CN115632018A - Wafer alignment method and alignment device - Google Patents

Abstract

The invention provides a wafer alignment method and an alignment device, the device comprises: enabling a first wafer carrying mechanism and a second wafer carrying mechanism to be in opposite alignment positions; identifying a first mark on a first wafer through a slide tray of a first slide mechanism, and determining the coordinate of the first mark in a target coordinate system; through a slide glass disc of the first slide glass mechanism and the first wafer, identifying a second mark on the second wafer, and determining the coordinate of the second mark in a target coordinate system; the first slide mechanism and/or the second slide mechanism is moved to align the first mark with the second mark based on first positional deviation data determined from coordinates of the first mark and the second mark. Based on the technical scheme of the invention, the two wafers are always opposite in the alignment process, and the wafers do not need to move repeatedly for marking identification by staggering the positions, so that additional movement errors caused by repeated movement of a moving mechanism are avoided.

Description

Wafer alignment method and alignment device

technical field

The present invention relates to the technical field of bonding wafer alignment, in particular to a wafer alignment method and an alignment device.

Background technique

During the wafer alignment process, it is necessary to identify the alignment marks of the upper wafer and the alignment marks of the lower wafer and record the position coordinates, and adjust the position of the upper wafer to align the alignment marks of the upper and lower wafers , to complete the wafer alignment process.

In the current process, high-precision wafer alignment uses a face-to-face alignment method, that is, the lower wafer faces up and the upper wafer faces down. At present, visible light imaging is mostly used for the recognition of wafer alignment marks. Since the wafer material is silicon, and there is a silicon dioxide coating on the surface, which are opaque materials, it is necessary to recognize the wafer alignment marks. The upper wafer is removed, and the lower wafer must be removed to identify the upper wafer alignment marks. During the reciprocating motion of the wafer carrier, deviations will inevitably occur, thereby affecting the final alignment accuracy.

In addition, the existing alignment method also has the biggest and most unknown influencing factor, that is, when the upper and lower wafer stages overlap to start wafer alignment, the upper and lower cameras using visible light can no longer identify the wafer on the wafer. Alignment marks, the alignment process at this time is completely realized by the coordinates of the previously recognized alignment marks, but in fact, it is not clear how much alignment accuracy is, and what is the real-time error of the current alignment.

Therefore, the existing alignment method, on the one hand, cannot detect the real-time error of the wafer, on the other hand, it increases the error detection components of each moving part of the machine and adds a large number of compensation algorithms in the software. It not only increases the hardware cost, but also has a great impact on the reliability of the machine operation. The most critical thing is that the final wafer alignment accuracy is in a state of lack of control.

Contents of the invention

Aiming at the problem that the wafer alignment accuracy cannot be detected in real time in the above-mentioned prior art, the present application proposes a wafer alignment method and an alignment device.

In the first aspect, a wafer alignment method proposed by the present invention includes:

making the first wafer carrying mechanism carrying the first wafer and the second wafer carrying mechanism carrying the second wafer be in an alignment position opposite to each other;

Using infrared identification to identify the first mark on the first wafer through the loading disc of the first loading mechanism, and determine the coordinates of the first mark in the target coordinate system;

Identifying the second mark on the second wafer through infrared recognition through the first wafer and the first wafer, and determining the coordinates of the second mark in the target coordinate system ;

According to the first position deviation data determined by the coordinates of the first mark and the second mark, move the first slide mechanism and/or the second slide mechanism so that the first mark Align with the second mark.

In one embodiment, before identifying the first mark on the first wafer through the loading disc of the first loading mechanism, further comprising:

identifying the target marks on the base where the first slide mechanism and the second slide mechanism are located, and constructing the target coordinate system.

In one embodiment, before identifying the first mark on the first wafer through the loading disc of the first loading mechanism, further comprising:

Moving the second slide mechanism so that the second slide mechanism moves toward the first slide mechanism within the identification range.

In one embodiment, after moving the first slide mechanism and/or the second slide mechanism to align the first mark with the second mark, it further includes:

re-identifying the first marker and the second marker, and determining the coordinates of the moved first marker and the second marker in the target coordinate system;

According to the moved coordinates of the first mark and the second mark, it is judged whether the first mark is aligned with the second mark.

