Patent Publication Number: US-9833980-B2

Title: Securing mechanism and method for wafer bonder

Description:
RELATED APPLICATIONS 
     Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
     BACKGROUND 
     Field 
     The present disclosure generally relates to the field of semiconductor wafer processing technology, and more particularly, to a securing mechanism for a wafer bonding device. 
     Description of the Related Art 
     In certain processing operations involving thin and/or fragile wafers, it may be desirable to mount a wafer to a plate for support and easier handling. Such a mounting process is sometimes referred to as a bonding process, and can be achieved by, for example, using an adhesive. 
     In certain bonding processes, a wafer joined to a plate can be cured application heat. During such application of heat, it is generally desirable to apply uniform mechanical pressure so that the wafer and the plate become bonded in a generally parallel manner. 
     SUMMARY 
     In certain implementations, the present disclosure relates to an apparatus for bonding a wafer to a plate. The apparatus includes a base member having a receiving side dimensioned to receive a wafer and a plate that are configured to be bonded. The apparatus further includes a lid having first and second opposing sides and configured to be placed in an open position and a closed position relative to the base member. The open position facilitates positioning of the wafer and the plate on the base member for bonding and removing of the bonded assembly of wafer and plate from the base member after the bonding. The closed position facilitates the bonding of the wafer and the plate. The first side is dimensioned to engage the receiving side of the base member when the lid is in the closed position. The apparatus further includes one or more securing mechanisms. Each securing mechanism is configured to engage and apply a securing force on the second side of the lid from the second side of the lid when the lid is in the closed position to thereby push the lid against the receiving side of the base member. 
     In certain embodiments, the lid can include a solid plate between the first and second side of the lid. The receiving side of the base member and the first side of the lid can define a bonding chamber when the lid is in the closed position. 
     In certain embodiments, the lid can be configured so as to substantially separate the bonding chamber from the second side of the lid. The lid can further include a diaphragm disposed on the lid&#39;s first side. The diaphragm can be dimensioned and configured to provide a bonding force to the wafer and the plate during the bonding. The lid can include a pressure pathway between a portion of its first side and a location behind the diaphragm. The pressure pathway can allow gas pressure to be provided to the location to allow the diaphragm to provide the bonding force. The receiving side of the base member can define a pressure pathway configured to receive gas from a source and in communication with the pressure pathway of the lid so as to provide the gas pressure to the location behind the diaphragm. The base member can further include a suction opening in communication with a suction source. The suction opening can be disposed so as to hold the assembly of wafer and plate during the bonding. 
     In certain embodiments, the base member can further include first and second seals disposed on the receiving side. The first seal can be configured to provide a gas seal between the outside and the pressure pathway of the base member. The second seal can be configured to provide a gas seal between the pressure pathway of the base member and the bonding chamber. 
     In certain embodiments, the securing mechanism can include a clamping device mounted to a mounting structure that is coupled to the base member. The clamping device can have a push rod configured to engage and push against the second side of the lid with one of its ends to provide the securing force. The mounting structure can be positioned at a location outside the periphery of the base member and the periphery of the lid when the lid is in the closed position. 
     In certain embodiments, the securing mechanism can further include a support beam configured to couple the push rod to the mounting structure. The support beam can be further configured to position the push rod to a location that is within the periphery of the lid when the lid is in the closed position. The push rod and the support beam can be configured so as to allow adjustment of the push rod&#39;s length from the support beam to the end that engages the second side of the lid. 
     In certain embodiments, the securing mechanism can further include a locking handle configured to engage and lock the support beam when the push rod is providing the securing force to the second side of the lid. The locking handle can be configured to lock the support beam by a camming action. 
     In certain implementations, the present disclosure relates to a wafer bonding station having one or more of the apparatus summarized above. 
     In certain implementations, the present disclosure relates to a method for bonding a wafer to a plate. The method includes applying an adhesive between a wafer and a plate so as to form an assembly of the wafer and the plate. The method further includes positioning the assembly on a bonding area. The method further includes positioning a lid over the bonding area. The lid has an outside surface and an inside surface that is configured to facilitate application of pressure to the assembly. The method further includes applying a pushing force on the outside surface of the lid from the outside surface side of the lid so as to secure the lid in a substantially fixed orientation. The pushing force is directed along a direction having a component that is perpendicular to a plane defined by the wafer. The method further includes bonding the assembly by applying pressure and heat to the assembly. 
     In certain embodiments, the method can further include removing the pushing force on the outside surface of the lid upon completion of the bonding so as to allow the lid to be removed from the bonding area. 
