直接敷铜技术中铜箔预氧化层的检测与控制

Detection and control of the pre-oxidation layer on copper film during direct bonded copper processing

通过控制氧化的方法对制备敷铜陶瓷基板(DBC基板)的铜层进行预氧化处理。研究了预氧化温度、氧分压对铜箔氧化层物相和厚度的影响,采用拉曼光谱仪测试铜箔氧化膜物相组成,采用紫外-可见分光光度计测试铜箔氧化膜的吸光度,确定了铜箔表面氧化物层吸光度与厚度的关系。结果表明:预氧化温度在400~800℃,氧分压控制在100×10^(–6)~700×10^(–6),铜箔表面生成一层氧化亚铜(Cu_2O)层;在过高的预氧化温度和氧分压条件下,铜箔表面就会生成Cu O物相,而且氧化膜层变厚,表面疏松、局部出现氧化膜脱落,不利于DBC基板的制备。当氧分压为500×10^(–6),预氧化时间为1 h,温度为600℃时,铜箔表面可以获得均匀致密的Cu_2O薄膜,并且氧化膜与基体Cu结合紧密,有效提高DBC基板的结合性能。

The copper layer of ceramic substrate coated copper was pre-oxidized by means of controlling oxidation method. The effects of per-oxidation temperature and oxygen partial pressure on the phase and thickness of copper oxide were studied. The phase of copper oxide film was measured by Raman spectroscopy. The absorbance of copper oxide film was tested by ultraviolet-visible spectrophotometer. The relationship between the absorbance and thickness of copper oxide was determined. The results indicate that Cu2O is formed on the surface of the copper foil when the oxidation temperature is between 400 ℃ and 800 ℃, and the oxygen partial pressure is controlled at 100×10–6-700×10–6. Under the condition of excessively high pre-oxidation temperature and oxygen partial pressure, copper foil surface produces CuO phase. The oxide film thickens, loose surface and local oxide film off are not conducive to the preparation of DBC substrate. The uniform and dense Cu2O film can be obtained on the surface of the copper foil when the oxygen partial pressure is 500×10–6, the pre-oxidation time is 1h and the temperature is 600 ℃.The oxide film and the matrix Cu are tightly bonded to improve the bonding performance of the DBC substrate.