An easily replaceable high-precision wafer stage

Abstract

An easily replaceable high-precision silicon wafer carrier stage. The carrier stage includes a base and a carrier plate disposed on the base by vacuum adsorption. The base and the carrier plate are positioned by positioning pins. At least one annular vacuum channel for adsorbing the base and the carrier plate is provided inside the carrier stage. Compared with the prior art, the upper surface of the carrier plate uses porous ceramics with high precision and good adsorption. The base and the carrier plate are fixed by vacuum adsorption. To process wafers of other sizes, only the corresponding carrier plate needs to be replaced, and the replacement of the carrier plate is convenient. In the carrier plate of the present invention, the main air paths and branch air paths of the carrier plate vacuum channels are evenly distributed; each main air path is connected to its own vacuum pipeline. In addition, in the present invention, the depth of the main air path is greater than the depth of the branch air path. In the same time, the negative pressure generated in the main air path and the branch air path is approximately equal or the difference becomes smaller. During the adsorption process, the position of the carrier plate is stable and the precision is high.

Description

Technical Field

[0001] The present invention belongs to the field of silicon wafer processing, and particularly relates to an easily replaceable high-precision silicon wafer carrier. Background Art

[0002] Wafer processing belongs to a high-precision processing industry. Tiny errors will have a certain impact on the wafer processing results, ultimately affecting the product quality. A silicon wafer chuck is a mechanism for placing silicon wafers in laser cutting and other processes. The stability and precision of silicon wafer adsorption can affect the position of the wafers placed thereon, thereby affecting the precision of the wafers. Improving the precision of the silicon wafer chuck is very important for high-precision wafer processing. In addition, different sizes of wafers require different wafer chucks, and the existing structure for replacing chucks is complex. Summary of the Invention

[0003] The present invention provides an easily replaceable high-precision silicon wafer carrier.

[0004] The object of the present invention is achieved in the following manner:

[0005] An easily replaceable high-precision silicon wafer carrier, the carrier includes a base and a carrier plate disposed on the base by vacuum adsorption, and the base and the carrier plate are positioned by positioning pins; at least one annular vacuum channel for adsorbing the base and the carrier plate is provided inside the carrier, and a true air cavity is further provided in the central region of the carrier inside the vacuum channel, a porous ceramic layer is provided at the upper end of the carrier plate, and the upper end of the true air cavity is communicated with the porous ceramic; the lower ends of the vacuum channel and the true air cavity are respectively communicated with a main vacuum port and a secondary vacuum port provided at the bottom of the base through pipes.

[0006] At least two concentric vacuum channels are provided inside the carrier, the cross-sectional shape of the true air cavity is circular, and the true air cavity and the vacuum channel are coaxially arranged; the vacuum channel and the true air cavity are not communicated.

[0007] At least one annular carrier plate vacuum channel is provided on the lower surface of the carrier plate, and a carrier plate true air cavity is further provided in the central region of the lower surface of the carrier plate located inside the carrier plate vacuum channel; positioning holes are provided at the lower end of the carrier plate; the carrier plate is integrally sintered and formed; a porous ceramic layer is provided at the upper end of the carrier plate, and the lower end of the carrier plate is a ceramic main body; the carrier plate vacuum channel and the carrier plate true air cavity are not communicated.

[0008] At least two annular wafer carrier vacuum channels are provided on the lower surface of the wafer carrier; the wafer carrier vacuum channels are connected through main air paths arranged along the radial direction; a plurality of main air paths are evenly distributed along the circumference on the wafer carrier vacuum channels; the main air paths divide the annular wafer carrier vacuum channels into several arc-shaped branch air paths; the depth of the main air paths is greater than the depth of the branch air paths; the width of the main air paths is equal to the width of the branch air paths; a main vacuum pipeline is provided at a position corresponding to the main air path on the base to communicate with the main vacuum port; a secondary vacuum pipeline is provided at a position corresponding to the wafer carrier vacuum cavity on the base to communicate with the secondary vacuum port.