     In certain implementations, the present disclosure relates to a device for securing a lid of a wafer bonding apparatus. The device includes a base coupled to a support structure of the wafer bonding device and disposed at a location that is outside the lid&#39;s periphery when the lid is in a closed position. The device further includes a support beam having a first end pivotably mounted to the base so as to allow the support beam to be placed in a disengagement position and an engagement position. The device further includes a push rod having an axis and mounted to the support beam at a mounting location on the support beam such that the push rod extends from the mounting location to a pushing end by a length at an angle relative to the support beam. The mounting location and the first end of the support beam are separated by a distance. At least one of the length, the angle, and the distance is selected so that when the support beam is in the engagement position, the pushing end of the push rod engages an upper surface of the lid in its closed position with the push rod&#39;s axis being less than approximately 20 degrees from a normal to a plane defined by the upper surface of the lid. The device further includes a locking mechanism configured to lock and unlock the support beam in and from, respectively, the engagement position. 
     In certain embodiments, the push rod&#39;s axis can be less than approximately 5 degrees from the normal. 
     For purposes of summarizing the disclosure, certain aspects, advantages and novel features of the inventions have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example sequence of wafer processing for forming through-wafer features such as vias. 
         FIGS. 2A-2V  show examples of structures at various stages of the processing sequence of  FIG. 1 . 
         FIGS. 3A and 3B  show an example of a bonding apparatus where a number of securing mechanisms such as threaded bolts extend through or near a wafer bonding chamber such that undesirable particles generated by the mechanism can be introduced to the wafer. 
         FIG. 4  shows an example wafer bonding station having a number of bonding apparatus, each having one or more securing mechanisms that reduce the likelihood of the undesirable effect associated with  FIGS. 3A and 3B . 
         FIGS. 5A and 5B  show the bonding apparatus of  FIG. 4  in its open and closed configurations. 
         FIGS. 6A and 6B  show the bonding apparatus of  FIG. 4  in the closed configuration, before and after application of securing force by the securing mechanisms. 
         FIG. 7  shows the bonding apparatus of  FIG. 4  where the bonding process has been completed. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
     The headings provided herein, if any, are for convenience only and do not necessarily affect the scope or meaning of the claimed invention. 
     Provided herein are various methodologies and devices for processing wafers such as semiconductor wafers.  FIG. 1  shows an example of a process  10  where a functional wafer is further processed to form through-wafer features such as vias and back-side metal layers. As further shown in  FIG. 1 , the example process  10  can include bonding of a wafer to a carrier for support and/or to facilitate handling during the various steps of the process, and debonding of the wafer from the carrier upon completion of such steps.  FIG. 1  further shows that such a wafer separated from the carrier can be further processed so as to yield a number of dies. 
     In the description herein, various examples are described in the context of GaAs substrate wafers. It will be understood, however, that some or all of the features of the present disclosure can be implemented in processing of other types of semiconductor wafers. Further, some of the features can also be applied to situations involving non-semiconductor wafers. 
     In the description herein, various examples are described in the context of back-side processing of wafers. It will be understood, however, that some or all of the features of the present disclosure can be implemented in front-side processing of wafers. 
     In the process  10  of  FIG. 1 , a functional wafer can be provided (block  11 ).  FIG. 2A  depicts a side view of such a wafer  30  having first and second sides. The first side can be a front side, and the second side a back side. 
       FIG. 2B  depicts an enlarged view of a portion  31  of the wafer  30 . The wafer  30  can include a substrate layer  32  (e.g., a GaAs substrate layer). The wafer  30  can further include a number of features formed on or in its front side. In the example shown, a transistor  33  and a metal pad  35  are depicted as being formed the front side. The example transistor  33  is depicted as having an emitter  34   b , bases  34   a ,  34   c , and a collector  34   d . Although not shown, the circuitry can also include formed passive components such as inductors, capacitors, and source, gate and drain for incorporation of planar field effect transistors (FETs) with heterojunction bipolar transistors (HBTs). Such structures can be formed by various processes performed on epitaxial layers that have been deposited on the substrate layer. 
     Referring to the process  10  of  FIG. 1 , the functional wafer of block  11  can be tested (block  12 ) in a number of ways prior to bonding. Such a pre-bonding test can include, for example, DC and RF tests associated with process control parameters. 
     Upon such testing, the wafer can be bonded to a carrier (block  13 ). In certain implementations, such a bonding can be achieved with the carrier above the wafer. Thus,  FIG. 2C  shows an example assembly of the wafer  30  and a carrier  40  (above the wafer) that can result from the bonding step  13 . In certain implementations, the wafer and carrier can be bonded using temporary mounting adhesives such as wax or commercially available Crystalbond™. In  FIG. 2C , such an adhesive is depicted as an adhesive layer  38 . 
     In certain implementations, the carrier  40  can be a plate having a shape (e.g., circular) similar to the wafer it is supporting. Preferably, the carrier plate  40  has certain physical properties. For example, the carrier plate  40  can be relatively rigid for providing structural support for the wafer. In another example, the carrier plate  40  can be resistant to a number of chemicals and environments associated with various wafer processes. In another example, the carrier plate  40  can have certain desirable optical properties to facilitate a number of processes (e.g., transparency to accommodate optical alignment and inspections) 
     Materials having some or all of the foregoing properties can include sapphire, borosilicate (also referred to as Pyrex), quartz, and glass (e.g., SCG72). 
     In certain implementations, the carrier plate  40  can be dimensioned to be larger than the wafer  30 . Thus, for circular wafers, a carrier plate can also have a circular shape with a diameter that is greater than the diameter of a wafer it supports. Such a larger dimension of the carrier plate can facilitate easier handling of the mounted wafer, and thus can allow more efficient processing of areas at or near the periphery of the wafer. 
     Tables 1A and 1B list various example ranges of dimensions and example dimensions of some example circular-shaped carrier plates that can be utilized in the process  10  of  FIG. 1 . 
     
