JPH0521565A - Semiconductor device and diffusion depth measuring method using the same - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device capable of easily obtaining diffusion depth, managing wafer process, and realizing a high quality wafer, and a diffusion depth measuring method using the semiconductor device. CONSTITUTION:Along one direction of a diffusion region 2a to be measured which is formed on a wafer 1, a plurality of comparison diffusion regions 2b, 2c, 2d which are different in the intervals from the region 2a are formed, a drain electrode 4 is formed on the region 2a, and source electrodes 3b, 3c, 3d are formed on the regions 2b, 2c, 2d. A gate electrode 5 is formed between the drain electrode and the source electrodes. Whether an FET structure is formed is examined about each of the pairs of the diffusion region 2a to be measured and the comparison diffusion regions 2b, 2c, 2d. About the pair in which the FET structure is formed, the interval between the source electrode and the drain electrode is measured, and the diffusion depth is obtained by multiplying the minimum value by a specified coefficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device such as a hybrid integrated circuit device and a diffusion depth measuring method using the device.

[0002]

2. Description of the Related Art FIG. 1 is a sectional structural view showing an implementation state when measuring a diffusion depth of a wafer of a semiconductor device, in which 1 is a wafer. A diffusion region 2 in which impurity atoms are diffused is formed on the wafer 1. The diffusion region 2 is partially divided, and is angle-polished obliquely downward from the upper surface at an angle θ. The length x of the hypotenuse 8 connecting the upper surface and the lower surface of the angle-polished portion of the diffusion region 2 is measured, and the length x is calculated as sin.
Multiplying θ gives the diffusion depth.

[0003]

According to the method described above, the wafer is diced, the diffusion region is angle-polished, and the length x of the hypotenuse 8 connecting the upper surface and the lower surface of this angle-polished portion is measured.
Since the diffusion depth is obtained through a complicated process of multiplying by n θ, there is a problem that it takes a long time.

The present invention focuses on the fact that there is a fixed relationship between the depth of diffusion and the length in the horizontal direction, and a plurality of comparative diffusions having different intervals with respect to a measured diffusion region formed in a semiconductor device. Forming a region, providing electrodes, and FET
The diffusion depth can be easily obtained by multiplying the minimum value of the electrode distance measured for the set of the measured diffusion area where the structure is formed and the comparison diffusion area by a predetermined coefficient, and the wafer process management Another object of the present invention is to provide a semiconductor device capable of improving the quality of a wafer and a diffusion depth measuring method using the device.

[0005]

In a semiconductor device according to a first aspect of the present invention, a plurality of comparison diffusion regions having different intervals from the diffusion region to be measured are formed along the longitudinal direction of the diffusion region to be measured, and the comparison target diffusion region is formed. A source electrode is provided on one side and a drain electrode is provided on the other side for each set of the diffusion region and the comparative diffusion region,
A gate electrode is provided between them. A diffusion depth measuring method according to a second aspect of the present invention forms a plurality of comparative diffusion regions having different distances from a measured diffusion region formed in a semiconductor device, and sets a pair of the measured diffusion region and the comparative diffusion region, respectively. A source electrode is provided on one side, a drain electrode is provided on the other side, and a gate electrode is provided between them to check whether or not an FET structure is formed. In the group in which the FET structure is formed, the source electrode and the drain are formed. The minimum value obtained by measuring the distance to the electrode is multiplied by a predetermined coefficient.

[0006]

2 is a sectional structural view showing the relationship between the distance between the source electrode and the drain electrode and the diffusion depth immediately before the change from the FET structure to the resistance structure, in which 1 is a wafer. Diffusion regions 2 and 2 are provided above the wafer 1. A source electrode 3 and a drain electrode 4 are formed on the diffusion regions 2 and 2, respectively.
Are provided, and the gate electrode 5 is provided between them. FIG. 2 shows a state immediately before the diffusion region 2 and the diffusion region 2 are short-circuited to change from the FET structure to the resistance structure, and the diffusion region 2 and the diffusion region 2 are in contact with each other. There is a certain relationship between the lateral lengths of the curved surface portions at both ends of the diffusion region 2 and the diffusion depth (Hisayoshi Yanai, Joe Nagata: Integrated Circuit Engineering (1) Process Device Technology, Corona Company p10.
2). Therefore, assuming that the diffusion depth of the diffusion region 2 is x _j , the lateral length of the curved surface portion of the diffusion region 2 is represented by k × x _j (k: type of wafer 1 and diffusion region after injection into the wafer 1) Coefficient determined by impurities forming 2). Here, when the distance between the source electrode 3 and the drain electrode 4 is x, the distance x is expressed by the following equation (1). x = 2 × k × x _j (1) From equation (1), the diffusion depth x _j is represented by the following equation (2). x _j = x / 2k (2) In the present invention, F is defined as the distance x between the source electrode and the drain electrode immediately before the FET structure is changed to the resistance structure.
The minimum value of the distance between the source electrode and the drain electrode measured for the set of the measured diffusion region in which the ET structure is formed and the comparative diffusion region is adopted. Therefore, the diffusion depth x _j can be easily obtained from the minimum value of the interval without requiring a long time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be specifically described below with reference to the drawings showing the embodiments. 3 and 4 are plan views showing an embodiment of the present invention. First, a diffusion region 2b, a diffusion region 2c, and a diffusion region, which are provided on the wafer 1 and serve as comparison diffusion regions having different distances from the diffusion region 2a along one direction of the impurity diffusion region 2a whose depth is to be measured. 2d is provided (FIG. 3). The distance from the diffusion region 2a is equal to the diffusion region 2b,
The diffusion area 2c and the diffusion area 2d are larger in this order. Next, the drain electrode 4 is provided on the diffusion region 2a, the source electrode 3b, the source electrode 3c, and the source electrode 3d are provided on the diffusion region 2b, the diffusion region 2c, and the diffusion region 2d, respectively.
The gate electrode 5 is provided between b, the diffusion region 2c, and the diffusion region 2d (FIG. 4).

