JPS5893338A - Evaluating method for quality of silicon single crystal wafer - Google Patents

Abstract

PURPOSE:To detect and evaluate the state of the generation of the heat-treatment induced defect of a Si single crystal wafer in a nondestructive manner by preparing the X-ray diffraction image of the silicon wafer annealed through an X-ray diffraction topography. CONSTITUTION:A thermal oxide film is formed to the main surface section of the Si wafer, which uses a (100) crystal face or a (111) crystal face as a main surface, through thermal oxidation treatment. The Si wafer to which the thermal oxide film is shaped is annealed in a nitrogen atmosphere. The X-ray diffraction image is prepared through the X-ray diffraction topography employing the characteristic X-rays of molybdenum in the (220) crystal face of the Si wafer.

Description

[Detailed Description of the Invention] This invention is a silicon (Si') I# crystal utsu-/'i
(hereinafter abbreviated as "Si wafer").

Usually, for substrates of semiconductor devices such as large-scale semiconductor integrated circuits (LSIs), a seed crystal is immersed in a 81 melt made by melting 81 polycrystals in a quartz melt heated with a carbon heater and rotated. The so-called Czochralski (
(OzOchralski) method (hereinafter referred to as “C2 method”)
A Si wafer made from a 81 single crystal according to the authors is used. Inside the S1 single crystal produced by this C2 method,
During the growth process of this 81 single crystal, a large amount of oxygen and carbon are released from the quartz heater and the carbon heater, respectively. Contains about am carbon.

In this way, when manufacturing a semiconductor device using a Si wafer made from an S1 single crystal containing oxygen and carbon, in the heat treatment process such as thermal oxidation and impurity diffusion, the S1 wafer contains Crystal defects such as stacking faults with oxygen and carbon as the core are induced, oxygen and carbon precipitates are formed, and carbon increases the occurrence of crystal defects with oxygen as the core. These crystal defects with oxygen and carbon as the core and oxygen and carbon precipitates are
This is called a heat treatment-induced defect.

When this heat treatment-induced defect is formed on the main surface of the B1 wafer where the active region of the semiconductor device is formed, the heat treatment-induced defect significantly deteriorates the electrical characteristics of the semiconductor device. To this end, conventional methods for evaluating the quality of 81 wafers include a method of measuring the mold cavity and carbon content in the Si wafer by absorption of infrared rays; After forming a thermal oxide film with a thickness of about 15.0OOA, this thermal oxide film was
tl) Etching liquid fc Lti Sec: 7 (Sec
co) Etching away using an etching solution to expose the main surface of the Si wafer, and observing the state of occurrence of heat treatment-induced defects on the exposed main surface of the Si wafer, and determining the formation of dislocation pits due to heat treatment-induced defects. The so-called O8 method, which performs counting, is used. By the way, 8
This is because the relationship between wR:I# and carbon content and the occurrence of heat treatment-induced defects is not fully clarified by the method of measuring the content of oxygen and carbon in a wafer. It is not possible to make a one-to-one correspondence between the measured values of oxygen and carbon content and the occurrence of heat treatment-induced defects. In addition, in the 08 method, since this method observes the occurrence of heat treatment-induced defects in the main surface where the active region of the semiconductor device of the 81 wafer is formed, the occurrence of heat treatment-induced defects inside the 81 wafer cannot be observed at all. Unable to detect and evaluate. However, it is difficult to detect and evaluate the occurrence of heat treatment-induced defects inside the 81 wafer.
'
A so-called intrinsic getter in which the strain field due to heat treatment-induced defects absorbs the heat treatment-induced defects generated on the main surface of the B1 wafer.
This is essential to effectively utilize the effects.

