CN103021898B - Measure chip and substrate relative inclination method of measurement and system - Google Patents

Abstract

The invention discloses a method for measuring a plane angle, a method for measuring a relative inclination of a chip and a substrate, and a system thereof. The method for measuring the relative inclination of a chip and a substrate includes step S21 of obtaining the angle between the first reference plane and the second reference plane by means of calibration. Error; S22 Obtain the first inclination angle between the chip and the first reference plane according to the method of measuring the plane angle combined with the height distance measured by the first height sensor, and according to the method of measuring the plane angle combined with the height distance measured by the second height sensor Obtain a second inclination angle between the substrate and the second reference plane; S23 perform a vector subtraction operation on the second inclination angle, the first inclination angle, and an angle error to obtain a relative inclination angle between the chip and the substrate. The invention uses a height sensor to measure multi-point heights to measure inclination angles, and then utilizes an inclination angle calibration method to conveniently, quickly and accurately measure the relative inclination angles between chips and substrates; the method is simple to implement, has high measurement accuracy, and has a compact measurement and leveling system.

Description

Method and system for measuring relative inclination between chip and substrate

technical field

The invention belongs to the technical field of precision testing and measurement, and more particularly relates to a method and system for measuring the relative inclination angle of a measuring chip and a substrate.

Background technique

Due to the development of high-density packaging technology, the chip size is getting smaller and smaller, and the requirements for placement accuracy are getting higher and higher. In the chip placement process, the placement head with a vacuum valve is usually used to pick up the chip, and move it to the substrate at a certain speed to perform the placement operation; The movement of the chip will cause the position and inclination of the chip relative to the substrate to be different every time, so it is necessary to correct the deviation and level before the chip is mounted. When the chip inclination is large, it will seriously affect the placement effect. Chip leveling is an important module in high-density packaging, and the leveling accuracy determines the quality of placement.

At present, focusing and leveling technology is generally only used in lithography machines, and chip leveling is usually not performed in the chip packaging process. The existing leveling technology is mainly applied to the photoelectric measurement method on the lithography machine, such as: ASML adopts the photoelectric measurement method based on grating moiré fringe and four-quadrant detector; Nikon uses the photoelectric measurement method based on slit and four-quadrant detector Detection method; Canon uses a photoelectric detection system based on pinhole and area array CCD.

The above-mentioned various photoelectric measurement methods have high precision. However, the measurement process is complex and the measurement system is relatively large. For the SMT process, the efficiency is not high, the space required for the leveling system is large, and the operation is inconvenient.

Contents of the invention

Aiming at the defects of the prior art, the purpose of the present invention is to provide a method for measuring the relative inclination of a chip and a substrate with a simple method and high measurement accuracy.

The present invention also provides a method for measuring the relative inclination of the chip and the substrate, comprising the following steps:

S21: Obtain the angular error α between the first reference plane and the second reference plane by means of calibration;

S22: According to the method of measuring the plane angle combined with the height distance measured by the first height sensor to obtain the first inclination γ between the chip and the first reference plane, and according to the method of measuring the plane angle combined with the height distance measured by the second height sensor Obtaining a second inclination β between the substrate and the second reference plane;

S23: Perform a vector subtraction operation on the second inclination angle, the first inclination angle, and an angle error to obtain a relative inclination angle β-γ-α between the chip and the substrate;

The method of measuring the plane angle is as follows:

S11: Take three points A1, B1, and C1 in the datum plane, so that the line connecting the three points forms a right triangle;

S12: Establish a reference coordinate system based on the three points taken, the reference coordinate system takes the right-angled vertex as the origin, the two right-angled sides as the X-axis and the Y-axis respectively, and a straight line passing through the origin and perpendicular to the plane where the three points are located is the Z axis;

S13: Using a height sensor to measure the distance h _A between point A1 on the reference plane and the corresponding point A on the plane to be measured, the line connecting point A and point A1 is perpendicular to the reference plane;

S14: Repeat step S13 and measure the distance h _B between point B1 on the datum plane and the corresponding point B on the plane to be measured and the distance hc between point C1 on the datum plane and the corresponding point _C on the plane to be measured; point B and point B1 The connection line of C is perpendicular to the reference plane; the connection line of C point and C1 point is perpendicular to the reference plane;

S15: According to the formula Calculate the angle α ₁ between the projection of the normal vector n of the plane to be measured on the XY plane and the X axis, and according to the formula Calculate the angle α ₂ between the projection of the normal vector n of the plane to be measured on the XZ plane and the Z axis; x _B is the displacement of point B relative to point A in the X direction, and y _C is the displacement of point C relative to point A in Y direction of displacement.