       
         
           
               
               
               
             
               
                 TABLE 1A 
               
               
                   
               
               
                 Carrier plate 
                 Carrier plate 
                   
               
               
                 diameter range 
                 thickness range 
                 Wafer size 
               
               
                   
               
             
            
               
                 Approx. 100 to 120 mm 
                 Approx. 500 to 1500 um 
                 Approx. 100 mm 
               
               
                 Approx. 150 to 170 mm 
                 Approx. 500 to 1500 um 
                 Approx. 150 mm 
               
               
                 Approx. 200 to 220 mm 
                 Approx. 500 to 2000 um 
                 Approx. 200 mm 
               
               
                 Approx. 300 to 320 mm 
                 Approx. 500 to 3000 um 
                 Approx. 300 mm 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
             
               
                 TABLE 1B 
               
               
                   
               
               
                 Carrier plate diameter 
                 Carrier plate thickness 
                 Wafer size 
               
               
                   
               
             
            
               
                 Approx. 110 mm 
                 Approx. 1000 um 
                 Approx. 100 mm 
               
               
                 Approx. 160 mm 
                 Approx. 1300 um 
                 Approx. 150 mm 
               
               
                 Approx. 210 mm 
                 Approx. 1600 um 
                 Approx. 200 mm 
               
               
                 Approx. 310 mm 
                 Approx. 1900 um 
                 Approx. 300 mm 
               
               
                   
               
            
           
         
       
     
