Front end of line plasma mediated ashing processes and apparatus

A plasma and ashing technology, applied in semiconductor/solid-state device manufacturing, discharge tubes, electrical components, etc., can solve the problem of low resist removal rate yield, affect device electrical properties, and is not suitable for removing photoresist agent and other issues

Active Publication Date: 2011-11-02
LAM RES CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Likewise, conventional fluorine-containing plasma methods have been found to cause dopant bleaching in addition to unacceptable substrate loss
Other FEOL plasma ashing methods use such as forming gas (forming gas) (N 2 / H 2 ), which gives good results because forming gas is associated with substrate oxidation, but has throughput issues due to its lower resist removal rate
Furthermore, hydrogen plasmas have been found to induce changes in dopant distribution, which deleteriously affect the electrical properties of devices
[0005] For this reason, previous plasma-mediated ashing methods were generally considered unsuitable for photoresist removal in the FEOL process flow for advanced design rules

Method used

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  • Front end of line plasma mediated ashing processes and apparatus
  • Front end of line plasma mediated ashing processes and apparatus
  • Front end of line plasma mediated ashing processes and apparatus

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] In this embodiment, the photoresist coated on the silicon substrate is exposed to the nitrous oxide in the RapidStrip320 plasma ashing tool available from Axcelis Technologies, Inc. Strip chemicals. The photoresist is an i-line photoresist available from Fuji Company under the trade name 10i, and is deposited on a silicon substrate with a thickness of 1.9 microns. At a pressure of 1 Torr, a temperature of 240° C., and a power setting of 3500 watts, nitrous oxide gas was flowed into the plasma ashing tool at 7 standard liters per minute (slm) to form plasma chemistry.

[0058] The ashing rate, cross wafer uniformity, and oxide growth of the nitrous oxide plasma stripping method were compared with oxygen-free reducing plasma (synthetic gas) and oxygen-based plasma. At a pressure of 1 Torr, a temperature of 240°C, and a power setting of 3500 watts, a reducing plasma is formed from a gas mixture of synthesis gas (3% hydrogen in nitrogen) entering the plasma ashing tool at a f...

Embodiment 2

[0062] In this embodiment, a small amount of CF 4 Added to different plasma gas mixtures and processed in RapidStrip320 plasma ashing tool. The silicon substrate was exposed to different plasma chemistries, and oxide growth was measured. The results are shown in Table 1 below. In each example, at a pressure of 1 Torr and a power setting of 3500 watts, various plasmas were formed using a gas mixture entering the plasma ashing tool at a flow rate of 7 slm. As indicated in the table, CF sprayed into the plasma ashing tool 4 The amount (where indicated) is 20 standard cubic centimeters per minute (sccm).

[0063] Table 1

[0064]

[0065] As shown, as evidenced by oxide growth, CF is sprayed during plasma formation 4 This causes minimal substrate loss, and advantageously, more energetic materials can be expected to be produced, which should effectively increase the ashing rate relative to the results observed in Example 1.

Embodiment 3

[0067] In this embodiment, for the plasma formed by nitrous oxide, the RapidStrip320 plasma ashing tool is used to measure the substrate damage in terms of silicon loss, oxide growth, and oxide loss, and compare it with the presence and absence of a small amount of tetrafluoroethylene. Carbonized O 2 / Compared with the prior art plasma formed by a synthetic gas mixture. The synthesis gas composition is 3% hydrogen in nitrogen. The results are shown graphically in Figure 5A in. In each example, at a pressure of 1 Torr, a temperature of 240° C. and a power setting of 3500 watts, various plasmas were formed using a gas mixture entering the plasma ashing tool at a flow rate of 7 slm. CF sprayed into the plasma ashing tool 4 The amount (where indicated) is 20 standard cubic centimeters per minute (sccm). Substrate damage includes (i) silicon loss from silicon-on-insulator (SOI) test structures, (ii) silicon oxide growth on bare silicon test wafers, and silicon oxide loss from sil...

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Abstract

Front end of line (FEOL) plasma mediated ashing processes for removing organic material from a substrate generally includes exposing the substrate to the plasma to selectively remove photoresist, implanted photoresist, polymers and / or residues from the substrate, wherein the plasma contains a ratio of active nitrogen and active oxygen that is larger than a ratio of active nitrogen and active oxygen obtainable from plasmas of gas mixtures comprising oxygen gas and nitrogen gas. The plasma exhibits high throughput while minimizing and / or preventing substrate oxidation and dopant bleaching. Plasma apparatuses are also described.

Description

Background of the invention [0001] The present disclosure generally relates to front end of line (FEOL) plasma-mediated ashing methods that provide effective removal of organic materials from semiconductor substrates while enabling reduction of substrate oxidation and reduction during processing. / Or erosion, and more specifically, relates to a plasma-mediated ashing method, wherein the ratio of active nitrogen to active oxygen in the plasma is substantially greater than that from oxygen (O 2 ) And nitrogen (N 2 ) The ratio of active nitrogen to active oxygen obtained by plasma of the gas mixture. [0002] Integrated circuit manufacturing methods can be generally divided into front-end manufacturing (FEOL) and back-end manufacturing (BEOL) processing. The FEOL method focuses on the manufacture of different devices that make up the integrated circuit, while the BEOL method focuses on the metal interconnections between the different devices that form the integrated circuit. The in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/311H01J37/32
CPCH01J37/32449H01L21/31138H01J37/3244H01L21/0273H01L21/30655
Inventor 罗士坚奥兰多·埃斯科尔西亚卡洛·瓦尔德弗里德伊万·贝里
Owner LAM RES CORP
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