阅读说明：本技术 一种晶片翘曲度的测量方法 (method for measuring warping degree of wafer ) 是由 周志豪 刘建飞 杨柳 施明向 吕建满 于 2019-09-03 设计创作，主要内容包括：本发明公开了一种晶片翘曲度的测量方法,包括以下步骤：先获取参考点阵图像数据,再获取被测点阵图像数据,最后控制终端通过分析计算参考点阵图像数据以绘制出参考晶片边际线轮廓,控制终端通过分析计算被测点阵图像数据以绘制出被测晶片边际线轮廓,计算被测晶片边际线轮廓相对于参考晶片边际线轮廓的偏移量,就可得出晶片的翘曲度值,以来分析判断晶片边缘的整体形态。采用上述技术方案后,采用影像方式撷取晶片边际线的方式计算,可节省雷射光束的机构建置成本,同时CCD相机可与外观检验同时使用,可降低检验与量测机台的成本,更有利于业界所需；能够对成叠的晶片外观进行快速的检测,检验效率提高了30％以上。(The invention discloses a measuring method of kinds of wafer warping degree, which comprises the following steps of firstly obtaining reference lattice image data, then obtaining measured point array image data, finally, a control terminal analyzes and calculates the reference lattice image data to draw a reference wafer marginal line outline, the control terminal analyzes and calculates the measured point array image data to draw a measured wafer marginal line outline, calculates the offset of the measured wafer marginal line outline relative to the reference wafer marginal line outline, and then obtains the warping degree value of the wafer to analyze and judge the integral shape of the wafer edge.)

1, A method for measuring warpage of wafer, comprising the steps of:

step , obtaining reference dot matrix image data, namely, reflecting light rays irradiated on marginal lines of the edge of the reference wafer to an image acquisition element, acquiring the reference dot matrix image by the image acquisition element, and storing the coordinate data of each key point in the reference dot matrix image as the reference dot matrix image data through a control terminal;

step two: acquiring measured dot array image data: the light rays irradiated on the marginal line of the edge of the wafer to be measured are reflected to the image acquisition element, are acquired by the image acquisition element to obtain an array image of the point to be measured, and the coordinate data of each key point in the array image to be measured are stored as the array image data of the point to be measured through the control terminal;

step three: the control terminal analyzes and calculates the reference dot matrix image data to draw a reference wafer edge line profile, the control terminal analyzes and calculates the measured dot matrix image data to draw a measured wafer edge line profile, and calculates the offset of the measured wafer edge line profile relative to the reference wafer edge line profile to obtain the warping value (wave value is peak a + valley b) of the wafer so as to analyze and judge the integral shape of the wafer edge.

2. The method for measuring the warpage of wafers as claimed in claim 1, wherein the second step comprises irradiating the light reflected from the light source (6) onto the edge line of the wafer (1) to be measured, which is horizontally rotated, via the reflector (5) and the beam splitter (2), diffusely reflecting the surface of the wafer (1) to be measured, receiving the reflected light via the beam splitter (2), and focusing the reflected light onto the image capture element (3), the image capture element (3) transmitting the electrical signals of different pixels to the image capture card via the photoelectric effect of the photodiode therein, and converting the electrical signals into corresponding gray values, and accumulating the gray values to obtain the image of the wafer to be measured and outputting the image to the computer (4).

3. The method of kinds of wafer warp degree measurement according to claim 1, wherein the marginal lines of the wafer edge are composed of a surface marginal line and a bottom marginal line.

4. The method of claim 1, wherein the light emitted from the LED light source is the same as the light emitted from the reference wafer, and the wavelength of the light is 535nm and the bandwidth of the light is 30 nm.

5. The method of measuring the warpage of wafers according to claim 1, wherein the image sensor is a CCD camera or a CMOS sensor.

Technical Field

The invention relates to a method for measuring warpage of an wafer.

Background

The warpage of the wafer is mostly obtained by surface scanning analysis, after the wafer is taken out by a detecting machine with a robot (robot), the wafer is placed on a carrying platform, a sensor (sensor) is used to collect signals, and the signals are transmitted to an exchanger for analysis, and various wafer characteristic parameters such as Thickness, ttv (total Thickness variation), Warp, Bow, etc. are obtained. Although more accurate wafer values can be obtained, the measurement efficiency is low because the arm needs to take 1 wafer and 1 wafer for measurement, and the measurement analysis process should be more optimized because the transportation of the arm easily causes the contamination and static electricity generated by the contact and sliding between the wafer and the cassette.