     An enlarged portion  39  of the bonded assembly in  FIG. 2C  is depicted in  FIG. 2D . The bonded assembly can include the GaAs substrate layer  32  on which are a number of devices such as the transistor ( 33 ) and metal pad ( 35 ) as described in reference to  FIG. 2B . The wafer ( 30 ) having such substrate ( 32 ) and devices (e.g.,  33 ,  35 ) is depicted as being bonded to the carrier plate  40  via the adhesive layer  38 . 
     As shown in  FIG. 2D , the substrate layer  32  at this stage has a thickness of d 1 , and the carrier plate  40  has a generally fixed thickness (e.g., one of the thicknesses in Table 1). Thus, the overall thickness (T assembly ) of the bonded assembly can be determined by the amount of adhesive in the layer  38 . 
     In a number of processing situations, it is preferable to provide sufficient amount of adhesive to cover the tallest feature(s) so as to yield a more uniform adhesion between the wafer and the carrier plate, and also so that such a tall feature does not directly engage the carrier plate. Thus, in the example shown in  FIG. 2D , the emitter feature ( 34   b  in  FIG. 2B ) is the tallest among the example features; and the adhesive layer  38  is sufficiently thick to cover such a feature and provide a relatively uninterrupted adhesion between the wafer  30  and the carrier plate  40 . 
     Referring to the process  10  of  FIG. 1 , the wafer—now mounted to the carrier plate—can be thinned so as to yield a desired substrate thickness in blocks  14  and  15 . In block  14 , the back side of the substrate  32  can be ground away (e.g., via two-step grind with coarse and fine diamond-embedded grinding wheels) so as to yield an intermediate thickness-substrate (with thickness d 2  as shown in  FIG. 2E ) with a relatively rough surface. In certain implementations, such a grinding process can be performed with the bottom surface of the substrate facing downward. 
     In block  15 , the relatively rough surface can be removed so as to yield a smoother back surface for the substrate  32 . In certain implementations, such removal of the rough substrate surface can be achieved by an O2 plasma ash process, followed by a wet etch process utilizing acid or base chemistry. Such an acid or base chemistry can include HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 , H 3 COOH, NH 4 OH, H 2 O 2 , etc., mixed with H 2 O 2  and/or H 2 O. Such an etching process can provide relief from possible stress on the wafer due to the rough ground surface. 
     In certain implementations, the foregoing plasma ash and wet etch processes can be performed with the back side of the substrate  32  facing upward. Accordingly, the bonded assembly in  FIG. 2F  depicts the wafer  30  above the carrier plate  40 .  FIG. 2G  shows the substrate layer  32  with a thinned and smoothed surface, and a corresponding thickness of d 3 . 
     By way of an example, the pre-grinding thickness (d 1  in  FIG. 2D ) of a 150 mm (also referred to as “6-inch”) GaAs substrate can be approximately 675 μm. The thickness d 2  ( FIG. 2E ) resulting from the grinding process can be in a range of approximately 102 μm to 120 μm. The ash and etching processes can remove approximately 2 μm to 20 μm of the rough surface so as to yield a thickness of approximately 100 μm. (d 3  in  FIG. 2G ). Other thicknesses are possible. 
     In certain situations, a desired thickness of the back-side-surface-smoothed substrate layer can be an important design parameter. Accordingly, it is desirable to be able to monitor the thinning (block  14 ) and stress relief (block  15 ) processes. Since it can be difficult to measure the substrate layer while the wafer is bonded to the carrier plate and being worked on, the thickness of the bonded assembly can be measured so as to allow extrapolation of the substrate layer thickness. Such a measurement can be achieved by, for example, a gas (e.g., air) back pressure measurement system that allows detection of surfaces (e.g., back side of the substrate and the “front” surface of the carrier plate) without contact. 
     As described in reference to  FIG. 2D , the thickness (T assembly ) of the bonded assembly can be measured; and the thicknesses of the carrier plate  40  and the un-thinned substrate  32  can have known values. Thus, subsequent thinning of the bonded assembly can be attributed to the thinning of the substrate  32 ; and the thickness of the substrate  32  can be estimated. 
     Referring to the process  10  of  FIG. 1 , the thinned and stress-relieved wafer can undergo a through-wafer via formation process (block  16 ).  FIGS. 2H-2J  show different stages during the formation of a via  44 . Such a via is described herein as being formed from the back side of the substrate  32  and extending through the substrate  32  so as to end at the example metal pad  35 . It will be understood that one or more features described herein can also be implemented for other deep features that may not necessarily extend all the way through the substrate. Moreover, other features (whether or not they extend through the wafer) can be formed for purposes other than providing a pathway to a metal feature on the front side. 
     To form an etch resist layer  42  that defines an etching opening  43  ( FIG. 2H ), photolithography can be utilized. Coating of a resist material on the back surface of the substrate, exposure of a mask pattern, and developing of the exposed resist coat can be achieved in known manners. In the example configuration of  FIG. 2H , the resist layer  42  can have a thickness in a range of about 15 μm to 20 μm. 
     To form a through-wafer via  44  ( FIG. 2I ) from the back surface of the substrate to the metal pad  35 , techniques such as dry inductively coupled plasma (ICP) etching (with chemistry such as BCl 3 /Cl 2 ) can be utilized. In various implementations, a desired shaped via can be an important design parameter for facilitating proper metal coverage therein in subsequent processes. 
