JPS58135636A - Heat treatment equipment for semiconductor wafer - Google Patents

Abstract

PURPOSE:To enable to perform heat treatment eliminated with the temperature difference inside of the reaction tube face of the heat treatment equipment when the semiconductor wafers of the plural number are to be taken in and out from the reaction tube by a method wherein the condition of the most suitable temperature rise or temperature drop is bestowed to the whole wafers. CONSTITUTION:Non contacting temperature detecting means 8, 9 measure the temperatures at the voluntary points on the surfaces of the semiconductor wafers w1, wn to input the results thereof to a control means 10, while a scanning means to make the non contacting temperature sensors 8, 9 to transfer in the vertical, lateral, and voluntary directions is provided, and the transferring direction and the distance thereof are controlled by the control means 10. Independent heating elements a1-an having temperature sensors and equipped circularly at the circumference of the core tube 1 are set respectively at the voluntary temperatures according to the informations outputted from the control means 10 to form temperature distribution of voluntary largeness at the voluntary positions in the core tube 1. An autoloader 5 controls the rotation of a motor according to the informations outputted from the control means 10, and by pushing and drawing a connected quartz bar 4, a wafer-boat 3 mounting the semiconductor wafers of the plural number is made to transfer into the inside of the core tube 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat treatment apparatus for semiconductor wafers, and more particularly to a heat treatment apparatus for semiconductor wafers that prevents the occurrence of defects such as wafer warpage or slip dislocation in manufacturing processes that perform various heat treatments. It is something.

When manufacturing semiconductor devices, for example, ICs.

Usually, semiconductor wafers such as silicon are placed in parallel in a boat so that the wafers are parallel to each other, and the boat is placed in a cylindrical reaction tube so that its main surface is perpendicular to the axis of the reaction tube. The semiconductor wafer is heated at K such that the semiconductor wafer is subjected to a predetermined heat treatment.

Since these heat treatments are usually performed at high temperatures, dislocations such as warping and slipping of the wafer occur, causing poor characteristics of the wafer and significantly reducing the yield of semiconductor device manufacturing.

Conventionally, when loading and unloading the boat into and out of the reaction tube, in order to minimize the slippage, an automatic sample moving means (hereinafter referred to as an autoloader) was used to load the wafers at the slowest possible speed. , and consideration has been given to things like loading and unloading.

However, when the processing concentration becomes high temperature, the above-mentioned measures are not sufficient, and in order to prevent defects such as dislocations and to show the temperature distribution, a rod-shaped heating element 2 is installed in the length direction of the reaction tube 1.
It has a mountain-shaped temperature gradient that decreases toward the front and rear of the reaction tube 10, centered around the soaking zone (area where the temperature is constant at 11 degrees) shown by the broken line. Therefore Kf
f When a semiconductor wafer is inserted into or pulled out from the reaction tube 1, the semiconductor wafer placed at the front of the reaction tube 1 and the wafer placed at the rear of the reaction tube 1 are heated according to the temperature gradient inside the reaction tube 1. Each semiconductor wafer has a different temperature.

Further, as shown in FIG. 2, in the semiconductor wafer W placed on the wafer boat 3 of FIG. 1, each point a + in the plane
There is a temperature difference between b + e Hd +, and this temperature difference causes warpage, slip dislocation, etc.

This temperature difference that occurs within the wafer surface is unavoidable in conventional heat treatment.In other words, in the conventional method, as shown in FIG. Temperature difference Δ occurring between a and C
t (because c is in contact with the wafer boat 3, the cooling rate is faster than other points, and the temperature is relatively lower than other points), so Running slips tended to occur more easily.

In order to prevent the occurrence of this slip as much as possible, the conventional method
In order to make t as small as possible, it took a long time to load and unload the wafer.

However, in actual semiconductor manufacturing processes, it is not a good idea to take a long time to load and unload wafers for reasons such as time efficiency of the process and reduction of manufacturing costs.

