Product Categories
Product Categories
1 . Large jumps in film thickness readings during the coating process
| Cause analysis | Solution |
| 1. Mode jumping due to crystal damage | 1. Replacing the crystal oscillator with a new one |
| 2. High stress on the film material causes the coated layer to peel off from the surface of the wafer and warp the layer. | 2. Replace the crystal oscillator with a new one |
| 3. Micro-particles or “spatter” or “impurities” from the evaporation source (crucible) strikes the wafer. | 3. Thoroughly clean the material impurities of the evaporation source before coating, and extend the baffle opening time during pre-melting. |
| 4. Small particles or foreign particles on the surface of the base (probe cap) of the wafer (base not functioning properly). | 4. Clean or polish the surface of the base with weak acid and install the crystal oscillator to contact the base. |
| 5. Small pieces of material fall on the crystal (crystal side is facing the source of evaporation) | 5. Check the surface of the crystal oscillator for particulate impurities and blow it off with clean gas |
2 . During the coating process, the crystal stops oscillating before the normal end of crystal life
| Cause analysis | Solution |
| 1. Particles or “spatter” “impurities” from an evaporation source strike the crystal. | 1. Thoroughly clean the material impurities of the evaporation source before coating, and extend the baffle opening time during pre-melting. |
| 2. A buildup of film on the base of the crystal (probe cap) obscures the exposed monitoring hole in the crystal. | 2. Weak acid cleaning crystal chip base (probe cap) |
| 3. There is a short or open circuit | 3. Use a multimeter to check the sensor cable to the middle of the film thickness meter, the cable is loose, the contact of each connecting piece, contact shrapnel, the sensor internal connecting wires as well as the electrical connectivity of the feedthrough. |
| 4. Check for shorted or open circuits due to high temperatures. | 4. See above 3 |
Note: Crystal life is highly dependent on the film material, the thermal radiation of the evaporation source, the location, and the composition of the residual gas during the coating process.
3 . Crystal does not oscillate or oscillates intermittently (in vacuum or atmosphere)
| Cause analysis | Solution |
| 1. Intermittent contact or poor contact between shrapnel and crystal oscillator (oxidized contact points). | 1. Use a multimeter to check electrical continuity, resistance should be less than 1 ohm, clean shrapnel contacts. |
| 2. the shrapnel has lost elasticity, is deformed, or has broken legs, and the shrapnel is loose from the ceramic ring. | 2. Bend the shrapnel at an angle of about 45 degrees, or replace the ceramic triangular piece with a new one. |
| 3. RF interference from an evaporative source. | 3. Check the ground wire, use a grounded copper strip that meets RF grounding requirements, relocate the instrument away from the oscillator and away from the RF power cord, and connect the instrument to a different power supply. |
| 4. The cable/oscillator is not connected properly or is connected to the wrong sensor input. | 4. Check that the connections and inputs associated with the programmed sensor parameters are correct. |
NOTE: Contact shrapnel, ceramic triangular piece (ceramic bottom ring) should be replaced after about 4000 times of use. You should not wait until the foot breaks, or the ceramic is badly loosened and broken.
4 . Crystals oscillate in vacuum but stop oscillating in the atmosphere
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| Cause analysis | Solution |
| 1. The wafer is close to its end-of-life; opening it to air causes the film to oxidize, increasing the stress on the film. | 1. Replace the crystal oscillator plate with a new one |
| 2. When the vacuum is broken, a large amount of moisture accumulates on the surface of the wafer, and the cooling water flow through the wafer is small or ineffective. | 2. Extend the cooling time before the system breaks vacuum; maintain the cooling water pipe regularly, weak acid or compressed air to unclog the scale on the inner wall. |
5 . Crystals oscillate in the atmosphere but stop oscillating in a vacuum
| Cause analysis | Solution |
| 1. This phenomenon is the probe base ( single probe, multi-probe ) internal contact shrapnel deformation, fracture, or poor contact, not bad crystal oscillator. | 1. Check the contact area of the crystal oscillator probe and renew or wrench with tweezers to make good contact. |
| 2. Ion source neutralization is not well adjusted, resulting in excessive charged ions instantly penetrate the crystal oscillator, forming a click pattern on the surface of the crystal oscillator. | 2. Adjust the neutralizer so that the charged ions are fully neutralized into molecules. |
6 . Thermal instability: large changes in film thickness readings during the warming of the evaporation source (typically resulting in a decrease in film thickness readings) and after termination of the coating (typically resulting in an increase in film thickness readings).
