TW436380B - A progressive chemical mechanical polisher - Google Patents

Abstract

The present invention provides a progressive chemical mechanical polisher to reduce the sharp pressure of a polish head and to prevent the wafer fracture. The progressive CMP polisher comprises a wafer head, a polishing head, a damper and a sensor. Reducing the gas flow rate by the smaller diameter of a gas outlet tube connected to the damper than the one of a gas inlet tube connected to the damper and adding the gas temporary storage between the gas inlet and outlet of the damper effectively decrease the sharp pressure range resulted from the initial gas delivery and make DP=Pwafer-Ppolish<0. Moreover, a sensor mounted in the gas tube under the gas temporary storage delivers a signal, which automatically stops related parts, to the control system of the progressive CMP polisher when the slurry membrane is broken and the slurry flows in the gas tube; therefore, the polishing wafer slips off the protection ring and fractures can be avoided during polishing.

Description

436380 V. Description of the invention (1) 5 -1 Field of the invention: The present invention relates to a chemical mechanical polishing (CMP) machine, and in particular to a method for reducing the transient pressure of a polish head gas Sharp chemical pressure mechanical polishing machine to prevent cracking of the wafer to be polished. 5-2 Background of the Invention: The chemical-mechanical polishing method is the only technology that can currently provide the ultra-large integrated circuit (ULSI) process '11 comprehensive flattening π. This technology comes from the International Business Machines Corporation (IBM), IBM After decades of development, the company has successfully applied to many products, such as osmium processors. The principle is to use a mechanical grinding method similar to the 11 sharpening knife, with appropriate chemical agents. , To flatten the contours of the wafer with varying heights and flatness. Once the parameters of various processes are properly controlled, the chemical mechanical polishing method can provide a flatness of more than 94% of the surface being polished, which is indeed quite amazing. Therefore, semiconductor factories worldwide, as well as suppliers of equipment and chemical additives, have successively invested in the development of this technology. Refer to the first figure, which shows a partial structural diagram of a conventional chemical mechanical polishing machine, which is composed of a wafer head (wafer head) 110 and a polishing head (ha 1 ^ 3〇120. Wafer head 11) Including wafer gas inlet ^ ″ = air inlet) 112, carrier firm ι14, protective ring $

Page 6 43 63 8 0 V. Description of the invention (2) wear ring 116; grinding head 120, including polishing gas inlet (polis airi η 1 e ΐ) 1 2 2. polishing gas outlet (p 〇1 ishair 〇u 11 et) 1 2 4, pad air inlet 126, slurry diaphragm 1 28. When the wafer to be polished 1 18 is placed on the wafer head 110, the carrier sheet 1 1 4 is placed on the wafer to be polished 11 8 in a flat shape, which is made of a polymer material such as plastic, rubber, etc. Then, a gas is passed in from the wafer gas inlet 112, and the gas pressure at the wafer head 110 is Pwafer ', and the pressure is uniformly pressed on the wafer 1 1 8 to be polished through the carrier 1 1 4. The role of the guard ring 11 6 is It is to prevent the wafer to be polished π 8 from slipping out of the wafer head 110 and causing the wafer to be polished to be broken. Next, a gas is passed in from the grinding gas inlet 122, and this gas will uniformly apply pressure to the grinding slurry film 1 2 8 ', which is made of a polymer material; a soft film composed of materials such as plastic, rubber, etc.' The gas outlet j 2 4 leaves, and the gas pressure at the grinding head 120 is Ppc) iish. It should be particularly noted here that the difference between the dagger heart and the dagger must be negative, that is, =-ρρ &lt; 〇 The pPoLiSh is larger than Pwafer, so that the wafer to be polished Π 8 can be closely attached to the carrier sheet 114 to perform the polishing process, if Pwafer and dagger. The difference between ^ is a positive value, ^ P = Pwafer_Ppolish> 〇 'At this time,' because it is less than ^ 'to be researched 1 a circle 11 8 can not be closely attached to the carrier sheet π 4, when the polishing process is performed = polishing wafer slip out protection The circumstance outside the circle 116 caused a break of circle 11 δ. In addition, when grinding the wafer to be polished, in addition to directly grinding the wafer to be polished with a pad (not shown in the figure), the grinding film m will also be released, so as to increase the lining gas inlet m. Gas to maintain the system as:

