CN103808285A - Calibration method of pre-alignment machine and mechanical arm relative coordinate system - Google Patents

Abstract

The invention discloses a calibration method of a pre-alignment machine and mechanical arm relative coordinate system. The calibration method comprises the steps of (1) setting the coordinate system of a pre-alignment machine as an xoy coordinate system and the coordinate system of a mechanical arm as an x'o'y' coordinate system, (2) using a wafer in the xoy coordinate system to move in a radial way relative to the x'o'y' coordinate system, and determining the attitude of the x'o'y' coordinate system in the xoy coordinate system, (3) rotating the wafer relative to the x'o'y' coordinate system, determining the position of the x'o'y' coordinate system in the xoy coordinate system, which means that the relative position relation of the mechanical arm and the pre-alignment machine is obtained. According to the calibration method, the accurate positioning of a vacuum adsorption type mechanical arm in a vacuum adsorption type pre-alignment machine coordinate system can be realized, and thus the pre-alignment accuracy and transmission accuracy of the wafer can be effectively raised.

Description

The scaling method of prealignment machine and mechanical arm relative coordinate system

Technical field

The present invention relates to mechanical arm manipulation technical field, the particularly scaling method of a kind of prealignment machine and mechanical arm relative coordinate system, be mainly used in determining mechanical arm with by the relative position of controlling equipment so that manipulate more accurate.

Background technology

Mechanical arm is a kind of automatic pilot that can imitate some holding function of staff and arm, capture, carry object or operation tool according to fixed routine.At present, in production of integrated circuits technology, vacuum adsorption type single shaft prealignment machine all needs jointly to complete the prealignment to wafer with mechanical arm, identify the wafer center of circle and breach or trimming position and make breach or trimming towards a certain default direction, and mostly adopt vacuum adsorption type mechanical arm.When prealignment machine identifies behind the wafer center of circle, should adjust wafer position by mechanical arm, make the rotating shaft of vacuum cup on prealignment machine by the wafer center of circle.If now do not know the relative position information of prealignment machine and robot coordinate system, system will refer to that it makes accurately and to adjust wafer cannot to mechanical arm instruction, after prealignment finishes, also cannot learn the accurate location of wafer on mechanical arm, prealignment will lose meaning.Now need to demarcate, the task of demarcation is to determine the attitude of two coordinate systems (being the relative rotation of prealignment machine coordinate system and robot coordinate system) and position (being that prealignment machine coordinate origin and robot coordinate are the relative position of initial point).

Realizing in process of the present invention, inventor finds that prior art at least exists following problem: existing position definite and adjusting mechanical arm and prealignment machine is to use artificial pilot teaching, make mechanical arm and prealignment machine relative position be difficult to determine or precision very low, thereby the alignment precision of wafer reduces greatly.

Summary of the invention

In order to solve the problem of prior art, the embodiment of the present invention provides the scaling method of a kind of prealignment machine and mechanical arm relative coordinate system, the method obtains the relative position information of prealignment machine and robot coordinate system by demarcation, realize the accurate location of arm end in prealignment machine coordinate system, thereby improve the precision to wafer prealigning.Described technical scheme is as follows:

A scaling method for prealignment machine and mechanical arm relative coordinate system, described scaling method comprises:

S1, the residing coordinate of setting prealignment machine are xoy coordinate system, and the residing coordinate of mechanical arm is x ' o ' y ' coordinate system;

S2, utilize a wafer in described xoy coordinate system to move radially with respect to described x ' o ' y ' coordinate system, determine the attitude of described x ' o ' y ' coordinate system in described xoy coordinate system;

S3, described wafer is rotated with respect to described x ' o ' y ' coordinate system, determine the position of described x ' o ' y ' coordinate system in described xoy coordinate system, obtain the relative position relation of described mechanical arm and described prealignment machine.

Further, in step S2, determine that the method for described x ' o ' y ' coordinate system attitude in described xoy coordinate system comprises:

S201, the center of circle of the described wafer in described xoy coordinate system is transferred to a certain position B, draws the offset d=BO of B point with respect to described xoy coordinate origin;

S202, described mechanical arm is moved to and approaches a certain position A that B is ordered, then by described mechanical arm together with described wafer along O ' A direction displacement d, write down position A ', the described wafer center of circle Xin Chu position B ' at the new place of described mechanical arm;

S203, measure offset d '=B ' O of B ', the attitude angle t=B ' BO of described x ' o ' y ' coordinate system in described xoy coordinate system, tries to achieve according to the cosine law:

$t=\arccos \left(\frac{2\·d^2-d^{\′2}}{2\·d^2}\right)=\arccos (1-\frac{1}{2}\·{\left(\frac{d^{\′}}{d}\right)}^2).$

Further, step S2 also comprises the step of corrected parameter:

S204, demarcating after the attitude angle t of described x ' o ' y ' coordinate system in described xoy coordinate system, described mechanical arm is coordinated described wafer bias is compensated with described prealignment machine, after compensation, again calculate the offset of described wafer;

If offset reading, in claimed range, is generally less than CCD precision, demarcate successfully; If offset reading, outside claimed range, re-starts demarcation.