| Cause analysis | Solution |
| 1. Cooling water does not meet the requirements / cooling water temperature is too high | 1. Check cooling water flow, keep cooling water temperature below 25 degrees. 2. heat radiation from evaporative source, move sensor away from source or use high temperature probe, thermal stability is better |
| 2. Excessive heat is fed into the crystal | 2. Heat radiation from evaporating source, move sensor away from source or use high temperature probe with better thermal stability |
| 3. The crystal is not placed correctly on the base, there are particles of impurities on the bottom or it is placed at an angle | 3. Clean or polish the crystal chip base and clean the bottom of any residual debris |
| 4. Poor heat transfer from the cooling water pipe to the probe site | 4. Open the vacuum connection flange, replace the cooling water pipe with a new one; if there is no new water pipe, wrap the cooling water pipe with a single layer of aluminum foil between the cooling water pipe and the crystal oscillator probe, if the process permits, to provide thermal insulation |
| 5. The crystal is heated by a high energy electron beam | 5. Use a high temperature crystal oscillator probe |
7 . Poor reproducibility of film thickness
| Cause analysis | Solution |
| 1. Variable ion source beam distribution | 1. Move the crystal control probe closer to the center for more reliable sampling (plated grains). |
| 2. Scanning beam spot, crucible position, possible change in electron beam and crucible position since last coating. | 2. Position constant scanning frequency, manually adjust the spot position, check the crucible position is correct. |
| 3. Film is not adsorbed onto the wafer. | 3. Ensure the surface of the crystal oscillator is clean, avoid finger contact, so that there is an attached layer in the center. |
| 4. Cyclic variation in coating rate | 4. Check whether the power and rate are matched and whether the material has impurities. |
8. Large deviation in film thickness after termination of coating (>200 Angstroms at 5g/ml density)
| Cause analysis | Solution |
| 1. Yhe crystal is heated due to poor thermal contact | 1. Clean or polish the surface of the crystal base. |
| 2. External magnetic field interferes with the magnetic field of the sensor, such as an ion source | 2. Rotate the sensor magnetic field to the correct position as far away from the magnetic field as possible. |
| 3. Negative jumps in the coating process of the crystal sheet | 3. Replace the crystal with a new one |
9 . Bicrystal or polycrystal conversion problems (non-conversion or misalignment of aperture centers)
| Cause analysis | Solution |
| 1. No air source, or insufficient pneumatic pressure | 1. Adjust the air supply pressure to 80-90PSIG. |
| 2. Coating material collects on the cover and obstructs operation | 2. Remove accumulated material as required for maintenance |
| 3. Incorrect collimation (mainly multi-probe) | 3. Recollimate |
| 4. 0.0225' diameter hole not installed on air supply side of solenoid valve ( mainly multiprobe ) | 4. Install small holes and re-install per multi-probe installation instructions. |
10 . Crystal mounted, readings always the same, no drop during coating, no tips
| Cause analysis | Solution |
| 1. Broken probe connection | 1. Measured with a multimeter, the oscillator front voltage value according to the instructions measured 3.3V, 4.7V or 5.3V; oscillator to the probe part of the measurement of resistance, should be less than 1 ohm. |
| 2. Damaged oscillator | 2. Replace the oscillator with a new one |
| 3. Crystal control system failure | 3. Turn off the power, restart the computer and the film thickness controller; if it can not be solved, reinstall the system driver. |
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