[0009] On the upper surface of the base, corresponding annular base vacuum channels are provided for each wafer carrier vacuum channel. The main vacuum pipeline includes transverse vacuum pipelines respectively provided at positions corresponding to each main air path inside the base; the transverse vacuum channels are connected to the base vacuum channels through longitudinal vacuum pipelines; each transverse vacuum pipeline is connected to a longitudinal total vacuum pipeline, and the total vacuum pipeline is connected to the main vacuum port; a base vacuum cavity is also provided in the central area of the base vacuum channels on the upper surface of the base; the position of the base vacuum cavity corresponds to the position of the wafer carrier vacuum cavity; the base vacuum cavity is directly connected to the secondary vacuum port through a secondary vacuum pipeline; positioning holes are also provided on the base.

[0010] Respective transverse vacuum pipelines are provided between each transverse vacuum pipeline and all the base vacuum channels.

[0011] The depth of one end of the main air path close to the wafer carrier vacuum cavity is greater than the depth of the end far from the wafer carrier vacuum cavity; from the end close to the main air path to the middle position of the branch air path, the depth of the branch air path gradually becomes smaller.

[0012] The precision of the upper and lower surfaces of the base is at the micron level.

[0013] Compared with the prior art, the upper surface of the wafer carrier uses porous ceramics with high precision and good adsorption. The vacuum cavity keeps the porous ceramic layer in a negative pressure state, thereby adsorbing the wafers thereon. The vacuum channels enable the base and the wafer carrier to be tightly connected. The base and the wafer carrier are fixed by vacuum adsorption. When processing wafers of other sizes, only the corresponding wafer carrier needs to be replaced, and the replacement of the wafer carrier is convenient.

[0014] The wafer carrier vacuum channels of the wafer carrier of the present invention are provided with evenly distributed main air paths and branch air paths; each main air path is connected to its own vacuum pipeline. In addition, in the present invention, the depth of the main air path is greater than the depth of the branch air path. In the same time, the negative pressure generated in the main air path and the branch air path is roughly equal or the difference becomes smaller. During the adsorption process, the position of the wafer carrier is stable and the precision is high. Description of the Drawings

[0015] Figure 1 It is a perspective view of the stage.

[0016] Figure 2 It is a side view of the stage.

[0017] Figure 3 It is a perspective view of the base.

[0018] Figure 4 It is a perspective view of the other side of the base.

[0019] Figure 5 It is a sectional view of the base taken along the A-A direction.

[0020] Figure 6 It is a perspective view of the carrier plate.

[0021] Figure 7 It is a perspective view of the other side of the carrier plate.

[0022] Figure 8 It is the front view of the carrier plate.

[0023] Figure 9 is Figure 8 It is the B-B view.

[0024] Among them, 2 is the base, 20 is the main vacuum port, 21 is the secondary vacuum port, 22 is the base vacuum channel, 23 is the base vacuum cavity, 24 is the transverse vacuum pipeline, 25 is the longitudinal vacuum pipeline, 26 is the total vacuum pipeline, 27 is the secondary vacuum pipeline, 4 is the carrier plate, 40 is the porous ceramic layer, 41 is the ceramic main body, 42 is the carrier plate vacuum cavity, 43 is the main gas path, 44 is the branch gas path, and 5 is the positioning hole. Specific embodiments

[0025] In the present invention, unless otherwise clearly defined and limited, the technical terms used in this application shall have the ordinary meanings understood by those skilled in the art to which the present invention pertains. Terms such as "connected", "joined", "fixed", "arranged", etc. should be understood in a broad sense and can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium; it can be a mechanical connection or an electrical connection. Unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact or in indirect contact through an intermediate medium. Moreover, the first feature being "above" or "over" or "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under" or "beneath" or "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature has a lower horizontal height than the second feature. Relative terms such as first, second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Terms used in the description such as "center", "lateral", "longitudinal", "length", "width", "thickness", "height", "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation.

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings and specific embodiments. As Figures 6 - 9 shown, there is a high-precision wafer carrier ceramic tray, and a porous ceramic layer 40 is arranged at the upper end of the tray 4; at least one annular vacuum channel of the tray 4 is arranged on the lower surface of the tray 4, and a tray vacuum cavity 42 is further arranged in the central area of the lower surface of the tray 4 where the vacuum channel of the tray 4 is located; the upper end of the tray vacuum cavity 42 communicates with the porous ceramic; positioning holes 5 are arranged at the lower end of the tray 4. In the present invention, the tray 4 is adsorbed by the base 2 through the vacuum channel of the tray 4. The adsorption is stable. The tray vacuum cavity 42 communicates with the porous ceramic transfer layer, and the wafer is evenly adsorbed through the porous ceramic. Air can freely flow on the surface of the porous ceramic. The upper surface of the tray 4 uses porous ceramic with high precision and good adsorption performance.