A voltage is applied to the gate electrode 5, and the drain electrode 4, the source electrode 3b, the source electrode 3c, and the source electrode 3
A voltage is applied between each d. The relationship between Vsd (source-drain voltage) and Isd (source-drain current) is investigated for each set of the diffusion region 2a and the diffusion region 2b, the diffusion region 2a and the diffusion region 2c, and the diffusion region 2a and the diffusion region 2d. Show. If the graph showing the relationship between Vsd and Isd is a saturation curve, the FET structure is formed between the measured diffusion region and the comparison diffusion region, and if it is linear, the resistance structure is formed. I understand.

Here, the set of the diffusion region 2a and the diffusion region 2b, the set of the diffusion region 2a and the diffusion region 2c form the FET structure, and the set of the diffusion region 2a and the diffusion region 2d form the resistance structure. And FIG. 5 is a sectional view taken along line VV of FIG. The diffusion region 2a and the diffusion region 2c are not in contact with each other,
The FET structure is formed. FIG. 6 shows VI-VI of FIG.
It is a line sectional view. The diffusion region 2a and the diffusion region 2d intersect each other to form a resistance structure.

After determining whether the FET structure or the resistance structure is formed from the graph showing the relationship between Vsd and Isd, the distance x between the source and drain electrodes of the FET structure immediately before the resistance structure is formed is determined. Alternatively, FET
Select a value for the smallest electrode spacing in the set in which the structure is formed. Since the set of the diffusion region 2a and the diffusion region 2c corresponds to this here, the distance x between the source electrode 3c and the drain electrode 4 formed on the diffusion region 2c is measured. The diffusion depth x _j is obtained by multiplying this interval x by 1/2 k (k: a coefficient determined by the type of the wafer 1 and impurities forming the diffusion region 2 by implanting the wafer 1).

[0011]

As described above, according to the present invention, a plurality of comparative diffusion regions having different intervals from the measured diffusion region formed in the semiconductor device are formed, electrodes are provided, and an FET structure is formed. The distance between the electrodes is measured for the set of the measurement diffusion region and the comparison diffusion region, and the minimum value is multiplied by a predetermined coefficient, so that the diffusion depth can be easily obtained. Further, the present invention has excellent effects such as contribution to the management of the wafer process and the improvement of the quality of the wafer.

[Brief description of drawings]

FIG. 1 is a cross-sectional structure diagram showing an implementation state of a conventional method.

FIG. 2 is a cross-sectional structural diagram showing the relationship between the distance between the source electrode and the drain electrode and the diffusion depth immediately before the change from the FET structure to the resistance structure.

FIG. 3 is a plan view showing an implementation state of the method of the present invention.

FIG. 4 is a plan view showing an implementation state of the method of the present invention.

5 is a sectional view taken along line VV of FIG.

6 is a sectional view taken along line VI-VI of FIG.

[Explanation of symbols]

1 wafer 2a diffusion area 2b diffusion area 2c diffusion area 2d diffusion area 3b source electrode 3c source electrode 3d source electrode 4 drain electrode 5 Gate electrode

Claims (2)

[Claims] 1. A plurality of comparison diffusion regions having different intervals from the measurement diffusion region are formed along one direction of the measurement diffusion region, and a set of the measurement diffusion region and the comparison diffusion region is formed. A semiconductor device, wherein a source electrode is provided on one side and a drain electrode is provided on the other side, and a gate electrode is provided between them. 2. A plurality of comparison diffusion regions having different distances from the measurement diffusion region are formed along one direction of the measurement diffusion region formed in the semiconductor device, and the comparison diffusion region and the comparison diffusion region are formed. For each set of diffusion regions, a source electrode is provided on one side and a drain electrode is provided on the other side, and a gate electrode is provided between them to check whether or not an FET structure is formed, and a set in which an FET structure is formed is formed. The diffusion depth measuring method is characterized in that the distance between the source electrode and the drain electrode is measured, and the minimum value of the measured distance is multiplied by a predetermined coefficient to obtain the diffusion depth.