JPH0437027A - Wafer retaining boat - Google Patents

Abstract

PURPOSE:To increase shape stability in a high temperature atmosphere, improve resistance to thermal stress and shock, and prevent the generation of dust and wafer defect, by constituting a plurality of retaining groove parts for retaining a semiconductor wafer by using single crystal silicon. CONSTITUTION:In circular type flat plates 1a, 1b arranged parallel to each other, aperture parts 3 for fixing both ends of, e.g., four retaining rods 2 are formed along the outer peripheries of the flat plates. On both ends of the retaining rods 2, ring type grooves for fixing the rods to the flat plates by using U-shaped fixing members 4 are formed. In the longitudinal direction of the retaining rods 2, retaining grooves 7 for engaging with the periphery of a semiconductor wafer 6 at equal intervals are formed. A longitudinal boat is constituted as follows; the flat plates 1a, 1b, the retaining rods 2 both ends of which are fixed to the flat plates, and the fixing members 4 are composed of single crystal silicon, which is formed by a CZ method, and oxygen is contained in said single crystal silicon.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wafer support boat, and the present invention relates to a wafer support boat in which a holding groove portion for supporting a semiconductor wafer is made of single crystal silicon.

[Prior Art and Problems] As is well known, as semiconductor devices become more highly integrated and have higher performance, there is an increasing demand for wafer support boats that can be used for high-temperature heat treatment and have high purity. Along with this,
In particular, vertical furnaces are used because they have excellent uniformity of temperature inside the furnace and are suitable for manufacturing highly integrated and high-performance devices.

Conventionally, as a wafer support boat (assembly type support), Japanese Patent Application Laid-open No. 107843/1984 is known.

This boat consists of two end plates, a plurality of holding rods, and a guide rod, each of which is made of quartz or silicon.

However, boats made of quartz have a problem in that they cannot withstand use at high temperatures. On the other hand, in the case of silicon boats, polycrystalline silicon is known, and although it has the advantage of being able to maintain high purity with little thermal deformation, it has defects throughout the bulk and has large internal strain stress. (50Kg/c 2), weak against thermal stress and shock due to temperature differences, and easily damaged. Furthermore, since the surface orientation of the polycrystalline silicon boat is different when the boat is manufactured, the oxide film growth rate will not be uniform when used for oxidation heat treatment. If this phenomenon occurs, especially in the multiple holding parts that hold semiconductor wafers, the uneven boat surface will damage the wafers during scooking or de-stacking, which may cause line defects (slips) during heat treatment. It causes dust generation.

The present invention has been made in view of the above circumstances, and by constructing at least the plurality of holding grooves for holding semiconductor wafers from single-crystal silicon, it has excellent shape stability in a high-temperature atmosphere. It is an object of the present invention to provide a wafer support boat that is resistant to thermal stress and impact caused by thermal quenching, can maintain high purity for a long time, and can prevent the generation of dust due to contact with wafers and the occurrence of defects in the wafers.

[Means for Solving the Problems] The present invention is a wafer support boat characterized in that at least a plurality of holding groove portions for holding semiconductor wafers are made of single crystal silicon.

In the present invention, the oxygen content is 2×1017~
It is preferable to use single-crystal silicon with a concentration of 2 X 10" atoms/Cm3. Here, the reason why the concentration of oxygen contained is limited as above is that the concentration is 2 X 10" atoms/Cm3.
If it exceeds 8toIIls/c113, crystal defects will occur on the wafer support boat.

It is easy to slip, and on the contrary, 2 x 101017ato
/ Cm3, the effect of the present invention cannot be obtained.

In addition, the above-mentioned method for measuring the oxygen content concentration is FTIR.
The conversion factor for this time is A S TM (Asetrie
an 5ociety for Testjngan
d Material) 4,81X 10”a
toms/ei2 was used. In addition, as a manufacturing method of single crystal silicon having the above-mentioned oxygen concentration range, CZ method,
An example is the MCZ method.

[Function] According to the present invention, by configuring the plurality of holding groove portions for holding at least the semiconductor urchin/% from single crystal silicon, there are no defects inside the bulk, the internal strain stress is small, and the furnace Resistant to thermal stress and shock caused by rapid heating and cooling during unloading. In addition, the crystal orientation of the boat surface is uniform on the plane, and when used for oxidation heat treatment, the oxide film growth rate is uniform and a uniform oxide film grows. Dust generation can be prevented. Therefore, the durability of the wafer support boat is significantly improved, and the occurrence of defects (scratches) on semiconductor wafers can be extremely reduced.

