CN117419654A - Wafer warpage measurement system and method - Google Patents

Abstract

The invention belongs to the field of wafer measurement and discloses a wafer warpage measurement system and a wafer warpage measurement method. The wafer warp measuring fixture is horizontally arranged in the fixture mounting opening, and the laser comprises an upper laser and a lower laser which are respectively arranged at the upper end and the lower end of the wafer warp measuring fixture, and the calibration laser device is arranged on the measuring platform; the data processing system is electrically connected with the upper laser, the lower laser and the calibration laser device. The invention has simple structure and convenient operation. Through the structural design of the wafer warp measurement clamp, convenience and operability of sample taking and placing can be guaranteed, the damage probability of samples is reduced, and meanwhile, the test accuracy is further designed and ensured through the positioning assistance of the fixing piece. The wafer warpage measurement method has high accuracy and can well meet the use of the non-standard wafer warpage measurement.

Description

Wafer warpage measurement system and method

Technical Field

The invention belongs to the field of wafer measurement, and relates to a wafer warpage measurement system and a wafer warpage measurement method.

Background

The continuous development of electronic packaging technology has driven electronic packaging products to gradually develop towards thinness, miniaturization, light weight and high integration. The silicon wafer is used as a base material of electronic packaging, and the wafer is required to be thinned before packaging in order to meet the packaging thickness requirement. Wafer self-rotation grinding technology has become the dominant craftsman technology for wafer grinding due to the advantages of low damage and high efficiency. However, mechanical grinding inevitably generates wafer surface damage and residual stress. The damaged layer and residual stress will cause wafer warpage, thereby seriously affecting wafer transmission and reducing the efficiency of subsequent processes. Therefore, the warp of the grinding wafer is measured, and the warp amount is used as a characterization parameter of the grinding quality of the wafer, so that the method has important significance for researching the optimization grinding process.

The existing wafer warpage equipment is a standard wafer testing device and cannot meet the non-standard wafer warpage measurement. Therefore, it is necessary to study a warp measurement system and a measurement method for a non-standard wafer.

Disclosure of Invention

In view of the foregoing problems in the prior art, one of the purposes of the present invention is to provide a wafer warp measurement system that can be used for non-standard wafers, and has the advantages of convenient taking and placing, simple operation and high measurement accuracy.

The second objective of the present invention is to provide a wafer warpage measurement method.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the wafer warp measurement system comprises a measurement platform, a wafer warp measurement clamp, a laser, a calibration laser device and a data processing system, wherein a clamp installation opening is formed in the measurement platform, the wafer warp measurement clamp is horizontally arranged in the clamp installation opening, the laser comprises an upper laser and a lower laser which are respectively arranged at the upper end and the lower end of the wafer warp measurement clamp, the upper laser and the lower laser are positioned on the same vertical line, a laser connecting line of the upper laser and the lower laser is perpendicular to the measurement platform, and the calibration laser device is arranged on the measurement platform; the data processing system is electrically connected with the upper laser, the lower laser and the calibration laser device;

the wafer warp measurement clamp comprises a tray, a fixing piece and a clamp main body;

the middle of the tray is provided with a first opening penetrating through the upper end and the lower end of the tray; the clamp body is arranged in the first opening through a fixing piece, one end of the fixing piece is fixed with the tray, and the other end of the fixing piece is fixed with the clamp body;

the middle of the clamp main body is provided with a second opening penetrating through the upper end and the lower end of the clamp main body; the second opening edge of anchor clamps main part bottom is equipped with the step that is used for placing the wafer, the top of step and the bottom parallel and level of anchor clamps main part.

Further, the second opening is of a rectangular structure, the step comprises a rectangular annular structure which is arranged around the second opening, a boss used for placing a wafer is arranged on the inner side of the rectangular annular structure, and at least three bosses are arranged. The invention is suitable for accommodating and placing wafers in various non-standard wafers through the structural arrangement of the second opening and the steps of the clamp main body, the second opening is further arranged into a rectangular structure, the steps are arranged into a rectangular ring-shaped structure matched with the rectangular structure, bosses for placing the wafers are arranged in the structure, and at least three bosses are arranged, so that the wafers can be placed more stably. It is further preferable that the bosses are provided in four, and the four bosses are provided at four corners of the rectangular annular structure, respectively. Still more preferably, the boss has a fan-shaped structure with an arc of 90 °. Specifically, the boss and the rectangular annular structure are integrally formed.