Furthermore, in step S21, the calibration method is specifically:

Use the first height sensor to measure the first normal inclination b1 of the plane where the calibration plate is located,

Use the second height sensor to measure the second normal inclination b2 of the plane where the calibration plate is located,

The angle error α between the first reference plane and the second reference plane is obtained by performing a vector subtraction operation on the first normal inclination b1 and the second normal inclination b2.

Furthermore, the first reference plane is a plane formed by the movement of the first height sensor, and the second reference plane is a plane formed by the movement of the second height sensor.

The present invention also provides a measurement system for the relative inclination of a chip and a substrate, including an XY motion module, a Z motion module, a second height sensor, a first height sensor and a mounting head; the second height sensor is fixed Connected directly below the Z-direction movement module, the placement head is located on the left side of the Z-direction component and the second height sensor, the placement head is connected to the chip, and the substrate is located under the second height sensor In the horizontal plane, the first height sensor is located in the horizontal plane below the placement head; through the external motion control mechanism, the XY motion module and the Z motion module are respectively controlled to move in the X, Y, and Z directions and rotate.

Furthermore, the measuring system further includes a calibration plate, which is arranged at the middle position between the first height sensor and the second height sensor, and is used for calibrating the inclination angle.

Furthermore, when measuring the inclination angle of the substrate, the second height sensor is located directly above the substrate, and the measurement distance between the lens of the second height sensor and the substrate is 25 mm to 35 mm.

Furthermore, when measuring the chip inclination, the placement head is located directly above the first height sensor, and the axis of the placement head coincides with the axis of the lens of the first height sensor.

The invention provides a high-precision measuring method and a leveling system applied to small inclination angles in a patching process. By using the height sensor to measure the multi-point height to measure the inclination angle, and then use the inclination angle calibration method to measure the relative inclination angle between the chip and the substrate conveniently, quickly and accurately, and use the corresponding motion module to complete the chip leveling. The method is simple to implement, has high measurement accuracy, and the measurement and leveling system is compact.

Description of drawings

Fig. 1 is the schematic diagram of the principle of the method for measuring plane angle provided by the embodiment of the present invention;

Fig. 2 is a flow chart of the implementation of the method for measuring the relative inclination between the chip and the substrate provided by the embodiment of the present invention;

3 is a schematic structural diagram of a chip and substrate relative inclination measurement and leveling system provided by an embodiment of the present invention;

Fig. 4 is a schematic diagram of the implementation flow of the method for measuring the inclination angle in the patching process provided by the embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The invention provides a high-precision measuring method and a leveling system applied to small inclination angles in a patching process. By using the height sensor to measure the multi-point height to measure the inclination angle, and then use the inclination angle calibration method to measure the relative inclination angle between the chip and the substrate conveniently, quickly and accurately, and use the corresponding motion module to complete the chip leveling. The method is simple to implement, has high measurement accuracy, and the measurement and leveling system is compact.

In an embodiment of the present invention, the method for measuring a plane angle specifically includes the following steps:

S11: Take three points A1, B1, and C1 in the datum plane, so that the line connecting the three points forms a right triangle;

S12: Establish a reference coordinate system based on the three points taken, the reference coordinate system takes the right-angled vertex as the origin, the two right-angled sides as the X-axis and the Y-axis respectively, and a straight line passing through the origin and perpendicular to the plane where the three points are located is the Z axis;

S13: Using a height sensor to measure the distance h _A between point A1 on the reference plane and the corresponding point A on the plane to be measured, the line connecting A and A1 is perpendicular to the reference plane;

S14: Repeat step S3 and measure the distance h _B between point B1 on the datum plane and the corresponding point B on the plane to be measured and the distance hc between point C1 on the datum plane and the corresponding point _C on the plane to be measured; the connection between B and B1 The line is perpendicular to the reference plane; the line connecting C and C1 is perpendicular to the reference plane;

S15: According to the formula Calculate the angle α ₁ between the projection of the normal vector n of the plane to be measured on the XY plane and the X axis, and according to the formula Calculate the angle α ₂ between the projection of the normal vector n of the plane to be measured on the XZ plane and the Z axis; x _B is the displacement of point B relative to point A in the X direction, and y _C is the displacement of point C relative to point A in Y direction of displacement.

