JP2012533649A - Advanced substrate cleaner and cleaning system - Google Patents

Abstract

Embodiments of the present invention provide an improved cleaning agent, apparatus and method for cleaning a wafer surface, particularly the surface of a patterned wafer (or substrate). The cleaning agents, apparatus and methods described herein have the effect of cleaning a patterned substrate with fine features without substantially damaging the features. The cleaning agent includes a polymer composed of one or more polymer compounds. The cleaning agent can be used for various types of surface cleaning in a wide viscosity range and a wide pH range. The cleaning agent is in the liquid phase and deforms around the device features and traps contaminants on the substrate. The polymer incorporates contaminants so that they do not return to the substrate surface. The cleaning device is designed to rinse with a supply of cleaning agents having a wide range of viscosities.
[Selection] Figure 3C

Description

  In the manufacture of semiconductor devices such as integrated circuits and memory cells, features are formed on a semiconductor wafer (hereinafter “wafer”) by executing a series of manufacturing steps. A wafer (or substrate) includes integrated circuit devices formed on a silicon substrate in the form of a multilayer structure. A transistor device having a diffusion region is formed in the substrate layer. On top of that, interconnect metallized lines and vias are patterned and electrically connected to the transistor device to form the desired integrated circuit device. The patterned conductive layer is insulated from other conductive layers by a dielectric.

  During the series of manufacturing processes, the wafer surface is exposed to various types of contaminants. Basically, all substances present in the manufacturing process can be a source of contamination. For example, process gases, chemical substances, vapor deposition substances, liquids, and the like can be sources of contamination. Thus, various contaminants can be deposited on the wafer surface in the form of particulate matter. If the particulate contaminant is not removed, the device in the vicinity of the contaminant may not perform the desired operation. The size of particulate contaminants that can lead to device failure is as large as (or larger than) the critical dimensions of features formed on the wafer and damages the features on the wafer. It is very difficult to remove small particulate contaminants without the need for advanced technology technology nodes with feature miniaturization.

  Many conventional wafer cleaning methods rely on mechanical forces to remove particulate contaminants from the wafer surface. As feature sizes become smaller and more delicate, the probability of damaging features by applying mechanical forces to the wafer surface increases. For example, fine features with a high aspect ratio are prone to collapse or breakage if sufficient mechanical force is applied for cleaning. Further complicating the problem with cleaning is the smaller feature size and the smaller allowable size for particulate contaminants. Very small sized particulate contaminants can enter difficult-to-access areas on the wafer surface, such as trenches surrounded by high aspect ratio features. Therefore, removing contaminants efficiently without damaging in the latest semiconductor manufacturing process remains a problem even as the wafer cleaning technology advances. The flat panel display manufacturing process also has the same problems as the integrated circuit manufacturing process described above.

  In view of the above-described problems, there is a need for a patterned wafer cleaning agent, apparatus, and method that can effectively remove contaminants without damaging features on the patterned wafer.

  Embodiments of the present invention provide improved cleaning agents, apparatus and methods for cleaning wafer surfaces, particularly the surface of patterned wafers (or substrates). The cleaning agents, apparatus and methods described herein have the effect of cleaning a patterned substrate with fine features without substantially damaging the features. The cleaning agent includes a polymer composed of one or more polymer compounds dissolved in a solvent. Since the cleaning agent is in the liquid phase and deforms around the device feature, the cleaning agent does not substantially damage the device feature. The polymer in the cleaning agent traps contaminants on the substrate. In addition, the polymer incorporates contaminants so that they do not return to the substrate surface. The cleaning agent can be used to clean various types of substrate surfaces, including hydrophilic surfaces, hydrophobic surfaces, and surfaces where both hydrophobic and hydrophobic portions are present. The composition range (formation window) and treatment range (process window) of the cleaning agent are wide, and the prepared cleaning agent can be used for cleaning various types of substrate surfaces. The cleaning device may be designed to supply and rinse with cleaning agents of various viscosities.

  The polymer may be crosslinked. However, the degree of cross-linking is such that the hardness and stiffness of the polymer will not be too high, resulting in dissolution of the polymer in the solvent and preventing the polymer from deforming around device features on the substrate surface. It is relatively limited.

  The present invention can be implemented in various ways, including systems, methods, and chambers. Hereinafter, some embodiments of the present invention will be described.

  In one embodiment, a cleaning agent is provided that is used on the surface of a patterned substrate that defines an IC device to remove contaminants from the surface. The cleaning agent includes a solvent and a polymer composed of one or more polymer compounds. One or more polymer compounds are dissolved in a solvent. The solubilized polymer comprises long polymer chains that capture and capture at least some contaminants from the surface of the patterned substrate that defines the IC device. The cleaning agent is in the liquid phase. The viscosity of the cleaning agent, measured at a reference shear rate of less than about 100 / sec, ranges from about 100 cP to about 10,000 cP. When a force is applied to the cleaning agent covering the patterned substrate, the cleaning agent deforms around device features on the surface of the patterned substrate.

  In another embodiment, a cleaning agent is provided that is used on the surface of a patterned substrate defining an IC device to remove contaminants from the surface. The cleaning agent includes a solvent and a buffering agent that changes a hydrogen ion index (pH) value of the cleaning agent, and the buffering agent and the solvent form a cleaning solution. The cleaning agent also comprises a polymer composed of one or more polymer compounds that are dissolved in the cleaning solution. The detergent has a pH in the range of about 7 to about 12. The solubilized polymer comprises long polymer chains that capture and capture at least some contaminants from the surface of the patterned substrate that defines the IC device. The cleaning agent is in the liquid phase. The viscosity of the cleaning agent, measured at the reference shear rate, ranges from about 100 cP to about 10,000 cP. When a force is applied to the cleaning agent covering the patterned substrate, the cleaning agent deforms around device features on the surface of the patterned substrate. The cleaning agent further comprises a surfactant that helps disperse the polymer in the cleaning agent and wet the surface of the patterned substrate. Furthermore, the cleaning agent comprises an ion supply compound that is ionized in the cleaning solution to adjust the viscosity of the cleaning agent.

  The present invention will be readily understood by the following detailed description with reference to the accompanying drawings. In the following description, the same reference numerals indicate the same components.

FIG. 4 illustrates defects and device features on a substrate in one embodiment of the present invention.

The figure which shows three response curves at the time of using a cleaning agent on the patterned board | substrate in one Embodiment of this invention.

The figure which shows three response curves at the time of using a cleaning agent on a patterned board | substrate.

FIG. 3 shows three damage curves and detergent force intensity curves for different technology nodes in one embodiment of the present invention.

The figure which shows the cleaning agent containing the polymer which consists of a high molecular compound with a big molecular weight melt | dissolved in the washing | cleaning solution in one Embodiment of this invention.

FIG. 3B is a diagram illustrating how the cleaning agent of FIG. 3A captures contaminants in an embodiment of the present invention.

FIG. 3B is a diagram illustrating how the cleaning agent of FIG. 3A supplied onto the patterned wafer cleans contaminants from the substrate surface in an embodiment of the present invention.

FIG. 3B is a diagram showing how the cleaning agent of FIG. 3A supplied onto a patterned wafer cleans contaminants from the substrate surface in another embodiment of the present invention.

The figure which shows a mode that the cleaning agent of FIG. 3A supplied on the patterned wafer provided with a trench and a via in one Embodiment of this invention cleans a contaminant from a substrate surface.

The figure which shows the cleaning agent containing the gel-like polymer droplet emulsified in the washing | cleaning solution in one Embodiment of this invention.

FIG. 3 shows a cleaning agent containing gel-like polymer lumps suspended in a cleaning solution in an embodiment of the present invention.

The figure which shows a foaming cleaning agent in one Embodiment of this invention.

In one embodiment of the present invention, a graph showing particle removal efficiency (PRE) as a function of molecular weight of polyacrylic acid (PAA) and hydroxyethyl cellulose (HEC).

In one embodiment of the invention, a graph showing PRE as a function of the molecular weight of polyacrylamide (PAM).

The graph which shows the result of the experiment which reduces the viscosity of the cleaning agent formed using polyacrylamide (PAM) in one Embodiment of this invention using ammonium chloride.

In one embodiment of the present invention, a graph showing viscosity data for detergents having different pH values and different ionic strengths.

1 illustrates a system for cleaning contaminants from a substrate in an embodiment of the invention. FIG.

In one embodiment of the present invention, a longitudinal section of a chamber provided with a substrate holding part arranged on a lower processing head under an upper processing head.