[Embodiment 1] Hereinafter, a vertical boat according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. Here, FIG. 1 is an overall view of the vertical boat, FIG. 2 is a schematic plan view of FIG. 1, and FIG. 3 is an explanatory diagram of a holding rod used in the boat of FIG. 1.

In the figure, la and lb are circular flat plates arranged parallel to each other. Each of these flat plates is provided with openings 3 along the outer periphery of the flat plate, into which both ends of, for example, four holding rods 2 are attached.

An annular groove 5 is provided at both ends of the holding rod 2 for fixing the rod to the flat plate using a U-shaped fixing member 4. In the longitudinal direction of the holding rod 2, holding grooves 7 for locking the peripheral edge of the semiconductor wafer 6 are provided at equal intervals.

The flat plates 1a, 1b and the holding rod 2 are each made of single crystal silicon formed by the CZ method, and the single crystal silicon contains oxygen of S x 10]8toms/Cm3.

The vertical boat according to the above embodiment has a flat plate 1a.

lb, the holding rod 2 and the fixing member 4 whose ends are fixed to these flat plates are each made of single crystal silicon formed by the CZ method, and 1.6
Since the structure contains 101018ato/Cm3 of oxygen, the boat has a high physical strength against rapid heating and cooling when it is taken in and out of the furnace, and deformation of the boat can be significantly reduced. Therefore, it is possible to prevent the generation of dust due to contact with the wafer and the occurrence of defects in the wafer.

[Example 2] Compared to Example 1, the flat plates 1a and ib, the holding rod 2 whose both ends are fixed to these flat plates, and the fixing member 4 are FZ.
2 x 101017ato/c11 in the single crystalline silicon
It has a structure containing less than 3 oxygen atoms.

[Comparative Example] Compared to Example 1, the holding rod 2 and the guide rod 4 are each made of polycrystalline silicon formed by the CZ method, and the polycrystalline silicon contains 2×1017 atoms.
/cyi" is contained.

By the way, a vertical boat (made of polycrystalline silicon, oxygen concentration 2 x 10"ato
ms/cm3), and the present invention (Example 1゜2)
The vertical boat was taken in and out continuously at a speed of 2QOtxm/gin, and the amount of deformation of the boat at this time was measured, and the results shown in Table 1 below were obtained. however,
The amount of deformation of the boat refers to the levelness of the upper flat plate when the boat 11 is stood upright on a horizontal platform, as shown in FIG.

Table 1 However, in the above Table 1, the unit of each numerical value is am (excluding the number of times).

In addition, we conducted a heat resistance stress test on each of the above boats when they were inserted into a furnace maintained at 1000°C at different insertion speeds (continuously put in and taken out from the furnace 10 times), and the results are shown in Table 2 below. It became a street.

Table 2 further shows that each of the boats mentioned above was subjected to oxidation heat treatment to grow an oxide film on the surface, then the wafer was etched, kept at 900°C, put in and taken out of the oven 10 times in a row, and no slips (line defects) were observed.
We investigated the occurrence of As a result, in the case of the comparative example, slip occurred at the 8th time, but in the cases of Examples 1 and 2, it was confirmed that no slip occurred.

[Effects of the Invention] As described in detail above, according to the present invention, at least the plurality of holding groove portions for holding semiconductor wafers are made of single crystal silicon, so that it has excellent shape stability in a high temperature atmosphere and is easy to put in and take out of a furnace. It is possible to provide a wafer support boat that is resistant to thermal stress and shock caused by rapid heating and cooling during heating, maintains high purity for a long period of time, and prevents the generation of dust due to contact with wafers and the accompanying defects on the wafers.

[Brief explanation of the drawing]

FIG. 1 is an overall view of a vertical boat according to an embodiment of the present invention;
FIG. 2 is a schematic plan view of FIG. 1, FIG. 3 is an explanatory diagram of a holding rod used in the boat of FIG. 1, and FIG. 4 is an explanation for testing the levelness of boats according to the prior art and the present invention. It is a diagram. la, lb...flat plate, 2...holding rod, 3...
Opening portion, 4...fixing member, 7...retaining groove. Applicant's agent Patent attorney Takehiko Suzue Figure 3

Claims (1)

[Claims] A wafer support boat characterized in that at least a plurality of holding groove portions for holding semiconductor wafers are made of single crystal silicon.