JP4440356B2 - Evaluation method of semiconductor processing jig - Google Patents

Description

【００１２】
例２
ウエーハボートの製造工程ごとにサンプル溝棒のパーティクル評価を実施した結果を表２に示す。工程が進むごとの差が確認できる。
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【表２】

【００１４】
【発明の効果】
本発明は、高価な設備を使用せず、簡単な装置と液中パーティクルカウンターを使用して半導体処理用治具の研削工程のチェックをすることができる。
【図面の簡単な説明】
【図１】 パーティクル測定説明図
【符号の説明】
１ サンプル
４ 超音波槽
６ 純水[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for evaluating particles generated from a semiconductor processing jig made of quartz glass used in semiconductor manufacturing.
[0002]
[Prior art]
With the high integration of semiconductors, it is important to evaluate the particles on the wafer surface in order to ensure a fine and clean wafer surface. In addition to particle contamination from the furnace atmosphere in the semiconductor manufacturing process, It is important to evaluate particles adhering to the wafer from the processing jig.
Conventionally, as a method for evaluating particles of a quartz glass semiconductor processing jig, a wafer is mounted on a semiconductor processing jig, and after appropriate processing, particles adhering to the wafer are removed with a particle analyzer. I was analyzing directly.
Further, as disclosed in JP-A-7-183347, a simulated wafer is manufactured from a jig material and subjected to high temperature treatment in the same manner as the wafer to evaluate the influence.
[0003]
[Problems to be solved by the invention]
The conventional method requires an expensive measuring device and incidental equipment, and has a problem that it cannot be easily evaluated. An object of the present invention is to provide a method for evaluating a semiconductor processing jig made of quartz glass easily without requiring expensive equipment.
[0004]
[Means for Solving the Problems]
Conventional quartz glass semiconductor processing jigs, especially wafer boats, are baked and finished with an oxyhydrogen flame to prevent them from being damaged by scratches on the surface of quartz glass jigs. It is carried out. However, since the groove portion was deformed by the heat and the groove interval was distorted by the heat, it could not be completely baked. When the groove portion is observed in detail, the surface is considerably rough, and microcracks are generated due to the ground surface.
[0005]
Moreover, when the surface state of the groove | channel after the etching process by the inorganic acid in the manufacturing process of the jig | tool for semiconductor processing was observed, it discovered that the degree of etching was different in each.
The surface of the grinding surface has countless minute irregularities, and when a wafer is mounted on this surface, particles that become point loads are generated from the fine glass, and the wafer surface is drawn by convex portions. Particles are generated during processing due to scratches on the wafer surface.
When microcracks exist, the grinding fluid penetrates into the interior, and chips contained in the grinding fluid remain, but the chips and grinding fluid cannot be removed by the inorganic acid and remain inside, and during the processing of the wafer. Chips come out of the microcracks and cause particles.
Microcracks are cracked by stress concentration during use, and dust generated from quartz glass at this time becomes particles.
[0006]
The present invention has been found from these findings.
That is, the present invention is to immerse the sample quartz glass in pure water, apply ultrasonic vibration to the pure water, release the particles present on the quartz glass jig sample surface and inside the microcrack into the pure water by vibration, The quartz glass semiconductor jig is evaluated by counting with an in-liquid particle counter.
This makes it possible to evaluate the particles that remain without being completely removed by the semiconductor processing jig, which becomes a contamination source of the wafer.
In order to improve the reproducibility and reliability of the evaluation, the surface area of the immersed portion of the sample is set to a constant value with respect to the amount of pure water.
[0007]
In addition, by making a quartz glass sample through the same manufacturing process as a semiconductor processing jig, it is possible to perform the same predictive evaluation as when the semiconductor processing jig is used as it is. The particles can be predicted and evaluated as one member representing the manufacturing process of the jig. By carrying out like this, the particle evaluation of the semiconductor processing jig for every manufacturing process can be performed, and the manufacturing process of the semiconductor processing jig can be checked.