       FIG. 2J  shows the formed via  44 , with the resist layer  42  removed. To remove the resist layer  42 , photoresist strip solvents such as NMP (N-methyl-2-pyrrolidone) and EKC can be applied using, for example, a batch spray tool. In various implementations, proper removal of the resist material  42  from the substrate surface can be an important consideration for subsequent metal adhesion. To remove residue of the resist material that may remain after the solvent strip process, a plasma ash (e.g., O 2 ) process can be applied to the back side of the wafer. 
     Referring to the process  10  of  FIG. 1 , a metal layer can be formed on the back surface of the substrate  32  in block  17 .  FIGS. 2K and 2L  show examples of adhesion/seed layers and a thicker metal layer. 
       FIG. 2K  shows that in certain implementations, an adhesion layer  45  such as a nickel vanadium (NiV) layer can be formed on surfaces of the substrate&#39;s back side and the via  44  by, for example, sputtering. Preferably, the surfaces are cleaned (e.g., with HCl) prior to the application of NiV.  FIG. 2K  also shows that a seed layer  46  such as a thin gold layer can be formed on the adhesion layer  45  by, for example, sputtering. Such a seed layer facilitates formation of a thick metal layer  47  such as a thick gold layer shown in  FIG. 2L . In certain implementations, the thick gold layer can be formed by a plating technique. 
     In certain implementations, the gold plating process can be performed after a pre-plating cleaning process (e.g., O 2  plasma ash and HCl cleaning). The plating can be performed to form a gold layer of about 3 μm to 6 μm to facilitate the foregoing electrical connectivity and heat transfer functionalities. The plated surface can undergo a post-plating cleaning process (e.g., O 2  plasma ash). 
     The metal layer formed in the foregoing manner forms a back side metal plane that is electrically connected to the metal pad  35  on the front side. Such a connection can provide a robust electrical reference (e.g., ground potential) for the metal pad  35 . Such a connection can also provide an efficient pathway for conduction of heat between the back side metal plane and the metal pad  35 . 
     Thus, one can see that the integrity of the metal layer in the via  44  and how it is connected to the metal pad  35  and the back side metal plane can be important factors for the performance of various devices on the wafer. Accordingly, it is desirable to have the metal layer formation be implemented in an effective manner. More particularly, it is desirable to provide an effective metal layer formation in features such as vias that may be less accessible. 
     Referring to the process  10  of  FIG. 1 , the wafer having a metal layer formed on its back side can undergo a street formation process (block  18 ).  FIGS. 2M-2O  show different stages during the formation of a street  50 . Such a street is described herein as being formed from the back side of the wafer and extending through the metal layer  52  to facilitate subsequent singulation of dies. It will be understood that one or more features described herein can also be implemented for other street-like features on or near the back surface of the wafer. Moreover, other street-like features can be formed for purposes other than to facilitate the singulation process. 
     To form an etch resist layer  48  that defines an etching opening  49  ( FIG. 2M ), photolithography can be utilized. Coating of a resist material on the back surface of the substrate, exposure of a mask pattern, and developing of the exposed resist coat can be achieved in known manners. 
     To form a street  50  ( FIG. 2N ) through the metal layer  52 , techniques such as wet etching (with chemistry such as potassium iodide) can be utilized. A pre-etching cleaning process (e.g., O 2  plasma ash) can be performed prior to the etching process. In various implementations, the thickness of the resist  48  and how such a resist is applied to the back side of the wafer can be important considerations to prevent certain undesirable effects, such as via rings and undesired etching of via rim during the etch process. 
       FIG. 2O  shows the formed street  50 , with the resist layer  48  removed. To remove the resist layer  48 , photoresist strip solvents such as NMP (N-methyl-2-pyrrolidone) can be applied using, for example, a batch spray tool. To remove residue of the resist material that may remain after the solvent strip process, a plasma ash (e.g., O 2 ) process can be applied to the back side of the wafer. 
     In the example back-side wafer process described in reference to  FIGS. 1 and 2 , the street ( 50 ) formation and removal of the resist ( 48 ) yields a wafer that no longer needs to be mounted to a carrier plate. Thus, referring to the process  10  of  FIG. 1 , the wafer is debonded or separated from the carrier plate in block  19 .  FIGS. 2P-2R  show different stages of the separation and cleaning of the wafer  30 . 
     In certain implementations, separation of the wafer  30  from the carrier plate  40  can be performed with the wafer  30  below the carrier plate  40  ( FIG. 2P ). To separate the wafer  30  from the carrier plate  40 , the adhesive layer  38  can be heated to reduce the bonding property of the adhesive. For the example Crystalbond™ adhesive, an elevated temperature to a range of about 130° C. to 170° C. can melt the adhesive to facilitate an easier separation of the wafer  30  from the carrier plate  40 . Some form of mechanical force can be applied to the wafer  30 , the carrier plate  40 , or some combination thereof, to achieve such separation (arrow  53  in  FIG. 2P ). In various implementations, achieving such a separation of the wafer with reduced likelihood of scratches and cracks on the wafer can be an important process parameter for facilitating a high yield of good dies. 
