JPS62843Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a semiconductor wafer polishing apparatus.

Polishing liquids with mechanochemical action are used in polishing semiconductor wafers.
Processing ability is greatly influenced by the temperature of the polishing liquid. Further, if the temperature rises excessively during polishing, in the case of a surface plate or single-sided polishing apparatus for polishing semiconductor wafers, thermal deformation will occur in the substrate holding the semiconductor wafer, reducing polishing accuracy. Therefore, it is necessary to accurately measure the temperature of the polishing liquid that is directly acting on the semiconductor wafer during polishing. However, when measuring the temperature of the polishing liquid that is directly acting on the semiconductor wafer, single-sided polishing equipment requires
It is necessary to measure the temperature of the polishing liquid between the rotating wafer-attached substrate and the rotating polishing surface plate.
In addition, in a double-sided polishing apparatus, it is necessary to measure the temperature of the polishing liquid interposed between the rotating upper and lower polishing plates. Therefore, it is necessary to devise a method for attaching the temperature measuring element so as to immerse it in the polishing liquid and for taking out the detected temperature signal outside the polishing apparatus.

As an example of this innovation, in a single-sided polishing device, a small hole is made in the wafer-attached substrate, a thermocouple is inserted and fixed into the hole, and the tip of the thermocouple is immersed in polishing liquid.The detected temperature signal is transmitted to the wafer-attached substrate. There is a method of detecting and reading the temperature using a thermometer placed on the side opposite to the one on which it is pasted. In this method, if the wafer-attached substrate rotates during polishing,
The thermometer also rotates, making reading difficult. In addition, the thermometer is too large to be placed on the bonding substrate, and a battery must be used as a power source for the thermometer, making it heavy and placing an eccentric load on the wafer. Undesirable. In order to eliminate this inconvenience, the output from the thermocouple is taken out through a slip ring attached to the rotating shaft of the pasting substrate, and is led to a thermometer installed outside the polishing device by an electric wire.
A method of detecting and displaying the information may also be considered. Although this method made it easier to read the temperature, it required a special slip-ring mechanism to be installed around the rotating shaft, and the slip-ring was a stiffener between the stationary conductive brush and the rotating conductive ring. sliding,
Because of this mechanism, powdered powder is generated, and if this powder lands on the polishing surface plate, it will cause scratches and stains on the wafer being polished, which will seriously degrade the quality of the wafer. large and undesirable. Also in a double-sided polishing device, if the wafer-attached substrate in the single-sided polishing device described above is replaced with the upper polishing surface plate,
A similar device and its drawbacks arise.

Therefore, this idea was made based on the above circumstances, and it consists of a polishing surface plate that rotates at a constant
The present invention provides a polishing device having a mechanism for directly measuring the temperature of the polishing liquid acting on the polishing of the wafer in the polishing area of the semiconductor wafer being polished, and wirelessly detecting this temperature. be.

This invention will be described below with reference to drawings showing embodiments.

Figure 1 shows an embodiment applied to single-sided polishing, in which 1 is a rotating surface plate, 2 is a polishing cloth stuck to the surface of this surface plate, and 3 is a semiconductor wafer 4, which is held with adhesive or the like. , is a holding board that rotates independently. As shown in FIG. 2, the holding substrate 3 has a hole 5 whose center coincides with a circle where each center of the wafers 4 bonded at equal angles is located. A surface acoustic wave temperature sensor 6 is inserted. During this insertion, the tip temperature sensing portion of the temperature sensor 6 is aligned with the wafer holding surface of the holding substrate 3, or is projected by an amount smaller than the wafer thickness. Furthermore, when inserting the detector, in order to prevent temperature conduction from the outer wall of the detector, the outer wall of the detector shown in FIG. 3 is covered with a heat insulating material 8, and the detector is inserted into the hole 5 and fixed to the substrate. . A detector with a built-in oscillator is used, and an antenna for transmitting a signal is attached annularly around the rotation axis of the holding substrate 3. A thermometer (not shown) is placed outside the polishing device, and a receiver built into the thermometer receives a signal from the detector and displays the temperature.

With the above configuration, the temperature sensor 6 always comes into contact with the polishing liquid 7 flowing in the area where the semiconductor wafer 4 is rotating and revolving during polishing, and measures the liquid temperature. In addition to being able to accurately determine the processing temperature, it has also become possible to accurately control the polishing processing temperature. Additionally, because the temperature is measured wirelessly, the drawbacks of conventional methods are eliminated.

FIG. 4 shows another embodiment in which the temperature measuring element 6 is embedded in the upper polishing rotating surface plate 10 of the double-sided polishing device.
In this case as well, the embedding position is the polishing area flowing within the polishing area of the semiconductor wafer 4 which is rotated by the carrier 12 which rotates while being sandwiched between the upper polishing rotary surface plate 10 and the lower polishing rotary surface plate 11. It is desirable to measure the liquid at a location, particularly at the center of the radial width of the upper polishing surface plate. In addition, when embedding the temperature probe 6, it is necessary to choose as appropriate whether to drill a hole up to the abrasive cloth 13 as shown in FIG. 5 or 6, or to drill only the rotary surface plate. In the example shown in FIG. 6 in which no hole is made in the temperature probe 13, it is necessary to keep the temperature sensing part of the temperature probe 6 and the polishing cloth 13 in close contact with each other. In this way, the polishing liquid that has permeated the polishing cloth will definitely come into contact with the temperature sensing part, so the same effect as when holes are made can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of this invention, Fig. 2 is a plan view showing the mounting position of the temperature probe in Fig. 1, Fig. 3 is a partially enlarged sectional view of Fig. 1 above, FIG. 4 is a block diagram showing another embodiment of this invention, and FIGS. 5 and 6 are diagrams showing the embedded state of the temperature probe in FIG. 3, respectively. 4...Semiconductor wafer, 6...Temperature measuring element, 7...
...Polishing liquid.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A semiconductor wafer is polished while rotating and revolving in contact with a polishing cloth attached to a rotating substrate, with the polishing liquid interposed therebetween, and the polishing liquid that flows within the above-mentioned rotational and revolving region. A polishing apparatus for semiconductor wafers, characterized in that a wireless temperature measuring element is provided at a position in contact with a temperature measuring part. (2) The semiconductor according to claim 1 of the utility model registration claim, characterized in that a temperature measuring probe is embedded in a wafer bonded substrate at one location on a circle passing through the center of the wafer attached at equal angles. Wafer polishing equipment. (3) The semiconductor wafer polishing apparatus according to claim 1, wherein a temperature measuring probe is embedded in a central position of the radial width of the upper polishing surface plate.