Si DRIE System for MEMS Devices Manufacturing
RIE-800iPBC
Nowadays, MEMS devices can add high value in many products, and can be applied to a wide variety of products.
Nanofabrication processes for MEMS device manufacturing are also used in various applications, such as biotechnologies,
medical and optical communications. The Bosch process for Si Deep Reactive Ion Etching (DRIE) is one of such nanofabrication
processes, and has been widely applied to the manufactruing of accelometers and gyroscopes in automotive components,
medical applications such as Micro Total Analysis Systems (μTAS) for diagnostics, and Through Silicon Via (TSV) for three-demensional LSI.
SAMCO obtained the ﬁrst Bosch Process license in Japan from Robert Bosch GmbH, and has been providing the processsolutions to customers worldwide. This report describes the speciﬁcations of SAMCO’s production DRIE system, the RIE-800iPBC,and its processes.
■ Speciﬁcations■ Process Advantages

The SAMCO RIE-800iPBC has a small footprint of 1200×2270×2190 mm(not including dry pumps and a chiller for stage cooling), yet it has apowerful 5 kW RF generator as its ICP source, plus a high-volumeturbo molecular pump capable of more than 1000 sccm SF6 ﬂow, to enablehigh-speed Si etching. Its optimized gas ﬂow design enables a high rate ofgas ﬂow; moreover, its high-speed valves switching of etching gas anddeposition gas minimizes scallops.
Additionally, the SAMCO RIE-800iPBC has temperature-controlledreaction chamber wall and reduces contamination of by-products.
These capabilities largely contribute to the highly reproducible Boschprocess. The RF generator, with its Bias power source, is capable ofpulsing, and prevents notches at the boundary of the SOI substrates.

1. Tilt Prevention
Precise tilt control is critical in the TSV process, because tilt angle ofjust 1° could result in the misalignment of a 200 µm thick TSV by
as much as 2 µm. An absolutely vertical Si DRIE process can be achieved
with uniform plasma discharge, and the SAMCO RIE-800iPBC creates
the highly uniform plasma by means of its lower electrode design foruniform electric ﬁeld, and its optimized process recipe. As shown in Fig. 2,Summary of the speciﬁcations
Reaction Chamber

Al, inner diameter ø430 mm

Sample StageAl, ø221 mm, ESCICP RF Power

13.56 MHz, crystal oscillation
Max. 5 kW automatching

BIAS RF Power

13.56 MHz, crystal oscillation
Max. 1 kW automatching

Gas Lines

5 mass ﬂow controlled lines

Vacuum System

R.Chamber：turbo molecular pump + dry pump
L.L. Chamber : dry pump

Dimensions

1200(W) × 2270(D) × 2190(H) mm

the etched proﬁles are vertical on the whole ø8”wafers.

2. Scallop Reduction and Removal
The scallops on sidewalls of TSV can result in ununiformity of the seedlayers and ends up with gaps in the copper ﬁllings. SAMCO resolved thisissue by two approaches. One is to minimize scallops in the Bosch process
and the other is to remove scallops after the Bosch process. The SAMCO
RIE-800iPB is capable of high-speed gas switching of 0.1 sec and minimize
the scallops. In the recipe for alternating CFx passivation ﬁlm deposition(0.2 sec), passivation ﬁlm etching (0.2 sec) and silicon etching (0.2 sec),
the scallop size was reduced to less than 50 nm, while maintaining the etchrate of 9 µm/min. In the recipe for switching CFx passivation ﬁlm deposition(0.2 sec) and silicon etching (0.2 sec), etch rate was 1 µm/min, and the scallop
was reduced to less than 5 nm (below the resolution of a ScanningElectron Microscope). SAMCO has also developed the sidewall smoothing
technologies. Please refer our Technical Report Vol. 82, for moredetails on this subject.

■ SummaryFig.1 Appearance of RIE-800iPBC
5 mm from wafer edge 10 mm from wafer edge 15 mm from wafer edge

89.8°

90.0°

center of wafer

90.0°

Fig.2 The tilt angle of grating on the ø8” silicon wafer

90.0°

SAMCO has delivered many Si DRIE systems to universities and device
manufacturers since 2003. The RIE-800iPBC, along with our accumulated
experiences and process knowledge, can provide the etching processes
suitable for our customers’ various applications. One of SAMCO’s advantages
is a wide range of systems for MEMS device manufacturing. SAMCO
provides not only the Si DRIE systems, but also low-temperature plasma
deposition systems and XeF2 dry etching systems for Si sacriﬁcial layer
etching, and can meet the variety of our user’s needs. As the pioneerof thin ﬁlm technologies, SAMCO continues to provide cutting-edge
process solutions.