Normally, in the manufacturing of semiconductor devices, this type of
) □ heat treatment is repeated many times, and as the material undergoes cessation, thermal distortion and defects increase, resulting in a significant decrease in the yield of the final product.

FIG. 3 schematically represents a conventional device. In the conventional apparatus, when inserting or removing a wafer from a reaction tube 1, the tip of a quartz rod 4 is fixed to the wafer or boat 3 carrying the wafer, and the terminal end is fixed to a fitting 6, and the command from the control circuit 7 is used. Accordingly, the autoloader 5 pushes the quartz rod 4 at a constant speed when inserting a semiconductor wafer, and pulls the quartz rod 4 at a constant speed when taking out a character conductor wafer.

In such a conventional apparatus, when loading and unloading the wafer boats 3 into and out of the furnace core tube 1, one of the plurality of semiconductor wafers is removed due to the temperature gradient that exists within the reaction tube 1, as shown in the first example. Even if only one semiconductor wafer was taken in and out of the reaction tube 1 under optimal conditions, this could not be guaranteed for many other semiconductor wafers 1-. Furthermore, no measures were taken to correct the temperature difference existing within the plane of the semiconductor wafer shown in FIG.

The purpose of the present invention is to eliminate the drawbacks of such conventional devices,
A large number of semiconductor wafers are placed in a reaction tube IK for heat treatment.
When loading and unloading semiconductor wafers, we provide heat treatment equipment that provides optimal temperature rise or concentration drop conditions for all semiconductor wafers, and also enables heat treatment that eliminates in-plane temperature differences for each semiconductor wafer. Then there it is.

According to the present invention, an electric furnace includes a furnace core tube and a plurality of independent heating elements that are divided so as to surround the skeleton furnace core tube in an annular manner, and a concentration sensor that detects the temperature of each heating element. and an automatic sample moving means for inserting a semiconductor wafer into the furnace core tube, and a pair of non-contact type temperature detection means for detecting the in-plane temperature of the semiconductor wafer inserted into the furnace core tube, and the non-contact method includes: A control means for controlling each of the heating elements and the automatic movement means for the sample based on the in-plane temperature of the semiconductor wafer detected by the mold temperature detection means and the temperature from a temperature sensor provided for each of the heating elements. A semiconductor wafer heat treatment apparatus is obtained.

The present invention will be specifically explained below using the drawings.

FIG. 4 shows a schematic diagram of this device, and FIG. 5 shows a view of the heating element layer side part of FIG. 4 viewed from the longitudinal direction of the furnace core tube. , cl ~(!@1
dl ~dn+et~ell fl~fm+gt~ge
thx - hll indicates divided and independent heating elements surrounding the furnace core tube, and each heating element has temperature sensors 81 to Shn that measure the humidity of the furnace core f1, which is close in amount to the respective heating element. The temperature of each part of the furnace core tube 1 obtained by the temperature sensors s&1 to Shn is inputted to the control means IO.

The sixth factor shows a view of FIG. 5 viewed from the side of the furnace core tube, and in FIG. 6, among the heating elements a1 to h, a I to a
n! e I −@tr is illustrated.

In a 1- & t* + 61 to efl in Figure 6, the temperature at each point of the furnace core t1 obtained from the temperature sensor included in each heating element, which was not shown in Figure 5, is sent to the control means 10. The input lead wire and each heating element a from the control means 10
Connect the lead wires that supply power to the heating elements a, ~a''+e)~・1 to the control means 1° and the arrows from the control means 10 to the respective heating elements. It represents.

As shown in FIG. 4, the non-contact humidity and temperature detection means 8 and 9 are equipped with a non-contact temperature sensor that detects the temperature of the sample using a silicon 7 cell, and is equipped with an automatic focusing mechanism. The temperature at any point on the surface is measured and the result is input to the control means 10.

The non-contact temperature detection means 8.9 each have a scanning means (not shown) for moving the non-contact temperature sensor 8.9 in any direction such as up and down, left and right, and the movement direction of the scanning means and the distance are controlled by the control means 10.