The figure which shows the upper process head arrange | positioned on a board | substrate in one Embodiment of this invention, and the lower process head arrange | positioned under a board | substrate facing an upper process head.

The figure which shows the board | substrate cleaning system in one Embodiment of this invention.

The figure which shows the washing | cleaning apparatus which wash | cleans a board | substrate using the cleaning agent containing the polymer which consists of a high molecular compound which has a large molecular weight in one Embodiment of this invention, and a rinsing apparatus which rinses off a cleaning agent.

The figure which shows the washing | cleaning and rinse apparatus using the cleaning agent containing the polymer which consists of a high molecular compound which has a big molecular weight in one Embodiment of this invention.

The processing flowchart which prepares the cleaning agent containing the polymer which consists of one or more high molecular compounds which have a big molecular weight in one Embodiment of this invention.

In one Embodiment of this invention, the processing flow figure using the cleaning agent containing the polymer which consists of one or more high molecular compounds which has a big molecular weight.

  Embodiments of cleaning agents, apparatus and methods for cleaning the surface of a wafer, particularly the surface of a patterned wafer (or substrate), are provided. The cleaning agents, apparatus and methods described herein have the effect of cleaning a patterned substrate with fine features without substantially damaging the features. In one embodiment, the cleaning agent comprises a polymer composed of one or more polymer compounds dissolved in a solvent. Since the cleaning agent is in a liquid phase and deforms around the device feature, the cleaning agent does not substantially damage or reduce the damage to the device feature. The cleaning polymer captures contaminants on the substrate. In addition, the polymer incorporates contaminants so that they do not return to the substrate surface. The cleaning agent can be used to clean various types of substrate surfaces including hydrophilic and hydrophobic surfaces. The composition range (formation window) and treatment range (process window) of the cleaning agent are wide, and the prepared cleaning agent can be used for cleaning various types of substrate surfaces. The cleaning device may be designed to supply and rinse with cleaning agents of various viscosities. The polymer may form a long polymer chain, and the polymer chain may be cross-linked to form a network (or polymer network). Long polymer chains and / or polymer networks have better contaminant capture and uptake capabilities compared to conventional detergents.

  In another embodiment, the cleaning agent also contains a buffer that changes the pH of the cleaning agent. The cleaning agent further contains a surfactant that helps disperse the polymer in the solvent and wet the surface of the patterned substrate. Furthermore, the cleaning agent contains an ion-feeding compound that changes the viscosity of the cleaning agent.

  It will be apparent to those skilled in the art that the present invention may be practiced without some or all of these details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.

  Embodiments described herein are cleaning agents and cleanings that are effective in removing contaminants without damaging features on the patterned wafer that may partially contain high aspect ratio features. Provide a method. In the following embodiments, specific examples relating to semiconductor cleaning applications will be described. However, the description relating to cleaning applications can be extended to any technique that requires removal of contaminants from the substrate.

  FIG. 1 shows a substrate 100 including a substrate body 101 according to an embodiment of the present invention. In the vicinity of the surface 105 on the substrate 101, there are device structures 102 and particles 103. The particle 103 has an approximate diameter 107 that is, for example, as large as the width 104 of the device structure 102.

  In 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 65 nm or less. The width of the device structure, such as the width 104 of the device structure 102, is getting smaller with each technology node to allow more devices to be placed within the limited surface area of the chip. On the other hand, the height of the device structure, such as the height 106 of the device structure 102, is generally not reduced in proportion to the width of the device feature in view of the increased resistance. In conductive structures such as polysilicon lines and metal interconnects, reducing the width and height of the structure can increase resistance, cause significant RC delay, and generate too much heat for the conductive structure. As a result, device structures such as structure 102 have a large aspect ratio and are susceptible to damage due to the application of force 111 to the structure. In one embodiment, the aspect ratio of the device structure is, for example, in the range of about 2 or greater. By applying a force 112 to the particles 103, the particles 103 are easily removed. By applying forces 111 and 112 to the substrate surface near the device structure 102 with a cleaning agent (not shown), surface particulate matter such as particles 103 can be removed. In one embodiment, the force 111 and the force 112 are very close in size because they are close to each other. The forces 111 and 112 applied to the substrate surface may be applied by relative movement between the cleaning agent and the substrate surface. For example, by applying a cleaning agent or rinsing the cleaning agent.

  Since the width 104 of the device structure 102 is reduced and has a relatively large aspect ratio, the device structure 102 is prone to breakage upon application of force 111 or accumulation of energy by the applied force 111. Damaged device structure 102 becomes a particle source, leading to a reduction in production. Furthermore, the damaged device structure 102 may become inoperable due to damage.

FIG. 2A is a diagram showing three response curves when a cleaning agent is used on a patterned substrate in an embodiment of the present invention. Curve 201 is an intensity-energy (as a result of applying force) curve due to the cleaning agent on the substrate surface. The intensity of cleaning energy by the cleaning agent is maximized at Ep. Curve 202 is a curve showing particle removal efficiency as a function of energy applied on the substrate by the cleaning agent. The particle removal efficiency is maximized near Er. When the energy applied by the cleaning agent reaches Er, the cleaning agent is most efficient at removing particles from the substrate surface. Curve 203 is a curve showing the amount of damage to the device structure by the cleaning agent as a function of energy applied on the substrate surface by the cleaning agent. The device structure is damaged at an Es higher than the upper limit E _{N of} energy applied by the cleaning agent on the substrate. Since the device structure damage curve 203 is outside the energy distribution 201 on the patterned substrate by the cleaning agent, it is considered that the device structure on the patterned substrate is not damaged. It can be seen from the particle removal efficiency curve 202 that the cleaning agent can remove particles (or contaminants) from the substrate surface without damaging the structure on the substrate.

FIG. 2B is a diagram showing three response curves when using a cleaning agent on a patterned substrate. Curve 201 'is an intensity-energy curve due to the cleaning agent on the substrate surface. The strength of the cleaning agent is maximized at Ep ′. Curve 202 'is the particle removal efficiency-energy curve applied on the substrate. The particle removal efficiency is maximized near Er ′. When the energy applied by the cleaning agent reaches Er ′, the efficiency with which the cleaning agent removes particles from the substrate surface is maximized. Curve 203 ′ is a curve showing the amount of damage to the device structure by the cleaning agent as a function of the energy applied on the substrate surface by the cleaning agent. The device structure of the substrate is damaged at Es ′ lower than the upper limit E _{N ′} of the energy distribution of energy by the cleaning agent. Since the device structure damage curve 203 ′ is inside the energy distribution 201 ′ on the patterned substrate by the cleaning agent, the device structure on the patterned substrate may be damaged by the cleaning agent and generate particles (or defects). There is.

  As described above, if the device structure is damaged during the cleaning process, the device may become inoperable, and the damaged device structure may remain on the substrate surface, reducing the output of the device. Therefore, the relationship between the cleaning curve 201 ′ and the damage curve 203 ′ shown in FIG. 2B is not desirable, and conversely, the relationship between the cleaning curve 201 and the damage curve 203 shown in FIG. 2A is desirable.

  Conventional substrate cleaning apparatuses and methods remove particles from a substrate surface by a mechanical force using a brush and a pad. As the device structure becomes narrower and the aspect ratio becomes higher as technology advances, the method of applying mechanical force with a brush and pad can damage the device structure. Furthermore, a rough brush or pad surface may scratch the substrate surface. Cleaning methods such as megasonic cleaning or ultrasonic cleaning that use cavitation bubbles or acoustic flow to clean the substrate can damage fragile structures. Cleaning methods that utilize jets or sprays can cause film corrosion and still damage fragile structures.

FIG. 2C shows a cleaning curve 201 ″ for a conventional cleaning agent used in conventional methods such as megasonic cleaning in one embodiment of the present invention. 203 _I , 203 _II and 203 _III are 90 nm and 65 nm, respectively. in and curves for patterning substrate technology nodes .90nm showing the damage curve in three technology nodes of 45 nm 203i, damage .E _SI beginning with energy E _SI, the upper limit of the energy distribution of the patterned substrate by the cleaning agent Greater than E _N ″. Therefore, the device structure is not damaged. The conventional cleaning agent of FIG. 2C works similarly at the 65 nm technology node because damage begins at E _SII greater than E _N ″. Damage begins at lower energy levels as the technology node width becomes smaller. When the technology node is 45 nm or less, the conventional cleaning agent and cleaning method indicated by the curve 201 ″ may damage the device structure. For 45 nm technology nodes, damage begins with _{ES III} smaller than E _N ″. From FIG. 2C, cleaning agents and methods that work with conventional technology nodes also work with advanced technology nodes with narrower feature widths. Accordingly, there is a need to find a cleaning mechanism that uses a cleaning agent that is gentle on the device structure and that is effective in removing particles from the substrate surface.