The edge of the chip also needs to be inspected for corner chipping (chipping) or crack (crack), and the current technology is mostly performed by image recognition, but since the chip is divided into three parts, i.e. an upper surface, a lower surface and an end surface, 3 lenses are needed to capture the edge image and then determine when a lens (CCD) is mounted for sampling, which is costly.

Disclosure of Invention

In view of the above problems, the present invention provides methods for measuring wafer warpage.

In order to solve the technical problem, the technical scheme adopted by the invention is that the method for measuring the warpage of the wafer comprises the following steps:

step , obtaining reference dot matrix image data, namely, reflecting light rays irradiated on marginal lines of the edge of the reference wafer to an image acquisition element, acquiring the reference dot matrix image by the image acquisition element, and storing the coordinate data of each key point in the reference dot matrix image as the reference dot matrix image data through a control terminal;

step two: acquiring measured dot array image data: the light rays irradiated on the marginal line of the edge of the wafer to be measured are reflected to the image acquisition element, are acquired by the image acquisition element to obtain an array image of the point to be measured, and the coordinate data of each key point in the array image to be measured are stored as the array image data of the point to be measured through the control terminal;

step three: the control terminal analyzes and calculates the reference dot matrix image data to draw a reference wafer edge line profile, the control terminal analyzes and calculates the measured dot matrix image data to draw a measured wafer edge line profile, and calculates the offset of the measured wafer edge line profile relative to the reference wafer edge line profile to obtain the warping value (wave value is peak a + valley b) of the wafer so as to analyze and judge the integral shape of the wafer edge.

, irradiating the light on the marginal line of the edge of the wafer to be tested, which rotates horizontally, after passing through the reflector and the spectroscope, generating diffuse reflection on the surface of the wafer to be tested, receiving the reflected light through the spectroscope, focusing the reflected light on the image collecting element, transmitting the electric signals of different pixels to the image collecting card through the photoelectric effect of the photodiode in the image collecting element, converting the image collecting card into corresponding gray value, and accumulating the gray value as the image of the array to be tested and outputting the image to the computer.

Further , the marginal line of the wafer edge is comprised of a surface marginal line and a bottom marginal line.

Further , the light impinging on the reference wafer and the light impinging on the measured wafer are the same light and the light is emitted from the LED light source, wherein the light has a wavelength of 535nm and a bandwidth of 30 nm.

And , the image acquisition element is a CCD camera or a CMOS photosensitive element.

From the above description of the structure of the present invention, compared with the prior art, the present invention has the following advantages:

1. the kinds of chip warp degree measuring method provided by the invention adopts the image mode to capture the chip boundary line for calculation, which can save the mechanism construction cost of laser beam, and simultaneously the CCD camera can be used with the appearance inspection, which can reduce the cost of the inspection and measuring machine, and is more beneficial to the industry.

2. The wafer warping degree measuring method provided by the invention can be used for rapidly detecting the appearance of stacked wafers (such as the appearance corner collapse detection of wafers after crystal bars are cut or ground), and the detection efficiency is improved by more than 30%.

Drawings

The accompanying drawings, which form a part hereof , are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention.

In the drawings:

FIG. 1 is a schematic diagram illustrating the operation of wafer warpage measuring methods according to the present invention;

FIG. 2 is a schematic diagram of the outline of the marginal line (surface marginal line and bottom marginal line) of the measuring method of warpage of wafers;

FIG. 3 is a schematic diagram of a wafer defect in wafer warpage measurement methods according to the present invention;

FIG. 4 is a comparison graph of the edge line profile of the reference wafer and the edge line profile of the tested wafer for the wafer warpage measurement methods of the present invention.

1. The wafer 2 to be tested, the spectroscope 3, the image acquisition element 4, the computer 5, the reflector 6 and the light source.

Detailed Description

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

In the description of the present invention, it is to be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

In the description of the present invention, it should be noted that unless otherwise specifically stated or limited, the terms "mounted," "connected," and "connected" are used to mean, for example, either fixedly or removably connected or physically connected, mechanically or electrically connected, directly or indirectly connected through an intermediary, or communicating between two elements.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.