     In  FIGS. 2P and 2Q , the adhesive layer  38  is depicted as remaining with the wafer  30  instead of the carrier plate  40 . It will be understood that some adhesive may remain with the carrier plate  40 . 
       FIG. 2R  shows the adhesive  38  removed from the front side of the wafer  30 . The adhesive can be removed by a cleaning solution (e.g., acetone), and remaining residues can be further removed by, for example, a plasma ash (e.g., O 2 ) process. 
     Referring to the process  10  of  FIG. 1 , the debonded wafer of block  19  can be tested (block  20 ) in a number of ways prior to singulation. Such a post-debonding test can include, for example, resistance of the metal interconnect formed on the through-wafer via using process control parameters on the front side of the wafer. Other tests can address quality control associated with various processes, such as quality of the through-wafer via etch, seed layer deposition, and gold plating. 
     Referring to the process  10  of  FIG. 1 , the tested wafer can be cut to yield a number of dies (block  21 ). In certain implementations, at least some of the streets ( 50 ) formed in block  18  can facilitate the cutting process.  FIG. 2S  shows cuts  61  being made along the streets  50  so as to separate an array of dies  60  into individual dies. Such a cutting process can be achieved by, for example, a diamond scribe and roller break, saw or a laser. 
     In the context of laser cutting,  FIG. 2T  shows an effect on the edges of adjacent dies  60  cut by a laser. As the laser makes the cut  61 , a rough edge feature  62  (commonly referred to as recast) typically forms. Presence of such a recast can increase the likelihood of formation of a crack therein and propagating into the functional part of the corresponding die. 
     Thus, referring to the process  10  in  FIG. 1 , a recast etch process using acid and/or base chemistry (e.g., similar to the examples described in reference to block  15 ) can be performed in block  22 . Such etching of the recast feature  62  and defects formed by the recast, increases the die strength and reduces the likelihood of die crack failures ( FIG. 2U ). 
     Referring to the process  10  of  FIG. 1 , the recast etched dies ( FIG. 2V ) can be further inspected and subsequently be packaged. 
     As described herein in reference to  FIGS. 1 and 2 , some operations in the process  10  can benefit from having a wafer temporarily bonded to a carrier plate. Once such operations are completed, the wafer can be removed or debonded from the carrier plate.  FIGS. 3-7  show by way of examples a bonding apparatus having a securing mechanism that reduces the likelihood of unwanted debris or small objects being introduced into an area where the bonding process occurs. 
     It will be understood that one or more features associated with debonding devices and methodologies can be implemented in the example through-wafer via process described in reference to  FIGS. 1 and 2 , as well as in other processing situations. It will also be understood that one or more features associated with debonding devices and methodologies can be implemented in different types of semiconductor-based wafers, including but not limited to those formed from semiconductor materials such as groups IV, III-V, II-VI, I-VII, IV-VI, V-VI, II-V; oxides; layered semiconductors; magnetic semiconductors; organic semiconductors; charge-transfer complexes; and other semiconductors. Further, some of the features described herein can also be implemented in situations involving separation of non-semiconductor-based wafers from another structure. 
     Various wafer processing operations can be performed in controlled environments such as those associated with various clean rooms. Among other controlled environmental factors, “cleanliness” of a clean room greatly reduces the concentration of small particles (e.g., dust particles, lint, etc.) circulating in the air so as to reduce the likelihood of such particles settling on wafers. Detrimental effects of such particles on wafers are known. 
       FIGS. 3A and 3B  show side and plan views of a bonding apparatus  100  having a lower member  102  and an upper member  104 . The lower member  102  and/or the upper member  104  can define a bonding chamber  106  where a wafer (not shown) can undergo a bonding process with a carrier plate (not shown). In some situations, such a bonding process can involve curing of an adhesive that has already been applied (e.g., spun on). Such a curing process can be facilitated by an application of heat. The bonding apparatus  100  can be configured appropriately so as to yield a bonded assembly of wafer and carrier plate where the wafer and the carrier plate are substantially parallel. 
     The upper member  104  can be moved (depicted as an arrow  124 ) so as to allow it to open and close the bonding chamber  106 . The upper member  104  can be opened to allow loading of the uncured wafer-carrier assembly and unloading of the cured wafer-carrier assembly. The upper member  104  can be closed facilitate the curing process. 
     The opening and closing of the upper member  104  can be facilitated by a handle  108  that is attached to the upper member  104  by, for example, one or more screws  110 . The handle  108  can also be attached to a hinge  114  by, for example, one or more screws  112 . The hinge  114  can be coupled to a support member  118  through a pivot  116  so at to allow the upper member  104  to rotate between its open and closed positions about the pivot  116 . 
     When in the closed position, the upper member can be secured to the lower member by a number of screws  120 . In the example shown in  FIG. 3B , four of such screws ( 120   a - 120   d ) are depicted as being distributed circumferentially so as to provide a distributed securing force. As shown in  FIG. 3A , each of the screws  120  can include a threaded portion  122  that extends through the upper member  104  to engage a portion of the lower member  102 , thereby allowing the screw to be tightened to secure the upper member  104  to the lower member  102 . 