Further, in step S3, determine that the method for described x ' o ' y ' coordinate system position in described xoy coordinate system comprises:

The initial position B of the wafer center of circle in described xoy coordinate system described in S301, mark, the initial position A of mechanical arm in described xoy coordinate system described in mark;

S302, by described mechanical arm together with described wafer around O ' rotational angle T, write down position A ', the described wafer center of circle Xin Chu position B ' at the new place of described mechanical arm;

S303, position according to B, B ' in described xoy coordinate system, and drift angle ∠ B O ' B '=T of isosceles triangle BO ' B ', calculate the position of O ' in described xoy coordinate system, i.e. the position of described x ' o ' y ' coordinate system in described xoy coordinate system.

The beneficial effect that the technical scheme that the embodiment of the present invention provides is brought is:

Can realize the accurate location of vacuum adsorption type mechanical arm under vacuum adsorption type prealignment machine coordinate system, and then can realize the accurate location of wafer under vacuum adsorption type prealignment machine and robot coordinate system by the combination of vacuum adsorption type mechanical arm and vacuum adsorption type prealignment machine, thereby can effectively improve prealignment precision and the transmission precision to wafer.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing of required use during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the schematic diagram that x ' o ' y ' coordinate system attitude in xoy coordinate system is provided in the scaling method of the prealignment machine that provides of the embodiment of the present invention and mechanical arm relative coordinate system;

Fig. 2 is the schematic diagram that x ' o ' y ' coordinate system position in xoy coordinate system is provided in the scaling method of the prealignment machine that provides of the embodiment of the present invention and mechanical arm relative coordinate system.

In figure, xoy is prealignment machine coordinate system, and x ' o ' y ' is robot coordinate system, B is the initial position in the wafer center of circle, B ' is the home position of wafer after moving, and A is the initial position at manipulator clamping center, and A ' is residing position, rear Clamping Center for mechanical arm moves.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.

Embodiment

The present embodiment provides the scaling method of a kind of prealignment machine and mechanical arm relative coordinate system, and referring to Fig. 1 and Fig. 2, this scaling method comprises:

S1, the residing coordinate of setting prealignment machine are xoy coordinate system, and the residing coordinate of mechanical arm 1 is x ' o ' y ' coordinate system.At the residing xoy coordinate system of prealignment machine, place is provided with CCD(Charge-Coupled Device; Chinese full name: charge coupled cell) camera.

S2, utilize a wafer 2 in xoy coordinate system to move radially with respect to x ' o ' y ' coordinate system, determine the attitude of x ' o ' y ' coordinate system in xoy coordinate system.Be about to a wafer 2 and be placed in xoy coordinate system, the initial point of the center of circle of this wafer 2 and xoy coordinate system has certain offset, if the B point of the center of circle of these wafer 2 original states in xoy coordinate system, the offset d=BO in these wafer 2 centers of circle now; When this wafer 2 moves radially a new position B ' with respect to x ' o ' y ' coordinate system together with mechanical arm 1, now these wafer 2 residing new positions, the center of circle have new offset d '=B ' O, can calculate accordingly the attitude of mechanical arm 1 with respect to xoy coordinate system, i.e. direction.

S3, this wafer 2 is rotated with respect to x ' o ' y ' coordinate system, determine the position of x ' o ' y ' coordinate system in xoy coordinate system, obtain the relative position relation of mechanical arm 1 and prealignment machine.Be placed in xoy coordinate system by this wafer 2, the initial point of the center of circle of this wafer 2 and xoy coordinate system has certain offset, if the B point of the center of circle of these wafer 2 original states in xoy coordinate system; When this wafer 2 together with mechanical arm 1 with respect to the initial point of the x ' o ' y ' coordinate system new position B ' that turns an angle, position according to B, B ' in described xoy coordinate system, and the angle of rotating, can calculate the position of x ' o ' y ' coordinate system in xoy coordinate system.

Preferably, in step S2, determine that the method for x ' o ' y ' coordinate system attitude in xoy coordinate system comprises:

S201, the center of circle of the wafer in xoy coordinate system 2 is transferred to a certain position B, draws the offset d=BO of B point with respect to xoy coordinate origin;

S202, mechanical arm 1 is moved to and approaches a certain position A that B is ordered, then by mechanical arm 1 together with wafer 2 along o ' A direction displacement d, write down position A ', wafer 2 Xin Chu position, the center of circle B ' at mechanical arm 1 new place.Preferably, when mechanical arm 1 is moved along o ' A direction together with wafer 2, wafer 2 is held up with mechanical arm 1, more together along o ' A direction displacement d, then mechanical arm 1 puts down wafer 2.