  FIG. 3A shows a liquid detergent 300 containing a polymer 310 having a large molecular weight that is dissolved in a solvent 305 in one embodiment of the present invention. In one embodiment, the liquid cleaning agent 300 is a gel. In another embodiment, the liquid cleaning agent 300 is a sol. In another embodiment, the liquid cleaning agent 300 is a solution. By using the liquid cleaning agent 300 on the substrate where the particles are present on the substrate surface, the particles on the substrate surface can be removed. In one embodiment, the removed particles 320 adhere to the polymer 310 as shown in FIG. 3B. The polymer has a large molecular weight. In one embodiment, the molecular weight of the polymer is greater than 10,000 g / mol. The polymer captures and captures the particles so that long polymer chains are formed and the removed particles do not return to the substrate surface. In one embodiment, the polymer chains form a polymer network. In one embodiment, the polymer 310 may be acidic or basic. The hydrogen ion activity (pH) of the solution in which the polymer 310 is dissolved in water may be lower or higher than that of pure water. That is, the pH may be lower or higher than 7.0. In another embodiment, the cleaning agent 300 contains a buffer that serves to adjust and maintain the pH of the cleaning agent.

  The polymer dissolved in the solvent may be a soft gel or a gel droplet suspended in the solvent. In one embodiment, the contaminants on the substrate surface may be ionic, van der Waals, electrostatic, hydrophobic, steric, or chemically bonded if the polymer molecule approaches the contaminant. To adhere to the solvated polymer. The polymer captures and captures contaminants.

  As described above, the polymer can form a network in the solvent 305. The polymer is dispersed in the liquid solvent 305. The liquid cleaning agent 300 acts gently on the device structure on the substrate in the cleaning process. As shown in the cleaning volume 330 of FIG. 3C, the polymer 310 contained in the cleaning agent 300 smoothes around a device structure such as the structure 302 without impacting the device structure 302 with a strong force. Move. On the other hand, a hard brush or pad as described above may come into strong contact with the device structure and damage the device structure. Even the force (or energy) generated by cavitation in megasonic cleaning and the high-speed impact caused by the liquid jet spray flow may damage the structure. Two or more kinds of polymers may be dissolved in a solvent to adjust the cleaning agent. For example, the polymer in the cleaning agent may include “A” polymer compound and “B” polymer compound.

  A polymer composed of one or more polymer compounds having a large molecular weight may form a long polymer chain and may be further crosslinked to form a polymer network, or may not be crosslinked. As described above, the polymer may be crosslinked. However, the degree of cross-linking is such that the hardness and stiffness of the polymer will not be too high, resulting in dissolution of the polymer in the solvent and preventing the polymer from deforming around device features on the substrate surface. It is relatively limited.

As shown in FIG. 3C, polymer 310 contacts and captures contaminants on the patterned (or unpatterned) substrate surface, such as contaminants 320 _I , 320 _II , 320 _III , 320 _IV, etc. To do. When the contaminant is trapped in the polymer, it adheres to the polymer and is suspended in the cleaning agent. FIG. 3C shows the contaminants 320 _III and 320 _IV attached to the polymer chains 311 _I and 311 _II , respectively. Contaminants 320 _I and 320 _II are also attached to other polymer chains. Alternatively, each contaminant 320 _I , 320 _II , 320 _III and 320 _IV may be attached to a plurality of polymer chains, or may be attached to a polymer network. When the polymer in the cleaning agent 300 is removed from the substrate surface by rinsing or the like, contaminants attached to the polymer chain from the substrate surface are removed together with the polymer chain.

In the embodiment shown in FIG. 3C, there is only one device structure 302, but in one embodiment of the invention, 302 _I , 302 _II , 302 _III and 302 _I on the substrate, such as the substrate 301 shown in FIG. 3D. A plurality of adjacent device structures such as 302 _IV may form a cluster structure. As in FIG. 3C, in the cleaning volume 330 ′, the liquid cleaning agent 300 gently acts on the device structure on the substrate in the cleaning process. The polymer 310 contained in the cleaning agent 300 moves smoothly around the device structures 302 _I , 302 _II , 302 _III and 302 _IV without giving an impact that would apply a strong force on the device structure. Contaminants 325 _I , 325 _II , 325 _III, and 325 _IV attach to the polymer chain, similar to the attachment of contaminants 320 _I , 320 _II , 320 _III, and 320 _IV to the polymer chain in FIG. 3C.

In addition to cleaning substrates with linear features as shown in FIGS. 3C and 3D, substrates with other patterns of features can be similarly cleaned with the cleaning agents and cleaning methods described in this invention. FIG. 3E illustrates a substrate 301 ′ that includes a structure 302 ′ that forms a via 315 and a trench 316 in one embodiment of the invention. Contaminants 326 _I , 326 _II , 326 _III and 326 _IV can be removed by the cleaning agent 300 by the mechanism described above with reference to FIGS. 3C and 3D.

As described above, a polymer composed of one or more polymer compounds having a large molecular weight is dispersed in a solvent. Examples of the polymer compound having a large molecular weight include, but are not limited to, polyacrylic acid (PAA) such as polyacrylamide (PAM), Carbopol 940 (registered trademark) and Carbopol 941 (registered trademark), poly- Acrylic polymers such as (N, N-dimethylacrylamide) (PDMAAm), poly- (N-isopropylacrylamide) (PIPAAm), polymethacrylic acid (PMAA), polymethacrylamide (PMAAm), polyethyleneimine (PEI), polyethylene oxide (PEO), polyimines and oxides such as polypropylene oxide (PPO), polyvinyl alcohol (PVA), polyethylenesulfonic acid (PESA), polyvinylamine (PVAm), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP) Vinyl derivatives such as methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), cellulose derivatives such as carboxymethyl cellulose (CMC), acacia gum (gum arabic), agar and agarose, heparin, guar gum, xanthan gum, etc. Examples include polysaccharides and proteins such as egg white, collagen, and gluten. To give some examples of polymer structures, polyacrylamide is an acrylic acid-based 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 (—CH ₂ ═CH—COOH—) o formed from acrylic acid subunits. Here, n, m, and o are integers. The polymer composed of one or more polymer compounds having a large molecular weight may be soluble in an aqueous solution, or may have a high water absorption property and form a soft gel in the aqueous solution. As described above, in one embodiment, the molecular weight of the one or more polymer compound is greater than 10,000 g / mol. In another embodiment, the molecular weight of the one or more polymer compound is greater than 100,000 g / mol. In another embodiment, the molecular weight of the one or more polymer compound ranges from about 0.01 Mg / mol to about 100 Mg / mol. In another embodiment, the molecular weight of the one or more polymeric compounds ranges from about 0.1 Mg / mol to about 50 Mg / mol. In yet another embodiment, the molecular weight of the one or more polymer compound ranges from about 1 Mg / mol to about 20 Mg / mol. In yet another embodiment, the molecular weight of the one or more polymer compound ranges from about 15 Mg / mol to about 20 Mg / mol. In one embodiment, the weight percent of polymer in the cleaning agent ranges from about 0.001% to about 20%. In another embodiment, the weight percent ranges from about 0.001% to about 10%. In another embodiment, the weight percent ranges from about 0.01% to about 10%. In yet another embodiment, the weight percent ranges from about 0.05% to about 5%. The polymer can be dissolved in the solvent, completely dispersed in the solvent, can form droplets (emulsify) in the solvent, or can form a small mass (or mass) in the solvent. You may do it.

  Alternatively, the polymer may be a copolymer obtained from two or more monomer species. For example, the copolymer may be a 90% PAM and 10% PAA copolymer formed from PAM and PAA monomers. The concentration of the copolymer component is not limited to this. Furthermore, the polymer may be a mixture of two or more polymers. For example, a polymer may be formed by mixing two types of polymers such as 90% PAM and 10% PAA in a solvent. By using a copolymer or a mixture of different polymers as the cleaning agent, there is an effect that an optimum cleaning result can be obtained by using different strengths of different polymers.

