TWI590293B - Apparatus and method for compensating for etch rate inhomogeneities in ICP etching and ICP etching elements - Google Patents

Description

Apparatus and method for compensating for etch rate non-uniformity in ICP etching and ICP etching element

The present invention relates to the field of semiconductor fabrication, and more particularly to an apparatus and method for compensating for etch rate non-uniformity in an ICP etch and an ICP etched element.

The 1CP (Inductively Coupled Plasma) etched element has strict requirements on the uniformity of the etching result, and it is necessary to control the unevenness within 1%. The ICP components currently used affect the symmetry of the etching results due to the asymmetry in the arrangement of the hardware structures.

As shown in FIG. 1 , it is a schematic structural diagram of an ICP etching element 1 . The ICP etching element includes a planar spiral induction coil 2 . Both ends of the induction coil 2 are connected to the RF source 3 by a lead 201 , and the ceramic RF window 103 is planarly induced by a spiral. The coil 2 is separated from the vacuum chamber 101. The vacuum chamber 101 is filled with a reactive gas. Under the action of the electromagnetic field, the gas discharge generates a plasma 102, and the semiconductor substrate 5 is etched. The cooling system 4 is disposed at the upper center of the ceramic RF window 103. The induction coil 2 is cooled.

The test results show that the position of the lead 201 affects the etching uniformity, and the etching rate near the lead 201 and the far position is unevenly distributed, and the uneven distribution is affected by the RF power, the reactive gas, and the antenna hardware. Due to factors such as setting, it is not easy to find a fixed etch rate (hot spot) or a particularly low point (cold spot), so it is impossible to effectively compensate for these non-uniform factors by other existing means. for Overcoming this effect, the arrangement positions of the leads 201 can be arranged in a symmetrical structure, such as placing the leads 201 at a central position of the ceramic RF window 103. However, in practical applications, it is difficult to obtain the symmetric arrangement of the leads 201. As shown in FIG. 2, it is a simple top view of the induction coil 2. The induction coil 2 is spirally wound, and the lead 201 is disposed on the ceramic RF window 103. On one side, if the lead 201 is to be disposed at the middle of the ceramic RF window 103, the cooling system 4 cannot be simultaneously disposed at the upper center position of the ceramic RF window 103. Once the cooling system 4 is not disposed at the center position, Uneven cooling causes new etch non-uniformities.

The present invention provides an apparatus and method for compensating for etch rate non-uniformity in an ICP etch, and an ICP etch element, which compensates for non-uniformity of etch rate by using a compensation device to obtain a uniform etch rate.

In order to achieve the above object, the present invention provides an apparatus for compensating for etch rate non-uniformity in an ICP etching, the apparatus being disposed in an ICP etched element, the ICP etched element comprising: an induction coil, the two ends of the induction coil being connected to the RF by wires a vacuum chamber, a reaction gas in the vacuum chamber generates a plasma under the action of an electromagnetic field generated by the induction coil, and etches the semiconductor substrate; the ceramic RF window isolates the induction coil from the vacuum chamber; the device includes at least one compensation And a driving device connected to the compensator, the compensator is disposed above the induction coil, and the induced magnetic field generated by the compensator cancels the electromagnetic field generated by the induction coil; According to the detected plasma distribution data, the driving device drives the compensator to move over the induction coil to adjust the density of the electromagnetic field, thereby adjusting the etching rate, so that the ICP etching element obtains a uniform etching rate; the compensator is in a potential floating state. The compensator may be an antenna made of a conductor or a conductor plate.

The compensator is of any shape.

The position of the compensator is asymmetrically distributed.

The driving device is a component that can fix the compensator and set the compensator at a predetermined position, and adjusts the influence degree on the magnetic field energy distribution in the vacuum cavity by changing the distance between the compensator and the induction coil.

The drive unit uses a mechanical fixture located above the compensator to hold the compensator in place, or the drive unit directly uses the top assembly of the ICP etched element.

The ICP etching element further includes a cooling system disposed at an upper portion of the induction coil and located at a central portion of the upper portion of the ceramic RF window to cool the induction coil.

The invention further provides a method for compensating for etch rate non-uniformity in an ICP etched component by using a compensation device, wherein the compensator in the device is disposed above the induction coil, and the induced magnetic field generated by the compensator cancels the generated by the induction coil The electromagnetic field, the compensator is connected to the driving device, and according to the detected plasma distribution data, the driving device drives the compensator to move over the induction coil to adjust the density of the electromagnetic field, thereby adjusting the etching rate and obtaining a uniform etching rate of the ICP etching element. .