It was attached in a ring around the furnace core vl. The independent heating elements 11 to 11, each having a temperature sensor, are each set to an arbitrary temperature based on the information output by the control means 10, thereby creating a temperature distribution of an arbitrary size at an arbitrary position within the furnace core t1. .

The auto loader 5 pushes or pulls the quartz rod 4 connected to the auto p-goo 5 by controlling the rotation of the motor equipped with the auto loader KA based on the information output from the control means lO. do. As a result, the wafer boat 3 carrying a plurality of semiconductor wafers is transferred to the furnace core tube l.
move inside.

FIG. 7 is a block diagram showing the control means 1o in FIG. 4.

Wafer Wj measured by non-contact temperature detection means 8, 9,
The surface temperature of W is input to a wafer surface temperature measurement section 11, passes through an A/D converter 12, and is input to a comparison calculation section 14.

In the scanning mechanism 11III section 13 of the non-contact temperature detection means, the infrared thermometer 8 is moved by a vertical driving mechanism 19, a horizontal driving mechanism 20, and a horizontal driving mechanism 20. The non-contact temperature detection means 9 drives a vertical drive mechanism 21 and a left-right drive mechanism 22 provided therein to detect the non-contact temperature detection means 8,
Move 9 to any position.

The furnace core tube temperature input section 15 includes temperature sensors 81 to IJ for the independent heating elements a1 to h, respectively.

The temperature of the furnace core tube l at the point in contact with is input. The temperature side chamber value of the furnace core tube 1 containing the furnace core tube temperature input section 15 is A/
The signal is input to the comparison calculation section 14 via the D converter 16.

In the heating element power control section 17, each heating element a1 to a Adjust the power supplied to the optimum heating element among h.

The auto 1112-goo control unit 18 is an auto-loader.
5 is controlled to move the wafer boat 3 within the furnace core tube 1.

Furthermore, depending on the case, the moving speed of the auto/four-goo 5 is adjusted based on the value output from the comparison calculation section 14.

Regarding the wafer surface temperature, the comparison calculation unit 14 calculates A/
The temperatures at arbitrary points on the surfaces of the wafers W4 and VB measured by the non-contact temperature detection means 8 and 9 through the D converter 12 are inputted, and the temperature of the heat-treated wafers W1 and W1 is determined by internally performing optimal calculations. W
gB surface temperature distribution for each, wl and wf
The temperature difference for individual locations of l can be determined.

Thereby, the three-dimensional temperature distribution of the entire heat-treated wafer can be determined.

Regarding the furnace core tube temperature, A is input from the core tube temperature input section 15.
/D converter 16, based on the temperature measurement values at each point of the furnace core tube 1 measured by the temperature sensors ea1 to 5hfl included in each heating element, the furnace core tube is A three-dimensional temperature distribution of the furnace core tube 1 can be created by combining the temperature distribution in the length direction of the furnace core tube 1 with the temperature distribution in the radial direction of the furnace core tube 1 in which each heating element is placed. By optimally changing the three-dimensional temperature distribution of the furnace core tube from time to time, the three-dimensional temperature distribution of the entire heat-treated wafer is controlled. This is realized by changing the value output to the heating element power control section 17 in a form suitable for the above.

Next, the operations of these control systems will be specifically explained regarding insertion of a heat-treated wafer and heat treatment.

First, when inserting a heat-treated wafer, before actually inserting the wafer into the furnace core tube 1, the heating element power control unit 17 first sets a length required for the number of heat-treated wafers in the center of the furnace core tube according to the number of heat-treated wafers. Rather, we created a somewhat longer soaking zone, and created an appropriate temperature gradient between the front and back sides of the soaking zone when viewed from the direction of insertion of the wafer into the soaking zone, as shown in Figure 1. A trapezoidal temperature gradient is created in the lateral direction of the core tube 1, and in the radial direction of the furnace core tube 1,
The heating element al-JL on the upper part of the furnace core tube is relatively close to the furnace core tube 1.
Create a radial temperature gradient that is higher than the heating element at the bottom of the heating element.

