CN102809903B - Secondary pre-alignment device and pre-alignment method - Google Patents

Abstract

The invention relates to a secondary pre-alignment device. The secondary pre-alignment device is arranged between a movement station and a main substrate, is used for carrying out secondary pre-alignment on a wafer placed on the movement station and comprises three area array CCDs (Charge Coupled Device), three groups of optical path systems and an image processor. The three groups of optical path systems are used for respectively projecting three edge images of the wafer to the corresponding area array CCDs; a light source required by the three groups of optical path systems is arranged outside the movement station; the three area array CCDs are connected with the image processor; and the image processor is used for processing wafer edge image information from the three area array CCDs and then calculating the residual eccentric deviation of the wafer. A direct irradiation principle is adopted and the light source and the area array CCDs are respectively arranged at both sides of the wafer, so that not only is the accuracy higher, but also the secondary pre-alignment device is difficult to influence by the installing angle; and moreover, the design optical path is simple and the light energy dissipation is low. Moreover, the light source is arranged far away from key parts sensitive to a heat source, such as a projection objective, an objective, the main substrate, the movement station and the like, so that the performance stability of the secondary pre-alignment device is improved and the alignment accuracy is further improved.

Description

Secondary prealignment device and alignment methods

Technical field

The present invention relates to semiconductor lithography field, particularly relate to a kind of wafer secondary alignment device and alignment methods thereof.

Background technology

At present, along with constantly reducing of litho machine critical size, the requirement of litho machine Inner-world is also improved constantly, wafer prealignment device is placed on the external world, by transmission manipulator, wafer is put into Inner-world, measure by secondary prealignment measurement mechanism the remnants bias deflection that wafer arrives Inner-world, the mode allowing sports platform compensate becomes a kind of development trend.Wafer is transferred to sports platform process from film magazine, eccentric large about 10 μm after prealignment, deflection is large about 150 μ rad, the edge of wafer is made up of with the breach or flat limit playing orientation the circular arc of the overwhelming majority, after completing centering orientation, transfer to the handing-over position above sports platform again, a part of positioning precision can be lost with the handing-over of the handing-over sheet mechanical arm on sports platform, and, prealignment is in the external world, sports platform is in Inner-world, introduce the skew of the inside and outside world, eccentric deflection is caused to become large, for making up these losses and improving positioning precision further, wafer also will carry out secondary prealignment in handing-over position.By secondary prealignment, obtain remnants bias and the deflection of wafer, then by sports platform, remaining bias and deflection are compensated.

Along with the raising of litho machine precision, the requirement of each parts of litho machine to environment is also more and more higher, typically, projection objective is just very sensitive to the temperature field of surrounding, Fang Jing on sports platform, the light path of interferometer, the wafer distortion on sports platform is all subject to the impact of temperature field surrounding.Therefore, if be arranged on main substrate by thermal source, near the sensor of projection objective with other subsystems, very large impact can be caused on temperature field surrounding.If be arranged on sports platform by thermal source equally, very large impact can be caused on the temperature field of sports platform.

Therefore, how to provide that a kind of can to reduce thermal source to the secondary prealignment device of the impact of litho machine Inner-world and alignment methods be those skilled in the art's technical matterss urgently to be resolved hurrily.

Summary of the invention

The object of the present invention is to provide a kind of secondary prealignment device and alignment methods thereof, by the critical component of thermal source stow away from heat sensitivity is reduced the impact of thermal source on litho machine Inner-world.

To achieve the above object, the present invention adopts following technical scheme:

A kind of secondary prealignment device, be located between sports platform and main substrate, for carrying out secondary prealignment to the wafer be placed on sports platform, comprise three area array CCDs, three groups of light path systems and an image processor, three place's edge images of wafer are projected to corresponding area array CCD by described three groups of light path systems respectively, light source needed for three groups of light path systems is arranged on the outside of sports platform, described three area array CCDs are connected with described image processor, the remnants bias deflection of wafer is obtained after the crystal round fringes image information of described image processor process from described three area array CCDs.

Preferably, often organize light path system and comprise the first catoptron received from the light beam of light source, described first catoptron and described area array CCD correspondence are located at the both sides up and down at edge, described wafer one place, and the edge image of wafer is projected to corresponding area array CCD by described light beam after the first catoptron.The described first catoptron inside being distributed in described sports platform triangular in shape, the below of described main substrate is located at by corresponding the first respective catoptron of described area array CCD.

Preferably, often organize light path system and comprise the first catoptron and the second catoptron that receive from the light beam of light source, described first catoptron and the second catoptron correspondence are located at the both sides up and down at edge, described wafer one place, and the edge image of wafer is projected to corresponding area array CCD by described light beam successively after the first catoptron and the second catoptron.The described first catoptron inside being distributed in described sports platform triangular in shape, the below of described main substrate is located at by corresponding each first catoptron of described second catoptron, and described area array CCD is located at the side of described second catoptron respectively.Described area array CCD is located on the battle array installing plate of face respectively, and the below that described battle array installing plate is fixedly arranged on described main substrate one end makes described area array CCD relative with described second catoptron.