Page 7 436380 V. Description of the invention (3) The second figure shows a part of the gas pressure adjustment system. When the gas enters the grinding head 120 along the gas supply line 132, it must first pass through the first gas converter 136 (regulator E / P) 'Its function is that the gas pressure control system (not shown in the figure) transmits signals in a digital (digita 1) manner: it must be converted into an analog signal by this device to adjust the gas pressure sent to the grinding head 120. When the gas leaves the grinding head 1 20 along another gas line 1 34, it must also pass through the second gas converter 138 (polish pressure transducer P / I). Its role is to convert the pressure of the flowing gas from analog to digital The signal is sent back to the gas pressure control system to adjust the gas pressure to the grinding head 120. But 'At the beginning of the process of introducing gas for chemical mechanical polishing, whether it is the wafer gas inlet 112, the grinding gas inlet 122, or the gasket gas inlet 126, the pressure curve of the gas input will be as shown in the third figure. As shown in the figure, a sharp pressure transient state of gas is presented for a period of time, and then the gas pressure is gradually entered into a stable state. In the transient state of gas pressure fluctuations, due to the fluctuation of the gas pressure, It is quite large. (1) When the wafer gas pressure pressure fer is at the transient high point and the grinding fluorine pressure pPQlish is at the transient low point, the probability of Pp (3lish &gt; The circle 1 1 8 slides out of the protective ring i, causing the wafer to be polished Π8 to crack. (2) The pressure difference between Pwafer and PpoHsh is too large, resulting in a thin slurry of slurry! 28 Fracture 'During the polishing process, the slurry From

436380 V. Description of the invention (4) The rupture enters the grinding gas inlet 122 / outlet 124, and then flows along the gas supply lines 132 and 134 to the first gas converter 136 and the second gas converter 1 38, making it impossible to detect To the real gas pressure, and send a distorted signal to the gas pressure control system, resulting in incorrect gas pressure adjustment, causing DP P »afer Ppolish &gt; 0 'Slide the wafer to be polished 11 8 out of the protective ring 11 6 and break ^ 5 ~ 3 Purpose and Summary of the Invention: In view of the above-mentioned background of the invention, the conventional chemical mechanical polishing machine is liable to cause the wafers to be polished to slide out of the protective ring and break. Therefore, the present invention provides an advanced chemical mechanical polishing machine. "In order to solve the problem that the wafer to be polished slides out of the protective ring and breaks. ^ An object of the present invention is to provide an advanced chemical mechanical polishing machine to reduce the transient fluctuation of the pressure of the conveying gas and reduce DP = Pwafer —PpQlish &gt; 0 probability. 'Another object of the present invention is to provide an improved chemical mechanical polishing machine having a polishing slurry from the polishing slurry. Rupture of the stream to the gas supply line detection capabilities. The present invention relates to a progressive-type CMP machines, the wafer-based head, the polishing head, the damper, the sensing member composed of other benefits. Even using

Page 9 436380 Description of the invention (5) The diameter of the pipeline of the damper gas inlet is smaller than the line diameter of the damper gas outlet, which slows down the flow rate of the gas, and increases the gas at the damper gas inlet and the damper gas outlet. Temporary storage, to effectively reduce the transient fluctuation of pressure at the beginning and the beginning of transportation, so that DPu. ㈣ &lt; u, that is, the wafer to be polished can be closely adhered to the carrier sheet to perform the grinding process, and the wafer to be polished does not slide out of the protective ring and cause the wafer to break. . In addition, 'a sensor is installed in the gas line below the gas temporary storage tank' When the slurry is broken by the slurry film i 28 and flows in the gas line, the sensor will send a signal to the progressive chemical machinery The control system of the grinding machine automatically stops the relevant parts of the grinding machine to avoid the situation where the wafer to be polished slips out of the protective cymbal and breaks during the grinding process. 5 ~ 4 Schematic illustrations ... The first diagram is part of the structure of a traditional chemical mechanical polishing machine. The first one is a schematic diagram of a part of a gas pressure adjustment system of a conventional chemical mechanical polishing machine. The third figure is the pressure curve of the traditional chemical mechanical grinding machine. π The fourth figure is part of the structure of the advanced chemical mechanical polishing machine of the present invention ® 〇, ′. The fifth figure is a graph of the pressure of the gas introduced into the advanced chemical mechanical polishing machine of the present invention. Figures 6A and 6B show the sensing of the advanced chemical mechanical polishing machine of the present invention.

Page 10 436380 V. Description of the invention (6) Schematic diagram of the working principle of the device. Symbols of the main parts. 10 Traditional chemical mechanical polishing machine 11 0 Wafer head 11 2 Wafer gas inlet 114 Carrier sheet 11 6 Guard ring 11 8 Wafer to be polished 1 2 0 Grinding head 122 Grinding gas inlet 124 Grinding Gas outlet 126 Liner gas inlet 128 Grinding slurry film 132 Gas supply line 134 Gas supply line 136 First gas converter 138 Second gas converter 20 Advanced chemical mechanical polishing machine 2 1 0 Wafer head 21 2 Wafer gas Inlet 21 4 Carrier sheet 21 6 Guard ring 2 1 8 Wafer to be polished

