DIE SHIFT CORRECTION METHOD OF MASKLESS EXPOSURE MACHINE
A die shift correction method for use by a maskless exposure machine is applied to a die bonded to a substrate. The substrate has plural contact holes. The die has plural contact points each intended to be subjected to a light exposure in order to form a conductive contact portion connected to the corresponding contact hole. The correction method includes: obtaining the state information of the die by a first pre-scanning means, wherein the state information includes shape and location information; comparing the state information of the die against a reference state, and calculating compensation values with which to correct the reference state and thereby bring the reference state into conformity to the state information of the die; and calculating a compensation section for the light exposure according to the compensation values in order for each conductive contact portion to have an exposure pattern formed at the corresponding contact hole.
The present invention relates to photolithography and more particularly to the die shift correction method of a maskless exposure machine.
2. Description of Related ArtA die undergoing integrated circuit (IC) fabrication has a plurality of contact points, and a wafer substrate carrying such dies has a corresponding number of contact holes. The dies are “bonded” to the substrate and then exposed to light in order for a conductive contact portion to be formed at each contact point and constitute part of a circuit. The other end of each conductive contact portion is supposed to be formed at the corresponding contact hole so that an external circuit can be properly connected to the conductive contact portion in a subsequent fabrication step. However, as shown in
One conventional method to solve the aforesaid problem is to enlarge the area of each substrate contact hole 71 so that even if the die 6 is shifted in place because of a die bonding error, each shifted conductive contact portion 81 will still fall within the extent of the corresponding contact hole 71. With the advancement of materials and technology, however, the die 6 and the substrate 7 are decreasing in volume and having more and more intricate structures that prevent the areas of the contact holes 71 from being sufficiently enlarged. Moreover, increasing the areas of the contact holes 71 will reduce the structural strength of the substrate 7, making the substrate 7 more susceptible to breakage. This conventional solution, therefore, leaves much to be desired.
To solve this problem, one prior art approach is to provide the exposure machine with a distance measuring device for measuring the distance between the light source and each die. The distance is measured while the exposure machine is performing a light exposure operation, and the focal length of the light exposure operation is adjusted in real time after the distance information is sent back to the exposure machine, the objective being to keep the focal point at each die being irradiated. However, referring to
The primary objective of the present invention is to provide a die shift correction method for use by a maskless exposure machine. The correction method involves calculating a compensation section according to the shape and location of a die bonded to a substrate and changing the location of an exposure pattern accordingly so that, by correcting a shift or error in position caused by die bonding, it is ensured that the exposure pattern will be formed at the corresponding contact hole.
To achieve the foregoing objective, the present invention provides a die shift correction method for use by a maskless exposure machine. The correction method is applied to a die that is bonded to a substrate. The substrate has a plurality of contact holes. The die has a plurality of contact points, and each contact point is intended to be subjected to a light exposure in order to form a conductive contact portion connected to the corresponding contact hole. The correction method includes the following steps:
obtaining the state information of the die by a first pre-scanning means, wherein the state information includes shape and location information;
comparing the state information of the die against a reference state, and calculating compensation values with which the reference state can be corrected to conform to the state information of the die; and
calculating a compensation section for the light exposure according to the compensation values in order for each conductive contact portion to have an exposure pattern formed at the corresponding contact hole.
Preferably, the first pre-scanning means is capturing an image of the die on the substrate.
In one embodiment, the correction method further includes the steps of:
obtaining the elevation information of the die by a second pre-scanning means; and
inputting the elevation information of the die into the maskless exposure machine in order for the maskless exposure machine to adjust a focal length according to the elevation information of the die while performing a light exposure operation and thereby keep the focal point of the light exposure operation at the die.
Preferably, the second pre-scanning means is measuring the distance between a laser rangefinder and the die with the laser rangefinder.
The present invention provides a die shift correction method for use by a maskless exposure machine. The correction method is applied to a die structure bonded to a wafer substrate. The substrate has a plurality of contact holes. The die has a plurality of contact points, and each contact point is subjected to a light exposure operation by the maskless exposure machine, and hence to a light exposure, in order to form a conductive contact portion that makes up part of a circuit and is intended to extend to the corresponding contact hole of the substrate.
Referring to
obtaining the state information of the die by a first pre-scanning means, wherein the state information includes shape and location information;
comparing the state information of the die against a reference state, and calculating compensation values with which the reference state can be corrected to conform to the state information of the die; and
calculating a compensation section for the light exposure according to the compensation values in order for each conductive contact portion to have an exposure pattern formed at the corresponding contact hole.
Referring to
Referring to
obtaining the elevation information of the die by a second pre-scanning means; and
inputting the elevation information of the die into the maskless exposure machine in order for the maskless exposure machine to adjust a focal length according to the elevation information of the die while performing a light exposure operation and thereby keep the focal point of the light exposure operation at the die.
The second pre-scanning means may involve a laser rangefinder. For example, the elevation information of the die is plotted by measuring the distance between the laser rangefinder and the die with the laser rangefinder. The second pre-scanning means is put to use before the light exposure operation begins so that the elevation information of the die can be obtained in advance. Preferably, the second pre-scanning means is carried out together with the first pre-scanning means. The obtained elevation information of the die is input into the maskless exposure machine so that while performing the light exposure operation, the maskless exposure machine can change the focus length of the light exposure operation in real time according to the previously obtained elevation information of the die 1 as shown in
Claims
1. A die shift correction method of a maskless exposure machine, wherein the correction method is applied to a die bonded to a substrate, the substrate has a plurality of contact holes, the die has a plurality of contact points, and each said contact point is intended to be subjected to a light exposure in order to form a conductive contact portion connected to a corresponding one of the contact holes, the correction method comprising the steps of:
- obtaining a state information of the die by a first pre-scanning means, wherein the state information comprises shape and location information;
- comparing the state information of the die against a reference state, and calculating compensation values with which to correct the reference state and thereby bring the reference state into conformity to the state information of the die; and
- calculating a compensation section for the light exposure according to the compensation values in order for each said conductive contact portion to have an exposure pattern formed at the corresponding one of the contact holes.
2. The die shift correction method of the maskless exposure machine as claimed in claim 1, wherein the first pre-scanning means is capturing an image of the die on the substrate.
3. The die shift correction method of the maskless exposure machine as claimed in claim 1, further comprising the steps of:
- obtaining an elevation information of the die by a second pre-scanning means; and
- inputting the elevation information of the die into the maskless exposure machine in order for the maskless exposure machine to adjust a focal length according to the elevation information of the die while performing a light exposure operation and thereby keep a focal point of the light exposure operation at the die.
4. The die shift correction method of the maskless exposure machine as claimed in claim 1, wherein the second pre-scanning means is measuring a distance between a laser rangefinder and the die with the laser rangefinder.
Type: Application
Filed: Sep 17, 2020
Publication Date: Mar 17, 2022
Inventors: Ta Yu Liu (Taichung City), Chihhua Chien (Taichung City), Chien Hua Lai (Taichung City), ShihHsun Chen (Taichung City)
Application Number: 17/023,366