Hamai co. ltd specialize in high-precision lapping machines and polishing machines.
Lapping machines are used to achieve parallelism and flatness, while polishing machines are used to achieve surface roughness.
The structure consists of an upper plate, a lower plate, a sun gear, and an internal gear.
There are 4-way and 3-way types, with the numbers indicating the number of axes.
For example, For the 4-way model, the upper plate, lower plate, sun gear, and internal gear each rotate indipendently.
On the other hand, for the 3-way model, the upper plate does not rotate, while the lower plate, sun gear, and internal gear have independent drives.
The upper table of the 3-way is suspended by a single wire via a flexible link mechanism, sliding parallel to the workpiece on the lower table and applying uniform load.
Initially, the 4-way system was developed first, but during machining, inevitable differences in workpiece processes resulted in uneven load distribution and uneven load application, which could lead to workpiece cracking. To solve this problem, the 3-way system was developed. Generally, the 3-way system provides higher precision than the 4-way system, but on the other hand, the 4-way system is characterized by faster machining speeds than the 3-way system.
Next, we will explain the rotation ratios of the 4-way and 3-way systems.
In the 4-way system, the rotation ratios are 3:1:-1 for the lower table, carrier rotation, and upper table, resulting in a lap length ratio of 2:2 between the upper and lower tables.
In the 3-way system, the rotation ratios are 4:2:0 for the lower table, carrier rotation, and upper table, also resulting in a lap length ratio of 2:2 between the upper and lower tables.
Therefore, the rotation ratios are identical in both systems.
Next, I will explain the fluid bearing, for which we have obtained a second patent.
There is a mechanism called a lower plate holder under the lower plate. Unlike other companies' fluid bearings, which use general bearings, we do not use general bearings. Instead,
oil is stored in the lower base plate holder, and the lower plate holder floats slightly (a few microns) on the oil due to its own rotational dynamic pressure. This floating action creates
an oil film layer, which cuts off vibrations. This enables the maintenance of workpiece precision. Specifically, with conventional bearings, after three years of use, the bearings
deteriorate over time, and the amplitude of vibrations increases. On the other hand, our devices using fluid bearings do not experience a significant increase in vibration amplitude.
This suppresses vibrations to the workpiece, enabling the maintenance of high-precision processing.
regarding the sizes. We handles a wide range of sizes from 2B to 74B. The numbers represent the inch size of the carrier.
Next, we will explain the delivery results for each model.
[Sales results examples for each model]
・32BNE is for φ300 mm silicon wafers (20 wafers per batch).
・32BF is for support glass (φ300 mm, □300 mm).
• 24BN is for 6025 photomasks and φ8-inch silicon wafers.
• 24BF is for 6025 photomasks and φ8-inch silicon wafers.
• 16BN is for lithium tantalate wafers (LT wafers) and lithium niobate wafers (LN wafers).
• 16BF is for 3.5-inch HDD glass and φ6–8-inch SiC wafers.
• 9BN is for ① crystal wafers and ② ceramic wafers.
• 9BF is for ① crystal wafers and ② ceramic wafers.
Our patents mainly cover ①3-way and ②fluid bearings mentioned above, but finally, we will explain the features of the device below.
(This content is listed in the catalog.
Please refer to the catalog for more details.
1. Precision ground drive gears
⇒The drive gears, which are hardened and precision-ground, greatly suppress vibration during processing.
２．Upper plate swiveling(for easy plate change＆Maintenance)
⇒Bridge type upper plate supported with a swivel arm for easy changing out of lapping plates and polishing pads.
3. High precision polishing plates.
⇒Finished elaborately and securely the lapping plate surface, which greatly affects the processng accuracy.
4.Plate Flattening
⇒Reversing carrier axial spin direction keeps plates flat during production.
Carrier clockwise spinning concaves the lower plate toward the center.
Carrier counterclockwise spnning convexes the lower plate towerd the center.
5. Opearation Panel
⇒The custom designed software prompts the operator for specific operating parameters and
stores up to 8 different lapping and polishing routines.
Allows setting the rotation speed ratio by considering plate flattening and work piece lapping accuracy.
6. Plate rotation speed and lapping pressure multi-step control system
⇒Controls the pressure and lower plate rotation speed simultaneously in multi-steps, thereby controlling processing according to
work pieces and achieving stable mass production.
The machine starts processing at light load and low peed, thereby relieving stress without damaging work pieces.
by gradually rasing processing condition. it finishes work pieces to the target thickness and ends processing slowly.