As shown in Figure 1, the plane where the height sensor is located is the X1Y1 plane, and ABC is the plane to be measured. It is assumed that the plane to be measured and the plane where the height sensor is located have a certain inclination angle. Measure the height of the plane to be measured at point A1 on the X1Y1 plane as h _A (that is, the distance from point A on the plane to be measured to the X1Y1 plane); translate the height sensor from point A1 along the X1 axis to point B1 by x _B , and measure the plane to be measured The height of the plane is h _B ; the height sensor is translated y _C from point A1 along the Y1 axis, and the height of the plane to be measured is h _C . At this time, point B only has a translation x _B in the X direction relative to point A, and point C has only a translation y _C in the Y direction relative to point A. Therefore, the relative coordinates of points A, B, and C relative to point A are A (0,0,0), B(x _B ,0,h _B -h _A ), C(0,y _C ,h _C -h _A ). set vector is (x ₂ , y ₂ , z ₂ ), and the normal vector of the plane to be measured is but $\stackrel{\&Right\; Arrow;}{\mathrm{AB}}\&Center\; Dot;\stackrel{\&Right\; Arrow;}{\mathrm{no}}=0,\stackrel{\&Right\; Arrow;}{\mathrm{AC}}\·\stackrel{\&Right\; Arrow;}{\mathrm{no}}=0,$ therefore $\stackrel{\&Right\; Arrow;}{\mathrm{AB}}\·\stackrel{\&Right\; Arrow;}{\mathrm{no}}=0,\stackrel{\&Right\; Arrow;}{\mathrm{AC}}\·\stackrel{\&Right\; Arrow;}{\mathrm{no}}=0$ The substitution coordinates are calculated as follows: $\left\{\begin{array}{c}{x}_1{x}_{\mathrm{no}}+{\mathrm{the\; y}}_1{\mathrm{the\; y}}_{\mathrm{no}}+z_1=0\\ x_2{x}_{\mathrm{no}}+{\mathrm{the\; y}}_2{\mathrm{the\; y}}_{\mathrm{no}}+z_2=0\end{array}\right.$

so

${\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

where x ₁ =x _B , y ₁ =0, z ₁ =h _B -h _A ; x ₂ =0, y ₂ =y _C , z ₂ =h _C -h _A ; so the normal vector The angle between the projection on the XY plane and the X axis is: normal vector The angle between the projection on the XZ plane and the Z axis is:

In the method for measuring the plane angle provided by the embodiment of the present invention, in the method for measuring the plane angle, three points are taken in the reference plane, and a corresponding coordinate system is thus established, and the height of the plane to be measured is measured with a height sensor at the three points, The space angle of the normal of the plane to be measured can be calculated from the height value and the coordinates of the three points; the method is simple and the measurement accuracy is high.

As shown in Figure 2, the method for measuring the relative inclination of the chip and the substrate provided by the present invention specifically includes the following steps:

S21: Obtain the angular error α between the first reference plane and the second reference plane by calibration; the first reference plane is the plane formed by the movement of the first height sensor, and the second reference plane is the second height sensor the plane formed by the movement;

S22: According to the method of measuring the plane angle combined with the height distance measured by the first height sensor to obtain the first inclination γ between the chip and the first reference plane, and according to the method of measuring the plane angle combined with the height distance measured by the second height sensor Obtaining a second inclination β between the substrate and the second reference plane;

S23: Perform a vector subtraction operation on the second inclination angle, the first inclination angle, and an angle error to obtain a relative inclination angle β-γ-α between the chip and the substrate.

Among them, the calibration method is as follows:

Use the first height sensor to measure the first normal inclination b1 of the plane where the calibration plate is located,

Use the second height sensor to measure the second normal inclination b2 of the plane where the calibration plate is located,

The angle error α between the first reference plane and the second reference plane is obtained by performing a vector subtraction operation on the first normal inclination b1 and the second normal inclination b2.