Preferably, often organize light path system and also comprise described light source and beam path alignment mechanism respectively, described light beam is sent by light source and obtains after the process of beam path alignment mechanism.

Preferably, three groups of light path systems share a light source and a beam path alignment mechanism, described three groups of light path systems are first group of light path system, second group of light path system and the 3rd group of light path system, and three corner reflectors that first group of light path system also comprises three corner reflectors of 2/3 transmittance, second group of light path system also comprises 1/2 transmittance, the 3rd group of light path system also comprises the 3rd catoptron; The light beam that described light source sends becomes through beam path alignment mechanism three corner reflectors being mapped to 2/3 transmittance after parallel beam, wherein 1/3 light beam carries out launching as the light beam needed for first group of light path system and 2/3 light beam is transmitted to three corner reflectors of 1/2 transmittance by three corner reflectors of described 2/3 transmittance, the half light beam received carries out reflecting the light beam as needed for second group of light path system by three corner reflectors of described 1/2 transmittance, and second half is transmitted to the 3rd catoptron as the light beam needed for the 3rd group of light path system.

The invention also discloses a kind of secondary pre-alignment method, comprise the steps:

The first step, wafer arrives secondary prealigned position after prealignment;

Second step, adopts secondary prealignment device as above, makes area array CCD gather three place's edge image information of wafer respectively, and by edge image information transmission to described image processor;

3rd step, described image processor process is from the actual home position obtaining wafer after the described edge image information of described area array CCD, and the standard home position of the actual home position of wafer with the wafer pre-set in the image processor is contrasted, obtain the remnants bias deflection of wafer;

4th step, micropositioner carries out fine motion compensation according to remaining eccentric deflection;

5th step, by wafer transfer on micropositioner, prepares exposure.

Preferably, in 3rd step, the actual home position of described acquisition wafer realizes as follows: described image processor calculates the actual edge image information of each area array CCD collection respectively by following equation, then the three place's actual edge image informations gathered by process three area array CCDs obtain the actual home position of wafer, and described equation is as follows:

$\left[\begin{array}{c}{x}_0\\ y_0\end{array}\right]=\left[\begin{array}{cc}1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2}& -{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\·{\mathrm{Ry}}_0}{2}\\ {\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\·{\mathrm{Ry}}_0}{2}& 1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2}\end{array}\right](\left[\begin{array}{c}{x}_0^{\′}\\ y_0^{\′}\end{array}\right]-\left[\begin{array}{c}{\mathrm{offset}}_{x0}\\ {\mathrm{offset}}_{y0}\end{array}\right])$

$=\left[\begin{array}{c}(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2})x_0^{\′}+(-{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\·{\mathrm{Ry}}_0}{2})y_0^{\′}-{\mathrm{offset}}_{x0}\\ ({\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\·{\mathrm{Ry}}_0}{2})x_0^{\′}+(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2})y_0^{\′}-{\mathrm{offset}}_{y0}\end{array}\right]$

$=\left[\begin{array}{c}{\mathrm{ax}}_0^{\′}+{\mathrm{by}}_0^{\′}+c\\ {\mathrm{dx}}_0^{\′}+{\mathrm{ey}}_0^{\′}+f\end{array}\right]$

Wherein, offsetx0, offsety0 refer to the position of the projection of the initial point of CCD coordinate system in SPCS coordinate system, and wherein, Rx0, Ry0, Rz0 represent the anglec of rotation of CCD coordinate system respectively about X, Y, Z in SPCS coordinate system respectively; On wafer in CCD visual field an edge, place the projection coordinate of CCD coordinate system be (x ' ₀, y ' ₀), described SPCS coordinate system is the frame of reference that the bias of wafer is biased as the position of 0.

Preferably, in second step, secondary prealignment device gathers three place's edge image information of wafer by three area array CCDs, and one of them area array CCD gathers the breach information of wafer simultaneously.

Beneficial effect of the present invention is as follows:

Secondary prealignment device of the present invention and alignment methods thereof, by the light source needed for three groups of light path systems being arranged on the outside of sports platform, make light source as thermal source away from the critical component to thermal source sensitivity such as projection objective setting, object lens, main substrate and sports platform, the temperature field surrounding of light source on the sensor of projection objective and other subsystems is avoided to cause very large impact, improve the stability of this secondary prealignment device, improve alignment precision further.In addition, respectively three place's edge images of wafer are projected to corresponding area array CCD by three groups of light path systems, have employed direct-injection type principle, light source and CCD are divided the both sides being in wafer, not only precision is higher, and is not subject to the impact of setting angle, and design light path is simple, luminous energy dissipates little.

Accompanying drawing explanation

Secondary prealignment device of the present invention is provided by following embodiment and accompanying drawing.