[0027] The carrier plate 4 is integrally sintered and formed; a porous ceramic layer 40 is provided at the upper end of the carrier plate 4, and the lower end of the carrier plate 4 is a ceramic main body 41; the vacuum channel of the carrier plate 4 and the vacuum cavity 42 of the carrier plate are not connected. The porous ceramic layer 40 can be an annular area in the middle of the carrier plate 4 and does not necessarily occupy the entire upper end of the carrier plate 4. The height of the porous ceramic layer 40 is slightly higher than that of the ceramic main body 41.

[0028] At least two annular vacuum channels of the carrier plate 4 are provided on the lower surface of the carrier plate 4; the vacuum channels of the carrier plate 4 are connected by a main air path 43 arranged along the radial direction; a plurality of main air paths 43 are evenly distributed along the circumference on the vacuum channels of the carrier plate 4; the main air path 43 divides the annular vacuum channels of the carrier plate 4 into several arc-shaped branch air paths 44. The center of the radial direction here refers to the common center of the vacuum channels of the carrier plate 4. The main air path 43 connects all the annular vacuum channels of the carrier plate 4. Gas can be extracted or introduced through an air outlet. In the embodiment of the drawing, there are 3 vacuum channels of the carrier plate 4; there are also 3 branch air paths 44.

[0029] The depth of the main air path 43 is greater than the depth of the branch air path 44; the width of the main air path 43 is equal to the width of the branch air path 44. When extracting the gas inside the vacuum channel of the carrier plate 4, the air flow flows from the branch air path 44 to the main air path 43 and flows out from the main air path 43. If the depths of the main air path 43 and the branch air path 44 are the same, the gas extraction speed of the main air path 43 is greater than the gas extraction speed in the branch air path 44, and the adsorption force of the main air path 43 will be greater than the adsorption force of the branch air path 44. During the air extraction process, the adsorption between the carrier plate 4 and the base 2 is unstable. It may cause slight rotation or movement between the carrier plate 4 and the base 2, resulting in a change in the position of the carrier plate 4 and affecting the position stability of the wafer adsorbed on the carrier plate 4. Wafer processing belongs to a high-precision processing industry, and small errors will have a certain impact on the wafer processing results, ultimately affecting the product quality. In the present invention, the depth of the main air path 43 is greater than the depth of the branch air path 44. In the same time, the negative pressure generated in the main air path 43 and the branch air path 44 is roughly equal or the difference becomes smaller. During the adsorption process, the position of the carrier plate 4 is stable and the precision is high. Moreover, after adding the main branch, the gas flow efficiency is increased and the adsorption efficiency is higher. In fact, the effect of the present invention can be achieved as long as the cross-sectional area of the main air path 43 is greater than the cross-sectional area of the branch air path 44.

[0030] From the end close to the main air path 43 to the middle position of the branch air path 44, the depth of the branch air path 44 gradually becomes smaller. The closer to the main air path 43, the faster the gas extraction speed and the easier it is to generate negative pressure. The solution of the present invention can further reduce the uneven negative pressure on the branch air path 44.

[0031] The depth of one end of the main air path 43 close to the vacuum chamber 42 of the carrier plate is greater than that of the end far from the vacuum chamber 42 of the carrier plate. The air flow rate is faster at the position corresponding to the air outlet of the vacuum chamber 42 of the carrier plate on the base 2 near the vacuum chamber 42 of the carrier plate.