In one embodiment, judging whether the first mark and the second mark are aligned according to the moved coordinates of the first mark and the second mark includes:

If the coordinates of the moved first mark and the second mark are consistent or the coordinate deviation of the two is within an error range, it is determined that the first mark is aligned with the second mark.

In one embodiment, also include:

If it is judged that the first mark and the second mark are not aligned, then determine the second position deviation data according to the moved coordinates of the two;

According to the second position deviation data, the first slide mechanism and/or the second slide mechanism are moved to align the first mark with the second mark.

In one embodiment, also include:

determining actual movement data according to the original coordinates of the first marker and/or the second marker and their moved coordinates;

Comparing the actual movement data with the theoretical movement data determined according to the first position deviation data, to determine movement error data of the first slide mechanism and/or the second slide mechanism;

Correcting the movement adjustment parameters according to the movement error data, re-moving the first slide mechanism and/or the second slide mechanism so that the first mark is aligned with the second mark.

In the second aspect, a wafer alignment device proposed by the present invention includes:

base;

a slide unit, which is arranged on the base, and the slide unit includes a first slide mechanism and a second slide mechanism oppositely arranged;

An infrared identification mechanism, which is arranged on a side of the first sheet loading mechanism away from the second sheet loading mechanism, and the infrared identification mechanism has an identification end facing the first sheet loading mechanism;

An alignment adjustment mechanism is arranged on the base, the alignment adjustment mechanism is connected to the first slide loading mechanism and/or the second slide loading mechanism and can drive the corresponding slide loading mechanism to move.

In one embodiment, the infrared identification mechanism is arranged on the identification adjustment mechanism, and the identification adjustment mechanism is movably arranged on the base, which can drive the infrared identification mechanism to move in the target plane, and the target The plane is parallel to the plane where the wafers loaded on the loading mechanism are located.

In one embodiment, the identification and adjustment mechanism includes a mechanism main body erected on the top of the base, and two ends of the main body of the mechanism are respectively slidably matched with guide rails provided on the top of the base.

The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

Compared with the prior art, a wafer alignment method and an alignment device provided by the present invention have at least the following beneficial effects:

A wafer alignment method and alignment device of the present invention replaces the currently used visible light recognition with infrared recognition that can pass through the carrier tray and the wafer, so that during the alignment process, the two wafers are always facing each other , it is not necessary to move repeatedly in order to stagger the position for mark recognition, avoiding the additional movement error caused by the repeated movement of the moving mechanism.

Description of drawings

Hereinafter, the present invention will be described in more detail based on the embodiments with reference to the accompanying drawings. in:

FIG. 1 shows a block diagram of the principle of the alignment method of the present invention;

Figure 2 shows a perspective view of the structure of the alignment device of the present invention;

Fig. 3 shows the front view of the structure of the alignment device of the present invention;

Fig. 4 shows a top view of the structure of the alignment device of the present invention.

In the figures, the same parts are given the same reference numerals. The drawings are not to scale.

Reference signs:

1-Base, 11-Guide, 2-Carrier Unit, 21-First Carrier, 211-First Carrier, 22-Second Carrier, 222-Second Carrier, 3-Infrared Identification mechanism, 4-recognition adjustment mechanism, 5-lifting mechanism, 6-alignment adjustment mechanism, 7-target mark.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

Example 1

The invention provides a wafer alignment method, comprising:

Step S100: making the first wafer loading mechanism carrying the first wafer and the second wafer loading mechanism carrying the second wafer be in an alignment position opposite to each other;

Specifically, referring to Figure 2 of the accompanying drawings, based on the alignment method proposed by the present invention, the first slide mechanism and the second slide mechanism do not need to be staggered for mark recognition, and the two are in a position facing each other from the beginning, that is, alignment bit.

Step S110: moving the second slide mechanism so that the second slide mechanism moves toward the first slide mechanism within the recognition range;

Specifically, the initial state is that the second wafer loading mechanism is far away from the first wafer loading mechanism, so that the space between the two is large, which facilitates wafer loading. During alignment, in order to improve the recognition effect, it is necessary to move the second loading mechanism toward the direction of the first loading mechanism (the identification mechanism is arranged on the side of the first loading mechanism). Of course, it is also possible that the first slide mechanism moves toward the direction of the second slide mechanism (the identified mechanism is arranged on the side of the second slide mechanism).