Fig. 1 is the structural representation of embodiment 1;

A wherein road light path system path schematic diagram of Fig. 2 embodiment 1;

Fig. 3 is the cross-sectional schematic of the sports platform of embodiment 1;

Fig. 4 is the structural representation of a right angle circular hole of the motion platform of embodiment 1;

Fig. 5 is the sports platform of embodiment 1 and the schematic top plan view of light source bracing frame;

Fig. 6 is three area array CCDs of embodiment 1 and the schematic diagram of image processor;

The position relationship of the coordinate system of Fig. 7 secondary prealignment coordinate system and three area array CCDs;

Fig. 8 is the structural representation of embodiment 2;

Fig. 9 is wherein one group of light path system path schematic diagram of embodiment 2;

Figure 10 is the schematic top plan view of sports platform and light source bracing frame in embodiment 3;

Figure 11 is the structural representation of embodiment 4;

Figure 12 is the schematic top plan view of sports platform and light source bracing frame in embodiment 4;

Figure 13 is wherein one group of light path system path schematic diagram of embodiment 4;

Embodiment

Below will be described in further detail secondary prealignment device of the present invention.

Below with reference to accompanying drawings the present invention is described in more detail, which show the preferred embodiments of the present invention, should be appreciated that those skilled in the art can revise the present invention described here and still realize advantageous effects of the present invention.Therefore, following description is appreciated that extensively knowing for those skilled in the art, and not as limitation of the present invention.

In order to clear, whole features of practical embodiments are not described.They in the following description, are not described in detail known function and structure, because can make the present invention chaotic due to unnecessary details.Will be understood that in the exploitation of any practical embodiments, a large amount of implementation detail must be made to realize the specific objective of developer, such as, according to regarding system or the restriction about business, change into another embodiment by an embodiment.In addition, will be understood that this development may be complicated and time-consuming, but be only routine work to those skilled in the art.

In addition, first, second, third catoptron related in following embodiment of the present invention illustrates for 45 degree of three corner reflector, but not limit the present invention with this, in 45 degree of three corner reflector, there is identical reflection function as long as have and the catoptron in the corresponding CCD face battle array of incident beam reflection all can be belonged to the scope that the present invention contains.

For making object of the present invention, feature becomes apparent, and is further described the specific embodiment of the present invention below in conjunction with accompanying drawing.It should be noted that, accompanying drawing all adopts the form that simplifies very much and all uses non-ratio accurately, only in order to object that is convenient, the aid illustration embodiment of the present invention lucidly.

Embodiment 1

Refer to Fig. 1-Fig. 7, this secondary prealignment device, be located between sports platform 101 and main substrate 102, for carrying out secondary prealignment to the wafer 103 be placed on sports platform 101, described wafer 103 is placed on sports platform 101.Main substrate 102 is provided with projection objective 117, and the top of projection objective 117 is provided with mask platform 118.Described sports platform 101 is arranged on marble slab 119.

This secondary prealignment device comprises three area array CCDs 104 (comprising CCD1, CCD2 and CCD3), three groups of light path systems (comprising first group of light path system, second group of light path system and the 3rd group of light path system) and an image processor 105.Described area array CCD 104 full name refers to Charge-coupled device, refers to charge-coupled image sensor.Edge images different for three places of wafer is projected to corresponding area array CCD 104 by described three groups of light path systems respectively.That is, light source and area array CCD are divided in the light path system of the correspondence of the both sides being in wafer, have employed direct-injection type principle, not only precision is higher, and is not subject to the impact of setting angle, and design light path is simple, and luminous energy dissipates little.

Described three area array CCDs 104 are connected with described image processor 105 respectively, and described image processor 105 obtains the physical location of wafer 103 and the remnants bias deflection of wafer after processing three place's crystal round fringes image informations from described three area array CCDs 104.

Preferably, often organize light path system and comprise the one 45 degree of three corner reflector 106 received from the light beam of light source, described one 45 degree of three corner reflector 106 and described area array CCD 104 correspondence are located at the both sides up and down at edge, described wafer 103 1 place, described light beam after the one 45 degree of three corner reflector 106 by the edge image information projection of wafer 103 to corresponding area array CCD 104.Described one 45 degree of three corner reflector 106 inside being distributed in described sports platform triangular in shape, corresponding the one 45 degree of three respective corner reflector 106 of described area array CCD is located at the below of described main substrate 102.

Light source needed for described three groups of light path systems is disposed on the outside of sports platform.By the light source needed for three groups of light path systems being arranged on the outside of sports platform, make light source as thermal source away from the critical component to thermal source sensitivity such as projection objective setting, object lens, main substrate and sports platform, the enclose temperature field of light source on the sensor of projection objective and other subsystems is avoided to cause very large impact, improve the stability of this secondary prealignment device, improve alignment precision further.

In the present embodiment, often organize light path system and also comprise light source 107 and beam path alignment mechanism 108 respectively, described light beam is sent by light source 107 and obtains after beam path alignment mechanism 108 processes.Described light source 107 is arranged through the outside that light source mounting bracket 109 is arranged on sports platform 101.

