Valve-cell vacuum deposition apparatus including a leak detection device and method for detecting a leak in a vacuum deposition apparatus

A valve-cell vacuum deposition apparatus (10;

• 200;
• 300) including:
• at least one valve cell (20;
• 220;
• 320) comprising:
• an outer enclosure (21),
• an inner tank (24;
• 224), located inside the outer enclosure (21) and adapted to contain a material to be evaporated (26),
• an inner tank valve (28;
• 228) comprising a valve input port (28A;
• 228A) in fluidic communication with the inner tank (24;
• 224) and a valve output port (28B;
• 228B),
• a vacuum deposition chamber (30),
• a transfer tube (11) comprising a tube input port (11A) and connected to the valve output port (28B;
• 228B) of the inner tank valve (28;
• 228) and a tube output port (11B), in such a manner that the tube output port (11B) is located inside the vacuum deposition chamber (30), the tube output port (11B) including an injector (12) adapted to generate a jet of vapour of the material to be evaporated (26) inside the vacuum deposition chamber (30), the vacuum deposition chamber (30) being connected to the outer enclosure (21) by means of a connecting flange (13), and
• pumping means (40) adapted to evacuate the inside of the vacuum deposition chamber (30), the pumping means comprising:
• a primary pump (41) having a primary pump input (41A) and a primary pump output (41B), and
• a secondary pump (42) having a secondary pump input (42A) and a secondary pump output (42B), the secondary pump output (42B) being connected to the primary pump input (41A),
• characterized in that it includes a leak detection device (50) comprising:
• gas injection means (52, 53) adapted to introduce helium in the vacuum deposition chamber (30),
• gas pumping means adapted to pump the helium present in the vacuum deposition chamber (30),
• a helium detector (51) comprising a detector input (51A), the helium detector (51) delivering a signal representative of the helium flow rate through it,
• pressure measuring means (54, 54A) adapted to measure the pressure inside the vacuum deposition chamber (30), and
• signal processing means (55) adapted to process the signal relating to the helium flow rate delivered by the helium detector (51) and the signal delivered by the pressure measuring means (54, 54A), to deliver a signal representative of the leak rate of the inner tank valve (28;
• 228), and in that the pumping means (40) also include:
• a secondary pump valve (43) placed between the vacuum deposition chamber (30) and the secondary pump input (42A),
• a primary pump valve (44) placed between the secondary pump output (42B) and the primary pump input (41A), and
• a by-pass valve (45) placed between the secondary pump output (42B) and the detector input (51A), the by-pass being made upstream the primary pump valve (44).