Step S120: Identify the target marks on the base where the first slide mechanism and the second slide mechanism are located, and construct a target coordinate system;

Specifically, referring to Figures 1 and 3 of the accompanying drawings, a target mark is provided on the base, and a target coordinate system can be constructed by identifying the target mark, and the target mark can be used as the origin of the target coordinate system. Of course, the target mark can actually also be set on a stationary slide mechanism, such as the first stationary slide mechanism in this embodiment.

Step S200: using infrared recognition to identify the first mark on the first wafer through the loading tray of the first loading mechanism, and determine the coordinates of the first mark in the target coordinate system;

Step S300: Using infrared to identify the loading disc and the first wafer passing through the first loading mechanism, identifying the second mark on the second wafer, and determining the coordinates of the second mark in the target coordinate system;

Specifically, the first mark of the first wafer can be identified through the loading tray (quartz chuck) of the first loading mechanism by infrared identification, the loading tray (quartz chuck) and the The first wafer (silicon) identifies the second mark of the second wafer, so as to obtain the coordinates of the first mark and the second mark in the target coordinate system.

Step S400: According to the first position deviation data determined by the coordinates of the first mark and the second mark, move the first slide mechanism and/or the second slide mechanism so that the first mark is aligned with the second mark;

Specifically, the first positional deviation data between the first mark and the second mark can be determined according to the coordinates of the first mark and the second mark, including data such as the direction and distance of the relative deviation. According to the first position deviation data, the first slide mechanism is kept stationary, and the second slide mechanism is moved until the first mark is aligned with the second mark. Of course, it is also possible to keep the second slide mechanism still and move the first slide mechanism until the first mark is aligned with the second mark; or both move simultaneously. In this embodiment, it is preferable to keep the first slide mechanism still and move the second slide mechanism until the first mark is aligned with the second mark.

Step S500: Alignment result detection step;

Step S510: re-identify the first mark and the second mark, and determine the coordinates of the moved first mark and the second mark in the target coordinate system;

Step S520: According to the coordinates of the moved first mark and the second mark, determine whether the first mark and the second mark are aligned;

Step S521: If the coordinates of the moved first mark and the second mark are consistent or the coordinate deviation of the two is within the error range, it is determined that the first mark is aligned with the second mark;

Step S522: If it is judged that the first mark and the second mark are not aligned, then determine the second position deviation data according to the coordinates of the two moved;

Step S523: According to the second position deviation data, move the first slide mechanism and/or the second slide mechanism so that the first mark is aligned with the second mark.

Specifically, after the adjustment of the moving direction and distance determined according to the first position deviation data is completed, it is detected whether the first mark and the second mark are aligned, that is, the coordinates of the first mark and the second mark are reacquired, and the two are judged. The relative deviation of the coordinates (second position deviation data), if the deviation is zero or within a preset range, it is judged to be aligned, otherwise it is not aligned. When misaligned, re-adjust the movement according to the second position deviation data. After re-moving and adjusting, the step of detecting the alignment result can be performed again according to actual needs.

Further, during the movement adjustment process of steps S400 and S500, the following steps Sa to Sc can be performed at any time, that is, the steps of detecting movement errors in real time and correcting movement parameters:

Step Sa: Determine the actual movement data according to the original coordinates of the first marker and/or the second marker and their moved coordinates;

Specifically, the moved coordinates here may be the coordinates at a certain moment in the process of moving according to the first position deviation data or the second position deviation data (not completely moved in place), or according to the first position deviation data or The final coordinates after the second position deviation data is moved (completely moved into place), according to the moved coordinates and the original coordinates, the actual moving data of the first or second loading mechanism, including the direction of movement, can be determined and the distance traveled.

Step Sb: comparing the actual movement data with the theoretical movement data determined according to the first position deviation data or the second position deviation data, and determining the movement error data of the first film loading mechanism and/or the second film loading mechanism;

Step Sc: correcting the movement adjustment parameters according to the movement error data, and re-moving the first slide mechanism and/or the second slide mechanism so that the first mark is aligned with the second mark.