That is, often organize light path system and comprise light source 107, beam path alignment mechanism the 108, the 1 degree of three corner reflectors 106 respectively, to be sent by light source 107 and after beam path alignment mechanism 108 processes, by the area array CCD 104 of the edge image information projection of wafer 103 to correspondence after described one 45 degree of three corner reflector reflection.

Described light source 107 is arranged on light source respectively and installs on bracing frame 109.The wavelength requirement of the light beam of light source 107 is the non-sensitive light of photoresist, and do not affect exposure, the LED light source of such as 610nm ~ 650nm, the intensity of light source is adjustable.Described light source 107 is consistent respectively with the mounting interface of light source mounting bracket 109, can realize the adjustment in Rz, Rx direction, to ensure that the light beam of three light sources 107 penetrates on a surface level.Light source is installed on bracing frame 109 framework mounted externally.The power summation of three light sources should be less than 10W.

The light that described beam path alignment mechanism 108 realizes penetrating from light source 107, after collimation mechanism process, penetrates directional light.The homogeneity of the directional light that described beam path alignment mechanism 108 penetrates is less than < 5%, and spot diameter is greater than 5mm, and when ensureing the drift of the inside and outside world, the movement of hot spot can not affect measurement.

Described sports platform 101 can carry wafer 103 and move between handing-over position and exposure position.Sports platform 101 forms by realizing the coarse motion platform 111 of sports platform Long Distances motion, the micropositioner 112 realizing the high-accuracy fine motion of little stroke and the handing-over sheet mechanical arm 113 be loaded on coarse motion platform 111.Wafer 103 is after prealignment device prealignment completes, sports platform 101 moves to handing-over position, by transmission manipulator 114, wafer 103 being moved to sports platform 101 joins above position, the handing-over sheet mechanical arm 113 of sports platform 101 can rise and join wafer 103 with transmission manipulator 114, after having joined, handing-over sheet mechanical arm 113 is raised in most significant digit, prepares to carry out secondary prealignment and takes pictures.

In the present embodiment, described one 45 degree of three corner reflector 106 inside being distributed in described sports platform 101 triangular in shape.Concrete structure is as follows: sports platform 101 has at least three right angle circular holes, and each right angle circular hole is made up of with the vertical circular hole 116 of micropositioner 112 the horizontal circular hole 115 of coarse motion platform 111, and right angle is provided with the one 45 degree of three corner reflector 106.Light beam enters from the horizontal circular hole 115 of coarse motion platform 111, reflects through the one 45 degree of three corner reflector 106, penetrates from the vertical circular hole 116 of micropositioner 112; The diameter of described right angle circular hole is not less than 5mm, one 45 degree of three corner reflector 106 is fixedly mounted on coarse motion platform 111, requires that installation level will ensure be loaded on the handing-over sheet mechanical arm 113 on coarse motion platform 111 due to caused sag of conducting oneself with dignity higher than wafer 103.When sports platform 101 moves to handing-over position, light penetrates from light source 107, by beam path alignment mechanism 108, injection parallel beam, enter the light beam of the horizontal circular hole 115 of coarse motion platform 111, be injected into the one 45 degree of three corner reflector 106 being arranged on sports platform 101, after reflection, light beam is through the vertical circular hole 16 of micropositioner 112, handing-over sheet mechanical arm 113 on segment beam passive movement platform 101 hands over the wafer 3 of absorption to shelter from, another part light beam is mapped on a corresponding area array CCD 104, and area array CCD 104 defines the crystal round fringes pattern that light and shade is clearly demarcated.Wafer 3 is handed off to the handing-over sheet mechanical arm 113 of sports platform 101 from the external world by mechanical transfer hand 114, and the Directional Sign of wafer 103 at least will be placed in the visual field of one of them area array CCD 104.

And corresponding the one 45 degree of three respective corner reflector 106 of described area array CCD 104 is located at the below of described main substrate 102.The visual field of described area array CCD 104 is 4mm*4mm, and pixel resolution is 4um, and data export the output format for 8/10/12bit.Three area array CCDs 104 are arranged on main substrate 3 bottom in triangle distribution, the inclination of three area array CCD 104 installations will ensure that the information of crystal round fringes can correctly be imaged in the visual field of area array CCD 104, light beam is after the right angle circular hole injection of sports platform 101, part is blocked by the edge of wafer 103, the picture of the crystal round fringes image information with correspondence is formed respectively on three area array CCDs, this crystal round fringes image information is sent to image processor 105 by area array CCD, image processor 105 receives the edge image information from three area array CCDs 104, one of them picture is with notched wafer information and a crystal round fringes image information, second picture is with another crystal round fringes image information, 3rd picture is with another crystal round fringes image information.As shown in Figure 6, three area array CCDs 104 gather crystal round fringes image information, identify three place's crystal round fringes image informations and just this crystal round fringes image information be transferred to this image processor 105, described image processor 105, according to three crystal round fringes image informations, calculates the physical location in the center of circle of wafer and the remnants bias deflection of wafer 103.