Further preferably, the size of the opening on the inner side of the rectangular ring-shaped structure is the same as that of the second opening, and is one of 20×30mm, 25×30mm, 30×30mm and 40×40 mm; the depth of the second opening is 0.5mm; the thickness of the step is 0.5mm; the width of the rectangular annular structure is 1mm.

Further, the fixing piece comprises at least three groups of supporting feet and supporting bars which are arranged in a matched mode, the supporting feet are fixed at the edge of the first opening of the tray, one end of each supporting bar is fixed with each supporting foot, and the other end of each supporting bar is used for supporting the clamp main body.

Further preferably, the feet are evenly distributed on the edge of the first opening.

Further preferably, a first mounting groove for mounting the bracket is formed at the first opening edge of the upper part of the tray; one end of the supporting leg is arranged in the first mounting groove and is detachably fixed through a bolt; the other end of the supporting leg and one end of the supporting bar are detachably fixed through bolts; and the top of the other end of the supporting bar is convexly provided with a supporting ball for supporting the clamp main body.

Further, the wafer warp measurement clamp further comprises clamping pins, and a track for the clamping pins to slide towards the clamp main body is arranged on the tray.

Further preferably, the clamping pin is provided with a strip-shaped through hole along the track direction and an elastic bolt which can pass through the strip-shaped through hole, the track is provided with an elastic bolt hole matched with the elastic bolt, and the clamping pin can be fixed on the track by the elastic bolt; the track is a clamping foot groove arranged on the tray, and the depth of the clamping foot groove is the same as the thickness of the clamping foot.

A wafer warpage measuring method, using the wafer warpage measuring system, comprises the following steps:

(1) Determining the distance L between the upper laser and the lower laser through a calibration laser piece;

(2) The method comprises the steps that the distances from the upper surface and the lower surface of a wafer to the upper laser and the lower laser are detected through the upper laser and the lower laser respectively, the distance L1 from the upper laser to the upper surface of the wafer and the distance L2 from the lower laser to the lower surface of the wafer are obtained through difference calculation, and the absolute thickness of the wafer is L-L1-L2;

(3) And establishing a wafer thickness model through scanning the whole upper surface and the whole lower surface of the wafer, and calculating to obtain the wafer warpage.

Compared with the prior art, the invention has the beneficial effects that:

the wafer warp measurement system has the advantages of simple structure and simple and convenient operation. In the in-service use process, through the structural design of the wafer warp measurement clamp, convenience and operability of sample taking and placing can be guaranteed, the probability of sample breakage is reduced, and meanwhile, the test accuracy is further designed and ensured through the positioning assistance of the fixing piece.

The wafer warpage measurement method has high accuracy and can well meet the use of the non-standard wafer warpage measurement.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:

fig. 1 is a schematic top view of a wafer warp measurement jig.

Fig. 2 is a schematic view of a bottom view of a wafer warp measurement jig.

Fig. 3 is a schematic perspective view of a wafer warp measurement jig.

Fig. 4 is a schematic top view of the tray.

Fig. 5 is a schematic perspective view of a tray.

Fig. 6 is a perspective view of the first structure of the jig main body.

Fig. 7 is a second perspective view of the clamp body.

Fig. 8 is a perspective view of the bracket.

Fig. 9 is a perspective structural view of the support bar.

Fig. 10 is a perspective view of the clip leg.

FIG. 11 is a schematic diagram of a wafer warp measurement system.