In the embodiment shown in FIGS. 3A-3C, a polymer composed of one or more polymer compounds having a large molecular weight is uniformly dissolved in a solvent. The solvent may be a nonpolar solvent such as turpentine oil or a polar solvent such as water (H ₂ O). Other examples of solvents include isopropyl alcohol (IPA), dimethyl sulfoxide (DMSO), and dimethylformamide (DMF). In one embodiment, the solvent is a mixture of two or more liquids. In the case of a polymer having polarity, such as PAM, PAA or PVA, a polar solvent such as water (H ₂ O) is suitable as the solvent.

  The polymer used for the cleaning agent may be acidic or basic. For example, a polymer containing acrylic acid units is acidic and the pH value of a mixture of PAA and water is about 3. Examples of the basic polymer include polymers containing a quaternary ammonium salt such as poly (diallyldimethylammonium chloride) and a tertiary amine such as polyethyleneimine (PEI). The pH value of the 50 weight percent PEI and water mixture is about 12.

For the purpose of adjusting (changing) the characteristics of the cleaning agent, an additive may be mixed with the cleaning agent. The additive may be mixed in the solvent before adding the polymer to prepare the cleaning agent. For example, the additive may be a buffer such as a weak acid or a weak base that adjusts the hydrogen ion index (pH) of the cleaning agent. An example of a weak acid that can be used as a buffering agent is citric acid. An example of a weak base that can be used as a buffering agent is ammonium hydroxide (NH ₄ OH).

  The pH value of the cleaning agent may be in the range of about 1 to about 12. In one embodiment, in the front end process (prior to the deposition of the copper and intermetal dielectric), the cleaning agent is basic. In one embodiment, the pH value of the cleaning agent in the front end process ranges from about 7 to about 12. In another embodiment, the pH value of the detergent in the front end process ranges from about 7 to about 10. In one embodiment, in the back-end process (after the deposition of copper and intermetal dielectric), the cleaning agent may be slightly basic, neutral, or acidic. Copper used for interconnection in the back-end process is incompatible with cleaning agents containing ammonium hydroxide as a buffer. Ammonium hydroxide interacts with copper and dissolves copper. In one embodiment, the pH value in the back-end process ranges from about 1 to about 7. In another embodiment, the pH value in the back-end process ranges from about 1 to about 5. In yet another embodiment, the pH value in the back-end process ranges from about 1 to about 2. However, if the buffer used is not ammonium hydroxide, the pH range in the back-end process can be widened. In one embodiment, the pH value in the back-end process ranges from about 1 to about 12.

  In another embodiment, the detergent additive comprises a surfactant, such as ammonium dodecyl sulfate (ADS), which helps disperse the polymer in the detergent. In one embodiment, the surfactant also helps in the cleaning agent wetting on the substrate surface. Due to the wetting of the cleaning agent on the substrate surface, the cleaning agent can be brought into intimate contact with the substrate surface and the particles on the substrate surface. Wetting improves cleaning efficiency. Other additives may be added to improve surface wetting, viscosity, substrate cleaning, rinsing, and other related properties.

Examples of buffered wash solutions (or simply “wash solutions”) include ammonium hydroxide buffers containing 0.44 wt% NH ₄ OH and 0.4 wt% citric acid and other basic and acidic buffers in the solution. A liquid (BAS) is mentioned. Alternatively, a predetermined amount of a surfactant such as 1 wt% ADS may be contained in a buffer solution such as BAS, and the polymer may be suspended and dispersed 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”. The solution “100” and the pH value of BAS are both about 10 times.

  In the liquid cleaning agent 300 of the embodiment shown in FIGS. 3A to 3E, the polymer 310 having a large molecular weight is uniformly dispersed (or dissolved) in the cleaning solution 305. As described above, in these embodiments, the polymer having a large molecular weight is uniformly dissolved in the water-soluble cleaning solution. The polymer may have high water absorption and form a soft gel in an aqueous solution. FIG. 3F shows an embodiment of a liquid cleaning agent 300 ′ in which gel polymer droplets 340 are emulsified in the cleaning solution 305 ′. The cleaning solution 305 ′ also contains a small separation polymer 306. A surfactant such as ADS may be added to the cleaning solution to uniformly disperse the gel polymer droplets 340 in the cleaning solution 305 ′. In the embodiment shown in FIG. 3F, a boundary 341 exists between the cleaning solution 305 ′ and the gelled polymer droplet 340. Gel-like polymer droplets 340 are soft and deform around device features on the substrate surface. Because the gel-like polymer droplet 340 deforms around the device feature, it does not apply large energy (or force) on the device feature to damage the device feature. In one embodiment, the droplet diameter ranges from about 0.1 μm to about 100 μm.

  In another embodiment, a polymer composed of one or more macromolecular compounds having a high molecular weight dissolves in the cleaning solution and does not form a clear boundary with the cleaning solution 305 ", as shown in FIG. 3G. It forms a gel-like polymer mass (or mass) 350. Wash solution 305 "further contains a small separation polymer 306. The gel polymer blob 350 is soft and deforms around the device features on the substrate surface, causing the device features on the substrate surface to have a large amount of energy (or force) that can damage the device features. ) Is not added. In one embodiment, the polymer blob diameter ranges from about 0.1 μm to about 100 μm.

All the cleaning agents described above are in the liquid phase. In another embodiment, as shown in FIG. 3H, the cleaning agents such as the liquid cleaning agents 300, 300 ′, and 300 ″ described above are agitated, and a gas such as N ₂ or an inert gas or a mixed gas such as air is used. In addition, the cleaning agent may be foamed, the cleaning agent 300 * shown in Figure 3H contains bubbles 360 dispersed in the cleaning solution 305. The polymer 310 is also dispersed in the cleaning solution 305. In another embodiment, the polymer 310 shown in Figure 3H may be a polymer droplet 340 or a polymer blob 350 as described in Figures 3F and 3G The cleaning agent 300 * has a gas phase and a liquid phase.

  The cleaning agent described above can be supplied onto the substrate surface by various mechanisms. As previously described in FIGS. 2A and 2B, in order not to damage the device features on the patterned substrate, the energy applied by the cleaning agent on the patterned surface is minimal to prevent damage to the device features. It is necessary to be less than the force Es or Es ′. The cleaning agents such as the liquid cleaning agents 300, 300 ′, 300 ″ and 300 * described above are either in liquid phase or gas phase / liquid phase. Liquid and bubbles flow over the substrate surface and on the substrate surface. Deformants around (or flows around) device features can therefore use a cleaning agent on the patterned substrate without applying significant forces to the device features on the substrate surface.

Table 1 shows a comparison of viscosity, rinse time, and particle removal efficiency (PRE) for various weight percent changes in Carbopol 941® PAA in BAS. The viscosity of the liquid detergent may be measured in a shear rate range of about 1 × 10 ⁻⁶ / second to about 1 × 10 ⁵ / second. In one embodiment, the viscosity of the liquid detergent may be measured at a reference shear rate of less than about 100 / second. In another embodiment, the viscosity may be measured at a reference shear rate of less than about 10 / second. In another embodiment, the viscosity may be measured at a reference shear rate of less than about 1 / second. The viscosity data in Table 1 was measured at a strain rate of 500 / sec. The rinsing time is a measurement of the time taken to rinse off the cleaning agent from the substrate surface. For the measurement of PRE, a particle monitor substrate on which silicon nitride particles of various sizes were intentionally deposited was used. In this experiment, only particles having a particle size ranging from 90 nm to 1 μm were measured. PRE was calculated by the following formula (1).

  The cleaning agents in Table 1 were prepared by mixing the above-mentioned BAS into commercially available Carbopol 941® PAA. The molecular weight of Carbopol 941 (registered trademark) PAA used was 1,250,000 (1.25 M) g / mol. As can be seen from the results in Table 1, PRE increased with increasing weight percent of Carbopol 941® PAA up to about 0.5% polymer concentration. There was no significant difference in PRE between 0.5% polymer concentration and 1% polymer concentration. Also, as can be seen from the results, the viscosity of the detergent increased with increasing polymer weight percent. Furthermore, the rinsing time, which is the time taken to rinse off the cleaning agent, increased with increasing viscosity of the cleaning agent. Water was used for rinsing the substrate.

  Table 2 shows a comparison of the ability to incorporate or suspend particles in the cleaning agent for various cleaning agents. In the cleaning agent, silicon nitride particles were intentionally added. After adding the silicon nitride particles, a cleaning agent was supplied on a clean substrate. Next, the cleaning agent was rinsed from the substrate, and the number of (silicon nitride) particles remaining on the substrate was measured.