At this time, the non-contact temperature detection means 8 and 9 measure the surface temperature of the wafers Wl and W, the scanning mechanisms (19 to 22) provided therein drive the non-contact temperature detection means, and the autoloader - is stopped.

When the temperature gradient of the furnace core tube 1 described above is completed by the feedback control by the temperature sensor provided in each heating element and the heating element power control section that controls the supply to each heating element according to the predetermined value of the temperature sensor, heat treatment is performed. One end of a quartz rod 4 is fixed to a wafer port 3 on which a wafer Wi-v is placed, and the other end is fixed to a fitting 6.

Then, the auto p-pow drive mechanism 23 is driven by the auto p-pow control unit 18 at the set moving speed of the auto p-pow 5, and the heat-treated wafers W ~ v are transferred to the furnace core tube I.
K Yes, there are people.

At the same time, the non-contact temperature detecting means 8 and 9 move onto the scanning mechanism (19 to 23) provided therein to detect the heat-treated wafer w1.
~Surface temperatures at arbitrary positions in the town are measured one after another and outputted to the comparison calculation section 14, where Wl, W are input one after another from the non-contact temperature detection means 8.9.
Calculate the temperature distribution on the surfaces of Wl and Wll from the temperature measurement value of
Then, from the three-dimensional temperature distribution of the furnace core tube 1, the heating element whose set temperature should be changed and its set temperature are calculated, and the heating element and set temperature are output to the heating element power control 1117. In the heating element control unit 17, the comparison calculation 1B14 is set based on the temperature value measured by the temperature sensor 8m1 to 8h included in the heating element whose power is to be adjusted according to the information on the heating element and set temperature inputted from the comparison calculation unit 14. WIW, adjust the power supplied to reach the specified temperature.
To make the temperature distribution on the surface of The section 14 transmits information to the autoloader control section 18 to slow down the moving speed of the autoloader only until the above conditions are created by controlling the temperature of the heating element. The autoloader control 1118 slows down the moving speed of the autoloader 5 in accordance with the information input from the comparison calculation section 14.

The above operations are repeated until all of the heat-treated wafers W1-WB reach the soaking zone, at which point the OF loader 5 stops. Furthermore, the heat-treated wafer Wl v
The in-plane temperature of , , is uniform, and the heat-treated wafer W) W@
The heat treatment is started when the temperature difference disappears.

Removal of heat-treated wafers W1 to W after heat treatment is completed'
, perform the same operation as when inserting the quartz rod, pull out all the heat-treated wafers W1 to W from the furnace core tube l, and after each heat-treated wafer w1 to W and the wafer boat 3 have been sufficiently cooled, remove the quartz rod. 4 is attached to the metal fitting 6 and the wafer.
Remove from boat 3.

In the apparatus according to the present invention, which performs each process of insertion, heat treatment, and withdrawal through the operations described above, when loading and unloading wafers, the furnace core tube near the first group of optimal heating elements 11 to a is heated. By increasing the temperature of the six groups of suitable heat generating elements from d1 to d1 and the f group of suitable heat generating elements from f to f, relative to the temperature, the temperature of the wafer can be increased. Even if the time required for loading and unloading is shortened, temperature uniformity within the wafer surface is maintained, and occurrence of slips and the like is suppressed.

As a result of the above-mentioned effects, the time required for semiconductor manufacturing process is shortened, so that the cost of manufacturing semiconductor devices such as IOs can be significantly reduced.

The semiconductor wafer thermal inspection apparatus of the present invention described above has the following remarkable effects that are not found in conventional apparatuses.

1) The temperature at each point within the surface of the semiconductor wafer is continuously measured, and no temperature difference is created within the surface of the semiconductor wafer in order to give independent individual temperatures to each heating element of the waste HO in the reaction tube.