For the occurrence of such heat treatment-induced defects in S1 wafers,
This Si wafer was created and the 81 single crystal properties such as the content of oxygen and carbon in the single crystal, the thermal history received during the crystal growth of the 1 single crystal on this day, and the 81 wafer is a semiconductor. Since the manufacturing conditions such as the heat treatment temperature, heat treatment time, and number of heat treatments (b) during the device manufacturing process are involved, the thermal sensation 4 vs. defect occurrence state of this B1 wafer is detected and evaluated to determine the quality of the semiconductor device. Conventionally, in order to optimize manufacturing efficiency, it has been necessary to conduct numerous experiments by repeatedly conducting Σ-destructive inspection using the OS method. It was impossible to detect and evaluate the

This invention was made in view of the above points, so S1
After forming a thermal oxide film on the main surface of the wafer and annealing the S1 wafer on which the thermal oxide film was formed, this Si
The present invention aims to provide a novel method for non-destructively detecting and evaluating the state of occurrence of heat treatment-induced defects in this S1 wafer by creating an xi diffraction image based on X-ray diffraction topography of the wafer and using this X-ray diffraction image.

Hereinafter, a method for evaluating the quality of a QSi wafer according to an embodiment of the present invention in the case of manufacturing a bipolar semiconductor integrated circuit device (IC) will be described.

In the method of this embodiment, first, a heat treatment step of 950 to 1
A first step of forming a thermal oxide film on the main surface of the S1 wafer with the (100) crystal plane or the (ill) crystal plane as the main surface by thermal oxidation treatment at a temperature of 150°C for 10 to 20 hours; A second step was performed in which the 81 wafer on which the oxide film was formed was annealed at a temperature of 950 to 1280° C. for 5 to 10 hours in a nitrogen atmosphere, and the S1 wafer was subjected to the first and second steps. X using characteristic X-rays of molybdenum (Mo) on the (2go) crystal plane of
Create an X-ray diffraction image using line diffraction topography. The X-ray diffraction image created at this time was (2
20) Since it is formed on a crystal plane, the state of occurrence of heat treatment-induced defects inside this 81-quafer is shown.

As shown in the X-ray diffraction image of wafer 81 in Fig. 1(a), when heat treatment-induced defects are observed on the entire surface of wafer 81, Fig. 1('b) shows the X-ray diffraction image of wafer 81. As shown in the optical photograph of the main surface of the 81 wafer, no heat treatment-induced defects were observed on the main surface of the 81 wafer.

Conversely, if no heat treatment-induced defects are observed on the entire surface of the Si wafer, as shown in the X-ray diffraction image in Figure 2(a), the optical As shown in the photograph, heat treatment-induced defects are clearly observed on the main surface of this S1 wafer. In addition, as shown in the X-ray diffraction image in FIG. 3(a), when heat treatment-induced defects are observed only at the peripheral edge of the Si wafer, the X-ray diffraction image shown in FIG. 3(b)
As shown in the optical photograph, heat treatment-induced defects are observed in the central portion of the main surface of this S1 wafer other than the peripheral portion. From the above, it is easily understood that the strain field due to the heat treatment-induced defects generated inside the Si wafer absorbs the heat treatment-induced defects generated on the main surface of the silicon wafer.

Next, the oxygen concentration at the head on the seed crystal side of the 81 single crystal pulled by the CZ method (1,8X 1018 fi atoms/am3) and the oxygen concentration at the tail on the 81 fusion side (1,5X 1018 atoms/am3) - Assessing the quality of S1 wafers made from the head, center and tail of each of the first and second 81 single crystals, which are considered to be identical when measured by infrared absorption. Another example is shown in Figure 4 (a
) and (b) will be explained.

In the method of this embodiment as well, the first and second 8
After completing the above-mentioned first and second steps of 81 wafers made from the head, center and tail of each single crystal and having the (100) crystal plane or (1XX) crystal plane as the main surface, these An X-ray diffraction image is created by X-ray diffraction topography using MO characteristic X-rays on the (220) crystal plane of the 81 wafer.

Figure 4 (ay- is 81 created from the head (a), center (b), and tail of the 1@1081 single crystal, respectively.
An X-ray diffraction image of the wafer is shown.