In the embodiment of the present invention, in step S22, the method for measuring the plane angle is specifically:

Take three points A1, B1, and C1 in the datum plane, so that the line connecting the three points forms a right triangle;

Establish a reference coordinate system based on the three points taken. The reference coordinate system takes the right-angled vertex as the origin, the two right-angled sides as the X-axis and the Y-axis respectively, and the straight line passing through the origin and perpendicular to the plane where the three points are located as Z axis;

Using a height sensor to measure the distance h _A between point A1 on the reference plane and the corresponding point A on the plane to be measured, the line connecting A and A1 is perpendicular to the reference plane;

Repeat the above steps and measure the distance h _B between point B1 on the datum plane and the corresponding point B on the plane to be measured and the distance hc between point C1 on the datum plane and the corresponding point _C on the plane to be measured; the line connecting B and B1 is perpendicular on the reference plane; the line connecting C and C1 is perpendicular to the reference plane;

According to the formula Calculate the angle α ₁ between the projection of the normal vector n of the plane to be measured on the XY plane and the X axis, and according to the formula Calculate the angle α ₂ between the projection of the normal vector n of the plane to be measured on the XZ plane and the Z axis; x _B is the displacement of point B relative to point A in the X direction, and y _C is the displacement of point C relative to point A in Y direction of displacement.

The present invention also provides a system for measuring and leveling the relative inclination of the chip and the substrate, including an XY direction movement module 1, a Z direction movement module 2, a second height sensor 3, a substrate 4, a first height sensor 5, and a chip 6 , placement head 7, calibration plate 8 constitute. Wherein the second height sensor 3 is fixedly connected with the Z-direction motion module 2 directly below it, and the placement head 7 is fixedly connected with the Z-direction component 2 and is located on the left side of the second height sensor 3 . The base plate 4 is fixed in the horizontal plane and located below the second height sensor 3 . The first height sensor 5 is fixed in the horizontal plane and located below the placement head 7 . The X, Y, and Z motion module has degrees of freedom of rotation and movement in the X, Y, and Z directions, and is controlled by the corresponding motion control mechanism, and can move and rotate in the X, Y, and Z directions.

In the embodiment of the present invention, when using the system to perform inclination calibration, substrate inclination measurement and chip inclination measurement, a certain positional relationship must be maintained. When performing inclination calibration, the second height sensor is directly above the first height sensor, and the lens axes of the first height sensor and the second height sensor coincide, and the calibration plate is located in the middle of the two height sensors. The calibration plate is only used for inclination calibration and removed in other cases. When measuring the inclination of the substrate, the second height sensor is located directly above the substrate, and the lens of the second height sensor and the substrate maintain an appropriate measurement distance of 25mm to 35mm, which can prevent the placement head from interfering with the substrate. When measuring the inclination of the chip, it must be ensured that the placement head has successfully picked up the chip during the measurement. The placement head is located directly above the first height sensor, and the axis of the placement head coincides with the axis of the lens of the first height sensor.

In order to further illustrate the present invention, the workflow of the chip and substrate relative inclination measurement and leveling system is described in detail in conjunction with Fig. 3 and Fig. 4 as follows:

Control Motion The motion module moves the second height sensor directly above the first height sensor. Then install the calibration plate between the two height sensors. At this time, the calibration plate is used as the plane to be measured, and the second height sensor and the chip sensor are used to measure the normal inclination angle of the calibration plate, and the inclination angle is subtracted to obtain the compensation angle α (α is the space angle, that is, the angle between the normal line and the XY plane). After the inclination calibration is completed, the inclination measurement of the chip and the substrate can be performed. The advantage of this method is that it is not necessary to make the measurement planes of the second height sensor and the first height sensor exactly parallel, and even if there is a relative inclination, the error can be eliminated by the compensation angle. As long as the measurement system does not change, the compensation angle remains unchanged, that is, only one inclination calibration is required.

Control the motion The motion module moves the second height sensor directly above the substrate. At this time, the substrate is used as the plane to be measured, and the second height sensor is used to measure the normal inclination angle β of the substrate (β is also a spatial angle). Since the position of the substrate remains unchanged after it is installed, the inclination angle of the substrate only needs to be measured once.