Adopt the secondary pre-alignment method of above-mentioned secondary prealignment device, comprise the steps:

The first step, wafer 103 arrives secondary prealigned position after prealignment.Detailed process is as follows: after wafer 103 completes prealignment on prealignment device, through transmission manipulator 114, wafer 103 is moved to above sports platform 101, sports platform 101 moves to handing-over position simultaneously, handing-over sheet mechanical arm 113 moves to the height preparing handing-over, handing-over sheet mechanical arm 113 carries out wafer 103 from transmission manipulator 114 and joins, handing-over sheet mechanical arm 113 is raised to most significant digit with wafer 103, and transmission manipulator 114 exits from handing-over position.

Second step, adopts secondary prealignment device as above, makes area array CCD 104 gather the edge image information (different edges, three places circular arc image) of wafer respectively, and by edge image information transmission to described image processor 105.Preferably, in second step, secondary prealignment device gathers the edge image information of wafer by three area array CCDs 104, and one of them area array CCD 104 gathers the breach information of wafer simultaneously.

3rd step, described image processor 105 obtains the actual home position of wafer 103 after processing the described edge image information from described area array CCD 104, and the standard home position of the actual home position of wafer 103 with the wafer 103 be set in advance in image processor 105 is contrasted, obtain the remnants bias deflection of wafer 103.Particularly, in the third step, the actual home position of described acquisition wafer realizes by the following method: first, and described image processor 105 calculates the actual edge image information of each area array CCD 104 collection by following equation; Then, three place's actual edge image informations by being gathered by process three area array CCDs 104 obtain the actual home position of wafer 103.Because circumferentially 3 can be determined its center of circle easily, be routine techniques means, do not repeat them here.Described equation is as follows:

$\left[\begin{array}{c}{x}_0\\ y_0\end{array}\right]=\left[\begin{array}{cc}1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2}& -{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}\\ {\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}& 1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2}\end{array}\right](\left[\begin{array}{c}{x}_0^{\&prime;}\\ y_0^{\&prime;}\end{array}\right]-\left[\begin{array}{c}{\mathrm{offset}}_{x0}\\ {\mathrm{offset}}_{y0}\end{array}\right])$

$=\left[\begin{array}{c}(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2})x_0^{\&prime;}+(-{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})y_0^{\&prime;}-{\mathrm{offset}}_{x0}\\ ({\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})x_0^{\&prime;}+(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2})y_0^{\&prime;}-{\mathrm{offset}}_{y0}\end{array}\right]$

$=\left[\begin{array}{c}{\mathrm{ax}}_0^{\&prime;}+{\mathrm{by}}_0^{\&prime;}+c\\ {\mathrm{dx}}_0^{\&prime;}+{\mathrm{ey}}_0^{\&prime;}+f\end{array}\right]$

Wherein, offsetx0, offsety0 refer to the position of the projection of the initial point of CCD coordinate system in SPCS coordinate system, and wherein, Rx0, Ry0, Rz0 represent the anglec of rotation of CCD coordinate system respectively about X, Y, Z in SPCS coordinate system respectively; On wafer in CCD visual field an edge, place the projection coordinate of CCD coordinate system be (x ' ₀, y ' ₀), described SPCS coordinate system is the frame of reference that the bias of wafer is biased as the position of 0.

The derivation of aforesaid equation is as follows: owing to always there is various alignment error when installing, and such as light source is installed bracing frame 109 and be there is certain inclination and rotate; It is not complete level that three the one 45 degree of three corner reflectors 106 of sports platform 1 are installed, the installation site of three area array CCDs 104 on main substrate 102 is not complete and design coincides, and there is certain inclination, these errors can affect the value of eccentric deflection.When each mechanical hardware is safeguarded, need the repeatability ensureing these alignment errors, therefore must set up the data that secondary prealignment model carrys out the wafer 3 edge image information that correcting measuring obtains.Set up and head on wafer 3 be in most significant digit to join sheet mechanical arm 113, and think that the position that now wafer 3 bias is biased as 0 is the frame of reference, i.e. secondary prealignment coordinate system (SPCS).

An edge, place (referring to a point) on wafer 3 in CCD1 visual field CCD1 coordinate system projection coordinate for (x ' ₀, y ' ₀), on the wafer 3 in CCD2 visual field another place edge the projection coordinate of CCD2 coordinate system be (x ' ₁, y ' ₁), on the wafer 3 in CCD3 visual field another place edge the projection coordinate of CCD3 coordinate system be (x ' ₂, y ' ₂).And these 3 under SPCS coordinate system corresponding invocation point be (x ₀, y ₀), (x ₁, y ₁), (x ₂, y ₂).According to datum transformation:

$P_{\mathrm{SPCS}}=S\&CenterDot;(P_{\mathrm{CCDCS}}-\left[\begin{array}{c}X\\ Y\end{array}\right])$

Wherein: for the rotation transition matrix of SPCS and CCD coordinate system, wherein RX, Ry, Rz are respectively CCD coordinate system respectively about X-axis in SPCS coordinate system, Y-axis, the anglec of rotation of Z axis; PSPCS is the coordinate of a point under SPCS coordinate system on the edge on wafer 3, P _cCDCSfor the coordinate figure that this point on wafer 3 projects under CCD coordinate system, for the position that the initial point of CCD coordinate system projects at SPCS coordinate system.