     Tightening and removing of the screws  120  involve surface engagements between the threaded portions  122  of the screws  120  and their respective matching threads on the lower member  102 . Consequently, such surface engagements can result in small metal and other particles being generated and falling or somehow being introduced into the bonding chamber  106 . Some of such particles can become undesirably attached to a wafer being bonded therein. 
     In the example shown in  FIGS. 3A and 3B , the screws  120  are depicted as extending into the bonding chamber  106 . However, even if the screws  120  do not invade the bonding chamber  106 , they need to extend through the mating surfaces of the upper and lower members  104 ,  102 . Consequently, any undesirable particles resulting from the thread engagements can collect on either or both of the mating surfaces, and move into the bonding chamber  106  during the opening and closing operations. 
       FIGS. 4-7  show various examples of a securing mechanism that can secure upper and lower members  220 ,  222  of a bonding apparatus  202  in a manner where the likelihood of introduction of undesirable particles from the securing mechanism into the bonding chamber is reduced or substantially eliminated. In certain implementations, such a reduction can be achieved by configuring the securing mechanism to reduce the amount of undesirable particles being generated and/or to provide the securing force without having to pull the upper and lower members  220 ,  222  together by a structure that extends through one of the members (e.g., upper member  220 ) into the other (e.g., lower member  222 ). 
       FIG. 4  shows an example bonding station  200  having a number of the wafer bonding apparatus  202 . In certain embodiments, the upper member  220 , the lower member  222 , and the handle  224  configured to operate in manners similar to those ( 104 ,  102 ,  108 ) described in reference to  FIGS. 3A and 3B . In certain embodiments, the upper member  220  can be secured to the lower member  222  by one or more securing mechanisms  230  as described herein. 
       FIG. 4  shows that the example bonding station  200  can include a base (within the housing  208 ) that supports the lower members  222 . The base can also be mechanically coupled to support legs  204  to facilitate positioning of the station  200  on a surface  206 . The station  200  can also include a control component  210  for controlling various operating parameters such as temperature for curing of the adhesive, gas pressure for applying pressing the wafer and carrier plate in a controlled manner, and vacuum for holding the wafer-carrier assembly during the curing process. In  FIG. 4 , a vacuum handling wand  212  is also shown. Such a device can be used to manipulate the wafer-carrier assembly during loading and unloading operations. 
     In certain embodiments, each bonding apparatus  202  can include one or more securing mechanisms  230 . In the example shown, there are two of such mechanisms  230   a ,  230   b  for each bonding apparatus  202 . In other embodiments, the number of such mechanisms can also be greater than or less than two. 
       FIGS. 5A and 5B  show the bonding apparatus  202  with ( FIG. 5B ) and without ( FIG. 5A ) a wafer-carrier assembly  260  in the bonding chamber. With the upper member  220  in its upper position (e.g., rotated open about a pivot  246 ), one can see that the bonding chamber can include a platform surface  256  dimensioned to receive the wafer-carrier assembly  260 . The surface  256  can define a vacuum aperture  258  in communication with a vacuum device (not shown) and configured to provide a suction hold of the wafer-carrier assembly  260 . Such a vacuum aperture  258  can also facilitate removal of gas pockets that may have formed between the surface  256  and the wafer-carrier assembly  260 . 
     The upper member  220  can include a pneumatic diaphragm  244  configured to provide a wide pushing force on the wafer-carrier assembly  260  during the curing process. The diaphragm  244  can be actuated by pressurized gas delivered through an aperture  242  in communication with a region behind the diaphragm  244 . The aperture  242  on the upper member  220  can be in communication with a ring space  254  defined between inner and outer sealing rings  252 ,  250  and a pressure input aperture  248 . Thus, when the upper member  220  is lowered onto the lower member  222 , the upper member&#39;s engaging surface  240  engages with the sealing rings  252 ,  250  to separate the pressure system (including the ring space  254 ) from the vacuum system of the bonding chamber and from the outside. 
     Referring to  FIG. 5A , the securing mechanism  230  can be secured to the base (not shown) by a support bar  232 . 
     In  FIG. 6A , the upper member  220  has been lowered to its closed position so as to engage the lower member  222 . Such closing and opening operations can be facilitated by the handle  224  attached to the upper member  220  by one or more fasteners such as screws  270 . The handle  224  is depicted as being mounted to a hinge by one or more fasteners such as screws  272 . 
     In  FIG. 6A , the upper member  220  has been lowered but not secured by the securing mechanisms  230   a ,  230   b . In  FIG. 6B , the securing mechanisms  230   a ,  230   b  are in their secured positions. 
     In certain implementations, each of the securing mechanism  230  can include a base  300  that is mounted on the support bar  232  in a manner that allows the securing mechanism  230  to rotate with the support bar  232  (about axis of the support bar  232 ) to facilitate the opening and closing of the upper member  220 . Once the securing mechanism  230  in rotated to allow engagement with the upper member  220  ( 230   b  in  FIG. 6A ), a push rod  280  can be swung down (arrow  282 ) so that its engagement end  284  can engage the upper surface  274  of the upper member  220 . Upon engagement, the push rod  280  can be pushed further against the upper surface  274  and generally maintained there so as to secure the upper member  220  against the lower member  222 . 