Control the motion The motion module moves the first height sensor directly above the placement head. At this time, the plane where the chip is located is the plane to be measured, and the first height sensor is used to measure the normal inclination γ of the chip plane (γ is also a spatial angle). A chip inclination measurement is required for each placement.

Calculate the inclination angle of the substrate and the chip measured by the height sensor, and the relative inclination angle between the chip and the substrate before the chip is attached to the substrate is β-γ-α (here, each angle is a space angle vector, that is, it is related to the X-axis Y axis has a certain angle). According to the calculated relative inclination, control the motion movement module, so that the placement head rotates the corresponding angles along the X axis and the Y axis respectively, and finally the chip before placement can be kept parallel to the substrate.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (7)

1. measure a method for chip and substrate relative inclination, it is characterized in that, comprise the steps:

(1) mode that employing is demarcated obtains the angular error α between the first datum plane and the second datum plane;

(2) the first tilt angle gamma of chip and the first datum plane is obtained in conjunction with the height distance that the first height sensor records according to the method for measurement plane angle, and the second angle of inclination beta of the height distance acquisition substrate recorded according to the method for measurement plane angle and in conjunction with the second height sensor and the second datum plane;

(3) described second inclination angle, the first inclination angle and angular error are done vector subtraction computing and obtain relative inclination β-γ-α between described chip and described substrate;

Wherein, the method for the measurement plane angle in step (2) is specially:

S11: get three somes A1, B1, C1 in datum plane, makes the line form right angle triangle of 3;

S12: set up the frame of reference according to got three points, the described frame of reference take right-angled apices as initial point, is respectively X-axis and Y-axis with two right-angle sides, with by initial point and perpendicular to the straight line of 3 place planes for Z axis;

S13: the distance h adopting respective point A on A1 point and plane to be measured in height sensor measuring basis plane _a, the line of A point and A1 point is perpendicular to described datum plane;

S14: repeat step S13 and record the distance h of respective point B on B1 point and plane to be measured on datum plane respectively _bwith the distance h of respective point C in C1 point on datum plane and plane to be measured _c; The line of B point and B1 point is perpendicular to described datum plane; The line of C point and C1 point is perpendicular to described datum plane;

S15: according to formula calculate the projection of normal vector n in XY plane and the angle α of X-axis of plane to be measured ₁, and according to formula calculate the projection of normal vector n in XZ plane and the angle α of Z axis of plane to be measured ₂; x _bfor B point is relative to the displacement in the X direction of A point, y _cfor C point is relative to the displacement in the Y direction of A point.

2. the method for claim 1, is characterized in that, in step (1), the mode of described demarcation is specially:

The first height sensor is adopted to measure the first normal inclination angle b1 of scaling board place plane,

The second height sensor is adopted to measure the second normal inclination angle b2 of scaling board place plane,

First normal inclination angle b1 and the second normal inclination angle b2 is done vector subtraction computing and obtain angular error α between the first datum plane and the second datum plane.

3. method as claimed in claim 1 or 2, is characterized in that, described first datum plane is the plane that the first height sensor motion is formed, and described second datum plane is the plane that the second height sensor motion is formed.

4. based on a measuring system for method according to claim 1, it is characterized in that, comprise XY to motion module, Z-direction motion module, the second height sensor, the first height sensor and mounting head; Described second height sensor is connected in immediately below described Z-direction motion module, described mounting head is positioned at the left side of described Z-direction motion module and the second height sensor, described mounting head connects chip, substrate is positioned at the horizontal plane below described second height sensor, and described first height sensor is positioned at the horizontal plane below described mounting head; By the motion control mechanism of outside respectively control XY carry out X, Y, the movement of Z-direction and rotation to motion module and Z-direction motion module.

5. measuring system as claimed in claim 4, is characterized in that, also comprises scaling board, being arranged at the position, middle of described first height sensor and the second height sensor, for demarcating inclination angle.

6. measuring system as claimed in claim 4, it is characterized in that, during to substrate measurement of dip angle, the second height sensor is positioned at directly over described substrate, and the measuring distance between described second height sensor camera lens and substrate is 25mm ~ 35mm.

7. measuring system as claimed in claim 4, it is characterized in that, during to chip measurement of dip angle, described mounting head is positioned at directly over described first height sensor, the axis of described mounting head and the dead in line of described first height sensor camera lens.