[0032] As Figures 1 - 9 shown, an easily replaceable high-precision silicon wafer carrier stage, the carrier stage includes a base 2 and a carrier plate 4 arranged on the base 2 by vacuum adsorption, and the base 2 and the carrier plate 4 are positioned by positioning pins; at least one annular vacuum channel for adsorbing the base 2 and the carrier plate 4 is arranged in the carrier stage, a vacuum chamber is also arranged in the central area of the carrier stage located in the vacuum channel, a porous ceramic layer 40 is arranged at the upper end of the carrier plate 4, and the upper end of the vacuum chamber is communicated with the porous ceramic; the lower ends of the vacuum channel and the vacuum chamber are respectively communicated with a main vacuum port 20 and a secondary vacuum port 21 arranged at the bottom of the base 2 through pipelines. The vacuum chamber enables the porous ceramic layer 40 to maintain a negative pressure state, thereby adsorbing the wafer thereon. The vacuum channel enables the base 2 and the carrier plate 4 to be tightly connected. The base 2 and the carrier plate 4 are fixed by vacuum adsorption, and only the corresponding carrier plate 4 needs to be replaced when processing wafers of other sizes, and it is convenient to replace the carrier plate 4. Here, the main vacuum port 20 and the secondary vacuum port 21 are only for distinguishing the two air outlets in name, and there is no actual primary-secondary relationship.

[0033] At least two concentric vacuum channels are arranged in the carrier stage, the cross-sectional shape of the vacuum chamber is circular, and the vacuum chamber and the vacuum channel are coaxially arranged; the vacuum channel and the vacuum chamber are not communicated.

[0034] The specific shape of the carrier plate 4 has been described in detail above. It will not be repeated here. A main vacuum pipeline is arranged at the position of the base 2 corresponding to the main air path 43 on the carrier plate 4 to communicate with the main vacuum port 20; a secondary vacuum pipeline 27 is arranged at the position of the base 2 corresponding to the vacuum chamber 42 of the carrier plate to communicate with the secondary vacuum port 21. In the existing structure of the carrier plate 4, only a plurality of annular vacuum channels of the carrier plate 4 are arranged, and the main air path 43 is not arranged. In the existing base 2, a vacuum pipeline is arranged. The vacuum pipeline communicates with each vacuum channel of the carrier plate 4. The air extraction speed is greater at the place close to the vacuum pipeline than at the place far from the vacuum pipeline, resulting in an unstable initial adsorption process. In the present invention, uniformly distributed main air paths 43 and branch air paths 44 are arranged; each main air path 43 communicates with its own vacuum pipeline. The adsorption process is uniform and stable. In addition, the depth of the main air path 43 in the present invention is greater than that of the branch air path 44, and in the same time, the negative pressure generated in the main air path 43 and the branch air path 44 is approximately equal or the difference becomes smaller. During the adsorption process, the position of the carrier plate 4 is stable and the precision is high.

[0035] On the upper surface of the base 2, corresponding to each vacuum channel of the carrier plate 4, a corresponding annular base vacuum channel 22 is provided. The main vacuum pipeline includes transverse vacuum pipelines 24 respectively arranged inside the base 2 corresponding to the positions of each main air passage 43. The transverse vacuum channels are communicated with the base vacuum channels 22 through longitudinal vacuum pipelines 25. Each transverse vacuum pipeline 24 is communicated with a longitudinal total vacuum pipeline 26, and the total vacuum pipeline is communicated with the main vacuum port 20. In the central area of the base vacuum channel 22 on the upper surface of the base 2, a base vacuum cavity 23 is also provided. The position of the base vacuum cavity 23 corresponds to the position of the carrier plate vacuum cavity 42. The base vacuum cavity 23 is directly communicated with the slave vacuum port 21 through a slave vacuum pipeline 27. Positioning holes 5 are also provided on the base 2. The base vacuum channels 22 and the vacuum channels of the carrier plate 4 together constitute the vacuum channels of the stage. The vacuum cavity of the base 2 and the vacuum cavity of the carrier plate 4 together constitute the vacuum cavity of the stage.

[0036] Further, between each transverse vacuum pipeline 24 and all the base vacuum channels 22, respective transverse vacuum pipelines 24 are provided.

[0037] The depth of one end of the main air passage 43 close to the carrier plate vacuum cavity 42 is greater than the depth of the end far from the carrier plate vacuum cavity 42. From the end close to the main air passage 43 to the middle position of the branch air passage 44, the depth of the branch air passage 44 gradually becomes smaller.

[0038] The upper and lower surface precision of the base 2 is at the micron level. The base 2 and the carrier plate 4 are both made of high-precision ceramic materials, which is convenient for sealing.