     In certain embodiments, the securing mechanism  230  can include a support beam  290  that is pivotably mounted ( 292 ) to the base  300  (of the securing mechanism  230 ). The push rod  280  can be mounted at a distance from the pivot  292  so that the pivot  292  facilitates the movement  282  of the push rod towards and away from the upper surface  274  of the upper member  220 . In certain embodiments, the push rod&#39;s orientation relative to the support beam  290  can be approximately perpendicular; however, the angle between the two can be greater or less than 90 degrees to facilitate an appropriate securing engagement of the push rod  280  with the upper member  220 . 
     In certain embodiments, the distance between the push rod&#39;s engagement end  284  and its mounting location on the support beam  290  can be adjusted to facilitate, for example, the amount of push force applied to the upper member. In the example shown, the push rod  280  can include a threaded portion so as to be mounted to the support beam  290  by threaded nuts  286 . Accordingly, the push rod  280  can be moved relative to the support beam  290  by loosening and tightening the nuts  286  appropriately. 
     In certain embodiments, the location where the push rod  280  is mounted (to the support beam  290 ) can be selected so that when secured, the push rod  280  pushes on a selected location (e.g., a peripheral portion) of the upper surface  274 . In the example shown in  FIGS. 6A and 6B , the mounting location of the push rod  280  along the support beam  290  can be adjusted by loosening one or more of the nuts  286 , sliding the mounting to a desired location on the support beam  290 , and tightening the nut(s)  286 . Thus, as shown in  FIG. 6B , two such pushing forces (provided by the two example push rods) on the upper member  220  can provide a distributed securing force on the upper member  220 . 
     In certain embodiments, a plurality of such securing mechanisms  230  can be distributed generally uniformly about the upper member  220 . In the example shown, the two securing mechanisms  230  are depicted as being distributed with about 180-degree separation. 
     In certain embodiments, the securing mechanism  230  can include a locking handle  294  that is configured to push the push rod  280  (through the support member  290 ) into its securing position and lock the securing mechanism  230  in such a position. To provide such a feature, the locking handle  294  can be pivotably mounted ( 296 ) to the base and include a locking mechanism (e.g., a camming action) that locks the securing mechanism  230  by pushing the handle  294  towards the center of the upper member  220  after the placement of the push rod  280  on the upper member  220 . Unlocking of the securing mechanism  230  can be achieved by pushing the handle  294  away from the center of the upper member  220  to thereby allow the push rod  280  to be moved away from the upper member  220 . 
     In certain implementations, a securing mechanism having some or all of the foregoing features can be configured to provide an amount of force that results in an acceptable sealing functionality of the seals  250 ,  252 . On the other hand, the amount of force is preferably less than an amount that would crush the seal(s) and possibly damage the wafer-carrier assembly. 
     In certain implementations, the amount of force can also be selected so to overcome the tendency of the upper member  220  to separate from the lower member  222  as the diaphragm  244  pushes on the wafer-carrier assembly. 
       FIG. 7  shows the upper member  220  in its open position after the completion of a bonding process. The bonded wafer-carrier assembly  260  is depicted as being removed from the lower member  222  by the vacuum handling device  212  previously referred to in  FIG. 4 . 
     In the non-limiting example described herein, the securing mechanism is configured to operate as a clamp or a clamp-like device to provide a pushing force on the upper member (also referred to as a lid herein). It will be appreciated that a number of other designs can also be implemented to provide one or more functionalities as described herein. 
     As described herein, the lid can include first and second opposing sides, with the first side dimensioned to engage a receiving side of the lower member (also referred to as a base member herein) base member when the lid is in the closed position, and with the second side separated from the first side by a substantially solid plate. Such a separation of the first and second sides of the lid by the plate reduces the likelihood that undesirable particles originating from the operation of the securing mechanism will be introduced to the first side of the lid and/or the bonding chamber. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” The word “coupled”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list. 
     The above detailed description of embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. For example, while processes or blocks are presented in a given order, alternative embodiments may perform routines having steps, or employ systems having blocks, in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these processes or blocks may be implemented in a variety of different ways. Also, while processes or blocks are at times shown as being performed in series, these processes or blocks may instead be performed in parallel, or may be performed at different times. 
     The teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. 
     While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.