When ultrasonic vibration is applied for a long time, the effect of bubbles due to cavitation appears, and it appears on the counter as a large numerical value. In addition, the release of particles is small in a short time and the difference from the blank is difficult to occur. 5 minutes is preferred.
The frequency is about 24 Hz, which is frequently used in ultrasonic cleaning, and the output is about 600W.
[0008]
When ultrapure water with a specific resistance value of 18 Ω · cm or more is used, the particle size of particles in pure water is 0.5 μm or less, reducing the number of blank particles in the evaluation sample and improving reproducibility. Preferred above.
[0009]
There is a possibility that dust and dirt will re-attach to the sample surface when the sample is left in the room. For this reason, when measuring blank particles, it is necessary to remove these secondary factors as much as possible. In principle, it is preferable to measure immediately after washing or store in a clean state, but as a simple method It was confirmed that dust could be removed by washing with pure water before measuring the particles. As a condition at this time, it was found that ordinary pure water cleaning with a specific resistance value of 2 Ω · cm or more was sufficient, but at 60 ° C or more, the movement of particles in water increases, so the reattachment increases and the removal effect Therefore, the preliminary cleaning is preferably performed at a temperature of less than 60 ° C. Since cleaning in this case is only to remove secondary re-adhesion from inside the room etc., forced cleaning such as ultrasonic cleaning is never performed, and only the pure water cleaning is used to return to the state before re-adhesion. It will be.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Examples of actual evaluation are shown in the examples.
Example 1
Particles were evaluated by using pure water as a blank and using a groove rod after grinding of a semiconductor wafer boat as a sample.
An overview is shown in FIG.
In order to weaken the standing wave and make the ultrasonic wave uniform, a stainless wire rod 7 was installed in the ultrasonic tank 4. A beaker 5 filled with pure water was set in the stainless wire rod 7.
Sample 1 was hung from stand 2 with stainless steel wire 3 and immersed in pure water 6 in beaker 5. In order to keep the surface area of the immersed part of the sample to a constant value with respect to pure water, the beaker is calibrated, the scale of the water surface that has risen when the sample is immersed is read, and the amount of increase in the water level reaches a predetermined value. Thus, the sample is immersed in a non-contact state except for pure water.
Alternatively, an immersion standard line is applied to the sample itself, and the sample is suspended with a stainless steel wire above the immersion standard line and immersed in pure water up to the standard line.
In this way, comparison is made while maintaining consistency with other measurement samples, and the reproducibility and reliability of evaluation are improved.
A tube 8 for guiding the sample from the beaker 5 to a submerged particle counter (not shown) was disposed.
Ultrasonic waves of 24 KHz were added to pure water for 5 minutes through the beaker 5, and the measurement range of 0.1 to 0.5 μm and 0.5 μm or more were measured three times continuously at a measurement capacity of 100 ml / time / minute.
The measurement results are shown in Table 1.
When the particle diameter is 0.5 μm or more, there is little influence of cavitation, and particles released from the sample can be counted.
[0011]
[Table 1]

[0012]
Example 2
Table 2 shows the results of the particle evaluation of the sample groove rod for each wafer boat manufacturing process. Differences as the process progresses can be confirmed.
[0013]
[Table 2]

[0014]
【The invention's effect】
The present invention can check a grinding process of a semiconductor processing jig using a simple apparatus and a submerged particle counter without using expensive equipment.
[Brief description of the drawings]
[Fig. 1] Particle measurement explanatory diagram [Explanation of symbols]
1 Sample 4 Ultrasonic tank 6 Pure water

Claims (1)

A quartz glass sample that has been ground in the same manner as the quartz glass that forms the semiconductor processing jig is pre-cleaned with pure water with a specific resistance of 2ΜΩ · cm or higher at less than 60 ° C, and the specific resistance is 18ΜΩ · A method for evaluating a semiconductor processing jig, which is immersed in ultrapure water having a size of cm or more, ultrasonic waves are applied to the ultrapure water for 2 to 5 minutes, particles generated by the grinding process are released, and the particles are counted. .

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