The invention further provides an ICP etching component, the ICP etching component comprises: an induction coil, wherein the two ends of the induction coil are connected to the RF source by wires; a vacuum chamber, the reaction gas in the vacuum chamber generates a plasma under the action of an electromagnetic field generated by the induction coil, and etches the semiconductor substrate; the ceramic RF window isolates the induction coil from the vacuum chamber; and the compensation device includes at least one a compensator and a driving device connected to the compensator, the compensator is disposed above the induction coil, and the induced magnetic field generated by the compensator cancels the electromagnetic field generated by the induction coil; and the compensator is driven by the driving device according to the detected plasma distribution data The upper side of the induction coil moves to adjust the density of the electromagnetic field, thereby adjusting the etching rate, so that the ICP etching element obtains a uniform etching rate; the compensator is in a potential floating state, the compensator can adopt an antenna made of a conductor, or a conductor plate.

The compensator is of any shape.

The position of the compensator is asymmetrically distributed.

The driving device is a component that can fix the compensator and set the compensator at a predetermined position, and adjusts the influence degree on the magnetic field energy distribution in the vacuum cavity by changing the distance between the compensator and the induction coil.

The drive unit uses a mechanical fixture located above the compensator to hold the compensator in place, or the drive unit directly uses the top assembly of the ICP etched element.

The ICP etching element further includes a cooling system disposed at an upper portion of the induction coil and located at a central portion of the upper portion of the ceramic RF window to cool the induction coil.

The present invention compensates for non-uniformity in etch rate using a compensated device to achieve a uniform etch rate.

1‧‧‧ICP etching elements

101‧‧‧vacuum chamber

102‧‧‧ Plasma

103‧‧‧Ceramic RF window

2‧‧‧Induction coil

201‧‧‧ lead

3‧‧‧RF source

4‧‧‧Cooling system

5‧‧‧Semiconductor substrate

6‧‧‧Compensator

1 is a schematic view showing the structure of an ICP etching element in the prior art.

2 is a top plan view of an induction coil.

3 is a schematic structural view of an apparatus for compensating for etch rate non-uniformity in ICP etching provided by the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be specifically described with reference to FIG.

As shown in FIG. 3, the ICP etching element 1 of the present invention comprises an induction coil 2, and both ends of the induction coil 2 are connected to the RF source 3 by a lead 201, and an electromagnetic field generated by the etching gas in the vacuum chamber 101 is generated by the induction coil 2. The plasma 102 is generated to etch the semiconductor substrate 5, and the ceramic RF window 103 isolates the induction coil 2 from the vacuum chamber 101. The cooling system 4 is disposed at the upper portion of the induction coil 2 and located at the upper center of the ceramic RF window 103. The induction coil 2 is cooled; the induction coil 2 connected to the RF source 3 generates an electromagnetic field, and the technical characteristics and effects of the apparatus of the present invention are described below by taking the first hot spot distribution as an example. In some cases, the density of the electromagnetic field at a position closer to the lead 201 is larger, forming a "hot spot", and the density of the plasma 102 at a position closer to the lead 201 in the vacuum chamber 101 is also larger, and the semiconductor substrate 5 is etched. The rate is higher. Conversely, the density of the electromagnetic field at a position farther from the lead 201 is smaller, forming a "cold spot", and the density of the plasma 102 at a position farther from the lead 201 in the vacuum chamber 101 is also smaller. The etching rate of the substrate 5 is lower.

A compensating device is arranged in the vicinity of the induction coil 2, the compensating device comprising at least one compensator 6 and a driving device (not shown) connected to the compensator 6, the compensator 6 The compensator 6 is disposed above the induction coil 2, and a compensator 6 is disposed at a position of a "hot spot" having a higher etching rate near the induction coil 2. The compensator 6 is in a floating state (that is, not connected to a power source or a ground) by the driving device. The compensator 6 can be driven to move at different positions above the induction coil 2. The movement of the compensator 6 may be a vertical movement or a horizontal movement. When the electromagnetic field generated by the induction coil 2 passes through the compensator 6, the inductive current is induced in the compensator 6, and the induced current further generates an induced magnetic field. The induced magnetic field generated by the compensator 6 is generated by the induction coil 2 and passes through the compensator. The electromagnetic field of 6 is opposite in direction, so that the electromagnetic field generated by a part of the induction coil 2 and going down through the ceramic RF window 103 into the vacuum chamber 101 can be offset, and finally the uneven distribution of the etching rate due to factors such as the wire access end can be compensated. The energy coupled to the compensator 6 can cancel the energy coupled into the reaction chamber 101, and the set position of the compensator 6 and the distance between the compensator 6 and the induction coil 2 both affect the amount of offset energy. . The unevenness of the etching rate can be controlled within 1% by adjusting the amount of energy fed into the reaction chamber 101.