Therefore, the equation from the position each area array CCD to the edge image information (data) of actual wafer 3 can be set up.

$\left[\begin{array}{c}{x}_0\\ y_0\end{array}\right]=\left[\begin{array}{cc}1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2}& -{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}\\ {\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}& 1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2}\end{array}\right](\left[\begin{array}{c}{x}_0^{\&prime;}\\ y_0^{\&prime;}\end{array}\right]-\left[\begin{array}{c}{\mathrm{offset}}_{x0}\\ {\mathrm{offset}}_{y0}\end{array}\right])$

$=\left[\begin{array}{c}(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2})x_0^{\&prime;}+(-{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})y_0^{\&prime;}-{\mathrm{offset}}_{x0}\\ ({\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})x_0^{\&prime;}+(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2})y_0^{\&prime;}-{\mathrm{offset}}_{y0}\end{array}\right]$

$=\left[\begin{array}{c}{\mathrm{ax}}_0^{\&prime;}+{\mathrm{by}}_0^{\&prime;}+c\\ {\mathrm{dx}}_0^{\&prime;}+{\mathrm{ey}}_0^{\&prime;}+f\end{array}\right]$

4th step, wafer 103 is handed off on micropositioner 12 by handing-over sheet mechanical arm 13, and micropositioner 112 carries out fine motion compensation according to remaining eccentric deflection.

5th step, is transferred to wafer 103 on micropositioner 112, prepares exposure.

Embodiment 2

The difference of the present embodiment and embodiment 1 is:

Refer to Fig. 8-Fig. 9, in Fig. 8 and Fig. 9,218-mask platform, 217-projection objective, 220-the 2 45 degree of three corner reflectors, 202-main substrate, 204-area array CCD, 203-wafer, 201-sports platform, 219-marble slab, 224-face battle array installing plate.The difference of the present embodiment and embodiment 1 is: often organize light path system and comprise the one 45 degree of three corner reflector 206 and the 2 45 degree of three corner reflector 220 that receive from the light beam of light source, described one 45 degree of three corner reflector 206 and the 2 45 degree of three corner reflector 220 correspondence are located at the both sides up and down at edge, described wafer 203 1 place, and the edge image of wafer 3 is projected to corresponding area array CCD 204 by described light beam successively after the one 45 degree of three corner reflector 206 and the 2 45 degree of three corner reflector 220.Described one 45 degree of three corner reflector 206 inside being distributed in described sports platform 201 triangular in shape, corresponding each one 45 degree of three corner reflector 206 of described 2 45 degree of three corner reflector 220 is located at the below of described main substrate 202, and described area array CCD 204 is located at the side of described 2 45 degree of three corner reflector 220 respectively.In the present embodiment, described area array CCD 204 is located on described battle array installing plate 224 respectively, and the below that described battle array installing plate 224 is fixedly arranged on described main substrate 202 one end makes described area array CCD 204 relative with described 2 45 degree of three corner reflector 220.Described battle array installing plate 224 adopts heat-barrier material, thus the heat stoping area array CCD 204 to send better is delivered to these thermal source sensitive keys parts of main substrate 202, and then improves the alignment precision of this secondary prealignment device.

Embodiment 3

Refer to Figure 10, Tu10Zhong, 301-sports platform, 306-the one 45 degree of three corner reflectors, 307-light source, 308-beam path alignment mechanism, 309-light source mounting bracket, 314-mechanical transfer hand, 317-projection objective, 319-marble slab.The difference of the present embodiment and embodiment 1 is: described three groups of light path systems are first group of light path system, second group of light path system and the 3rd group of light path system, three groups of light path systems share a light source 307 and a beam path alignment mechanism 308, and three corner reflectors the 322, three group of light path system that three corner reflectors, 321, second group of light path system that first group of light path system also comprises 2/3 transmittance also comprises 1/2 transmittance also comprises the 3 45 degree of three corner reflector 323.Described light source 307 is arranged on the outside of sports platform by light source mounting bracket 309, thus makes light source as one of thermal source away from sports platform 301 and projection objective 317, thus improves alignment precision.The light beam that described light source 307 sends becomes through beam path alignment mechanism 308 three corner reflectors 321 being mapped to 2/3 transmittance after parallel beam, wherein 1/3 light beam carries out launching three corner reflectors 322 being transmitted to 1/2 transmittance as the light beam needed for first group of light path system and by 2/3 light beam by three corner reflectors 321 of described 2/3 transmittance, the half light beam received carries out reflecting the light beam as needed for second group of light path system by three corner reflectors 322 of described 1/2 transmittance, and second half is transmitted to the 3 45 degree of three corner reflector 323 as the light beam needed for the 3rd group of light path system.