  In the experiment of Table 2, five types of cleaning agents (solvents or solutions) were used. DIW (deionized water) was used alone as the first cleaning agent. As the second cleaning agent, DIW adjusted to have a pH value greater than 10 by adding ammonium hydroxide was used. As the third cleaning agent, a “100” solution that is BAS to which 1 wt% of ADS was added was used. As described above, the pH value of the “100” solution was 10. As a fourth cleaning agent, a “100” solution in which 0.2 wt% Carbopol 940 (registered trademark) PAA was dissolved was used. The molecular weight of Carbopol 940® PAA was 4M (4 million) g / mol. As the fifth cleaning agent, a “100” solution in which 0.5 wt% PAM was dissolved was used. The molecular weight of PAM was 18 Mg / mol. The pH value of the fifth detergent was about 10. Two types of amounts of 1X and 50X silicon nitride particles were mixed with these five types of cleaning agents. The number of 50X silicon nitride particles is 50 times the number of 1X silicon nitride particles. 1X nitride particles are 0.00048 wt%, and 50X nitride particles are 0.024 wt%.

As can be seen from this result, the ability of DIW to suspend silicon nitride particles was not high, and a large amount of silicon nitride particles remained on the substrate surface (saturated state). The expression “saturated” used in Table 2 indicates that the number of particles (or defects) is greater than 75,000. In contrast, 0.2% Carbopol 940® PAA “100” solution and 0.5% PAM “100” solution had a high ability to suspend silicon nitride particles in the cleaning agent. . In particular, the “100” solution of 0.5% PAM was highly capable of incorporating or suspending silicon nitride particles added to the cleaning agent. In this case, among the silicon nitride (Si ₃ N ₄ ) particles added to the cleaning agent, the number of silicon nitride particles remaining on the substrate surface was a small number, 53 at 1 × and 104 at 50 ×.

  The molecular weight of the polymer used in the cleaning agent affects the particle removal efficiency (PRE). FIG. 4A shows a “100” solution containing 1% (wt%) PAA and a “100” solution containing 1% (wt%) hydroxyethyl cellulose (HEC) as cleaning agents. FIG. 4 is a graph showing the PRE of silicon nitride particles larger than 90 nm on a substrate as a function of the molecular weight of these two polymers (PAA and HEC). From the data in FIG. 4A, it can be seen that PRE increases as the molecular weight increases in the range of molecular weight of HEC from 100,000 g / mol to 1M (ie, 1,000,000) g / mol. Moreover, from the data of FIG. 4A, it can be seen that PRE increases with increasing molecular weight when the molecular weight of PAE is in the range of 500,000 g / mol to 1 Mg / mol. However, when the molecular weight of PAA was in the range of 1 Mg / mol to 1.25 Mg / mol, there was almost no change in PRE. FIG. 4B is a graph showing the PRE of silicon nitride particles larger than 90 nm on a substrate as a function of PAM molecular weight when a “100” solution containing 1% (wt%) PAM is used as a cleaning agent. It is. From the data in FIG. 4B, it can be seen that PRE increases with increasing molecular weight when the molecular weight of PAM is in the range of 500,000 g / mol to 18 Mg / mol. The data in these graphs shows the effect of molecular weight on PRE.

As described above, the viscosity of the cleaning solution is considered to affect the rinsing time for removing the cleaning agent from the substrate surface. FIG. 4C shows the results when ammonium chloride (NH ₄ Cl) is added to a cleaning solution in which 0.2 wt% to 1 wt% of PAM is dissolved in deionized (DI) water. The molecular weight of PAM was 18 Mg / mol. The added ammonium chloride is ionized in the cleaning solution to increase the amount of ions and increase the ionic strength of the cleaning agent. As the ionic strength increases, the viscosity of the cleaning agent decreases. For example, 1.5 wt% ammonium chloride can reduce the viscosity of a 1 wt% PAM-containing detergent from about 100 cP (centipoise) to 60 cP. 1.5 wt% ammonium chloride can also reduce the viscosity of a 0.5 wt% PAM containing detergent from about 50 cP to about 25 cP. The viscosity was measured at a shear rate of 500 / sec. As the viscosity decreases, the time taken to rinse off the cleaning agent from the substrate surface also decreases.

  The viscosity not only affects the rinsing time of the cleaning agent, but also affects the method of supplying the cleaning agent to the substrate surface. Compared with a cleaning agent having a low viscosity, a cleaning agent having a high viscosity requires a large opening for supply. Also, the rinse time for high viscosity cleaning agents can be shortened by more rinsing.

  Table 3 shows a comparison of the PRE, pH value and ionic strength data for the four cleaning compositions. For all four types of cleaning agents, a copolymer of acrylamide and acrylic acid was used as the polymer. This copolymer was mixed with the “100” solution. The pH value of the cleaning agent was adjusted using ammonium hydroxide. Citric acid was used to change the ionic strength of the detergent. In addition to the buffer (ammonium hydroxide) and the ionic strength regulator (citric acid), the detergent shown in Table 3 was further added with a small amount of ammonium dodecyl sulfate as a surfactant to dissolve the polymer in the detergent. In addition, wetting of the cleaning agent on the substrate surface was improved. The weight percent of acrylic acid in the copolymer was less than about 50%.

  As shown in the data in Table 3, all four detergents showed excellent PRE. The pH values of the detergents in Table 3 ranged from about 7 to about 10. The ionic strength of the detergent was about 0.15X to about 1X. Here, X represents a predetermined value. The viscosity of the 0.15X ionic strength detergent was greater than 5 times the viscosity of the 1X ionic strength detergent. The viscosity data for the cleaning agents shown in Table 3 is shown in FIG. 4D and described below. For a wide range of pH values, ionic strengths and viscosities, the cleaning agent showed very good cleaning efficiency. Such a wide processing range (process window) is important because the substrate surface will be in different states and require a wide range of processing conditions during the various processing steps of device fabrication. For example, the wafer used in the experiments of Table 3 is formed from silicon covered with a thin layer of native oxide. The surface of such a wafer is hydrophilic. In the case of a hydrophilic substrate surface, the composition range (formation window) or processing range (process window) of the cleaning agent becomes wide. However, when such a wafer is treated with an HF solution, the surface becomes hydrophobic. Table 4 shows the particle count data on the surface of the hydrophobic wafer after processing the substrate with three different compositions of cleaning agents. The compounds (raw materials) used to prepare the cleaning agents in Table 4 are the same as those used in Table 3. In the experiment of Table 4, after the wafer was brought into contact with each composition, the particle defects increased as a result of the contact were measured with a commercially available light scattering apparatus and classified as an addition number. The smaller the number of added particle defects, the more successful the process. In Table 4, 95% CI indicates a 95% confidence interval. A number of wafers were processed to obtain 95% CI data.

  From the data in Table 4, it can be seen that for hydrophobic surfaces, the lower the ionic strength and pH of the detergent, the better the particle addition results. As can be seen from the results in Table 3 and Table 4, different substrate surfaces require different compositions of cleaning agents. Further, depending on the application, a better cleaning result can be obtained when the ionic strength is lower. Such applications include the treatment of hydrophobic surfaces such as photoresists, polysilicon, low dielectric constant dielectrics, or low dielectric constant porous dielectrics. Since the viscosity of the cleaning agent increases as the ionic strength decreases, a cleaning system and a cleaning method using a cleaning agent having a higher viscosity are required as described above. FIG. 4D shows the viscosity data for the above-described detergents having different pH values and different ionic strengths in one embodiment of the present invention. From this data, it can be seen that the lower the ionic strength, the higher the viscosity. The viscosity of the cleaning agent was measured at a shear rate of 0.1 / second. For example, viscosities measured in less than about 1 / second (<1 / s) are considered measured at low shear rates. For standard ionic strength (1X), the viscosity increases with the pH value of the detergent. On the other hand, at low ionic strength (0.15X), the viscosity decreases with the pH value.

  In one embodiment, the viscosity of the detergent containing polymer at low shear rate ranges from 10 cP to about 100,000 cP. In another embodiment, the viscosity of the detergent containing polymer at low shear rate ranges from 100 cP to about 10,000 cP. As described above, the processing range (process window) of the viscosity of the cleaning agent can be widened by changing the design of the apparatus and the processing conditions. For example, the cleaning agent can be added (or supplied) onto the substrate at a reasonable rate by increasing the supply opening of the cleaning agent. Furthermore, the rinsing liquid may be supplied and removed so as to shorten the rinsing time of the cleaning agent having a high viscosity by performing more intense rinsing.