An etch rate profile above the semiconductor substrate 5 can be obtained by observing the plasma density distribution in the vacuum chamber or detecting the etching of the substrate after the etching is completed, and adjusting the compensation device of the present invention based on the detected plasma distribution data. By setting the position of the compensator 6, a more uniform substrate etching effect can be finally obtained.

The position of all compensators 6 is asymmetrically distributed. For example, the compensator 6 may be a flat conductor strip whose position is not at the center of the induction coil to compensate for the uneven distribution of the radio frequency electromagnetic field.

The compensator 6 is made of a metal material, and may be an antenna made of a conductor or a conductor plate.

The compensator 6 is of any shape. The shape of the compensator can be circular or other non-central symmetrical shape, and the specific shape can be freely selected according to the actual situation.

When the induction coil 2 or the etching apparatus is fixed, the driving device is a component that can fix the compensator 6 and set the compensator 6 at a predetermined position, and adjusts the vacuum chamber by changing the distance between the compensator 6 and the induction coil 2. The degree of influence of the magnetic field energy distribution in 101. The driving device may be a mechanical fixing device located above the compensator 6 to fix the compensator 6 at a designated position, and the driving device may also directly adopt a top component of the ICP etching component, such as a ceramic RF window 103, to compensate The device 6 is internally secured to a top component of the ICP etched component, such as a ceramic RF window 103.

The distance between the compensator 6 and the induction coil 2 is adjusted by the driving device to adjust the density of the electromagnetic field, thereby adjusting the etching rate, so that the ICP etching element obtains a uniform etching rate.

The present invention also provides a method of compensating for etch rate non-uniformity in an ICP etched component using the compensated device, which method provides a compensator 6 in the compensating device above the inductive coil 2, and the compensator 6 produces an inductive The magnetic field cancels the electromagnetic field generated by the induction coil 2, and the compensator 6 is connected to the driving device. According to the etching rate profile, the compensator 6 is driven to move over the induction coil 2 to adjust the density of the electromagnetic field, thereby adjusting the etching rate and making the ICP. The etched element is subjected to a uniform etch rate; an etch rate profile over the semiconductor substrate 5 can be obtained by observing the plasma density distribution in the vacuum chamber 101 or detecting the etching of the substrate 5 after the etch is completed.

The invention further provides an ICP etching element, the ICP etching element 1 comprises: an induction coil 2, the two ends of the induction coil 2 are connected to the RF source 3 by the lead 201; the vacuum chamber 101, the reaction gas in the vacuum chamber 101 is generated in the induction coil 2 The plasma 102 is generated by the electromagnetic field to etch the semiconductor substrate 5; a ceramic RF window 103 that isolates the induction coil 2 from the vacuum chamber 101; a cooling system 4 disposed at an upper portion of the induction coil 2 and located at an upper center of the ceramic RF window 103 to cool the induction coil 2; a compensation device Including at least one compensator 6 and a driving device connected to the compensator 6, the compensator 6 is disposed above the induction coil 2, and the induced magnetic field generated by the compensator 6 cancels the electromagnetic field generated by the induction coil 2; according to the etch rate profile, by driving The device drives the compensator 6 to move over the induction coil 2 to adjust the density of the electromagnetic field, thereby adjusting the etching rate to obtain a uniform etching rate of the ICP etching element; by observing the plasma density distribution in the vacuum chamber 101 or detecting the completion of etching An etch rate profile above the semiconductor substrate 5 can be obtained by etching the substrate 5.

The compensator 6 is made of a metal material, and may be an antenna made of a conductor or a conductor plate.

The compensator 6 is in a potential floating state.

The compensator 6 is of any shape.

The compensator 6 may comprise a plurality of conductor antennas, the position of which is asymmetrically distributed with an axis perpendicular to the center of the coil 2, and the asymmetrically distributed plurality of conductor antennas can better compensate for the plurality of plasma concentration distributions. Uneven point.

The driving means is an element which fixes the compensator 6 and sets the compensator 6 at a predetermined position to adjust the degree of influence on the magnetic field energy distribution in the vacuum chamber 101 by changing the distance between the compensator 6 and the induction coil 2.

The drive device uses a mechanical fixture located above the compensator 6 to compensate The device 6 is fixed at the designated location, or the drive unit directly uses the top assembly of the ICP etched component.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the description Various modifications and alterations of the present invention will become apparent to those skilled in the <RTIgt; Therefore, the scope of the invention should be limited by the scope of the appended claims.