436380

2 2 0 Grinding head 222 Grinding gas inlet 224 Grinding gas outlet 226 Liner gas inlet 228 Slurry film 2 3 0 Damper 232 Damper gas inlet 234 Damper gas outlet 236 Gas temporary storage 24 0 Sensor 242 launching end 2 4 4 Receiving end 5 ~ 5 Detailed description of the invention: Refer to the fourth figure, which shows a partial structural drawing of the mechanical grinding machine 20 according to the teaching theory. A wafer head 210 to be polished is placed, a polishing head 220 is provided by the polishing slurry to the wafer surface through the polishing head, and a gas input path connected to the polishing head is used for A daniper 230 to reduce the sharp pressure amplitude of the gas pressure delivered, and a gas input or output terminal connected to the grinding head or the damper to detect whether there is a flowing liquid The abnormal presence sensor (sensor) is composed of 240. Wafer head 210, including wafer gas inlet (wafei * air inlet) 212

Page 12 436380 V. Description of the invention (8), carrier firm 214, wear ring 216; grinding head 220, including polishing air inlet 222, polishing air outlet ) 224, pad air inlet 226, slurry diaphragm 228; damper 230 'includes damper gas inlet 232, damper gas outlet 234, gas temporary storage 236; sensor 240 : Contains a transmitter 242 and a receiver 244. When the wafer to be polished 218 is placed on the wafer head 210, the carrier sheet 214 is placed flat on the wafer to be polished 2 1 8 'It is made of a material of a high molecular polymer', such as plastic, rubber, etc. The round gas inlet 2 1 2 is filled with gas. Its gas pressure at the wafer head 210 is pwafer, and the pressure is uniformly applied to the wafer 2 1 8 to be polished through the carrier sheet 214, and the square guard ring 2 1 6 prevents The wafer to be polished 21 8 slides out of the wafer head 210, which causes the wafer to be polished 21 8 to break. Next, the gas is passed in from the grinding gas inlet 222, and this gas will uniformly pressure the grinding slurry film 228, and then leave from the grinding gas outlet 224. The gas pressure at the grinding head 220 is pv 1 polish. The difference must be controlled to a negative value. , Ie DP = Pwafef P »afer and! ^ Wafer ^ ^ ^ polish

Ppolish 〈By P, greater than Pwafer ′, the wafer to be polished 2 1 8 can be closely adhered to the carrier sheet 2 J 4ϋ 亍 polishing process. In addition, when grinding the wafer to be polished 218, the polishing slurry film 228 will release the polishing slurry to help more efficiently grind the to-be-polished circle '218, and at the same time, the liner gas inlet 226 will also pass in gas to maintain ^

436380 V. Description of the invention (9) We use the fourth and fifth diagrams to explain the principle of how the damper 2 works. When the gas is sunk p # 馎 k and Ge Shi are stored next to the body ^ damper gas inlet 232 into the gas temporary damper ^ into the 9th damper gas outlet 234 to leave, because the pipeline connected to the damper oxygen 屮Caliber, such as 1/4 inch, is smaller than the diameter of the pipeline due to the weeping handle * I ® body outlet 234 'for example, 3/8 inch, depending on which gas flow rate will accumulate to a larger cross-sectional area ", will slow down Can reduce the temporary j pressure (sharp pressure) amplitude of the gas pressure that has just begun to be transported. Furthermore, the chemical mechanical polishing machine 20 disclosed in the present invention is further located between the damper gas inlet 232 and the damper body outlet 234, The gas temporary storage 236 is added, which helps to reduce the transient fluctuation of the pressure of the gas that is just started. In this way, the probability of DP-Pwafer — ppQiish> can be effectively reduced, that is, the wafer to be polished 218 can be tight. Sticking to the carrier sheet 214 to enter the pestle grinding process, the wafer to be polished 2 1 8 does not slide out of the protective ring 21 6, which causes the wafer to be polished 21 8 to break. In addition, the damper 230 can also be based on actual needs , Installed on Any gas pipeline of the advanced chemical mechanical polishing machine disclosed in the invention, such as wafer gas inlet 21, gasket gas inlet 226, etc. In addition, to prevent the pressure difference between Pwa fer and Ppolish from being too large, Grinding polymer film 228 is broken. During the grinding process, the grinding polymer enters the grinding gas inlet 222 / outlet 224 from the broken part, and then flows along the gas supply line to the first gas converter and the second gas converter, making it impossible to detect Sending a distorted signal to the gas pressure control system to the true gas pressure, leading to incorrect gas pressure adjustment, causing DP = Pwafer —Ppc) lish &gt; ◦ to be studied 436380 V. Description of the invention (ίο) Grinding the wafer 2 1 8 slides out of the protective 圏 2 1 6 and breaks. The advanced chemical mechanical polishing machine disclosed in the present invention 20 is provided with a sensor 240 under a gas line 238 under the temporary gas storage 236. As shown in Figure 6B, 'When light is emitted from the transmitting end 242, under normal circumstances, it should pass through the gas in a straight line and proceed to the receiving end 244, and be received by the receiving end 244. When condensing and flowing in the gas pipeline, the sensor 240 emits; the light emitted from the end 242 will pass through an angle when it penetrates the grinding slurry, so that the receiving end 244 cannot receive the C sixth β picture). When this phenomenon occurs, the sensor 2 4 will send a signal to the control system of the progressive chemical mechanical grinding machine 2 0 (not shown in the figure) to automatically stop the relevant parts and avoid 'waiting during the grinding process'. The polishing wafer 2 1 8 slides out of the protective ring 2 1 6 and breaks. Of course, the form of the sensor is not limited to the ray line penetration type, but the light reflection type sensor and the wheel firing type can also be used. Or other sensors that can distinguish between the present and liquid in the pipeline. In addition, the sensor can also be installed on any gas line of the advanced chemical mechanical polishing machine disclosed in the present invention as needed. The above are merely preferred embodiments of the present invention, and are not intended to limit the scope of patent application for the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention shall be included in the following Within the scope of patent application.