2) During heat treatment of semiconductor wafers, the temperature of both the semiconductor wafer located at the forefront and the semiconductor wafer located at the rear is continuously measured, and each heating element around the reaction tube is individually controlled to have an individual temperature. In order to give Kl), all heat-treated wafers can be heat-treated under optimal temperature conditions.
I3) Furthermore, since the temperature of the semiconductor wafer is detected outside the reaction tube, O contamination of the reaction tube, wafer boat, etc. by the non-contact temperature detection means is prevented, and further contamination of the heat-treated wafers is prevented.

Furthermore, since the non-contact temperature detection means is not exposed to high temperatures, the life of the non-contact temperature detection means is extended.

In particular, the effects described in 1) and 2) above make it possible to significantly reduce the slippage and warping of the semiconductor φ-ever, which were problems with conventional equipment, and dramatically improve the yield of semiconductor device manufacturing. can bring.

Here, the present apparatus has been specifically explained using heat treatment of semiconductor wafers as an example, but it goes without saying that it is also effective in heat treatment of wafer samples made of other materials.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional furnace core tube and the temperature gradient inside the tube. FIG. 2 is a diagram showing that there is a temperature difference at each point within the surface of a semiconductor wafer. &r bg e@ (1: Each point on the semiconductor wafer surface. Figure 3 is a schematic diagram of the conventional device. Figure 4 is a schematic diagram of the present device. s: L pipe, 3: Wafer boat, 4: Quartz rod,
5; Oshi cedar, 6: Quartz zelkova mounting with metal fittings, 8.
9: Infrared temperature needle, 10: Control circuit, wllw, - semiconductor univer (dots indicate that there are Kll number of semiconductor wafers) (arrows in the figure indicate the flow of signals between the control circuit and each device ) Figure 115 and Figure 6 show a plurality of heating elements installed around the reaction tube in the present invention. FIG. 5 is a view seen from the length direction of the reaction tube, al~hn: heating element, 8 &1~sh; temperature detection mechanism provided in the heating element. Figure 6 is a view of the reaction tube viewed from the side (arrows in the diagram indicate the flow of signals between the control circuit and each heating element).
FIG. 2 is a block diagram of the control means 10 shown in the figure, and is an internal O splitter diagram of the control means 10 inside the broken line in the figure. Areas outside the broken line indicate a detector into which information is input and equipment controlled by information output from the control means 10. The dashed-dotted lines each represent the non-contact temperature detecting means 8.9 and its driving mechanism. 11; Wafer surface temperature input unit, 12; A/D converter, 13; Scanning mechanism control unit for non-contact temperature detection means, 1
4: Ratio axis calculation section, 15: Furnace tube temperature input section, (dots indicate that a large amount of information is input/output), 16- Mo/D converter (dots indicate that a large amount of information is input/output) ),
17: heating element power control unit (the output point represents a supply line that supplies power to a large number of heating elements), 19; vertical drive mechanism provided in the non-contact type temperature detection means 8, 20; non-contact type A left/right direction drive mechanism is specified in the temperature detection means 8. 21: Vertical drive mechanism provided in the non-contact temperature detection means 9, 22: Lateral drive mechanism provided in the non-contact temperature detection means 9, 23 Ni-)Geo 1 mouth*7'T:, inside the pipe Position spear 20 3rd mouth 4th gall

Claims (1)

[Claims] An electric furnace comprising a furnace core tube, a plurality of independent ideas divided into annular surroundings around the furnace core tube, and a temperature sensor for detecting the temperature of each heating element, and the furnace core. automatic sample moving means for inserting a semiconductor wafer into the tube;
a pair of non-contact temperature detection means for detecting the in-plane temperature of the semiconductor wafer inserted into the furnace core tube, and the in-plane temperature of the semiconductor wafer detected by the non-contact temperature detection means, and the heat generation. 1. A heat processing apparatus for semiconductor wafers, comprising a control means for controlling each of the heating elements and the automatic movement means for the sample based on the temperature from a temperature riser provided for each body.