S203, measure offset d '=B ' O of B ', the attitude angle t=B ' BO of x ' o ' y ' coordinate system in xoy coordinate system, tries to achieve according to the cosine law:

$t=\arccos \left(\frac{2\·d^2-d^{\′2}}{2\·d^2}\right)=\arccos (1-\frac{1}{2}\·{\left(\frac{d^{\′}}{d}\right)}^2).$

Preferably, step S2 also comprises the step of corrected parameter:

S204, demarcating after x ' o ' y ' coordinate system attitude angle t in xoy coordinate system, mechanical arm 1 is coordinated wafer 2 bias is compensated with prealignment machine, after compensation, again calculate the offset of wafer 2; If offset reading, in claimed range, is generally less than CCD precision, demarcate successfully; If offset reading, outside claimed range, re-starts demarcation.

Preferably, in step S3, determine that the method for x ' o ' y ' coordinate system position in xoy coordinate system comprises:

S301, the initial position B of marking wafer 2 centers of circle in xoy coordinate system, the initial position A of mark mechanical arm 1 in xoy coordinate system.

S302, by mechanical arm 1 together with wafer 2 around O ' rotational angle T, and the length that mechanical arm 1 extends is constant, writes down position A ', wafer 2 Xin Chu position, the center of circle B ' at mechanical arm 1 new place.In this step, mechanical arm 1 drives wafer 2 to rotate predetermined angle by controller driving device hand 1 together with wafer 2 in the time of O ' rotation.

S303, position according to B, B ' in xoy coordinate system, and drift angle ∠ B O ' B '=T of isosceles triangle BO ' B ', calculate the position of O ' in xoy coordinate system, i.e. the position of x ' o ' y ' coordinate system in xoy coordinate system.

In the present embodiment, demarcate the step of the attitude of x ' o ' y ' coordinate system in xoy coordinate system and can exchange with the step order of demarcating the position of x ' o ' y ' coordinate system in xoy coordinate system, also can carry out separately respectively.

The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (4)

1. a scaling method for prealignment machine and mechanical arm relative coordinate system, is characterized in that, described scaling method comprises:

S1, the residing coordinate of setting prealignment machine are xoy coordinate system, and the residing coordinate of mechanical arm is x ' o ' y ' coordinate system;

S2, utilize a wafer in described xoy coordinate system to move radially with respect to described x ' o ' y ' coordinate system, determine the attitude of described x ' o ' y ' coordinate system in described xoy coordinate system;

S3, described wafer is rotated with respect to described x ' o ' y ' coordinate system, determine the position of described x ' o ' y ' coordinate system in described xoy coordinate system, obtain the relative position relation of described mechanical arm and described prealignment machine.

2. the scaling method of prealignment machine according to claim 1 and mechanical arm relative coordinate system, is characterized in that, in step S2, determines that the method for described x ' o ' y ' coordinate system attitude in described xoy coordinate system comprises:

S201, the center of circle of the described wafer in described xoy coordinate system is transferred to a certain position B, draws the offset d=BO of B point with respect to described xoy coordinate origin;

S202, described mechanical arm is moved to and approaches a certain position A that B is ordered, then by described mechanical arm together with described wafer along o ' A direction displacement d, write down position A ', the described wafer center of circle Xin Chu position B ' at the new place of described mechanical arm;

S203, measure offset d '=B ' O of B ', the attitude angle t=B ' BO of described x ' o ' y ' coordinate system in described xoy coordinate system, tries to achieve according to the cosine law:

$t=\arccos \left(\frac{2\·d^2-d^{\′2}}{2\·d^2}\right)=\arccos (1-\frac{1}{2}\·{\left(\frac{d^{\′}}{d}\right)}^2).$

3. the scaling method of prealignment machine according to claim 2 and mechanical arm relative coordinate system, is characterized in that, step S2 also comprises the step of corrected parameter:

S204, demarcating after the attitude angle t of described x ' o ' y ' coordinate system in described xoy coordinate system, described mechanical arm is coordinated described wafer bias is compensated with described prealignment machine, after compensation, again calculate the offset of described wafer;

If offset reading, in claimed range, is demarcated successfully; If offset reading, outside claimed range, re-starts demarcation.

4. the scaling method of prealignment machine according to claim 3 and mechanical arm relative coordinate system, is characterized in that, in step S3, determines that the method for described x ' o ' y ' coordinate system position in described xoy coordinate system comprises:

The initial position B of the wafer center of circle in described xoy coordinate system described in S301, mark, the initial position A of mechanical arm in described xoy coordinate system described in mark;

S302, by described mechanical arm together with described wafer around O ' rotational angle T, and the length that mechanical arm extends is constant, writes down position A ', the described wafer center of circle Xin Chu position B ' at the new place of described mechanical arm;

S303, position according to B, B ' in described xoy coordinate system, and drift angle ∠ B O ' B '=T of isosceles triangle BO ' B ', calculate the position of O ' in described xoy coordinate system, i.e. the position of described x ' o ' y ' coordinate system in described xoy coordinate system.

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