TW202324624A - Ejector pin and wafer clamping device capable of ensuring tight clamping between the ejector pin and the wafer and also reducing internal stress generated by vibration in the radial direction of the wafer - Google Patents

Abstract

The present invention discloses an ejector pin, including: a casing provided with a protrusion on the top; and a clamping rod arranged inside the casing, wherein a top end of the clamping rod extends to the protrusion, and the clamping rod is configured to clamp a to-be-clamped workpiece through the protrusion; wherein the clamping rod is made of memory alloy. The present invention utilizes the property that the memory alloy returns to a trained shape at a phase transition temperature to press the memory alloy clamping rod into the ejector pin, such that the ejector pin can actively compensate its own thermal deformation in the high-temperature processing environment, so as to ensure tight clamping between the ejector pin and the wafer and also reduce internal stress generated by vibration in the radial direction of the wafer when the ejector pin clamps the wafer, thereby effectively improving the service life of the ejector pin.

Description

Ejector and wafer clamping device

The invention relates to the technical field of semiconductor device manufacturing, in particular to a thimble and a wafer clamping device.

In the semiconductor device manufacturing process, the wet process of the wafer is an important process that affects the product yield. In the current wet process, the wafer to be wet-etched or cleaned is generally fixed on the wafer chuck. The wafer chuck is provided with a thimble, and the wafer chuck clamps the wafer through the thimble and drives the wafer to rotate. At the same time, the chemical liquid sprayed from the nozzle above the wafer performs wet etching or cleaning on the surface of the wafer.

However, the long wet etching or cleaning process makes the thimble vulnerable to the following three aspects and reduces the service life of the thimble, as follows: First, when the thimble clamps the wafer, the clamped wafer will vibrate in the radial direction, therefore, there will be a certain mechanical load on the thimble in the radial direction of the wafer; Second, during the wet process on the surface of the wafer, some need to be carried out under certain high temperature conditions. The high temperature environment will cause thermal softening and thermal deformation of the ejector pins. Among them, thermal deformation of the ejector pins at high temperatures will cause As a result, there is a certain thermal load inside the thimble, and the thermal softening of the thimble will lead to a decrease in the elastic modulus of the material used for the thimble; Third, during the high-temperature cleaning process, the chemical liquid sprayed from the nozzle will be heated, and the high-temperature chemical liquid will cause certain chemical corrosion on the thimble.

Therefore, affected by the comprehensive effects of the above three aspects of mechanical load, thermal load and chemical corrosion, the thimble is prone to strength failure, which leads to the fracture of the thimble. In addition, the thermal softening of the thimble at high temperature leads to excessive deformation of the thimble, which will eventually lead to the inability of the thimble to effectively clamp the wafer, which in turn leads to instability of the chemical liquid film on the wafer surface, resulting in splashing of the chemical liquid.

To sum up, it is necessary to propose a novel thimble and wafer clamping device to solve the above problems.

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide an ejector pin and a wafer clamping device, aiming at solving the defects that traditional ejector pins are prone to breakage and thermal deformation when clamping a wafer.

To achieve the above purpose and other related purposes, the present invention provides a thimble, comprising: The shell is provided with a protrusion on the top; The clamping rod is arranged inside the housing. The top end of the clamping rod extends to the protrusion, and the workpiece to be clamped is clamped by the protrusion. The material of the clamping rod is memory alloy.

According to one embodiment of the present invention, the thimble also includes: The stepped hole is arranged inside the housing, the upper hole of the stepped hole extends to the inside of the protrusion, and the clamping rod is in interference fit with the upper hole of the stepped hole; The plug is arranged inside the housing and tightly fits with the lower hole of the stepped hole.

According to an embodiment of the present invention, the diameter of the upper hole of the stepped hole is smaller than the diameter of the lower hole.

According to an embodiment of the present invention, the memory alloy of the clamping rod is pre-trained so that when the temperature of the clamping rod exceeds the phase transition temperature of the memory alloy, the initial vertical state is deformed into a bent state toward the object to be clamped.

According to one embodiment of the present invention, when the temperature of the clamping rod exceeds the phase transition temperature of the memory alloy material, the bending value of the clamping rod is determined according to the deformation amount of the thermal deformation of the memory alloy and the displacement amount of the vibration of the part to be clamped. adjust.

According to an embodiment of the present invention, the material of the memory alloy is Nitinol, a two-way memory alloy.

According to an embodiment of the present invention, the casing is made of corrosion-resistant and high-temperature-resistant materials.

According to an embodiment of the present invention, the material of the plug is consistent with the material of the housing.

The present invention also provides a wafer clamping device, comprising: Wafer chuck for placing wafers; The above-mentioned thimble pins are arranged on the outer periphery of the wafer chuck, and are used to abut against the side wall of the wafer to clamp the wafer.

According to an embodiment of the present invention, there are multiple ejector pins, and the plurality of ejector pins are evenly distributed on the outer periphery of the wafer chuck.