Claims (1)

4363 80 VI. Scope of patent application 1. An advanced CMP machine includes at least: a wafer head for placing a wafer to be polished; a polishing head (po 1 i sh head), which is provided to the wafer surface via the grinding head; a damper, which is connected to the gas input path of the grinding head 'to reduce the transient pressure of the gas pressure transmitted (sharp pressure) Amplitude; and a sensor (sens 〇r), connected to the grinding head or the gas input or output end of the damper, to detect whether there is an abnormality of flowing liquid 〇2. If the scope of patent application for the first The chemical machine of the item: a mechanical grinding machine, wherein the above-mentioned damper includes at least: 'a damper gas inlet having a first pipe diameter; a damper gas outlet having a second pipe diameter, the first The two pipe diameters are larger than the first pipe diameter; and a gas temporary storage device for temporarily storing flowing gas to reduce the transient fluctuation range of the pressure of the gas being conveyed. 3. The chemical mechanical polishing machine according to item 1 of the patent application scope, wherein the above-mentioned sensor includes at least: a transmitting end 'for linearly transmitting sensing light; and a receiving end' being on the same straight line as the transmitting end On the axis for receiving the emitted sensing light. Page 16_43_63 8 〇 6. Patent application scope 4. For example, the chemical mechanical polishing machine of the patent application scope item 3, where the above-mentioned sensor, sends a signal to the chemical when it detects the flow of liquid The control system of the mechanical grinding machine makes it stop automatically. 5. For example, the chemical mechanical polishing machine of the scope of patent application: table, wherein the above-mentioned sensor 'is a penetrating sensor. 6 The chemical mechanical polishing machine according to item 1 of the patent application scope, wherein the above-mentioned sensor 'is a reflective sensor. 7. The chemical mechanical polishing machine according to item 1 of the patent application scope, wherein the above-mentioned sensor is a radiation sensor. 8. An advanced chemical mechanical polishing machine including at least: a wafer head for placing a wafer to be polished; a polishing head's polishing slurry is provided to the wafer surface through the polishing head; a damper 'In the gas input path connected to the grinding head, in order to reduce the sharp pressure amplitude of the gas pressure conveyed, the damper at least includes: a damper gas inlet having a first pipe diameter -A damper gas outlet having a second pipe diameter that is larger than the first pipe diameter: and a temporary gas reservoir for temporarily storing flowing gas; and Page 17 4363B0 VI. Scope of patent application A sensor ‘connected to one of the ports’ of the damper is used to detect the presence of abnormal liquid. 9. For example, a chemical mechanical polishing machine according to item 8 of the scope of patent application, wherein the above-mentioned sensor includes at least: a transmitting end for linearly emitting sensing light; and: a receiving end is located at the same position as the transmitting end. A linear axis is used to receive the emitted sensing light. 10. If the chemical mechanical polishing machine is applied for item 9 of the scope of the patent application, wherein the above-mentioned sensor 'sends a signal to the control system of the chemical mechanical polishing machine when a liquid is detected to flow, : Stop. 1 1. The chemical mechanical polishing machine according to item 8 of the patent application scope, wherein the above-mentioned sensor is a penetrating sensor. 1 2 · The chemical mechanical polishing machine according to item 8 of the scope of patent application, wherein the above-mentioned sensor is a reflective sensor. 1 3 · The chemical mechanical polishing machine according to item 8 of the scope of patent application, wherein the above-mentioned sensor is a radiation sensor.