Wherein:

1-a tray, 11-a first opening, 12-a tray mounting groove, 13-a clamping foot groove, 14-a tightening bolt hole, 15-a first mounting groove and 16-a first mounting hole;

2-fixing pieces, 21-supporting strips, 211-supporting strip fixing holes, 212-supporting balls, 22-supporting feet, 221-supporting foot fixing holes and 222-supporting strip mounting slots;

3-a clamp body, 31-a second opening, 32-a third opening, 33-a step, 34-a boss;

4-clamping feet, 41-strip-shaped through holes, 42-clamping angle fixing holes and 43-clamping foot bulges;

5-a measuring platform;

6-upper laser;

7-a lower laser;

8-calibrating the laser device;

9-clamp mounting opening.

Detailed Description

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments are shown, for the purpose of illustrating the invention, but the scope of the invention is not limited to the specific embodiments shown.

Unless defined otherwise, all technical and scientific terms used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the scope of the present invention.

Example 1

As shown in fig. 1 to 11, the present embodiment discloses a wafer warpage measurement system.

The wafer warp measurement system comprises a measurement platform 5, a wafer warp measurement clamp, a laser, a calibration laser device 8 and a data processing system, wherein a clamp installation opening 9 for horizontally placing the wafer warp measurement clamp is arranged on the measurement platform 5, the wafer warp measurement clamp is horizontally arranged in the clamp installation opening 9, the laser comprises an upper laser 6 and a lower laser 7 which are respectively arranged at the upper end and the lower end of the wafer warp measurement clamp, the upper laser 6 and the lower laser 7 are positioned on the same vertical line, and a laser connecting line of the upper laser 6 and the lower laser 7 is perpendicular to the measurement platform 5; the calibration laser device 8 is arranged on the measurement platform 5, and in this embodiment, the calibration laser device 8 is located at the upper right corner of the measurement platform 5 and is relatively independent from the wafer warpage measurement fixture; the data processing system is electrically connected with an upper laser 6, a lower laser 7 and a calibration laser device 8.

In this embodiment, the wafer warpage measuring fixture includes a tray 1, a fixing member 2, a fixture body 3, and a clamping leg 4; a tray mounting groove 12 matched with the clamp mounting opening 9 is formed in the periphery of the tray 1; the middle of the tray 1 is provided with a first opening 11 penetrating through the upper end and the lower end of the tray 1; the clamp body 3 is arranged in the first opening 11 through the fixing piece 2, one end of the fixing piece 2 is fixed with the tray 1, and the other end of the fixing piece 2 is fixed with the clamp body 3; the middle of the clamp main body 3 is provided with a second opening 31 penetrating through the upper end and the lower end of the clamp main body 3; the bottom of the clamp body 3 is provided with a step 33 for placing a wafer along the edge of the second opening 31, and the top of the step 33 is flush with the bottom of the clamp body 3.

Referring to fig. 6 and 7, as one of the preferred aspects of the present embodiment, the second opening 31 has a rectangular structure, the step 33 includes a rectangular ring structure disposed around the second opening 31, a boss 34 for placing a wafer is disposed on an inner side of the rectangular ring structure, and at least three bosses 34 are disposed. In this embodiment, four bosses 34 are provided, four bosses 34 are respectively disposed at four corners of the rectangular annular structure, the structure of the bosses is a fan-shaped structure with an arc of 90 °, and the bosses and the rectangular annular structure are integrally formed. In this embodiment, the size of the inner opening and the second opening of the rectangular ring structure are the same, and are one of 20×30mm, 25×30mm, 30×30mm, and 40×40 mm; the depth of the second opening is 0.5mm; the thickness of the step is 0.5mm; the width of the rectangular annular structure is 1mm.