  FIG. 5A illustrates a system for cleaning contaminants from a substrate in one embodiment of the invention. The system includes a chamber 500 defined by a peripheral wall 501. The chamber 500 includes an inlet module 519, a processing module 521, and an outlet module 523. The substrate 502 moves linearly from the inlet module 519 through the processing module 521 to the outlet module 523 by the substrate holding unit 503 and the corresponding driving device, as indicated by an arrow 507. The drive rail 505A and the guide rail 505B act to control the linear movement of the board holding portion 503, and the board 502 moves along a linear path defined by the drive rail 5105A and the guide rail 505B. It is held in a substantially horizontal posture.

  The inlet module 519 includes a door assembly 513, and the substrate handling apparatus inserts the substrate 502 into the chamber 500 from the door assembly 513. The entrance module 519 further includes a substrate lifter 509. When the center of the substrate holding part 503 is on the substrate lifter 509 in the entrance module 519, the substrate lifter 509 passes through the opening region of the substrate holding part 503 in the vertical direction. Move to. The substrate lifter 509 is raised to receive the substrate 502 inserted into the chamber 500 from the door assembly 513. Thereafter, the substrate lifter 509 is lowered to place the substrate 502 on the substrate holder 503.

  The processing module 521 includes an upper processing head 517, and the upper processing head 517 is disposed so as to process the upper surface of the substrate 502 while the substrate holder 503 on which the substrate 502 is placed moves under the upper processing head 517. Is done. The processing module 521 further includes a lower processing head 518 (see FIG. 5B) disposed under the linear movement path of the substrate holding unit 503, contrary to the upper processing head 517. The lower processing head 518 is configured and arranged to process the lower surface of the substrate 502 as the substrate holder 503 moves through the processing module 521. Each of the upper processing head 517 and the lower processing head 518 includes a front end portion 541 and a rear end portion 543, and the substrate holding portion 503 is provided in a linear path from the front end portion 541 to the rear end portion 543 during the processing operation. The substrate 502 is moved along. As described in detail below, in the present invention, the upper processing head 517 and the lower processing head 518 are each configured to perform a multi-stage cleaning process on the upper surface and the lower surface of the substrate 502.

  In some embodiments, one or more additional processing heads may be used with the upper processing head 517 disposed over the linear travel path of the substrate holder 503 and / or the substrate holder. One or more additional processing heads may be used with the lower processing head 518 disposed below the 503 linear travel path. For example, the processing heads that perform the drying process on the substrate 502 may be disposed behind the rear end portions of the upper processing head 517 and the lower processing head 518, respectively.

  The substrate holding unit 503 reaches the exit module 515 after moving through the processing chamber 521. The exit module 515 includes a substrate lifter 511, and when the center of the substrate holder 503 comes on the substrate lifter 511 in the exit module 511, the substrate lifter 511 moves vertically through the opening region of the substrate holder 503. To do. The substrate lifter 511 ascends and lifts the substrate 502 from the substrate holder 503 to the collection position from the chamber 500. The outlet module 511 further includes a door assembly 515, and the substrate 502 is retrieved from the chamber 500 via the door assembly 515 by the substrate handling device.

  FIG. 5B is a longitudinal cross-sectional view of a chamber 500 that includes a substrate holder 503 that is disposed below the upper processing head 517 and above the lower processing head 518 in one embodiment of the present invention. The upper processing head 517 is attached to the drive rail 505A and the guide rail 505B. When the vertical position of the upper processing head 517 is determined, the vertical position of the drive rail 505A and the vertical position of the guide rail 505B are determined. Further, the vertical positions of the substrate holding portion 503 and the substrate 502 placed thereon are determined.

  When the substrate 502 passes under the upper processing head 517 by the substrate holder 503, the upper processing head 517 cleans the upper surface of the substrate 502. Similarly, when the substrate 502 passes over the lower processing head 518 by the substrate holding unit 503, the lower processing head 518 rinses the lower surface of the substrate 502. In various embodiments, within the processing module 821, the upper processing head 517 and the lower processing head 518 are each configured to perform a one-step or multi-step substrate processing operation on the substrate 502. Furthermore, in one embodiment, the upper processing head 517 and the lower processing head 518 are disposed over the entire diameter of the substrate 502 within the processing module 821, and the substrate holder 503 is below / above the upper / lower processing heads 517/518. In one pass, the entire top / bottom surface of the substrate 102 is processed.

  FIG. 5C is a cross section illustrating 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 in one embodiment of the invention. FIG. The upper processing head 517 includes a first upper module 517A, and the first upper module 517A serves to supply the cleaning agent 561A to the substrate 502 via the cleaning agent supply port 529A. The upper processing head 517 further includes a second upper module 517B, and the second upper module 518A serves to supply the cleaning agent 561B to the substrate 502 via the cleaning agent supply port 529B. The chemical component of the cleaning agent 561A may be the same as or different from the chemical component of the cleaning agent 561B. In one embodiment, the cleaning agent supply ports 529 A and 529 B are long slits along the length of the upper processing head 517.

  In each of the first and second upper modules 517A / 517B, a rinsing agent supply port 541A / 541B supplies rinsing agent at the rear end side of the rinsing fluid meniscus while the first vacuum port row 547A / 547B. However, the fluid is removed at the tip side of the rinsing fluid meniscus. Since the first vacuum port row 547A / 547B is disposed on the leading end side of the rinsing fluid meniscus, in contrast to the configuration disposed on both the leading end side and the trailing end side of the rinsing fluid meniscus, the rinsing agent supply port row. Each port in 541A / 541B has a downward angle with respect to the first vacuum port row 547A / 547B.

  In one embodiment, each of the first and second upper modules 517A / 517B includes a second vacuum port row 549A / 549B disposed along the rear end side of the first vacuum port row 547A / 547B. . Second vacuum port row 549A / 549B is arranged to provide multiphase suction of cleaning and rinsing agents from the underlying substrate. The second vacuum port row 549A / 549B can be controlled independently of the first vacuum port row 547A / 547B. Each port of the second vacuum port row 549A / 549B is defined as a single-phase liquid recovery port and is configured so that the stability of the rinse fluid meniscus is not destroyed.

  The first upper module 517A flows the rinsing agent through the upper rinsing fluid meniscus 563A in substantially one direction toward the cleaning agent 561A and in a direction opposite to the direction of movement 560 of the substrate 502. The flow rate of the rinsing agent through the upper rinsing fluid meniscus 563A is set so that no leakage of cleaning agent through the upper rinsing fluid meniscus 563A occurs. The first upper module 517A leaves a uniform thin film of rinse agent 565 on the substrate 502.

  The second upper module 517B of the upper processing head 517 places the substrate 502 in contact with the upper rinse fluid meniscus 563B after adding the cleaning agent 561B onto the substrate 502. The second upper module 517B flows the rinsing agent in substantially one direction toward the cleaning agent 561B through the upper rinsing fluid meniscus 563B and in the direction opposite to the direction of movement 560 of the substrate 502. The flow rate of the rinse agent through the upper rinse fluid meniscus 563B is set so that no leakage of cleaning agent through the upper rinse fluid meniscus 563B occurs. The second upper module 517B leaves a uniform thin film of rinse agent 567 on the substrate 502.

  The first lower module 518A of the lower processing head 518 applies the lower rinse fluid meniscus 569A to the substrate 502 to balance the force applied to the substrate 502 by the upper rinse fluid meniscus 563A. The first lower module 518A flows rinsing agent in substantially one direction through the lower rinse fluid meniscus 569A and in the direction opposite to the direction of movement 560 of the substrate 502. The first lower module 518A leaves a uniform thin film of rinse agent 571 on the substrate 502.

  The second lower module 518B of the lower processing head 518 applies the lower rinse fluid meniscus 569B to the substrate 502 to balance the force applied to the substrate 502 by the upper rinse fluid meniscus 563B. The second lower module 518B causes the rinse agent to flow in substantially one direction through the lower rinse fluid meniscus 569B and in a direction opposite to the direction of movement 560 of the substrate 502. The second lower module 518B leaves a uniform thin film of rinse agent 573 on the substrate 502.

  Each of the first and second lower modules 518A / 518B includes a rinse agent supply port row 551A / 551B defined in the rinse fluid meniscus region 569A / 569B. The rinse agent supply port rows 551A / 551B are each configured to supply the rinse agent upward onto the substrate located thereon.

