaning material to alter the viscosity of the cleaning material. The method of claim 1,
And the viscosity of the cleaning material measured at the reference shear rate is about 100 cP to about 10,000 cP. The method of claim 1,
The device feature size has a critical dimension of about 45 nm or less. Cleaning material. The method of claim 1,
Some of the long polymer chains are crosslinked to form a polymerizable network that aids in the capture and entrap of the contaminants. The method of claim 1,
And the at least one polymerizable compound comprises polyacrylamide (PAM) and the molecular weight of the PAM is at least 1,000,000 g / mol. The method of claim 1,
And the at least one polymerizable compound comprises copolymers of acrylamide and acrylic acid, wherein the weight percentage of the acrylic acid in the copolymers is less than about 50%. The method of claim 1,
The cleaning material is supplied on a surface of the patterned substrate to remove contaminants from the surface without substantially damaging the device features on the surface,
And the cleaning material is substantially free of abrasive particles before the cleaning material is supplied onto the surface of the patterned substrate. The method of claim 1,
And the reference shear rate is less than about 1 / s. The method of claim 1,
And the molecular weight of the at least one polymerizable compound is greater than 10,000 g / mol. A cleaning material supplied on a surface of a patterned substrate for defining integrated circuit devices to remove contaminants from the surface, the cleaning material comprising:
menstruum;
A buffer for changing the pH (potential of hydrogen) value of the cleaning material, wherein the buffer and the solvent form a cleaning solution;
Polymers of one or more polymerizable compounds dissolved in the cleaning solution;
Surfactants to assist dispersion of the polymers in the cleaning material and to assist wetting the surface of the patterned substrate; And
An ion-providing compound that is ionized in the cleaning material to adjust the viscosity of the cleaning material,
The cleaning material has a pH of about 7 to about 12,
The solubilized polymers have long polymer chains that capture and entrap at least a portion of the contaminants from the surface of the patterned substrate for defining the integrated circuit devices,
The cleaning material is defined as a liquid phase,
The viscosity of the cleaning material measured at the reference shear rate is about 10 cP to about 100,000 cP,
And the cleaning material is deformed around device features on the surface of the patterned substrate when a force is applied on the cleaning material covering the patterned substrate. The method of claim 20,
The cleaning material is supplied on a surface of the patterned substrate to remove contaminants from the surface without substantially damaging the device features on the surface,
And the cleaning material is substantially free of coarse particles before the cleaning material is supplied onto the surface of the patterned substrate. The method of claim 20,
And the buffer is ammonium hydroxide. The method of claim 20,
And the ion-providing compound is citric acid.

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