阅读说明：本技术 一种在线校准晶圆微纳米台阶高度标准样板及其循迹方法 (On-line calibration wafer micro-nano step height standard template and tracking method thereof ) 是由 王琛英 张雅馨 蒋庄德 景蔚萱 林启敬 刘明 张易军 韩枫 毛琦 王松 杨亚威 于 2019-09-26 设计创作，主要内容包括：本发明公开了一种在线校准晶圆微纳米台阶高度标准样板及其循迹方法,用于实现在线校准,样板包括中心工作区域及第一、第二循迹区域；通过所述微纳米台阶高度标准样板的第一循迹区域和第二循迹区域内的等腰三角形循迹标识的指向配合设计单位标识确定样板的摆放方向与中心工作区域位置；通过所述中心工作区域内台阶结构左右两侧区域设置的四种循迹定位参考图形快速定位台阶结构位置,通过台阶结构两边对称设置的校准定位块快速定位台阶测量位置,完成整个定位过程。该样板上的台阶结构是在晶圆片上直接制备,并且台阶测量区域可通过循迹标记快速定位,因此该发明实现了对微电子集成电路产线中纳米测量仪器的在线溯源校准工作,大大提高了仪器校准效率。(The invention discloses an on-line calibration wafer micro-nano step height standard template and a tracking method thereof, which are used for realizing on-line calibration, wherein the template comprises a central working area, a first tracking area and a second tracking area; determining the placing direction and the position of the central working area of the template through the pointing direction of isosceles triangle tracking marks in a first tracking area and a second tracking area of the micro-nano step height standard template and the design unit marks; and the step structure is quickly positioned by four tracking positioning reference patterns arranged in the left and right side areas of the step structure in the central working area, and the step measurement position is quickly positioned by the calibration positioning blocks symmetrically arranged at the two sides of the step structure, so that the whole positioning process is completed. The step structure on the sample plate is directly prepared on the wafer, and the step measurement area can be quickly positioned through the tracking mark, so that the invention realizes the online tracing calibration work of the nanometer measurement instrument in the microelectronic integrated circuit production line, and greatly improves the instrument calibration efficiency.)

1. The on-line calibration wafer micro-nano step height standard template is characterized by comprising a wafer, wherein the surface of the wafer sequentially comprises a first tracking area (1), a second tracking area (4) and a central working area (6) from outside to inside;

a first tracking mark (2) pointing to a second tracking area (4) is arranged on the first tracking area (1),

the second tracking area (4) is provided with a first frame, and a second tracking mark (5) pointing to the central working area (6) is arranged in the first frame;

the central working area (6) is provided with a second frame, a step structure (10) is arranged in the second frame, and a plurality of groups of calibration positioning blocks (12) are symmetrically distributed on two sides of the step structure (10); the other areas inside the second frame are provided with a plurality of tracking and positioning reference patterns.

2. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the tracking positioning reference pattern is a digital ruler (11), a square frame (9), an isosceles triangle (8) and a square matrix (7); the digital scale (11) is positioned on one side of the plurality of calibration positioning blocks (12), and the square frame (9), the isosceles triangle (8) and the square matrix (7) are arranged at equal intervals and are respectively and longitudinally arranged on the other side of the plurality of calibration positioning blocks (12).

3. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the calibration positioning block (12) is a directional structural pattern; a plurality of groups of calibration positioning blocks (12) are distributed in the longitudinal range of the step structure (10) with certain lengths of the upper end and the lower end removed at equal intervals.

4. The on-line calibration wafer micro-nano step height standard template as claimed in claim 3, wherein the structural pattern is rectangular, triangular, trapezoidal or arrow-shaped.

5. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the first tracking marks (2) are arranged along a radial direction of the first tracking area (1), and the first tracking marks (2) are sequentially arranged to point to a first frame of the second tracking area (4); the second tracking marks (5) are uniformly distributed in the first frame, and the second tracking marks (5) point to the second frame.

6. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the first frame and the second frame are both square structures, and the geometric centers of the first frame and the second frame are coincident.

7. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the first tracking area (1) is further provided with a design unit identifier (3) for determining the placing direction of the wafer micro-nano step height standard template.

8. The on-line calibration wafer micro-nano step height standard template as claimed in claim 1, wherein the wafer micro-nano step height standard template is a unit structure with a whole wafer, the step structure (10) is directly prepared at the center of the wafer, and the specific preparation method is as follows:

wherein, the step structure with the step height more than 200nm is formed by uniformly coating photoresist on a wafer substrate, then exposing and developing, finally carrying out dry etching, and etching to obtain the required step height by controlling the number of etching circulation steps;

the step structure with the step height smaller than 200nm is prepared by growing oxide on a substrate by an atomic layer deposition technology, wherein the thickness of the oxide is the required step height, and then etching by a wet method.