[0039] During specific implementation, place the carrier plate 4 on the base 2. After the positions correspond, insert a pin shaft into the positioning hole 5 for positioning. Then, extract gas through the main vacuum port 20 and the slave vacuum port 21, so that a vacuum area is formed in the vacuum channels and a negative pressure area is formed in the vacuum cavities. The vacuum environment in the vacuum channels makes the carrier plate 4 and the base 2 firmly adsorbed. The negative pressure area in the vacuum cavity makes the porous ceramic layer 40 evenly adsorb the silicon wafer. When wafers of different sizes need to be processed, only need to stop the vacuum environment and then remove the carrier plate 4. Then replace it with a carrier plate 4 with a porous ceramic layer 40 of other sizes.

[0040] The technical features of the above-described embodiments can be combined arbitrarily. As long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. Without departing from the overall concept of the present invention, according to the technical solution of the present invention and with equivalent substitution or change, and several changes and improvements made, it should also be regarded as the protection scope of the present invention.

Claims

1. A replaceable high-precision silicon wafer carrier, characterized in that: The stage includes a base and a carrier plate disposed on the base by means of vacuum adsorption. The base and the carrier plate are positioned by positioning pins; an annular vacuum channel for adsorbing the base and the carrier plate is provided inside the stage. A vacuum cavity is also provided in the central region of the vacuum channel inside the stage. A porous ceramic layer is provided at the upper end of the carrier plate, and the upper end of the vacuum cavity communicates with the porous ceramic; the lower ends of the vacuum channel and the vacuum cavity are respectively communicated through pipes with a main vacuum port and a secondary vacuum port provided at the bottom of the base; At least two concentric vacuum channels are provided inside the stage. The cross-sectional shape of the vacuum cavity is circular, and the vacuum cavity and the vacuum channel are coaxially arranged; the vacuum channel and the vacuum cavity are not communicated; A carrier plate vacuum cavity is also provided in the central region of the lower surface of the carrier plate corresponding to the vacuum channel of the carrier plate; positioning holes are provided at the lower end of the carrier plate; At least two annular carrier plate vacuum channels are provided on the lower surface of the carrier plate; the carrier plate vacuum channels are communicated through main air paths arranged along the radial direction; a plurality of main air paths are evenly distributed along the circumference on the carrier plate vacuum channels; the main air paths divide the annular carrier plate vacuum channels into several arc-shaped branch air paths; the depth of the main air paths is greater than the depth of the branch air paths; the width of the main air paths is equal to the width of the branch air paths; main vacuum pipelines are provided at positions corresponding to the main air paths on the base to communicate with the main vacuum port; secondary vacuum pipelines are provided at positions corresponding to the carrier plate vacuum cavity on the base to communicate with the secondary vacuum port; Corresponding annular base vacuum channels are provided on the upper surface of the base corresponding to each carrier plate vacuum channel. The main vacuum pipeline includes transverse vacuum pipelines respectively provided at positions corresponding to each main air path inside the base; the transverse vacuum pipelines are communicated with the base vacuum channels through longitudinal vacuum pipelines; each transverse vacuum pipeline is communicated with a longitudinal total vacuum pipeline, and the total vacuum pipeline is communicated with the main vacuum port; a base vacuum cavity is also provided in the central region of the upper surface of the base corresponding to the base vacuum channel; the position of the base vacuum cavity corresponds to the position of the carrier plate vacuum cavity; the base vacuum cavity is directly communicated with the secondary vacuum port through a secondary vacuum pipeline; positioning holes are also provided on the base; the depth of one end of the main air path close to the carrier plate vacuum cavity is greater than the depth of the end far from the carrier plate vacuum cavity; from the end close to the main air path to the middle position of the branch air path, the depth of the branch air path gradually becomes smaller.

2. The easy-to-replace high-precision silicon wafer carrier according to claim 1, wherein: The carrier plate is integrally sintered and formed; the lower end of the carrier plate is a ceramic main body; the carrier plate vacuum channel and the carrier plate vacuum cavity are not communicated.

3. The easy-to-replace high-precision silicon wafer carrier according to claim 1, characterized in that: Respective longitudinal vacuum pipelines are provided between each transverse vacuum pipeline and all the base vacuum channels.

4. The easily replaceable high-precision silicon wafer stage according to claim 1, wherein the upper and lower surface precisions of the base are at the micron level.

Images