As mentioned above, compared with the prior art, the present invention provides a thimble and wafer clamping device, which has the following beneficial effects: The thimble and wafer clamping device provided by the present invention utilize the characteristic that the memory alloy returns to the trained shape at the phase transition temperature, and press the clamping rod of the memory alloy material inside the thimble, so that the thimble can actively compensate in the high-temperature process environment It reduces its own thermal deformation, thereby ensuring the tight clamping between the thimble and the wafer, and also reducing the internal stress generated by the vibration of the thimble in the radial direction of the wafer when the thimble clamps the wafer, effectively improving the quality of the wafer. Service life of the clamping device.

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

See Figures 1 through 4B. It should be noted that the diagrams provided in this embodiment are only schematically illustrating the basic idea of the present invention, although only the components related to the present invention are shown in the diagrams rather than the number, shape and Dimensional drawing, the shape, quantity and proportion of each component can be changed arbitrarily during actual implementation, and the layout of the components may also be more complex.

The disclosed embodiment of the present invention provides a thimble 1 , which includes a housing 101 , a protrusion 102 and a clamping rod 104 . Wherein, the protrusion 102 is disposed on the top of the housing 101 , the clamping rod 104 is disposed inside the housing 101 , and the top end of the clamping rod 104 extends to the protrusion 102 , and the object to be clamped is clamped by the protrusion 102 .

Preferably, as shown in FIG. 1 and FIG. 2 , the thimble 1 may further include a stepped hole 103 and a plug 105 . Specifically, the stepped hole 103 is arranged inside the casing 101. As shown in FIG. The upper hole 1031 is an interference fit, the plug 105 is set inside the housing 101, and tightly fits with the lower hole 1032 of the stepped hole 103, the top end of the clamping rod 104 extends to the protrusion 102, and the clamping part is treated through the protrusion 102 For clamping.

The material of the clamping rod 104 is a memory alloy, wherein, when the temperature of the memory alloy material exceeds the phase transition temperature _Tc at which the memory alloy material undergoes phase transformation, the phase transformation between the austenite state and the martensite state can be realized . Therefore, the memory alloy is trained so that the memory alloy of the clamping rod 104 is pre-trained so that when the temperature of the clamping rod 104 exceeds the phase transition temperature _Tc of the memory alloy, it is deformed from the initial vertical state to the direction to be clamped. The bending state of the piece is used to clamp the piece to be clamped.

In this embodiment, the diameter of the upper hole 1031 of the stepped hole 103 is smaller than the diameter of the lower hole 1032 . A stepped hole 103 is provided inside the housing 101 , so that the interference fit between the clamping rod 104 and the upper hole 1031 can be easily realized. Since the clamping rod 104 is prone to buckling when it is pressed into the inside of the housing 101, the inside of the housing 101 is set as a stepped hole 103 with a smaller diameter of the upper hole 1031 and a larger diameter of the lower hole 1032, which can facilitate the smooth operation of the clamping rod 104. Press into the upper hole 1031, and interference fit with the upper hole 1031, and then use the plug 105 to press into the lower hole 1032, so that the plug 105 and the lower hole 1032 tightly fit to support the clamping rod on the top of the plug 105 104.

The disclosed embodiment of the present invention also provides a wafer clamping device, as shown in Figure 3, the wafer clamping device includes a thimble 1 and a wafer chuck 2, as shown in Figure 3, the wafer chuck 2 uses When placing the wafer w , the thimble pin 1 is arranged on the outer periphery of the wafer chuck 2 for abutting against the side wall of the wafer w to clamp the wafer w .

Wherein, in this embodiment, there are a plurality of thimble pins 1, and a plurality of thimble pins 1 are evenly distributed on the outer periphery of the wafer chuck 2. As shown in FIG. peripheral. According to the enlarged view of the dotted frame in FIG. 3 , it can be seen that the six thimbles 1 respectively bear against the side walls of the wafer w to jointly clamp the wafer w and prevent the wafer w from vibrating during the process.

In this embodiment, as shown in Figure 4A, before the wet process starts, the process temperature T is room temperature, and the process temperature T is lower than the phase transition temperature T _c at which the memory alloy material undergoes phase transition. At this time, the clamping rod The top of 104 is in vertical state.

As shown in Figure 4B, when the process temperature T of the wet process is gradually increased, the heat is conducted to the clamping rod 104 through the chemical liquid and the wafer w , so that the temperature of the clamping rod 104 itself rises and exceeds the phase of the memory alloy material. The phase change temperature T _c changes, and the top of the clamping rod 104 becomes its training shape, that is, the clamping rod 104 bends from the vertical state to the center of the wafer w , so as to drive the protrusion 102 toward the wafer w The direction of the center of the circle is bent to bear against the side wall of the wafer w , so as to compensate the amount of thermal deformation of the protrusion 102 of the thimble 1 at high temperature, thereby avoiding the thermal deformation of the thimble 1 under the high temperature process environment, and at the same time, offsetting the wafer The displacement of w vibrating in the radial direction ensures the stability of the clamping of the wafer w , thereby reducing the stress generated by the mechanical load on the thimble 1 and effectively improving the service life of the thimble 1 .

As shown in FIG. 4A , when the process temperature T of the wet process gradually returns to room temperature, the tops of the clamping rods 104 gradually return to the initial vertical state.