Specifically, for the original alignment movement adjustment step of step S400: (1) Detect the coordinates of the first mark and/or the second mark at a certain moment during the movement process, and compare the coordinates at this moment with the original coordinates before the movement Yes, the actual movement data is obtained; the theoretical movement data is obtained through the first position deviation data, that is, the recorded distance at which the movement direction determined according to the first position deviation data has moved at this moment, according to the theoretical movement data and the actual movement The comparison of the data can determine the movement error data (mainly the movement error of the moving structure), including the direction deviation and distance deviation, and then can refer to the first position deviation data to perform compensation and correction of the direction and movement amount, and record the correction parameters to correct the subsequent The movement adjustment parameters of , finally make the first mark align with the second mark when the step S400 is completely moved in place. (2) Detect the coordinates of the first mark and/or the second mark after the movement is completed, compare the coordinates after the movement with the original coordinates before the movement, obtain the actual movement data, and compare the data according to the first position deviation in the same way The determined theoretical movement data is used to obtain movement error data and correction parameters, so as to guide and correct movement parameters for performing movement adjustment again according to the second position deviation data in step S500.

Similarly, in the realignment movement adjustment step of step S500, the error in the movement process can also be determined in the same manner as above and the movement parameters can be corrected, so as to improve the alignment accuracy between the first mark and the second mark.

Steps Sa to Step Sc realize real-time detection of the positional deviation of the marks of the two wafers during the movement adjustment process, so as to compensate the movement error, and can detect the compensation effect in real time during the movement process and carry out continuous Compensation, correcting the movement error of the moving mechanism until the error value is less than a prescribed threshold, thereby improving the alignment accuracy of the first mark and the second mark.

Example 2

The invention provides a wafer alignment device, comprising:

base 1;

A slide loading unit 2, which is arranged on the base 1, and the slide loading unit 2 includes a first slide loading mechanism 21 and a second slide loading mechanism 22 arranged oppositely;

An infrared identification mechanism 3, which is arranged on a side of the first loading mechanism 21 away from the second loading mechanism 22, and the infrared identification mechanism 3 has an identification end towards the first loading mechanism 21;

The alignment adjustment mechanism 6 is arranged on the base 1 , the alignment adjustment mechanism 6 is connected to the first slide loading mechanism 21 and/or the second slide loading mechanism 22 and can drive the corresponding slide loading mechanism to move.

Specifically, as shown in Figures 1 to 3 of the accompanying drawings, the alignment device of this embodiment can implement the alignment method in Embodiment 1, and the alignment device in this embodiment preferably uses the first slide mechanism 21 to maintain (the target mark 7 is arranged on the first slide mechanism 21), as a reference object, the second slide mechanism 22 is used as a moving part for movement adjustment, and the alignment adjustment mechanism 6 is set corresponding to the second slide mechanism 22. The infrared identification mechanism 3 is arranged on the side where the first loading mechanism 21 is located, and its identification end faces the first loading tray 211 of the first loading mechanism 21 .

In fact, since the alignment movement of the wafer is generally relatively precise, the positional deviation will not be too large, so in this embodiment, the moving part is actually the second loading tray 221 on the second loading mechanism 22, and the second loading tray 221 The main body of the mechanism 22 remains stationary during the movement adjustment process, and the alignment adjustment mechanism 6 is connected to the second loading disc 221 of the second loading mechanism 22 . However, the main body of the second loading mechanism 22 is arranged on the lifting mechanism 5, which can be lifted and lowered to realize the distance between the first loading mechanism 21 and the second loading mechanism 22, which is mainly convenient for wafer loading and marking. identification; at the same time, the lifting mechanism 5 has a plurality of different lifting points, which can adjust the parallelism between the second loading tray 221 of the second loading mechanism 22 and the first loading tray 211 of the first loading mechanism 21. Spend.

Further, the infrared identification mechanism 3 is arranged on the identification adjustment mechanism 4, and the identification adjustment mechanism 4 is movably arranged on the base 1, which can drive the infrared identification mechanism 3 to move in the target plane, and the target plane is parallel to the loading on the slide mechanism. The plane on which the wafer is located.

The identification adjustment mechanism 4 includes a mechanism main body erected on the top of the base 1 , and two ends of the main body of the mechanism are slidably matched with guide rails 11 provided on the top of the base 1 .