1‧‧‧ICP etching elements

101‧‧‧vacuum chamber

102‧‧‧ Plasma

103‧‧‧Ceramic RF window

2‧‧‧Induction coil

201‧‧‧ lead

3‧‧‧RF source

4‧‧‧Cooling system

5‧‧‧Semiconductor substrate

6‧‧‧Compensator

Claims (13)

A device for compensating for etch rate non-uniformity in an ICP etch, the device being disposed in an ICP etch element, the ICP etch element (1) comprising: an induction coil (2), both ends of the induction coil (2) Connecting a radio frequency source (3) through a lead (201); and a vacuum chamber (101), the reactive gas in the vacuum chamber (101) generates a plasma under the action of an electromagnetic field generated by the induction coil (2) (102) etching a semiconductor substrate (5); a ceramic RF window (103) that isolates the induction coil (2) from the vacuum chamber (101); wherein the device includes at least one compensator (6) and a driving device connected to the compensator (6), the compensator (6) is disposed above the induction coil (2), and the induced magnetic field generated by the compensator (6) cancels the generation of the induction coil (2) According to the detected plasma distribution data, the compensator (6) is driven by the driving device to move over the induction coil (2) to adjust the density of the electromagnetic field, thereby adjusting the etching rate and etching the ICP. The component is uniformly etched; the compensator (6) is in a potential floating state, the compensation (6) The antenna can be made of a conductor, or with the conductor plate. A device for compensating for etch rate non-uniformity in an ICP etch as described in claim 1 wherein the compensator (6) is of any shape. Non-uniform etch rate in ICP etching as described in item 2 of the patent application A device for compensating for uniformity, wherein the position of the compensator (6) is asymmetrically distributed. A device for compensating for etch rate non-uniformity in an ICP etching according to any one of claims 1-3, wherein the driving device is a fixed compensator (6), and the compensator (6) An element disposed at a predetermined position adjusts the degree of influence on the magnetic field energy distribution in the vacuum chamber (101) by changing the distance of the compensator (6) from the induction coil (2). A device for compensating for etch rate non-uniformity in an ICP etch as described in claim 4, wherein the drive device employs a mechanical fixture above the compensator (6) to secure the compensator (6) At the designated location, or alternatively, the drive device directly employs the top assembly of the ICP etched component. An apparatus for compensating for etch rate non-uniformity in an ICP etch as described in claim 5, wherein the ICP etch element (1) further comprises a cooling system (4) disposed on the induction coil (2) The upper part is located at the upper center of the ceramic RF window (103), and the induction coil (2) is cooled. A method of compensating for etch rate non-uniformity in an ICP etched element using a device as described in claim 6 wherein the compensator (6) in the device is disposed in the induction coil (2) Above, the induced magnetic field generated by the compensator (6) cancels the electromagnetic field generated by the induction coil (2), and the compensator (6) is connected to the driving device, according to the detected plasma distribution data, by the driving device To drive the compensator (6) to move over the induction coil (2) to adjust the density of the electromagnetic field, thereby adjusting The etch rate provides a uniform etch rate for the ICP etched component. An ICP etching element (1) comprising: an induction coil (2), the two ends of the induction coil (2) are connected to a radio frequency source (3) by a lead (201); a vacuum chamber (101) The reaction gas in the vacuum chamber (101) generates a plasma (102) under the action of an electromagnetic field generated by the induction coil (2) to etch a semiconductor substrate (5); a ceramic RF window (103) Separating the induction coil (2) from the vacuum chamber (101); and a compensating device comprising at least one compensator (6) and a driving device connected to the compensator (6), the compensator (6) disposed above the induction coil (2), the induced magnetic field generated by the compensator (6) cancels the electromagnetic field generated by the induction coil (2); wherein, according to the detected plasma distribution data, by the driving The device drives the compensator (6) to move over the induction coil (2) to adjust the density of the electromagnetic field, thereby adjusting the etching rate to obtain a uniform etching rate of the ICP etching element; the compensator (6) is in a potential floating state The compensator (6) may be an antenna made of a conductor or a conductor plate. The ICP etching element of claim 8, wherein the compensator (6) is of any shape. The ICP etching element according to claim 9, wherein the position of the compensator (6) is asymmetrically distributed. ICP etching element according to any one of claims 8-10 And wherein the driving device fixes the compensator (6) and sets the compensator (6) at a predetermined position by changing a distance between the compensator (6) and the induction coil (2) To adjust the degree of influence on the magnetic field energy distribution in the vacuum chamber (101). The ICP etching element according to claim 11, wherein the driving device adopts a mechanical fixing device located above the compensator (6) to fix the compensator (6) at a designated position, or the driving device directly The top component of the ICP etched component is employed. The ICP etching element of claim 12, wherein the ICP etching element (1) further comprises a cooling system (4) disposed on the upper portion of the induction coil (2) and located in the ceramic RF window (103) The induction coil (2) is cooled at the upper central position.