Referring to fig. 8 and 9, as one of the preferred embodiments of the present embodiment, the fixing member 2 includes at least three sets of supporting legs 22 and supporting bars 21, the supporting legs 22 are fixed to the edge of the first opening 11 of the tray 1, one end of the supporting bars 21 is fixed to the supporting legs 22, and the other end of the supporting bars 21 is used for supporting the clamp body 3. In this embodiment, three brackets 22 are disposed adjacent to each other and are uniformly and fixedly distributed at intervals on the edge of the first opening 11. In this embodiment, a first mounting groove 15 for mounting a bracket 22 is provided at the edge of the first opening 11 of the tray 1; one end of the supporting leg 22 is arranged in the first mounting groove 15 and is detachably fixed through a bolt, and a first mounting hole 16 matched with the bolt is formed in the first mounting groove 15; the other ends of the supporting legs 22 and one end of the supporting bar 21 are detachably fixed through bolts; the top of the other end of the supporting bar 21 is provided with a supporting ball 212 for supporting the clamp body 3. In this embodiment, two supporting leg fixing holes 221 are formed on the supporting leg 22, two supporting leg fixing holes 211 adapted to the supporting leg fixing holes 221 are formed on the supporting leg 21, a supporting leg mounting groove 222 for inserting the supporting leg 21 is formed at one end of the supporting leg 22, the supporting leg mounting groove 222 penetrates through the two supporting leg fixing holes 221, and the supporting leg 21 is inserted into the supporting leg mounting groove 222 until the supporting leg fixing holes 221 and the supporting leg fixing holes 211 are communicated, and bolts are used to penetrate and fasten the supporting leg fixing holes.

Referring to fig. 10, as one of the preferable aspects of the present embodiment, the tray 1 is provided with a rail on which the clip leg 4 slides toward the clip body 3, and the clip leg 4 is slidable on the rail. In this embodiment, the clamping leg 4 is provided with a strip-shaped through hole 41 along the track direction and an elastic bolt capable of penetrating through the strip-shaped through hole 41, the track is provided with an elastic bolt hole 14 adapted to the elastic bolt, and the elastic bolt can fix the clamping leg 4 on the track; the track is a clamping foot groove 13 arranged on the tray 1, and the depth of the clamping foot groove 13 is the same as the thickness of the clamping foot 4. In this embodiment, the clamp body 3 is provided with the third opening 32 towards the direction of the clamping pin 4, the clamping pin 4 is provided with two clamping pin protrusions 43, and the two clamping pin protrusions 43 respectively abut against two sides of the opening of the third opening 32, so that the clamp body 3 is further fixed and limited. In this embodiment, the clamping leg 4 is further provided with a clamping leg fixing hole 42 for fixing the clamping leg 4, and a fastening bolt adapted to the clamping leg fixing hole 42 is provided, so that after the clamp body 3 is fixed and limited, the position of the clamping leg 4 in the clamping leg groove 13 is further fixed through the fastening bolt and the clamping leg fixing hole 42.

Example 2

The present embodiment provides a wafer warp measurement method using the wafer warp measurement system in embodiment 1. The method comprises the following steps:

(1) Determining the distance L between the upper laser and the lower laser through a calibration laser piece;

(2) The method comprises the steps that the distances from the upper surface and the lower surface of a wafer to the upper laser and the lower laser are detected through the upper laser and the lower laser respectively, the distance L1 from the upper laser to the upper surface of the wafer and the distance L2 from the lower laser to the lower surface of the wafer are obtained through difference calculation, and the absolute thickness of the wafer is L-L1-L2;

(3) And establishing a wafer thickness model through scanning the whole upper surface and the whole lower surface of the wafer, and calculating to obtain the wafer warpage.

Specifically, in the measurement process, the whole wafer can be divided into a plurality of areas to cover the whole wafer for scanning, then the actual scanning data are integrated to construct a whole wafer material deformation map, and each independent scanning area scanning data comprises the absolute thickness of the point material, the deviation of the upper surface and the lower surface distance and the offset of the point from the center point.