  In one embodiment, the rinse agent is deionized water (DIW). However, in other embodiments, the rinse agent is any one of a variety of liquid materials and is readily miscible with, for example, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethyl acetate (DMAC), DIW A polar liquid, a mist liquid such as a mist polar solvent (eg, DIW), or any combination thereof. These rinse agents are exemplary only and are not a comprehensive limitation of the rinse agent.

  FIG. 5D illustrates a cleaning system 550 that includes a substrate cleaning chamber 500 'in one embodiment of the invention. The substrate cleaning chamber 500 'is the same as the chamber 500 described above. Within the chamber 500 ′, the substrate 502 ′ is held by the substrate holder 503 ′. The substrate cleaning chamber 500 'includes an upper processing head 517' and a lower processing head 518 '. In one embodiment, upper processing head 517 'is supported by arm 581 and lower processing head 518' is indicated by arm 581 '. The cleaning agent containing the polymer is supplied to the upper processing head 517 via the supply line 595. A rinse agent such as deionized water (DIW) is supplied to the upper processing head via supply line 597. The cleaning waste liquid is removed from the substrate 502 ′ via the waste liquid line 596. The rinsing agent is supplied to the lower processing head 518 'via the supply line 599. The rinse waste liquid is removed via the waste liquid line 598. Supply lines 595, 597 and 599 and waste lines 596 and 598 are connected to the proximity head manifold 583. The proximity head manifold 583 is further coupled to a rinse agent container 584, a cleaning agent container 585, and a waste liquid container 586. The waste liquid container 586 is further connected to a vacuum pump 587.

  The proximity head manifold 583 is connected to a proximity head control unit 588 controlled by the computer 590. An operator can issue a control command via a computer. In one embodiment, the proximity head controller 588 is connected to the computer 590 via the Internet 589. The environment around the substrate cleaning chamber 500 'may also be controlled. One or more kinds of gases may be supplied to the chamber 500 '. For example, the gas tank 593 may be connected to the chamber 500 '. The pressure in the chamber 500 ′ may be maintained via the vacuum pump 594. The gas flow rate from the gas tank 593 and the decompression of the chamber 500 ′ may be controlled by a chamber manifold 592 connected to the surrounding environment control unit 591. The peripheral environment control unit 591 may also be connected to the computer 590.

  For details of the above-described cleaning apparatus, see US patent application 12 / 431,731 (Attorney Docket Number) filed on April 28, 2009 under the name "Apparatus and System for Cleaning Substrate". LAM2P660) and US patent application 12 / 131,667 filed June 2, 2008 under the name of “Apparatus for Particle Removal by Single-Phase and Two-Phase Media”. (Attorney Docket Number LAM2P628G) The disclosures of these related applications are incorporated herein by reference.

  The above-described embodiments are merely examples. Other embodiments of the cleaning head that supply the cleaning agent on the substrate surface and remove the cleaning agent from the substrate surface are possible as well. FIG. 6A shows a cleaning tank 680 containing a cleaning agent 681 and a rinsing tank 690 containing a rinsing liquid 691 in one embodiment of the present invention. First, the substrate 620 'is held by the substrate holding unit 623 and immersed in the cleaning agent 481 of the tank 680 so that the contaminant on the substrate surface comes into contact with the cleaning agent. The substrate 620 ′ is moved up and down by a mechanical mechanism (not shown) so as to enter and exit the cleaning agent 681 in the cleaning tank 680. Thereafter, the substrate 620 'is held by the substrate holding unit 626 and immersed in the rinsing liquid 691 of the cleaning tank 690 so as to rinse off the cleaning agent. Using a mechanical mechanism (not shown), the substrate is raised and lowered to enter and exit the rinse tank 690. In the rinsing tank 690, contaminants are removed from the substrate surface along with the cleaning agent remaining on the substrate 620 'surface. The substrate 620 ′ is lowered by a mechanical mechanism (not shown) and put into the rinsing liquid 691 in the rinsing tank 690. The direction of the substrate shown in FIG. 6A is a vertical direction, but other directions are possible. For example, the substrate may be immersed in the horizontal direction in the cleaning tank and / or the rinsing tank.

  FIG. 6B shows a cleaning apparatus 699 for cleaning contaminants from the substrate surface in another embodiment. The cleaning apparatus includes a cleaning tank 685 having a substrate support portion 683. The substrate 620 * is placed on the substrate support 683 that rotates during the cleaning process. The cleaning device 699 includes a cleaning agent supply head 697 that supplies a cleaning agent onto the surface of the substrate 620 *. The cleaning agent supply head 697 (or supply nozzle) is connected to a cleaning agent storage tank 670. The cleaning device 699 further includes a rinsing liquid supply head 698 (or supply nozzle) that sprays the rinsing liquid onto the surface of the substrate 620 ″. The rinsing liquid supply head 698 is connected to a rinsing liquid storage tank 696. By rotating the substrate 620 *, the entire surface of the substrate can be covered with the cleaning agent and the rinsing liquid.After supplying the cleaning agent to the substrate surface, the rinsing liquid is supplied to remove the cleaning agent from the substrate surface. To do.

After rinsing the cleaning material from the surface of the patterned substrate, the patterned substrate is dried by rotating the substrate at a relatively high speed. During the rotation, the substrate is fixed by an apparatus (or mechanism) not shown in FIG. 6B. In one embodiment, a surface tension reducing gas may be supplied to the surface of the patterned substrate to facilitate removal of the rinsing liquid and any remaining cleaning agent if it remains. In one embodiment, the surface tension reducing gas is a mixture of isopropyl alcohol (IPA) and nitrogen (N ₂ ). Other surface tension reducing gas may be used.

  You may make it accommodate the waste liquid of a washing | cleaning process in the washing tank 685. FIG. The waste liquid of the cleaning process includes a cleaning agent waste liquid and a rinse liquid waste liquid. In one embodiment, the cleaning tank 685 includes a drain 603 that is connected to the waste line 604. The waste liquid line 604 is connected to a valve 605 that controls the discharge of the cleaning waste liquid from the cleaning tank 685. The cleaning waste liquid is sent to the recycle processing unit 606 or the waste liquid processing unit 607.

  The cleaning agents described above are particularly effective in cleaning substrates having fine features (topology) such as polysilicon lines (including trenches and / or vias) and metal interconnects on the substrate surface. The minimum width (ie critical dimension) of such fine features is 45 nm, 32 nm, 22 nm, 16 nm or less.

  FIG. 7A shows a process flow 700 for preparing a cleaning agent containing one or more polymer compounds having a large molecular weight in one embodiment of the present invention. In step 701, one or more polymer compounds are mixed with a solvent. In one embodiment, the one or more polymer compounds are in powder form and the amount is measured in advance. Prior to the mixing step, the amount of one or more polymer compounds is calculated and weighed. Similarly, the amount of solvent used is also measured. In step 702, additives are added to the mixture produced in step 701 to adjust the properties of the prepared cleaning agent. You may make it contain the buffer which adjusts the pH value of a cleaning agent in an additive. Moreover, you may make it contain the ion supply compound which adjusts the viscosity of a cleaning agent in an additive. Further, the additive may contain a surfactant that improves the solubility of the polymer compound and / or improves the wettability of the patterned substrate surface by the cleaning agent. Other types of additives that adjust the properties of the cleaning agent may be added.

  By preparing a cleaning agent using process flow 700, the resulting cleaning agent can have other desired properties such as target pH value, target viscosity, polymer solubilization and suitable wetting properties. . As mentioned above, the operable pH range and viscosity range can be very wide. The addition of the surfactant, buffer and ion supply compound may be performed in successive steps. In another embodiment, the various ingredients used in the preparation of the cleaning agent may be mixed in a single single processing step.

  FIG. 7B shows a process flow 750 for cleaning a patterned substrate using a cleaning agent containing one or more polymer compounds having a large molecular weight in one embodiment of the present invention. The cleaning agent has been described above. In step 751, the patterned substrate is placed in a cleaning apparatus. In step 752, a cleaning agent is provided on the surface of the patterned substrate. In step 753, a rinsing liquid is supplied onto the surface of the patterned substrate to rinse off the cleaning liquid. The rinsing liquid has been described above. In one embodiment, after supplying the rinsing liquid onto the substrate surface, the pressure may be reduced to remove the rinsing liquid, cleaning agent and contaminants on the substrate surface from the surface of the patterned substrate.