Specifically, as shown in Figure 1 of the accompanying drawings, the identification and adjustment mechanism 4 is a gantry moving mechanism arranged on the base 1 as a whole, and the two ends of the main body of the mechanism cooperate with both sides of the base 1 through sliders or rollers respectively, and the base The two sides of 1 are provided with the guide rail 11 that cooperates with it.

In describing the present invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", " The orientation or positional relationship indicated by "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, so as to Specific orientation configurations and operations, therefore, are not to be construed as limitations on the invention.

Although the invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It is therefore to be understood that numerous modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the invention as defined by the appended claims. It shall be understood that different dependent claims and features described herein may be combined in a different way than that described in the original claims. It will also be appreciated that features described in connection with individual embodiments can be used in other described embodiments.

Claims (10)

1. A wafer alignment method, comprising:

enabling a first wafer carrying mechanism and a second wafer carrying mechanism to be in opposite alignment positions;

identifying a first mark on the first wafer through a slide glass tray of the first slide glass mechanism by utilizing infrared identification, and determining the coordinate of the first mark in a target coordinate system;

identifying a second mark on the second wafer by infrared identification through the slide glass tray of the first slide glass mechanism and the first wafer, and determining the coordinate of the second mark in a target coordinate system;

moving the first slide mechanism and/or the second slide mechanism to align the first marker with the second marker according to first positional deviation data determined by coordinates of the first marker and the second marker.

2. The wafer alignment method as claimed in claim 1, wherein before the step of identifying the first mark on the first wafer through the slide tray of the first slide mechanism, the method further comprises:

and identifying target marks on the base where the first slide mechanism and the second slide mechanism are positioned, and constructing the target coordinate system.

3. The wafer alignment method as claimed in claim 1, wherein before the step of identifying the first mark on the first wafer through the slide tray of the first slide mechanism, the method further comprises:

and moving the second slide mechanism to enable the second slide mechanism to move to the recognition range towards the direction close to the first slide mechanism.

4. The wafer alignment method as claimed in claim 1, wherein after moving the first and/or second carrier mechanisms to align the first and second marks, further comprising:

re-identifying the first mark and the second mark, and determining the coordinates of the moved first mark and the second mark in the target coordinate system;

and judging whether the first mark and the second mark are aligned or not according to the coordinates of the first mark and the second mark after moving.

5. The wafer alignment method as claimed in claim 4, wherein determining whether the first mark and the second mark are aligned according to the moved coordinates of the first mark and the second mark comprises:

and if the coordinates of the first mark and the second mark after the movement are consistent or the coordinate deviation of the first mark and the second mark is in an error range, judging that the first mark is aligned with the second mark.

6. The wafer alignment method of claim 4, further comprising:

if the first mark and the second mark are not aligned, determining second position deviation data according to the coordinates of the first mark and the second mark after movement;

moving the first slide mechanism and/or the second slide mechanism to align the first mark with the second mark according to the second positional deviation data.

7. The wafer alignment method as claimed in any one of claims 1 to 6, further comprising:

determining actual movement data according to the original coordinates of the first mark and/or the second mark and the moved coordinates of the first mark and/or the second mark;

comparing the actual movement data with theoretical movement data determined according to the first position deviation data to determine movement error data of the first slide mechanism and/or the second slide mechanism;

and correcting movement adjustment parameters according to the movement error data, and re-moving the first slide mechanism and/or the second slide mechanism to align the first mark with the second mark.

8. A wafer alignment apparatus, comprising:

a base;

the slide glass unit is arranged on the base and comprises a first slide glass mechanism and a second slide glass mechanism which are oppositely arranged;

the infrared recognition mechanism is arranged on one side, far away from the second slide mechanism, of the first slide mechanism and is provided with a recognition end facing the first slide mechanism;

and the alignment adjusting mechanism is arranged on the base, is connected with the first slide mechanism and/or the second slide mechanism and can drive the corresponding slide mechanisms to move.

9. The wafer alignment device as claimed in claim 8, wherein the infrared recognition mechanism is disposed on a recognition adjustment mechanism movably disposed on the base, which can drive the infrared recognition mechanism to move in a target plane, which is parallel to a plane of the wafer loaded on the slide mechanism.

10. The wafer alignment device as claimed in claim 9, wherein the recognition adjusting mechanism includes a mechanism body mounted on the top of the base, and both ends of the mechanism body are slidably engaged with guide rails disposed on the top of the base, respectively.

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