9. The tracking method for the on-line calibration of the wafer micro-nano step height standard template as claimed in any one of claims 1 to 8, comprising the following steps:

determining the placing direction of the wafer micro-nano step height standard template and the position of a second tracking area (4) through a first tracking mark (2) and a design unit mark (3) on the first tracking area (1), and realizing preliminary quick positioning;

further determining the position of a central working area (6) of the wafer micro-nano step height standard template through a second tracking identifier (5) in a second tracking area (4);

rapidly positioning the step structure (10) in the central working area (6) through tracking positioning reference figures arranged in areas at two sides of the step structure (10) in the central working area (6);

the measuring position of the stepped structure (10) is rapidly positioned through the calibration positioning blocks (12) symmetrically arranged at two sides of the stepped structure (10), and the whole positioning process is completed.

10. The tracking method for the on-line calibration wafer micro-nano step height standard template according to claim 9, characterized in that: when using the nanometric measuring instrument for measurement, the lens of the instrument is focused on the tracking and positioning reference pattern within said central work area:

if a digital scale (11) appears in the visual field, determining the specific position of the current lens on one side of the calibration positioning block (12) according to the scale value of the digital scale (11);

if a part of graph of a square frame (9), a part of graph of an isosceles triangle (8) or a part of graph of a square matrix (7) appears in the visual field, determining the specific position of the current lens on the other side of the calibration positioning block (12);

and then the positioning platform of the operating instrument is moved to the position of the calibration positioning block (12) to quickly position the measurement position of the step structure (10), thereby completing the whole positioning process.

Technical Field

The invention relates to the technical field of micro-nano-scale precision measurement, in particular to a height standard template for calibrating a micro-nano step of a wafer on line and a tracking method thereof, which are used for calibrating a nano measuring instrument in a microelectronic integrated circuit production line on line.

Background

The nanometer standard substance is used as a substance carrier of nanometer geometric quantity, and is an important transfer medium for realizing the transfer of nanometer size from standard devices of national measurement standard departments to actual production and manufacturing.

In order to put the micro-nano step height standard template into industrial application, carry out online tracing calibration on a nano measuring instrument in a microelectronic integrated circuit production line and improve calibration efficiency, the development of the wafer micro-nano step height standard template which can be quickly positioned by utilizing a tracking mark and provides online calibration is very important.

Disclosure of Invention

In order to solve the problem of low online traceability calibration efficiency in the prior art, the invention provides the standard template for online calibrating the height of the micro-nano step of the wafer.

The invention also provides a tracking method for calibrating the wafer micro-nano step height standard template on line, which can realize the on-line tracing calibration work of the nano measuring instrument in the microelectronic integrated circuit production line and greatly improve the instrument calibration efficiency.

In order to achieve the purpose, the invention adopts the following technical means:

a standard template for calibrating the height of a wafer micro-nano step on line comprises a wafer, wherein the surface of the wafer sequentially comprises a first tracking area, a second tracking area and a central working area from outside to inside;

the first tracking area is provided with a first tracking mark pointing to the second tracking area,

the second tracking area is provided with a first frame, and a second tracking identifier pointing to the central working area is arranged in the first frame;

the central working area is provided with a second frame, a step structure is arranged in the second frame, and a plurality of groups of calibration positioning blocks are symmetrically distributed on two sides of the step structure; the other areas inside the second frame are provided with a plurality of tracking and positioning reference patterns.

As a further improvement of the invention, the tracking positioning reference graph is a digital scale, a square frame, an isosceles triangle and a square matrix; the digital scale is positioned on one side of the plurality of calibration positioning blocks, and the square frame, the isosceles triangle and the square matrix are arranged at equal intervals and are respectively and longitudinally arranged on the other side of the plurality of calibration positioning blocks.

As a further improvement of the invention, the calibration positioning block is a directional structural pattern; and a plurality of groups of calibration positioning blocks are distributed in the longitudinal range of the stepped structure after the upper end and the lower end of the stepped structure are removed by a certain length at equal intervals.

As a further improvement of the invention, the structural figure is a rectangle, a triangle, a trapezoid or an arrow.

As a further improvement of the present invention, the first tracking marks are arranged along a radial direction of the first tracking area, and the first tracking marks are sequentially arranged to point to a first frame of the second tracking area.

As a further improvement of the present invention, the second tracking marks are uniformly distributed in the first frame, and the second tracking marks are all directed to the second frame.

As a further improvement of the invention, the first frame and the second frame are both in a square structure, and the geometric centers of the first frame and the second frame are superposed.

As a further improvement of the invention, the first tracking area is further provided with a design unit identifier for determining the placing direction of the wafer micro-nano step height standard template.