Embodiment 4

Refer to Figure 11-Figure 13,401-sports platform, 402-main substrate, 403-wafer, 404-area array CCD 406-the one 45 degree of three corner reflectors, 407-light source, 408-beam path alignment mechanism, 409-light source mounting bracket, 414-mechanical transfer hand, 417-projection objective, 418-mask platform, 419-marble slab, 420-the 2 45 degree of three corner reflectors, 424-face battle array installing plate.

The difference of the present embodiment and embodiment 1 is:

Often organize the one 45 degree of three corner reflector 406 and the 2 45 degree of three corner reflector 420 that light path system also comprises receiving beam, described one 45 degree of three corner reflector 406 and the 2 45 degree of three corner reflector 420 correspondence are located at the both sides up and down at edge, described wafer 403 1 place, and the edge image of wafer 3 is projected to corresponding area array CCD 404 by described light beam successively after the one 45 degree of three corner reflector 406 and the 2 45 degree of three corner reflector 420.Described one 45 degree of three corner reflector 406 inside being distributed in described sports platform 401 triangular in shape, corresponding each one 45 degree of three corner reflector 406 of described 2 45 degree of three corner reflector 420 is located at the below of described main substrate 402, and described area array CCD 404 is located at the side of described 2 45 degree of three corner reflector 420 respectively.In the present embodiment, described area array CCD 404 is located on described battle array installing plate 424 respectively, and the below that described battle array installing plate 424 is fixedly arranged on described main substrate 402 one end makes described area array CCD 404 relative with described 2 45 degree of three corner reflector 420.Described battle array installing plate 424 adopts heat-barrier material, thus the heat stoping area array CCD 404 to send better is delivered to these thermal source sensitive keys parts of main substrate 402, and then improves the alignment precision of this secondary prealignment device.

And described three groups of light path systems (first group of light path system, second group of light path system and the 3rd group of light path system) light source 407 and a beam path alignment mechanism 408, and three corner reflectors the 422, three group of light path system that three corner reflectors, 421, second group of light path system that first group of light path system also comprises 2/3 transmittance also comprises 1/2 transmittance also comprises the 3 45 degree of three corner reflector 423.Described light source 407 is arranged on the outside of sports platform by light source mounting bracket 409, thus makes light source as one of thermal source away from sports platform 401 and projection objective 417, thus improves alignment precision.The light beam that described light source 407 sends becomes through beam path alignment mechanism 408 three corner reflectors 421 being mapped to 2/3 transmittance after parallel beam, wherein 1/3 light beam carries out launching three corner reflectors 422 being transmitted to 1/2 transmittance as the light beam needed for first group of light path system and by 2/3 light beam by three corner reflectors 421 of described 2/3 transmittance, the half light beam received carries out reflecting the light beam as needed for second group of light path system by three corner reflectors 422 of described 1/2 transmittance, and second half is transmitted to the 3 45 degree of three corner reflector 423 as the light beam needed for the 3rd group of light path system.

In sum, secondary prealignment device of the present invention and alignment methods thereof, by the light source needed for three groups of light path systems being arranged on the outside of sports platform, make light source as thermal source away from the critical component to thermal source sensitivity such as projection objective setting, object lens, main substrate and sports platform, the temperature field surrounding of light source on the sensor of projection objective and other subsystems is avoided to cause very large impact, improve the stability of this secondary prealignment device, improve alignment precision further.In addition, respectively three place's edge images of wafer are projected to corresponding area array CCD by three groups of light path systems, have employed direct-injection type principle, light source and CCD are divided the both sides being in wafer, not only precision is higher, and is not subject to the impact of setting angle, and design light path is simple, luminous energy dissipates little.

Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.

Claims (9)

1. a secondary prealignment device, be located between sports platform and main substrate, for carrying out secondary prealignment to the wafer be placed on described sports platform, it is characterized in that, comprise three area array CCDs, three groups of light path systems and an image processor, three place's edge images of wafer are projected to corresponding area array CCD by described three groups of light path systems respectively, light source needed for described three groups of light path systems is arranged on the outside of described sports platform, described three area array CCDs are connected with described image processor, the remnants bias deflection of described wafer is calculated after the crystal round fringes image information of described image processor process from described three area array CCDs, often organize light path system and comprise the first catoptron and the second catoptron that receive from the light beam of described light source, described first catoptron and the second catoptron correspondence are located at the both sides up and down at edge, described wafer one place, and the edge image of wafer is projected to corresponding area array CCD by described light beam successively after the first catoptron and the second catoptron, the described first catoptron inside being distributed in described sports platform triangular in shape, the below of described main substrate is located at by corresponding each first catoptron of described second catoptron, and described area array CCD is located at the side of described second catoptron respectively, described area array CCD is located on the battle array installing plate of face respectively, and the below that described battle array installing plate is fixedly arranged on described main substrate one end makes described area array CCD relative with described second catoptron.