In this embodiment, the process temperature T of the wet process is 60°-170°. The material of memory alloy can be selected two-way memory alloy Nitinol, and the phase transition temperature _Tc of two-way memory alloy Nitinol is 90 °, and the fatigue life of two-way memory alloy Nitinol satisfies: the deformation amount of memory alloy Nitinol is 2 %, the number of deformations is 10 ⁵ times; when the deformation of memory alloy Nitinol is 0.5%, the number of deformations is 10 ⁷ times. However, it should be noted that when the two-way memory alloy Nitinol is placed in an environment of 250° for a long time, the strength of its plastic deformation memory recovery will be greatly reduced.

Specifically, the chemical composition and mechanical properties of two-way memory alloy Nitinol are shown in Table 1 and Table 2 respectively: Table 1 Chemical composition of two-way memory alloy Nitinol 56.2% Ni Ti C h o N 56.2% 43.7% ＜0.07% ＜0.005% ＜0.05% ＜0.05% Table 2 Mechanical properties of two-way memory alloy Nitinol temperature ( ^° C) Young's modulus (GPa) Yield limit (MPa) room temperature 11.6 200 60 15 260 170 twenty three 600

In this embodiment, when the clamping rod 104 is at a process temperature T exceeding the phase transition temperature _Tc at which the memory alloy material undergoes phase transition, the bending value of the clamping rod 104 is based on the deformation amount of the thermal deformation of the memory alloy and the wafer w The amount of displacement that vibrates in the radial direction is jointly adjusted.

In this embodiment, the clamping rod 104 is wrapped inside the casing 101, which effectively prevents the memory alloy material from being corroded by the external high-temperature chemical liquid. The casing 101 is made of corrosion-resistant and high-temperature-resistant materials, and the material of the plug 105 is consistent with that of the casing 101 to avoid corrosion by high-temperature chemical liquids.

The invention provides a thimble and a wafer clamping device, which utilizes the property that the memory alloy returns to a trained shape at a phase transition temperature, and presses a clamping rod of a memory alloy material into the thimble, so that the thimble can actively compensate in a high-temperature process environment It reduces its own thermal deformation, thereby ensuring the tight clamping between the thimble and the wafer, and also reducing the internal stress generated by the vibration of the thimble in the radial direction of the wafer when the thimble clamps the wafer, effectively improving the quality of the wafer. Service life of the clamping device.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended patent application scope.

1: ejector pin 101: shell 102: protrusion 103: stepped hole 1031: upper hole 1032: lower hole 104: clamping rod 105: plug 2: wafer chuck w : wafer

Fig. 1 is a schematic structural diagram of a thimble provided in an embodiment of the present invention; Fig. 2 is a sectional view of the ejector pin structure provided in the embodiment of the present invention; 3 is a schematic structural view of a wafer clamping device provided in an embodiment of the present invention; FIG. 4A is a cross-sectional view of the thimble provided in the embodiment of the present invention in an initial vertical state at room temperature; Fig. 4B is a cross-sectional view of the thimble provided in the embodiment of the present invention in a bent state above the critical state.

101: shell

102: Raised

103: Ladder hole

1031: upper hole

1032: Bottom hole

104: Clamping rod

105: Plug

Claims (10)

A thimble comprising: The shell is provided with a protrusion on the top; A clamping rod is arranged inside the housing, the top end of the clamping rod extends to the protrusion, and the object to be clamped is clamped by the protrusion, and the material of the clamping rod is memory alloy . The thimble as claimed in item 1, further comprising: A stepped hole is arranged inside the housing, the upper hole of the stepped hole extends to the inside of the protrusion, and the clamping rod is in interference fit with the upper hole of the stepped hole; The plug is arranged inside the housing and closely fits with the lower hole of the stepped hole. The thimble according to claim 2, wherein the diameter of the upper hole of the stepped hole is smaller than the diameter of the lower hole. The thimble according to claim 1, wherein the memory alloy of the clamping rod is pre-trained so that when the temperature of the clamping rod exceeds the phase transition temperature of the memory alloy, it is deformed from the initial vertical state to the Bending state of the clamp. The thimble according to claim 1 or 4, wherein, when the temperature of the clamping rod exceeds the phase transition temperature of the memory alloy material, the bending value of the clamping rod is based on the amount of thermal deformation of the memory alloy and the part to be clamped The displacement of the vibration is adjusted together. The thimble according to claim 1, wherein the memory alloy is made of two-way memory alloy Nitinol. The thimble according to claim 1, wherein the housing is made of corrosion-resistant and high-temperature-resistant materials. The thimble according to claim 2, wherein the material of the plug is consistent with the material of the housing. A wafer holding device, comprising: Wafer chuck for placing wafers; The ejector pin described in any one of claims 1 to 8 is arranged on the outer periphery of the wafer chuck, and is used to abut against the side wall of the wafer to clamp the wafer. The wafer clamping device according to claim 9, wherein there are a plurality of ejector pins, and the plurality of ejector pins are evenly distributed on the outer periphery of the wafer chuck.

Images