Patent Application
20060164785
Not applicable.
Not applicable.
Not applicable.
This invention concerns an electrostatic maintenance chuck with radio frequency electrode and built-in thermostatic components. It applies but is not limited to the fabrication of electronic components.
In order to achieve the metallization of silicon substrates used for the fabrication of electronic components, for example MOS (Metal Oxide Semiconductor) transistors, aluminum is deposited using PVD (Physical Vapor Deposition). The sought-after optimization of electric performances connected to the gradual decrease of the component sizes, the problems of connection welds and the execution of connecting wells leads the industry to using copper in place of aluminum for the metallization step. It is to be noted that copper is deposited mainly through an electroplating reaction in liquid medium that requires prior depositing of a copper base layer using PVD.
This base layer has highly critical characteristics. This invention, through its specific properties, contributes to achieving these characteristics.
The presence of two gaps between, on one hand, substrate 100 and electrostatic chuck 110 and, on the other hand, between electrostatic chuck 110 and support 140, implies problems of temperature rise, temperature control (each gap causes a temperature difference of several tenths of degrees) and temperature uniformity over the surface of substrate 100.
The purpose of this invention is to eliminate these disadvantages.
To that effect, this invention concerns an electrostatic chuck characterized in that it includes:
Because of these arrangements, only one gap is present and temperature control and uniformity are made easier and safer and temperature rises quicker. The radio frequency electrodes make it possible to modulate the plasma around the substrate to be treated.
According to special characteristics, the ceramics are bonded together with heated glass. Because of these arrangements, the bonding is isolating and heavy duty and the stresses and arrangements relating to RF electrode isolation can be reduced as the base can be grounded.
According to special characteristics, the electrostatic chuck includes a base bearing cooling elements, with the lower ceramic attached to the base in a durable manner.
According to special characteristics, the lower ceramic is attached to the base through a brazed connection.
According to special characteristics, the brazing of the brazed connection is made with indium.
According to special characteristics, the lower ceramic is attached to the base by bonding.
According to special characteristics, bonding is silver-based.
Because of each of these arrangements, the lower ceramic and base have a good heat bond and the RF electrodes are isolated from the base.
According to special characteristics, the lower ceramic has cooling elements.
According to special characteristics, the lower ceramic is borne by lateral supports attached in a durable manner to said lower ceramic.
Other advantages, goals and characteristics will become clear from the description below, made in an explanatory but not at all limiting manner based on the attached drawing where:
The components shown in
Through these gas inlet central openings 210, 240 and 245, gas 255 is injected, for example helium or argon, facilitating heat transfers between the upper ceramic 205 and the substrate 200.
Thus, according to this invention, there is only one gap between substrate 200 and each of the heating, cooling or radiation elements, which reduces constraints with regard to temperature rise, temperature control (each gap causes a temperature difference of 30 cl) and temperature uniformity over the surface of the substrate 200.
Under an especially interesting embodiment, the bonding agent 260 is a bonding agent made of glass that is applied at a temperature where glass is liquid and malleable. The bonding also provides electric isolation between both ceramics. RF 220 radio frequency electrodes are, for example, flat electrodes positioned on the upper face of the lower ceramic 215. The heating elements 225 are, for example, flat electrodes positioned on the lower face of the lower ceramic 215.
The assembling between lower ceramic 215 and base 230 is for example achieved through a brazed connection using indium brazing 270 for good heat conduction bond. Under an alternative embodiment, the assembling between the lower ceramic 215 and the base 230 is achieved through bonding, for example with a silver-based bonding agent 270. The pins 265 make it possible to handle the wafers.
Through these gas inlet central openings 310 and 340, gas 350 is injected, for example helium or argon, facilitating heat transfers between the upper ceramic 305 and the substrate 300. Thus, according to this invention, there is only one gap between substrate 300 and each of the heating, cooling or radiation elements, which reduces constraints with regard to temperature rise, temperature control and temperature uniformity over the surface of the substrate 300.
Under an especially interesting embodiment, the bonding agent 360 is a bonding agent made of glass that is applied at a temperature where glass is liquid and malleable. The bonding also provides electric isolation between both ceramics. RF radio frequency electrodes 320 are, for example, flat electrodes positioned on the upper face of the lower ceramic 315. The heating elements 325 are, for example, flat electrodes positioned on the lower face of the lower ceramic 315.
The assembling between lower ceramic 315 and base 330 is for example achieved through a brazed connection using indium brazing 370 for good heat conduction bond. Under an alternative embodiment, the assembly between the lower ceramic 315 and the base 330 is achieved through bonding, for example with a silver-based bonding agent 370.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR0301323 | Feb 2003 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP04/50083 | 2/5/2004 | WO | 3/24/2006 |