2. secondary prealignment device according to claim 1, it is characterized in that, often organize light path system and comprise the first catoptron received from the light beam of described light source, described first catoptron and described area array CCD correspondence are located at the both sides up and down at edge, described wafer one place, and the edge image of described wafer is projected to corresponding area array CCD by described light beam after the first catoptron.

3. secondary prealignment device according to claim 2, is characterized in that, the described first catoptron inside being distributed in described sports platform triangular in shape, and the below of described main substrate is located at by corresponding the first respective catoptron of described area array CCD.

4. secondary prealignment device according to claim 1 and 2, is characterized in that, often organizes light path system and also comprises described light source and a beam path alignment mechanism respectively, and described light beam is sent by described light source and obtains after the process of described beam path alignment mechanism.

5. secondary prealignment device according to claim 1 and 2, is characterized in that, described three groups of light path systems share described light source and a light path aligning guide.

6. secondary prealignment device according to claim 5, it is characterized in that, described three groups of light path systems are first group of light path system, second group of light path system and the 3rd group of light path system, wherein, the catoptron that first group of light path system also comprises the catoptron of 2/3 transmittance, second group of light path system also comprises 1/2 transmittance, the 3rd group of light path system also comprises the 3rd catoptron; The light beam that described light source sends is mapped to three corner reflectors of 2/3 transmittance after described beam path alignment mechanism becomes parallel beam, wherein 1/3 light beam carries out launching as the light beam needed for described first group of light path system and 2/3 light beam is transmitted to the catoptron of 1/2 transmittance by three corner reflectors of described 2/3 transmittance, the half light beam received carries out reflecting the light beam as needed for described second group of light path system by the catoptron of described 1/2 transmittance, and second half is transmitted to described 3rd catoptron as the light beam needed for described 3rd group of light path system.

7. a secondary pre-alignment method, is characterized in that, comprises the steps:

The first step, wafer arrives secondary prealigned position after prealignment;

Second step, adopts the secondary prealignment device described in any one in as above 1-6, makes area array CCD gather three place's edge image information of wafer respectively, and by edge image information transmission to described image processor;

3rd step, described image processor process is from the actual home position obtaining wafer after the described edge image information of described area array CCD, and the standard home position of the actual home position of wafer with the wafer pre-set in the image processor is contrasted, obtain the remnants bias deflection of wafer;

4th step, micropositioner carries out fine motion compensation according to remaining eccentric deflection;

5th step, by wafer transfer on micropositioner, prepares exposure.

8. secondary pre-alignment method according to claim 7, it is characterized in that, in 3rd step, the actual home position of described acquisition wafer realizes as follows: described image processor calculates the actual edge image information of each area array CCD collection respectively by following equation, then the three place's actual edge image informations gathered by process three area array CCDs obtain the actual home position of wafer, and described equation is as follows:

$\begin{array}{c}\left[\begin{array}{c}{x}_0\\ y_0\end{array}\right]=\left[\begin{array}{cc}1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2}& -{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}\\ {\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2}& 1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2}\end{array}\right](\left[\begin{array}{c}{x}_0^{\&prime;}\\ y_0^{\&prime;}\end{array}\right]-\left[\begin{array}{c}{\mathrm{offset}}_{x0}\\ {\mathrm{offset}}_{y0}\end{array}\right])\\ =\left[\begin{array}{c}(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Ry}}_0}^2}{2})x_0^{\&prime;}+(-{\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})y_0^{\&prime;}-{\mathrm{offset}}_{x0}\\ ({\mathrm{Rz}}_0+\frac{{\mathrm{Rx}}_0\&CenterDot;{\mathrm{Ry}}_0}{2})x_0^{\&prime;}+(1-\frac{{{\mathrm{Rz}}_0}^2}{2}-\frac{{{\mathrm{Rx}}_0}^2}{2})y_0^{\&prime;}-{\mathrm{offset}}_{y0}\end{array}\right]\\ =\left[\begin{array}{c}{\mathrm{ax}}_0^{\&prime;}+{\mathrm{by}}_0^{\&prime;}+c\\ {\mathrm{dx}}_0^{\&prime;}+{\mathrm{ey}}_0^{\&prime;}+f\end{array}\right]\end{array}$

Wherein, offsetx0, offsety0 refer to the position of the projection of the initial point of CCD coordinate system in SPCS coordinate system, and wherein, Rx0, Ry0, Rz0 represent the anglec of rotation of CCD coordinate system respectively about X, Y, Z in SPCS coordinate system respectively; On wafer in CCD visual field, an edge, place is (x' in the projection coordinate of CCD coordinate system ₀, y' ₀), described SPCS coordinate system is the frame of reference that the bias of wafer is biased as the position of 0.

9. secondary pre-alignment method according to claim 7, is characterized in that, in second step, secondary prealignment device gathers three place's edge image information of wafer by three area array CCDs, and one of them area array CCD gathers the breach information of wafer simultaneously.