As a further improvement of the invention, the wafer micro-nano step height standard template takes the whole wafer as a unit structure, the step structure is directly prepared at the center of the wafer, and the specific preparation method comprises the following steps:

wherein, the step structure with the step height more than 200nm is formed by uniformly coating photoresist on a wafer substrate, then exposing and developing, finally carrying out dry etching, and etching to obtain the required step height by controlling the number of etching circulation steps;

the step structure with the step height smaller than 200nm is prepared by growing oxide on a substrate by an atomic layer deposition technology, wherein the thickness of the oxide is the required step height, and then etching by a wet method.

The tracking method for the on-line calibration of the wafer micro-nano step height standard template comprises the following steps:

determining the placing direction of the wafer micro-nano step height standard template and the position of a second tracking area through a first tracking identifier and a design unit identifier on the first tracking area, and realizing preliminary quick positioning;

further determining the position of a central working area of the wafer micro-nano step height standard template through a second tracking identifier in a second tracking area;

rapidly positioning the step structure in the central working area through tracking positioning reference patterns arranged in the areas on two sides of the step structure in the central working area;

the measuring position of the step structure is quickly positioned by the calibration positioning blocks symmetrically arranged at two sides of the step structure, and the whole positioning process is completed.

Preferably, when measurements are made using a nanometric measuring instrument, the lens of the instrument is focused on a tracking and positioning reference pattern within said central working area:

if a digital scale appears in the visual field, determining the specific position of the current lens on one side of the calibration positioning block according to the scale value of the digital scale;

if a square frame part graph, an isosceles triangle part graph or a square matrix part graph appears in the visual field, determining the specific position of the current lens on the other side of the calibration positioning block;

and then the positioning platform of the operating instrument is moved to the position of the calibration positioning block to quickly position the measurement position of the step structure, thereby completing the whole positioning process.

Compared with the prior art, the invention has the following advantages:

the on-line calibration wafer micro-nano step height standard template takes the whole wafer as a unit structure, and can obtain step height characteristic dimensions from hundreds of micrometers to nanometers through different preparation methods; the design of four tracking positioning reference graphs is adopted, and the position of the step structure is quickly positioned by judging the position of the tracking positioning reference graph; the calibration positioning blocks are symmetrically arranged on two sides of the step structure respectively, and the measurement position of the step is quickly positioned through the calibration positioning blocks, so that the nanometer measurement instrument is calibrated more quickly and conveniently. The isosceles triangle tracking marks and the design unit marks in the first and second tracking areas are beneficial to quickly determining the placing direction and the central working area position of the sample plate before calibrating the step height, and the measuring efficiency is greatly improved. The step structure on the sample plate is directly prepared on the wafer, and the step measurement area can be quickly positioned through the tracking mark, so that the invention realizes the online tracing calibration work of the nanometer measurement instrument in the microelectronic integrated circuit production line, and greatly improves the instrument calibration efficiency.

The tracking method of the invention is characterized in that isosceles triangles in a first tracking area and a second tracking area of a wafer micro-nano step height standard template are calibrated on line and point to match with a design unit identifier, the placing direction of the wafer micro-nano step height standard template and the specific position of a central working area can be rapidly determined, and when a lens of a nano measuring instrument focuses on the first tracking area and the second tracking area, the positioning is carried out through corresponding observed identifiers, so that a positioning platform of the instrument is conveniently moved to a position required during measurement, and the measurement efficiency is greatly improved.

Drawings

Fig. 1 is a schematic plan view of an overall structure of an embodiment of the standard template for calibrating the height of the wafer micro-nano step on line according to the invention.

FIG. 2 is a schematic plane view of a second tracking area structure of an embodiment of the standard template for calibrating the height of the micro-nano step of the wafer on line according to the invention.

FIG. 3 is a schematic plane view of a central working area structure of an embodiment of the standard template for calibrating the height of the wafer micro-nano step on line according to the present invention.

In the figure: 1. a first tracking area; 2. a first tracking identifier (e.g., an isosceles triangle); 3. designing a unit identifier; 4. a second tracking area; 5. a second tracking identifier (e.g., an isosceles triangle); 6. a central work area; 7. a square matrix; 8. an isosceles triangle; 9. a square frame; 10. a step structure; 11. a digital scale; 12. and calibrating the positioning block.

Detailed Description

The following detailed description of the present invention will be made with reference to the accompanying drawings, but the present invention is not limited to the embodiments. In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention.

As shown in fig. 1 to 3, the present invention provides an on-line calibration wafer micro-nano step height standard template, which includes a central working area 6, a first tracking area 1, and a second tracking area 4; the central working area 6 is provided with a step structure 10, six calibration positioning blocks 12 and four tracking positioning reference patterns.