The specific construction method comprises the following steps: and taking the positions of the upper laser and the lower laser as central planes, measuring the thickness at the center of the wafer as reference thickness, taking the reference thickness as a reference central plane, and constructing a sample morphology graph according to the reference central plane and the offset of different position points from the reference central plane. Thus, a material bending graph is constructed theoretically to obtain the material warpage, i.e. the difference between the highest point and the lowest point.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. The wafer warp measurement system is characterized by comprising a measurement platform, a wafer warp measurement clamp, a laser, a calibration laser device and a data processing system, wherein a clamp installation opening is formed in the measurement platform, the wafer warp measurement clamp is horizontally arranged in the clamp installation opening, the laser comprises an upper laser and a lower laser which are respectively arranged at the upper end and the lower end of the wafer warp measurement clamp, the upper laser and the lower laser are positioned on the same vertical line, a laser connecting line of the upper laser and the lower laser is perpendicular to the measurement platform, and the calibration laser device is arranged on the measurement platform; the data processing system is electrically connected with the upper laser, the lower laser and the calibration laser device;

the wafer warp measurement clamp comprises a tray, a fixing piece and a clamp main body;

the middle of the tray is provided with a first opening penetrating through the upper end and the lower end of the tray; the clamp body is arranged in the first opening through a fixing piece, one end of the fixing piece is fixed with the tray, and the other end of the fixing piece is fixed with the clamp body;

the middle of the clamp main body is provided with a second opening penetrating through the upper end and the lower end of the clamp main body; the second opening edge of anchor clamps main part bottom is equipped with the step that is used for placing the wafer, the top of step and the bottom parallel and level of anchor clamps main part.

2. The wafer warp measurement system of claim 1, wherein the second opening is a rectangular structure, the step comprises a rectangular ring-shaped structure disposed around the second opening, a boss for placing a wafer is disposed on an inner side of the rectangular ring-shaped structure, and at least three bosses are disposed.

3. The wafer warp measurement system of claim 2, wherein the bosses are provided in four, the four bosses being provided at four corners of the rectangular ring-shaped structure, respectively.

4. The wafer warp measurement system of claim 2, wherein the rectangular ring-like structure inner opening and the second opening are the same size, being one of 20 x 30mm, 25 x 30mm, 30 x 30mm, 40 x 40 mm; the depth of the second opening is 0.5mm; the thickness of the step is 0.5mm; the width of the rectangular annular structure is 1mm.

5. The wafer warp measurement system of claim 1, wherein the fixture comprises at least three sets of support legs and support bars configured to be mated, the support legs being secured to the first open edge of the tray, one end of the support bar being secured to the support legs, and the other end of the support bar being configured to support the clamp body.

6. The wafer warp measurement system of claim 5, wherein the standoffs are uniformly distributed at the first opening edge.

7. The wafer warp measurement system of claim 5, wherein a first opening edge of the upper portion of the tray is provided with a first mounting slot for mounting a pedestal; one end of the supporting leg is arranged in the first mounting groove and is detachably fixed through a bolt; the other end of the supporting leg and one end of the supporting bar are detachably fixed through bolts; and the top of the other end of the supporting bar is convexly provided with a supporting ball for supporting the clamp main body.

8. The wafer warp measurement system of any one of claims 1-7, wherein the wafer warp measurement jig further comprises a clamping foot, and the tray is provided with a track for sliding the clamping foot towards the jig main body.

9. The wafer warpage measurement system of claim 8, wherein the clamping leg is provided with a strip-shaped through hole along the track direction and an elastic bolt capable of penetrating the strip-shaped through hole, the track is provided with an elastic bolt hole matched with the elastic bolt, and the elastic bolt can fix the clamping leg on the track; the track is a clamping foot groove arranged on the tray, and the depth of the clamping foot groove is the same as the thickness of the clamping foot.

10. A wafer warp measurement method, characterized in that the wafer warp measurement system according to any one of claims 1 to 9 is used, comprising the steps of:

(1) Determining the distance L between the upper laser and the lower laser through a calibration laser piece;

(2) The method comprises the steps that the distances from the upper surface and the lower surface of a wafer to the upper laser and the lower laser are detected through the upper laser and the lower laser respectively, the distance L1 from the upper laser to the upper surface of the wafer and the distance L2 from the lower laser to the lower surface of the wafer are obtained through difference calculation, and the absolute thickness of the wafer is L-L1-L2;

(3) And establishing a wafer thickness model through scanning the whole upper surface and the whole lower surface of the wafer, and calculating to obtain the wafer warpage.