Two-dimensional arrays for medical ultrasound using multilayer flexible circuit interconnection
Two-dimensional arrays for medical ultrasound using multilayer flexible circuit interconnection
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DOI：
10.1109/58.660144
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发表时间：
1998-03-01
影响因子：
3.6
通讯作者：
Smith, SW
中科院分区：
文献类型：
--
作者：
Davidsen, RE;Smith, SW
二维阵列换能器的发展最近引起了人们的极大兴趣。不幸的是，高密度二维阵列的制造是困难的，因为必须在元件的背面进行大量的电气连接。在2.2 MHz工作的典型阵列可以在16.4 mm的圆形占地面积内具有256个或更多连接。为了解决这个问题，我们开发了一种多层柔性（MLF）电路互连，由聚酰亚胺电介质组成，层间通孔垂直布线信号，蚀刻金属迹线水平布线信号。通过将PZT芯片粘接在MLF表面并将芯片切割成单个元件，可以制造出换能器。锯口部分延伸到顶部聚酰亚胺层，以确保元件的物理和电气隔离。利用KLM模型比较了MLF二维阵列与传统的手线二维阵列的性能。制作了MLF换能器和导丝换能器，每个换能器有256个有效元件，元件间距0.4 mm，中心频率2.2 MHz。矢量阻抗、脉冲长度、带宽、角响应和交叉耦合在两种类型的阵列中被发现是可比较的。然而，使用MLF，制造时间大大缩短。更重要的是，MLF技术可用于提高二维阵列的连接密度，超越目前手工有线制造技术的限制。因此，MLF电路为当前和未来的高频二维阵列的互连提供了一种手段。
The development of 2-D array transducers has received much recent interest. Unfortunately, fabrication of high density 2-D arrays is difficult due to the large number of electrical interconnections which must be made to the back side of the elements. A typical array operating at 2.2 MHz may have 256 or more connections within a 16.4 mm circular footprint. Interconnection becomes even more challenging as operating frequencies increase, To solve this problem, we have developed a multilayer flexible (MLF) circuit interconnect consisting of a polyimide dielectric with inter-laminar vias routing signals vertically and etched metal traces routing signals horizontally, A transducer is fabricated from an MLF by bonding a PZT chip to its surface and dicing the chip into individual elements, with the saw kerf extending partially into the top polyimide layer to ensure physical and electrical isolation of the elements. The KLM model was used to compare the performance of an MLF 2-D array to a conventional hand wired 2-D array. MLF and wire guide transducers were fabricated, each with 256 active elements, 0.4 mm interelement spacing, and 2.2 MHz center frequency. Vector impedance, pulse length, bandwidth, angular response, and cross-coupling were found to be comparable in both types of arrays. Using the MLF, however, fabrication time was reduced dramatically. More importantly, MLF technology may be used to increase 2-D array connection density beyond the limitations of current of hand wired fabrication techniques. Thus MLF circuits provide a means for the interconnection of current and future high frequency 2-D arrays.