  The above-described cleaning agent, cleaning apparatus, and cleaning method have an advantage that a patterned substrate having fine features can be cleaned without damaging the fine features. The cleaning agent is a fluid in either liquid phase or liquid / gas phase (foam) form and deforms around the device feature so that the cleaning agent does not damage the device feature. The liquid phase cleaning agent may be liquid, sol, or gel. A cleaning agent containing a polymer with a large molecular weight traps contaminants on the substrate. In addition, the cleaning agent takes in contaminants and prevents them from returning to the substrate surface. The polymer may form a long polymer chain, and the polymer chain may be cross-linked to form a polymer network. Long polymer chains and / or polymer networks exhibit superior contaminant capture and uptake capabilities compared to conventional detergents.

  Before the cleaning agent is supplied to the substrate surface to remove contaminants or particles from the substrate surface, the cleaning agent is substantially free of non-deformable particles (or wearable particles). Non-deformable particles are hard particles such as slurry and sand particles, which can damage fine device features on the patterned substrate. During the substrate cleaning process, the cleaning agent collects contaminants or particles from the substrate surface. However, before the cleaning agent is supplied onto the substrate surface and the substrate is cleaned, the undeformable particles are not intentionally mixed with the cleaning agent.

  In the above-described embodiment, the cleaning agent, the cleaning method, and the cleaning system for cleaning the patterned substrate have been described. However, the cleaning agent, the cleaning method, and the cleaning system can be similarly applied to a non-patterned (blank) substrate. is there.

  The apparatus and method for cleaning contaminants from the patterned wafer have been mainly described above. However, the cleaning apparatus and the cleaning method can also be used for cleaning contaminants from the non-patterned wafer. Furthermore, as an example of the pattern on the patterned wafer described above, a convex line portion such as a polysilicon line, a metal line, or a dielectric line is illustrated, but the concept of the present invention is also applied to a substrate having a concave feature. Is possible. For example, a cleaning head with an optimal design may be used so that a pattern is formed on the wafer with concave trenches or vias after the CMP process, and an optimum contaminant removal efficiency is obtained.

  The “substrate” used as an example in the present specification is not limited to the following, but is a semiconductor wafer, a hard disk, an optical disk, a glass substrate, a flat panel that may be contaminated in a manufacturing process or a handling process. -Display surface, liquid crystal display surface, etc. Depending on the actual substrate, the surface can be subject to various contaminations, and the acceptable level of contamination is defined by the particular industry that the substrate is handled for.

  Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art, but the present invention can be implemented in various other modes and forms within the scope of the present invention. . Accordingly, the above-described embodiments and examples are illustrative only, and are not intended to limit the present invention in any way. The present invention is not limited to the above-described details, and various modifications and changes can be made within the scope of the appended claims. Can be implemented.

Claims (23)

A cleaning agent used on the surface of a patterned substrate defining an IC device to remove contaminants from the surface,
A solvent,
A polymer composed of one or more polymer compounds,
The one or more polymer compounds are dissolved in the solvent and the solubilized polymer comprises long polymer chains that capture and capture at least some contaminants from the surface of the patterned substrate defining the IC device. ,
The cleaning agent is in a liquid phase;
The viscosity of the detergent, measured at a reference shear rate of less than about 100 / sec, ranges from about 10 cP to about 100,000 cP;
A cleaning agent that deforms around device features on the surface of the patterned substrate when a force is applied to the cleaning agent that covers the patterned substrate. The cleaning agent according to claim 1,
A cleaning agent, wherein the solvent is selected from the group consisting of water, isopropyl alcohol (IPA), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), or a combination thereof. The cleaning agent according to claim 1,
The one or more polymer compounds may be polyacrylamide (PAM), polyacrylic acid (PAA) such as Carbopol 940 (registered trademark) or Carbopol 941 (registered trademark), a copolymer of PAM and PAA, poly- (N, N -Acrylic polymers such as dimethylacrylamide) (PDMAAm), poly- (N-isopropylacrylamide) (PIPAAm), polymethacrylic acid (PMAA), polymethacrylamide (PMAAm), polyethyleneimine (PEI), polyethylene oxide (PEO), Polyimines and oxides such as polypropylene oxide (PPO), vinyl polymers such as polyvinyl alcohol (PVA), polyethylene sulfonic acid (PESA), polyvinylamine (PVAm), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP) , Me Cellulose derivatives such as chill cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), polysaccharides such as acacia gum, agar and agarose, heparin, guar gum, xanthan gum, egg white, collagen A detergent selected from the group consisting of proteins such as gluten. The cleaning agent according to claim 1,
The cleaning agent wherein the molecular weight of the one or more polymer compounds ranges from about 0.01 Mg / mol to about 100 Mg / mol. The cleaning agent according to claim 1,
The cleaning agent, wherein the weight percent of the polymer in the cleaning agent ranges from about 0.001% to about 10%. The cleaning agent according to claim 1,
Furthermore, a cleaning agent that changes a hydrogen ion index (pH) value of the cleaning agent, the buffering agent forming a cleaning solution together with the solvent. The cleaning agent according to claim 1,
Further, a cleaning agent comprising a surfactant that helps disperse the polymer in the cleaning agent and wet the surface of the patterned substrate. A cleaning agent according to claim 7,
A detergent, wherein the surfactant is ammonium dodecyl sulfate (ADS). The cleaning agent according to claim 1,
The cleaning agent is a liquid, sol or gel fluid. A cleaning agent according to claim 6,
The pH of the cleaning agent ranges from about 1 to about 12 in the front-end and back-end processes. The cleaning agent according to claim 1,
Further, an ion supply compound that ionizes in the cleaning solution, the cleaning agent comprising an ion supply compound that increases an ionic strength of the cleaning agent and changes a viscosity of the cleaning agent. The cleaning agent according to claim 1,
The detergent having a viscosity measured at the reference shear rate in a range of about 100 cP to about 10,000 cP. The cleaning agent according to claim 1,
The device features are sized with a critical dimension of about 45 nm or less. The cleaning agent according to claim 1,
A cleaning agent in which a part of the long polymer chain is cross-linked to form a polymer network so that contaminants can be easily captured and taken up. The cleaning agent according to claim 1,
The one or more polymer compounds include polyacrylamide (PAM), and the molecular weight of PAM is 1,000,000 g / mol or more. The cleaning agent according to claim 1,
The one or more polymer processing tool portions include a copolymer of acrylamide and acrylic acid, and the weight percentage of acrylic acid in the copolymer is less than about 50%. The cleaning agent according to claim 1,
Using the cleaning agent on the surface of the patterned substrate to remove contaminants from the surface without substantially damaging the device features on the surface;
Before the cleaning agent is supplied onto the surface of the patterned substrate, the cleaning agent is substantially free of abrasive particles. The cleaning agent according to claim 1,
A cleaning agent wherein the reference shear rate is less than about 1 / second. The cleaning agent according to claim 1,
A cleaning agent having a molecular weight greater than 10,000 g / mol. A cleaning agent used on the surface of a patterned substrate defining an IC device to remove contaminants from the surface,
A solvent,
A buffer that changes the hydrogen ion index (pH) value of the cleaning agent, and forms a cleaning solution with the solvent;
A polymer comprising one or more polymer compounds dissolved in the cleaning solution,
The detergent has a pH in the range of about 7 to about 12,
The one or more polymer compounds are dissolved in the solvent and the solubilized polymer comprises long polymer chains that capture and capture at least some contaminants from the surface of the patterned substrate defining the IC device. ,
The cleaning agent is in a liquid phase;
The viscosity of the cleaning agent measured at a reference shear rate ranges from about 10 cP to about 100,000 cP;
A polymer in which the cleaning agent deforms around device features on the surface of the patterned substrate when a force is applied to the cleaning agent covering the patterned substrate;
A surfactant that helps disperse the polymer in the cleaning agent and wet the surface of the patterned substrate;
A cleaning agent comprising: an ion supply compound that is ionized in the cleaning solution to adjust the viscosity of the cleaning agent. A cleaning agent according to claim 20,
Using the cleaning agent on the surface of the patterned substrate to remove contaminants from the surface without substantially damaging the device features on the surface;
Before the cleaning agent is supplied onto the surface of the patterned substrate, the cleaning agent is substantially free of abrasive particles. A cleaning agent according to claim 20,
A detergent wherein the buffer is ammonium hydroxide. A cleaning agent according to claim 20,
A cleaning agent, wherein the ion supply compound is citric acid.

Images