The on-line calibration wafer micro-nano step height standard template takes a whole wafer as a unit structure, and a step structure 10 is directly prepared at the center of the wafer, wherein the step structure with the step height of more than or equal to 200nm is prepared by dry etching, and the step structure with the step height of less than 200nm is prepared by combining an atomic layer deposition technology and wet etching.

The step structure 10 is rectangular and is located at the center of the central working area. The six calibration positioning blocks 12 are divided into three groups in pairs, and the three groups are symmetrically distributed on two sides of the step structure, and the three groups of positioning blocks are distributed in the longitudinal range of the step structure with the upper end and the lower end removed by a certain length at equal intervals. The four tracking positioning reference figures are different and respectively are a digital scale, a square frame, an isosceles triangle and a square matrix. The digital scale is positioned on the left side of the three groups of calibration positioning blocks, and the square frame, the isosceles triangle and the square matrix are respectively and longitudinally arranged on the right side of the three groups of positioning blocks.

The second tracking area 4 is guided to the central working area through the direction marked by the isosceles triangle tracking. The first tracking area 1 points to the second tracking area 4 through four straight lines formed by isosceles triangle tracking marks. The first tracking area is also provided with a design unit mark 3.

The on-line calibration wafer micro-nano step height standard template takes the whole wafer as a unit structure, and the step structure is directly prepared at the center of the wafer. Wherein, the step structure with the step height more than 200nm is formed by uniformly coating photoresist on a wafer substrate, then exposing and developing, finally carrying out dry etching, and etching to obtain the required step height by controlling the number of etching circulation steps; the step structure with the step height smaller than 200nm is prepared by growing oxide on a substrate by an atomic layer deposition technology, wherein the thickness of the oxide is the required step height, and then etching by a wet method.

Two calibration positioning blocks in each set of calibration positioning blocks 12 of the central working area 6 are symmetrically distributed on two sides of the stepped structure 10 respectively, the calibration positioning blocks are shaped as directional structural figures, such as rectangles, triangles, trapezoids, arrows and the like, and can provide reference positions for measuring calibration steps, and three sets of positioning blocks are distributed in a longitudinal range of the stepped structure 10 without certain lengths at the upper end and the lower end.

In the four tracking positioning reference patterns of the central working area 6, the vertical digital scale is positioned at the central position of the central working area on the left side of the three groups of calibration positioning blocks. The square frames, the isosceles triangles and the square matrixes are arranged at equal intervals and are positioned at the center of the right area of the three groups of calibration positioning blocks. The four tracking reference positioning patterns and the step structure are integrally arranged in a 'Chuan' shape.

The second tracking area 4 is provided with isosceles triangle tracking marks at equal intervals with the central working area as the center, and can be guided to the central working area of the sample plate center by pointing to different isosceles triangles. The first tracking area is provided with four straight lines formed by equispaced arrangement of isosceles triangle tracking marks by taking the second tracking area as a center, and the isosceles triangle vertex angles point to the frame vertex angles corresponding to the second tracking area respectively.

The invention also provides a tracking method for calibrating the wafer micro-nano step standard template on line, which comprises the following steps:

four straight lines formed by isosceles triangle tracking marks are matched with the design unit mark 3 to determine the placing direction of the wafer micro-nano step height standard sample plate and the position of the second tracking area 4 in the first tracking area of the on-line calibration wafer micro-nano step height standard sample plate, so that preliminary quick positioning in measurement is realized. And further determining the position of the central working area of the wafer micro-nano step height standard template through the isosceles triangle tracking identification in the second tracking area. Four tracking positioning reference figures arranged in the left side area and the right side area of the step structure in the central working area 6 are used for quickly positioning the step structure in the central working area. The measuring position of the step is quickly positioned by the calibration positioning blocks symmetrically arranged at two sides of the step structure, so that the whole positioning process is completed.

Isosceles triangles in a first tracking area 1 and a second tracking area 4 of the on-line calibration wafer micro-nano step height standard template point to a matching design unit mark 3, the placing direction of the wafer micro-nano step height standard template and the specific position of a central working area can be rapidly determined, and when a lens of a nano measuring instrument focuses on the first and second tracking areas, the positioning is carried out through corresponding observed marks, so that a positioning platform of the instrument can be conveniently moved to a position required by measurement, and the measurement efficiency is greatly improved.

When the nanometer measuring instrument is used for measuring, the lens of the instrument focuses on the tracking positioning reference pattern in the central working area 6, and if the digital scale 11 appears in the visual field, the specific position of the current lens on the left side of the calibration positioning block can be determined through the scale value of the digital scale 11. If a square frame part graph, an isosceles triangle part graph and a square matrix part graph appear in the visual field, the specific position of the current lens on the right side of the calibration positioning block can be determined. And then the positioning platform of the operating instrument is moved to the position of the calibration positioning block to quickly position the measurement position of the step, thereby completing the whole positioning process.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.