As shown in FIG. 4(a), the head of the first 81 single crystal (
No heat treatment-induced defects were observed on the entire surface of the Si wafers prepared from a), center (b), and tail ←→, and the quality was the same from the head to the tail of the first 81 single crystal. I understand that.

Figure 4(b) shows S1 made from the head (a), center (b) and tail (c) of #I2 81 single crystal.
An X-ray diffraction image of the wafer is shown.

As shown in Figure 4(b), the head of the second 81 single crystal (
The occurrence of heat treatment-induced defects is observed on the entire surface of the S1 wafer created from the central region (b) and the center region (b), but no heat treatment-induced defects are observed on the entire surface of the S1 wafer created from the center region (b). As a result, the crystal orientation of the head (a) and tail part If1 of the 81 single crystal of M2 and the central part (
It can be seen that the crystal orientation of (b) is different.

As described above, in each of the above embodiments, it is possible to non-destructively detect and evaluate the state of occurrence of heat treatment-induced defects in the 81 wafer, and this can be performed on a bipolar IC manufacturing line.

In each of the above embodiments, the characteristic X-ray of MO is used, but this is not necessarily limited to the characteristic x1m of MO, and characteristic X-rays of other tungsten, copper, etc. may also be used.

Although the above has been described using an example of manufacturing a bipolar type semiconductor device, the present invention is not limited to this, but can also be applied to manufacturing other semiconductor devices such as MO8 type semiconductor devices. As explained above, in the 81 wafer quality evaluation method of the present invention, the 81 wafer I
After forming a thermal oxide film on the main surface of the S1 wafer and annealing the wafer 81 on which the thermal oxide film was formed, an X-ray diffraction image was created using the X-ray diffraction topography of this S1 wafer, and this X-ray diffraction image This method detects and evaluates the occurrence of heat treatment-induced defects in the 81-way I. Therefore, it is non-destructive and can be performed on the manufacturing line of semiconductor devices.

[Brief explanation of the drawing]

Figures 1(a), 2(al) and 3(a) show X-ray diffraction images based on an 81 way/S X-ray diffraction topography in one embodiment of the present invention, and Figure 1(b) , second
Figure (b) and Figure 3 (b) are respectively Figure 1 (a) and Figure 3 (b).
The above S1 ueno 1 in FIGS. 2(a) and 3(a)
An optical photograph of the main surface portion etched by the 08 method is shown. Figures 4 (&) and (b) are respectively created from the head (a), center (b) and tail C→ of the first and second 81 single crystals in other embodiments of the present invention. X of 81 wafers @X by diffraction topography
A line diffraction image is shown. Agent Makoto Kuzuno (1 other person) Procedural amendment (method) Mr. Commissioner of Patent J1■, Minor case indication Patent application No. 194696-1983 2
, Name of the invention Quality evaluation method for silicon single crystal wafers: (, Person making the correction 6, Figure 4 (,) and (b) of the drawing to be corrected 7. Contents of correction Tll Figure 1 of the drawing (,) and (b) are corrected as shown in the attached drawings. 8. After correction of the attached documents q) Drawing 1 showing Figure 4 (a) and (b) Procedural amendment (voluntary) Patent Office Mr. Secretary, 1, Matter (Display of 'I' Patent Application 1983-194696
No. 2, Title of the invention Quality evaluation method for silicon single crystal wafers 3, Person making the amendment 5, Detailed description of the invention in the specification subject to amendment 6, Contents of the amendment (1) Page 9 of the specification In lines 7 to #I8 and page 9, line 8 K, "crystal orientation" is corrected to "crystal quality."that's all

Claims (1)

[Claims] (1) Silicon single crystal wafer!・A step of forming a thermal oxide film on the main surface of the wafer, annealing the silicon single crystal wafer 1 on which the thermal oxide film is formed, and an X-ray analysis by X-ray diffraction topography of the annealed silicon single crystal wafer. It includes a step of creating a diffraction image,
A method for evaluating the quality of a silicon single crystal wafer, comprising detecting and evaluating the state of occurrence of heat treatment-induced defects in the silicon single crystal wafer using the X-ray diffraction image.